WO2020262505A1 - Image coding device, image coding method, image coding program, image decoding device, image decoding method, and image decoding program - Google Patents

Image coding device, image coding method, image coding program, image decoding device, image decoding method, and image decoding program Download PDF

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WO2020262505A1
WO2020262505A1 PCT/JP2020/024928 JP2020024928W WO2020262505A1 WO 2020262505 A1 WO2020262505 A1 WO 2020262505A1 JP 2020024928 W JP2020024928 W JP 2020024928W WO 2020262505 A1 WO2020262505 A1 WO 2020262505A1
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block
prediction
color difference
mode
intra
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French (fr)
Japanese (ja)
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博哉 中村
福島　茂
英樹 竹原
智 坂爪
徹 熊倉
宏之 倉重
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株式会社Ｊｖｃケンウッド
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/103—Selection of coding mode or of prediction mode
    • H04N19/11—Selection of coding mode or of prediction mode among a plurality of spatial predictive coding modes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/119—Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/134—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or criterion affecting or controlling the adaptive coding
    • H04N19/157—Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter
    • H04N19/159—Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/169—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
    • H04N19/17—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object
    • H04N19/176—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object the region being a block, e.g. a macroblock
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/169—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
    • H04N19/186—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being a colour or a chrominance component

Definitions

  • the present invention relates to an image coding and decoding technique for dividing an image into blocks and performing prediction.
  • the image to be processed is divided into blocks which are a set of a predetermined number of pixels, and processing is performed in block units. Coding efficiency is improved by dividing into appropriate blocks and appropriately setting in-screen prediction (intra prediction) and inter-screen prediction (inter prediction).
  • Patent Document 1 discloses an intra-prediction technique for obtaining a predicted image using decoded pixels adjacent to a block to be encoded / decoded.
  • Patent Document 1 uses only the decoded pixels adjacent to the block to be encoded / decoded for prediction, and the prediction efficiency is poor.
  • an image decoding device that decodes a coded bit string in which each picture of an image is encoded is divided into block units of each picture of the image. It includes a block division unit for dividing and an intra prediction unit that predicts a block by referring to a decoded pixel in the screen as a prediction value according to an intra prediction mode.
  • the luminance block and the color difference block are synchronized with each other and recursively divided according to a common division mode, and in the intra prediction, the color difference coding block having a predetermined color difference coding block minimum size or less is prohibited.
  • the color difference format is 4: 2: 0 and the luminance block is recursively divided, and the corresponding color difference block becomes a color difference coding block smaller than the predetermined color difference coding block minimum size when divided.
  • the division target block of the luminance signal is the first luminance signal coding block and the second luminance signal coding block.
  • the third luminance signal coding block is divided, and the color difference signal division target block is not divided into one color difference signal coding block, and the intra prediction unit is a color difference signal coding block.
  • Intra-prediction is performed by using the value of the intra-luminance prediction mode of the coded block including the pixel of the color difference signal corresponding to the position of the lower right pixel of the center as the value of the intra-luminance prediction mode of the coded block of the color difference signal.
  • the color difference format represents the ratio of the number of sampled pixels of three signals of one luminance information and two color difference information by X: Y: Z.
  • the color difference format of the image includes 4: 2: 0, 4: 2: 2, 4: 4: 4, monochrome, and the like.
  • 3A to 3E are diagrams for explaining each color difference format of the image.
  • X indicates the position of the pixel of the luminance signal on the screen plane of the image
  • ⁇ indicates the position of the pixel of the color difference signal.
  • 4: 2: 0 shown in FIG. 3A is a color difference format in which the color difference signal is sampled at a density of half in both the horizontal and vertical directions with respect to the luminance signal.
  • 4: 2: 0 has the same aspect ratio of the pixels of the luminance signal and the color difference signal.
  • the color difference signal may be sampled at the position shown in FIG. 3E.
  • 4: 2: 2 shown in FIG. 3B is a color difference format in which the color difference signal is sampled at half the density in the horizontal direction and the same density in the vertical direction with respect to the luminance signal. That is, the aspect ratios of the pixels of the luminance signal and the color difference signal are different in 4: 2: 2.
  • 4: 4: 4 shown in FIG. 3C is a color difference format in which both the luminance signal and the color difference signal are sampled at the same density.
  • Monochrome shown in FIG. 3D is a color difference format composed only of a luminance signal without a color difference signal. In the present embodiment, unless otherwise specified, the color difference format is assumed to be 4: 2: 0.
  • ⁇ Tree block> In the embodiment, as shown by a thick line in FIG. 4, the inside of the screen is evenly divided in units of arbitrary rectangular rectangles of the same size. This unit is defined as a tree block, and is used as a basic unit of address management for specifying a block of a processing target (encoding target in coding, decoding target in decoding) in an image. Except for monochrome, the tree block is composed of one luminance signal and two color difference signals. The size of the tree block can be freely set to the power of 2 according to the picture size and the texture in the screen.
  • the tree block divides the luminance signal and color difference signal in the tree block into four hierarchically (recursively), vertically into two, and vertically as necessary in order to optimize the coding process according to the texture in the screen. It can be divided into three, two horizontal or three horizontal to make a small block.
  • Each of these blocks is defined as a coded block, and is used as a basic unit of processing when encoding and decoding. Except for monochrome, it is composed of one luminance signal coding block and two color difference signal coding blocks.
  • the maximum size of the coded block is the same as the size of the tree block.
  • the coded block having the minimum size of the coded block is called the minimum coded block and can be freely set.
  • the block division mode is a 4-division mode (601 in FIG. 5A) in which the block is evenly divided into 4 parts at a ratio of 1: 1 and the width and height of the block are divided into 2 vertically at a ratio of 1: 1.
  • Vertical 2-division mode in which the cross section is in the vertical direction (602 in FIG. 5B)
  • vertical 3-division mode in which the block width is vertically divided into left, middle, and right at a ratio of 1: 2: 1 and the cross section is in the vertical direction.
  • the block height is divided into two vertically at a ratio of 1: 1 and the cross section is in the horizontal direction (604 in FIG. 5D), and the block height is 1: 2.
  • There is a horizontal three-division mode (605 in FIG. 5E) in which the cross section is in the horizontal direction by horizontally dividing the upper, middle, and lower parts at a ratio of 1.
  • the coded block A is a single coded block without dividing the tree block.
  • the coding block B is a coding block formed by dividing a tree block into four parts.
  • the coded block C is a coded block formed by further dividing a block formed by dividing a tree block into four.
  • the coded block D is a coded block formed by dividing a tree block into four and further hierarchically dividing the block into four.
  • the coded block E is a coded block formed by further dividing a block formed by dividing a tree block into four and further dividing it into two vertically.
  • the coded block F is a coded block formed by further dividing a block formed by dividing a tree block into four and further dividing the block into three vertically.
  • the coded block G is a coded block formed by further dividing a block formed by dividing a tree block into four and further dividing it into two vertically in the horizontal direction.
  • the coded block H is a coded block formed by further dividing a block formed by dividing a tree block into four and further dividing the block into three horizontally.
  • the color difference format is 4: 2: 0, the size of the tree block is set to 64 ⁇ 64 pixels for the luminance signal and 32 ⁇ 32 pixels for the color difference signal, and the size of the minimum coded block is set. It is assumed that the luminance signal is set to 8 ⁇ 8 pixels and the color difference signal is set to 4 ⁇ 4 pixels.
  • the size of the coding block A is 64 ⁇ 64 pixels for the luminance signal and 32 ⁇ 32 pixels for the color difference signal
  • the size of the coding block B is 32 ⁇ 32 pixels for the luminance signal and 16 ⁇ 16 pixels for the color difference signal.
  • the size of the coded block C is 16 ⁇ 16 pixels for the luminance signal and 8 ⁇ 8 pixels for the color difference signal
  • the size of the coded block D is 8 ⁇ 8 pixels for the luminance signal and 4 ⁇ 4 pixels for the color difference signal. ..
  • the color difference format is 4: 4: 4
  • the size of the luminance signal and the color difference signal of each coded block are equal.
  • the size of the coded block A is 32 ⁇ 64 pixels for the color difference signal
  • the size of the coded block B is 16 ⁇ 32 pixels for the color difference signal
  • the size of the coded block C is The color difference signal has 8 ⁇ 16 pixels
  • the size of the coded block D which is the smallest coded block, is 4 ⁇ 8 pixels for the color difference signal.
  • ⁇ Prediction mode> Processed image to be processed in units of coded blocks to be processed (in the coding process, the coded signal is used for the decoded image, image signal, tree block, block, coded block, etc., and in the decoding process Intra-prediction (MODE_INTRA) and IBC (intra-block copy) prediction (MODE_IBC), and processing that make predictions from image signals around the image, image signal, tree block, block, coded block, etc. that have been decoded. Switch the inter-prediction (MODE_INTER) that makes a prediction from the image signal of the completed image.
  • MODE_INTRA Intra-prediction
  • IBC intra-block copy prediction
  • the mode for discriminating between the intra prediction (MODE_INTRA), the IBC prediction (MODE_IBC) and the inter prediction (MODE_INTER) is defined as the prediction mode (CuPredMode).
  • the prediction mode (CuPredMode) has an intra prediction (MODE_INTRA), an IBC prediction (MODE_IBC), or an inter prediction (MODE_INTER) as values.
  • the IBC (intra-block copy) prediction is a process of predicting a processing target block by referring to a decoded pixel (block) in the processing target picture as a prediction value, and encoding / decoding the processing target block. Then, the distance from the processing target block to the reference pixel is represented by a block vector. Since the block vector refers to the picture to be processed and the reference picture is uniquely determined, the reference index is unnecessary. The difference between the block vector and the motion vector is whether the referenced picture is a processed picture or a processed picture at a different time. In addition, the block vector can be selected from 1-pixel accuracy or 4-pixel accuracy using the adaptive motion vector resolution (AMVR).
  • AMVR adaptive motion vector resolution
  • predicted intra block copy mode For intra block copy, two modes can be selected: predicted intra block copy mode and merge intra block copy mode.
  • the prediction intra-block copy mode is a mode in which the block vector of the block to be processed is determined from the prediction block vector derived from the processed information and the difference block vector.
  • the prediction block vector is derived from the processed block adjacent to the processing target block and the index for identifying the prediction block vector.
  • the index and difference block vector for specifying the predicted block vector are transmitted as a bit stream.
  • the merge intra-block copy mode is a mode in which the intra-block copy prediction information of the processing target block is derived from the intra-block copy prediction information of the processed block adjacent to the processing target block without transmitting the differential motion vector.
  • L0 prediction (pred_L0) is available for P-slices.
  • Pred_L0 L0 prediction
  • Pred_L1 L1 prediction
  • Pred_BI dual prediction
  • the L0 prediction (Pred_L0) is an inter-prediction that refers to a reference picture managed by L0
  • the L1 prediction (Pred_L1) is an inter-prediction that refers to a reference picture managed by L1.
  • the bi-prediction (Pred_BI) is an inter-prediction in which both L0 prediction and L1 prediction are performed, and one reference picture managed in each of L0 and L1 is referred to.
  • Information that identifies L0 prediction, L1 prediction, and bi-prediction is defined as an inter-prediction mode. In the subsequent processing, it is assumed that the constants and variables with the subscript LX attached to the output are processed for each L0 and L1.
  • the predicted motion vector mode is a mode in which an index for specifying a predicted motion vector, a differential motion vector, an inter-prediction mode, and a reference index are transmitted to determine inter-prediction information of a block to be processed.
  • the predicted motion vector is a predicted motion vector candidate derived from a processed block adjacent to the processing target block or a block belonging to the processed image and located at the same position as or near (near) the processing target block, and a predicted motion. Derived from the index to identify the vector.
  • ⁇ Merge mode> In the merge mode, the processed block adjacent to the processed block or the block belonging to the processed image and located at the same position as or near (near) the processed block without transmitting the differential motion vector and the reference index.
  • the inter-prediction information of the block to be processed is derived from the inter-prediction information of.
  • the processed block adjacent to the processing target block and the inter-prediction information of the processed block are defined as spatial merge candidates.
  • Blocks that belong to the processed image and are located at the same position as or near (near) the block to be processed, and inter-prediction information derived from the inter-prediction information of that block are defined as time merge candidates.
  • Each merge candidate is registered in the merge candidate list, and the merge index identifies the merge candidate used in the prediction of the block to be processed.
  • FIG. 11 is a diagram illustrating a reference block referred to for deriving inter-prediction information in the predicted motion vector mode and the merge mode.
  • A0, A1, A2, B0, B1, B2, and B3 are processed blocks adjacent to the processing target block.
  • T0 is a block belonging to the processed image, and is a block located at the same position as or near (near) the processing target block in the processing target image.
  • A1 and A2 are blocks located on the left side of the processing target coding block and adjacent to the processing target coding block.
  • B1 and B3 are blocks located above the processing target coding block and adjacent to the processing target coding block.
  • A0, B0, and B2 are blocks located at the lower left, upper right, and upper left of the coded block to be processed, respectively.
  • the coded block is divided into subblocks of a predetermined unit, and the motion vector is individually determined for each of the divided subblocks to perform the motion compensation.
  • the motion vector of each sub-block is derived from the inter-prediction information of the processed block adjacent to the processing target block or the block belonging to the processed image and located at the same position as or near (near) the processing target block. Derived based on one or more control points.
  • the size of the subblock is 4x4 pixels, but the size of the subblock is not limited to this, and the motion vector may be derived in pixel units.
  • FIG. 14 shows an example of affine transformation motion compensation when there are two control points.
  • the two control points have two parameters, a horizontal component and a vertical component. Therefore, the affine transformation when there are two control points is called a four-parameter affine transformation.
  • CP1 and CP2 in FIG. 14 are control points.
  • FIG. 15 shows an example of affine transformation motion compensation when there are three control points. In this case, the three control points have two parameters, a horizontal component and a vertical component. Therefore, the affine transformation when there are three control points is called a 6-parameter affine transformation.
  • CP1, CP2, and CP3 in FIG. 15 are control points.
  • Affine transformation motion compensation can be used in both the predicted motion vector mode and the merge mode.
  • the mode in which the affine transformation motion compensation is applied in the predicted motion vector mode is defined as the subblock predicted motion vector mode
  • the mode in which the affine transformation motion compensation is applied in the merge mode is defined as the subblock merge mode.
  • the POC is a variable associated with the encoded picture, and a value that increases by 1 according to the output order of the picture is set. Depending on the value of POC, it is possible to determine whether the pictures are the same, determine the context between the pictures in the output order, and derive the distance between the pictures. For example, if the POCs of the two pictures have the same value, it can be determined that they are the same picture. If the POCs of the two pictures have different values, it can be determined that the picture with the smaller POC value is the picture to be output first, and the difference between the POCs of the two pictures is the distance between the pictures in the time axis direction. Shown.
  • FIG. 1 is a block diagram of the image coding device 100 according to the first embodiment.
  • the image coding device 100 of the embodiment includes a block division unit 101, an inter prediction unit 102, an intra prediction unit 103, a decoded image memory 104, a prediction method determination unit 105, a residual signal generation unit 106, and an orthogonal conversion / quantization unit. It includes 107, a bit string coding unit 108, an inverse quantization / inverse orthogonal conversion unit 109, a decoded image signal superimposing unit 110, and a coding information storage memory 111.
  • the block division unit 101 divides the input image into tree blocks, and further recursively and hierarchically divides each tree block into coded blocks. In each layer, the block division unit 101 divides by four divisions, vertical two divisions, vertical three divisions, horizontal two divisions, and horizontal three divisions, and blocks division information is divided into an inter prediction unit 102, an intra prediction unit 103, and a prediction method. Supply to the decision section. Further, the generated image signal of the coded block to be processed is supplied to the inter prediction unit 102, the intra prediction unit 103, and the residual signal generation unit 106. Further, the block division unit 101 supplies information indicating the determined recursive division structure to the bit string coding unit 108. The detailed operation of the block dividing unit 101 will be described later.
  • the inter-prediction unit 102 performs inter-prediction of the coded block to be processed.
  • the inter-prediction unit 102 derives a plurality of inter-prediction information candidates from the inter-prediction information stored in the coded information storage memory 111 and the decoded image signal stored in the decoded image memory 104.
  • a suitable inter-prediction mode is selected from the plurality of derived candidates, and the selected inter-prediction mode and the prediction image signal corresponding to the selected inter-prediction mode are supplied to the prediction method determination unit 105.
  • the detailed configuration and operation of the inter-prediction unit 102 will be described later.
  • the intra prediction unit 103 performs intra prediction and intra block copy prediction of the coded block to be processed.
  • a prediction image signal is created from the same image signal as the processing target coded block stored in the decoded image memory 104, that is, the decoded area of the processing target image, and the prediction method is determined. Supply to unit 105.
  • the detailed configuration and operation of the intra prediction unit 103 will be described later.
  • the decoded image memory 104 stores the decoded image generated by the decoded image signal superimposing unit 110.
  • the decoded image memory 104 supplies the stored decoded image to the inter prediction unit 102 and the intra prediction unit 103.
  • the prediction method determination unit 105 divides each prediction into blocks by evaluating each prediction using the coding information, the code amount of the residual signal, the amount of distortion between the predicted image signal and the image signal to be processed, and the like. In each layer, it is determined whether or not to divide the block, and when the block is divided, one of 4 division, vertical 2 division, vertical 3 division, horizontal 2 division, and horizontal 3 division is determined. Further, in the coded block, it is determined whether the optimum prediction mode CuPredMode of the coded block to be processed is the intra prediction mode (MODE_INTRA), the IBC prediction mode (MODE_IBC), or the inter prediction mode (MODE_INTER).
  • the intra brightness prediction mode and the intra color difference prediction mode are determined.
  • the coding information related to IBC prediction such as merge mode information and block vector is determined.
  • inter-prediction the coding information related to inter-prediction (MODE_INTER) such as merge mode information, inter-prediction mode, reference picture, and motion vector is determined.
  • the determined coding information is supplied to the bit string coding unit 108 and the coding information storage memory 111.
  • the prediction method determination unit 105 supplies the residual signal generation unit 106 and the prediction image signal to the decoded image signal superimposition unit 110.
  • the residual signal generation unit 106 generates a residual signal by subtracting the predicted image signal from the image signal to be processed, and supplies the residual signal to the orthogonal transformation / quantization unit 107.
  • the orthogonal conversion / quantization unit 107 performs orthogonal conversion and quantization on the residual signal according to the quantization parameter, generates an orthogonal conversion / quantization residual signal, and uses the generated residual signal as a bit string code. It is supplied to the conversion unit 108 and the inverse quantization / inverse orthogonal conversion unit 109.
  • the bit string coding unit 108 encodes the block division information determined by the prediction method determination unit 105 and the coding information according to the prediction method for each coding block, in addition to the sequence, picture, and slice unit information. Specifically, in each layer of block division, information indicating block division, for example, a flag indicating whether or not to divide the block, a flag indicating whether or not to divide into four, and whether or not to divide into two or three A flag indicating, a flag indicating whether to divide vertically or horizontally, a flag indicating whether to divide into two or three, and the like are encoded. Further, the information indicating the prediction mode CuPredMode for each coding block is encoded.
  • the bit string coding unit 108 encodes a flag PredMode indicating whether or not the prediction mode for each coding block is inter-prediction.
  • the flag pred_mode_ibc_flag for determining whether or not it is an intra-block copy is encoded.
  • the prediction mode is intra prediction (MODE_INTRA)
  • the information regarding the intra-luminance prediction mode and the intra-color difference prediction mode is encoded and used as the first coded bit string.
  • the prediction mode is IBC prediction (MODE_IBC)
  • MODE_IBC IBC prediction
  • a flag for determining whether or not the merge mode is used, a merge index for the merge mode, a prediction block vector index for the non-merge mode, and a difference block vector are encoded.
  • the first coded bit string If the prediction mode is inter-prediction (MODE_INTER), a flag that determines whether or not it is in merge mode, a subblock merge flag, a merge index if it is in merge mode, an inter-prediction mode if it is not in merge mode, a prediction motion vector index, and a differential motion.
  • Coded information such as vector information and subblock predicted motion vector flags are coded according to the specified syntax (coded bit string syntax rules) to be the first coded bit string.
  • bit string coding unit 108 entropy-encodes the orthogonal conversion and the quantized residual signal according to the specified syntax to generate a second coded bit string.
  • the first coded bit string and the second coded bit string are multiplexed according to the specified syntax, and a bit stream is output.
  • the inverse quantization / inverse orthogonal conversion unit 109 calculates and calculates the residual signal by inversely quantizing and inversely orthogonalizing the orthogonal conversion / quantization residual signal supplied from the orthogonal conversion / quantization unit 107.
  • the generated residual signal is supplied to the decoded image signal superimposing unit 110.
  • the decoded image signal superimposition unit 110 superimposes the predicted image signal according to the determination by the prediction method determination unit 105 and the residual signal that has been inversely quantized and inversely orthogonally converted by the inverse quantization / inverse orthogonal conversion unit 109 to obtain the decoded image. Is generated and stored in the decoded image memory 104.
  • the decoded image signal superimposing unit 110 may store the decoded image in the decoded image memory 104 after performing a filtering process on the decoded image to reduce distortion such as block distortion due to coding.
  • the coded information storage memory 111 stores coded information such as a prediction mode (intra prediction, IBC prediction, or inter prediction) determined by the prediction method determination unit 105.
  • a prediction mode intra prediction, IBC prediction, or inter prediction
  • the coding information stored in the coding information storage memory 111 is intra-prediction information such as the determined intra-luminance prediction mode and intra-color difference prediction mode.
  • IBC prediction it is IBC information such as a determined block vector.
  • inter-prediction it is inter-prediction information such as a determined motion vector, a reference list, and a reference index. The construction of the history candidate list managed by the coded information storage memory 111 will be described later.
  • FIG. 2 is a block showing a configuration of an image decoding device according to an embodiment of the present invention corresponding to the image coding device of FIG.
  • the image decoding device of the embodiment includes a bit string decoding unit 201, a block division unit 202, an inter prediction unit 203, an intra prediction unit 204, a coded information storage memory 205, an inverse quantization / inverse orthogonal conversion unit 206, and a decoded image signal superimposition.
  • a unit 207 and a decoded image memory 208 are provided.
  • each configuration of the orthogonal conversion unit 206, the decoded image signal superimposing unit 207, and the decoded image memory 208 includes the coding information storage memory 111 of the image coding apparatus of FIG. 1, the inverse quantization / inverse orthogonal conversion unit 109, and the decoded image signal. It has a function corresponding to each configuration of the superimposing unit 110 and the decoded image memory 104.
  • the bit string decoding unit 201 separates the bit stream supplied to the bit string decoding unit 201 into a first coded bit string and a second coded bit string according to a predetermined syntax rule.
  • the bit string decoding unit 201 decodes the separated first coded bit string to obtain sequence, picture, slice, block division information, and coded block unit coding information.
  • information indicating block division for example, a flag indicating whether or not to divide the block, a flag indicating whether or not to divide into four, and whether or not to divide into two or three
  • the flag indicating, the flag indicating whether to divide vertically or horizontally, the flag indicating whether to divide into two or three, and the like are decoded.
  • the information indicating the prediction mode CuPredMode is decoded for each coded block.
  • the bit string coding unit 108 decodes the flag PredMode indicating whether or not the prediction mode for each coding block is inter-prediction.
  • the flag pred_mode_ibc_flag for determining whether or not it is an intra-block copy is decoded.
  • the prediction mode is the intra prediction (MODE_INTRA)
  • the intra prediction information such as the intra brightness prediction mode and the intra color difference prediction mode is decoded.
  • the specified syntax is the coding information such as the flag that determines whether or not it is in merge mode, the merge index if it is in merge mode, the predicted block vector index if it is not in merge mode, and the difference block vector. Decoding is performed according to the syntax rule of the coded bit string), and the coded information is supplied to the intra prediction unit 204 and the coded information storage memory 205.
  • inter-prediction MODE_INTER
  • the flag that determines whether or not it is in merge mode in the case of merge mode, the merge index, subblock merge flag, in the case of predictive motion vector mode, the inter-prediction mode, predicted motion vector index, differential motion.
  • the coded information related to the vector, the sub-block prediction motion vector flag, etc. is decoded according to the specified syntax, and the coded information is supplied to the inter-prediction unit 203 and the coded information storage memory 205. Further, the bit string decoding unit 201 decodes the separated second coded bit string, calculates the orthogonally converted / quantized residual signal, and dequantizes / reverses the orthogonally converted / quantized residual signal. It is supplied to the orthogonal conversion unit 206.
  • the inter-prediction unit 203 describes the code of the already decoded image signal stored in the coding information storage memory 205 when the prediction mode PredMode of the coded block to be processed is inter-prediction (MODE_INTER) and the prediction motion vector mode.
  • MODE_INTER inter-prediction
  • a plurality of predicted motion vector candidates are derived using the conversion information, and the derived candidates for the plurality of predicted motion vectors are registered in the predicted motion vector candidate list described later.
  • the inter-prediction unit 203 selects a predicted motion vector according to the predicted motion vector index decoded and supplied by the bit string decoding unit 201 from a plurality of predicted motion vector candidates registered in the predicted motion vector candidate list.
  • a motion vector is calculated from the differential motion vector decoded by the bit string decoding unit 201 and the selected predicted motion vector, and the calculated motion vector is stored in the coding information storage memory 205 together with other coding information.
  • the coding information of the coding block supplied and stored here is the flag predFlagL0 [xP] [yP], predFlagL1 [xP] indicating whether or not to use the prediction mode PredMode, the division mode PartMode, the L0 prediction, and the L1 prediction.
  • xP and yP are indexes indicating the positions of the upper left pixels of the coded block in the picture.
  • PredMode is inter-prediction (MODE_INTER) and the inter-prediction mode is L0 prediction (Pred_L0)
  • the flag predFlagL0 indicating whether to use L0 prediction is 1, and the flag predFlagL1 indicating whether to use L1 prediction. Is 0.
  • the flag predFlagL0 indicating whether or not to use the L0 prediction is 0, and the flag predFlag L1 indicating whether or not to use the L1 prediction is 1.
  • the flag predFlagL0 indicating whether or not to use the L0 prediction and the flag predFlag L1 indicating whether or not to use the L1 prediction are both 1.
  • the prediction mode PredMode of the coded block to be processed is inter-prediction (MODE_INTER) and the merge mode is set, merge candidates are derived.
  • a plurality of merge candidates are derived, registered in the merge candidate list described later, and registered in the merge candidate list.
  • a flag indicating whether or not to use the L0 prediction and the L1 prediction of the selected merge candidate by selecting the merge candidate corresponding to the merge index decoded and supplied by the bit string decoding unit 201 from the plurality of merge candidates.
  • PredFlagL0 [xP] [yP], predFlagL1 [xP] [yP], reference index refIdxL0 [xP] [yP], refIdxL1 [xP] [yP], L0, L1 motion vector mvL0 [xP] [yP] ], MvL1 [xP] [yP] and other inter-prediction information is stored in the coded information storage memory 205.
  • xP and yP are indexes indicating the positions of the upper left pixels of the coded block in the picture. The detailed configuration and operation of the inter-prediction unit 203 will be described later.
  • the intra prediction unit 204 performs intra prediction when the prediction mode PredMode of the coded block to be processed is intra prediction (MODE_INTRA), and performs intra block copy prediction when IBC prediction (MODE_IBC).
  • the coding information supplied from the bit string decoding unit 201 includes an intra luminance prediction mode and an intra color difference prediction mode, and decodes according to the intra luminance prediction mode and the intra color difference prediction mode.
  • a predicted image signal is generated by intra-prediction from the decoded image signal stored in the image memory 208, and the predicted image signal is supplied to the decoded image signal superimposing unit 207.
  • IBC prediction (MODE_IBC)
  • a block vector is derived and intra-block copy prediction is performed based on the coding information regarding the IBC prediction (MODE_IBC) supplied from the bit string decoding unit 201. Since the intra prediction unit 204 corresponds to the intra prediction unit 103 of the image coding device 100, the same processing as that of the intra prediction unit 103 is performed. The detailed configuration and operation of the intra prediction unit 204 will be described later.
  • the inverse quantization / anti-orthogonal conversion unit 206 performs anti-orthogonal conversion and inverse quantization on the orthogonal conversion / quantization residual signal decoded by the bit string decoding unit 201, and is inversely orthogonal conversion / inverse quantization. Get the residuals.
  • the decoded image signal superimposition unit 207 is inversely quantized and inversely orthogonally converted by the inverse quantization / inverse orthogonal conversion unit 206 with the predicted image signal inter-predicted by the inter-prediction unit 203 or the predicted image signal intra-predicted by the intra prediction unit 204.
  • the decoded image signal is decoded by superimposing the inverse quantized residual signal, and the decoded image signal is stored in the decoded image memory 208.
  • the decoded image signal superimposing unit 207 may perform a filtering process on the decoded image to reduce block distortion due to coding and then store in the decoded image memory 208. ..
  • FIG. 6 is a flowchart showing an operation of dividing an image into tree blocks and further dividing each tree block into coded blocks.
  • the input image is divided into tree blocks of a predetermined size (step S1001).
  • Each tree block is scanned in a predetermined order, that is, in the order of raster scan (steps S1002 to S1004), and the inside of the tree block to be processed is recursively and hierarchically divided into coded blocks (step S1003).
  • FIG. 7 is a flowchart showing a detailed operation of the coded block division process on the coded side in step S1003.
  • the block division section 101 on the coding side performs division or non-division by 4 divisions, vertical 2 divisions, vertical 3 divisions, horizontal 2 divisions, and horizontal 3 divisions (steps S1101 to S1111), and corresponds to each division mode.
  • Block division information such as the color difference block non-division flag chroma_non_split_flag, which will be described later, is supplied to the inter prediction unit 102, the intra prediction unit 103, and the prediction method determination unit 105. Further, the generated image signal of the coded block to be processed is supplied to the inter prediction unit 102, the intra prediction unit 103, and the residual signal generation unit 106.
  • step S1102 when the division mode set in step S1102 is 4-division (SPLIT_QT), vertical 2-division (SPLIT_BT_VER), vertical 3-division (SPLIT_TT_VER), horizontal 2-division (SPLIT_BT_HOR), or horizontal 3-division (SPLIT_TT_HOR) (step S1103). : YES), the luminance block to be divided is divided according to the division mode (step S1104). On the other hand, when the division mode set in step S1102 is non-division (SPLIT_NONE) (step S1103: NO), the division processing of steps S1104 to S1110 is skipped.
  • SPLIT_NONE non-division
  • step S1105 when the prediction mode is intra prediction (MODE_INTRA) or IBC prediction (MODE_IBC), it is determined whether or not to perform the color difference block division processing based on the division mode set in step S1102 (step S1105).
  • the prediction mode is intra prediction (MODE_INTRA) or IBC prediction (MODE_IBC)
  • it is determined whether or not to perform the color difference block division processing based on the division mode set in step S1102 (step S1105).
  • the size of the coded block of the luminance signal is 16 pixels (4 ⁇ 4, 8 ⁇ 2, 2 ⁇ 8) pixels.
  • inter-prediction is performed. Prohibit and make intra-prediction or IBC prediction.
  • the prediction mode is predetermined in intra prediction (MODE_INTRA) or IBC prediction (MODE_IBC) in order to reduce the amount of arithmetic processing and the number of memory accesses.
  • the color difference coded block having a color difference block size of 8 pixels or less (or less than 16 pixels), that is, 2 ⁇ 2, 4 ⁇ 2, 2 ⁇ 4 pixels is prohibited.
  • the color difference block to be divided is divided in the division mode set in step S1102, if the divided color difference block is 8 pixels or less, which is a predetermined size, the color difference block to be divided is not divided. It is a color difference coded block.
  • the above-mentioned color difference block non-division flag chroma_non_split_flag is a flag indicating that the color difference block to be divided is not divided based on the division mode in the intra prediction and the IBC prediction, but is used as the color difference coding block.
  • the size of the color difference block to be divided is 8 ⁇ 4.
  • the color difference block to be divided can be vertically divided into two, and the size of the divided color difference block is 4 ⁇ 4.
  • the color difference block to be divided can be horizontally divided into two, and the size of the divided color difference block is 8 ⁇ 2.
  • the division mode when the division mode is the 4-division mode, when the color difference block to be divided is divided, the size of the divided color difference block is 4 ⁇ 2, so the division is not performed.
  • the division mode when the division mode is the vertical 3-division mode, when the color difference block to be divided is divided, the size of the divided left color difference block and the right color difference block becomes 2 ⁇ 4, so the division is performed. Absent.
  • the division mode when the division mode is the horizontal 3-division mode, when the color difference block to be divided is divided, the upper color difference block and the lower color difference block become 8 ⁇ 1, so the division is not performed.
  • step S1105: YES When it is determined in the intra prediction (MODE_INTRA) or the IBC prediction (MODE_IBC) that the color difference block is to be divided (step S1105: YES), the color difference block to be divided is divided in the division mode set in step S1102 (step S1105: YES). Step S1107).
  • step S1105 If it is not determined in the intra prediction (MODE_INTRA) or IBC prediction (MODE_IBC) that the color difference block division processing is to be performed (step S1105: NO), the color difference block to be divided is divided in the division mode set in step S1102. Instead, the color difference coded block is used, and the color difference block non-split flag chroma_non_split_flag is set to 1 (true) (step S1106).
  • each of the divided blocks is scanned in a predetermined order, and the main coded block division process is recursively performed (steps S1108 to S1110).
  • each of the divided blocks is scanned in the order of the numbers shown in FIGS. 5A to 5E (hereinafter referred to as the divided index).
  • Numbers 0 to 3 of 601 in FIG. 5A, numbers 0 to 1 of 602 and 604 of FIG. 5D, 603 of FIG. 5C and 0 to 2 of 605 of FIG. 5E are numbers indicating the order of division processing.
  • the coded block division process is recursively performed for each of the divided blocks (step S1119 in FIG. 7).
  • the necessity of division may be limited depending on the number of divisions, the size of the block to be divided, and the like.
  • the information that limits the necessity of division may be realized in a configuration that does not transmit information by making an agreement in advance between the coding device and the decoding device, or the coding device limits the necessity of division. It may be realized by the configuration which transmits to the decoding apparatus by determining the information to be performed and recording it in the coded bit string.
  • each block after division is called the child block.
  • the color difference coded block smaller than the predetermined size is prohibited, but the color difference coded block smaller than the predetermined size may be prohibited.
  • the predetermined minimum color difference coded block size is 16 pixels (4 ⁇ 4, 8 ⁇ 2, 2 ⁇ 8) and the color difference block to be divided is divided in the division mode set in step S1102, it is divided. If the color difference block is smaller than the minimum color difference coded block size, the color difference block to be divided is not divided and is used as the color difference coded block.
  • the intra prediction (MODE_INTRA) or the IBC prediction (MODE_IBC) has been mainly described, but in the inter prediction (MODE_INTER), the color difference code of 2 ⁇ 2, 4 ⁇ 2, 2 ⁇ 4
  • the processing for intra prediction (MODE_INTRA) or IBC prediction (MODE_IBC) steps S1105 to S1110), the processing of steps S1106 and S1108 to S1110 for inter prediction (MODE_INTER) is also performed.
  • FIG. 9 is a flowchart showing an operation of encoding the block division information.
  • the block division information determined by the prediction method determination unit 105 is encoded.
  • This block division information is information for identifying whether the division mode is 4-division, vertical 2-division, vertical 3-division, horizontal 2-division, horizontal 3-division, or non-division in each layer of block division, and color difference block non-division.
  • a flag indicating whether or not to divide a block For example, a flag indicating whether or not to divide a block, a flag indicating whether or not to divide into four, a flag indicating whether or not to divide into two or three, and whether or not to divide vertically (vertically or horizontally).
  • a flag indicating whether to divide into two or not is encoded.
  • the division mode is the 4-division mode (step S1201: YES)
  • the flag indicating whether or not to divide the block is set to 1 (true)
  • the flag indicating whether or not to divide the block is set to 1 (true).
  • the division mode is the vertical 2-division mode (step S1203: YES)
  • the flag indicating whether or not to divide the block is 1 (true)
  • the flag indicating whether or not to divide the block is 0 (false)
  • the block is vertically divided.
  • the flag indicating whether to divide (divided horizontally) is set to 1 (true)
  • the flag indicating whether to divide into 2 (divided into 3) is set to 1 (true) and encoded (step S1204).
  • the division mode is the vertical 3-division mode (step S1205: YES)
  • the flag indicating whether or not to divide the block is 1 (true)
  • the flag indicating whether or not to divide the block is 0 (false)
  • the flag indicating whether to divide (divided horizontally) is set to 1 (true), and the flag indicating whether to divide into 2 (divided into 3) is set to 0 (false) and encoded (step). S1206).
  • the flag indicating whether or not to divide the block is 1 (true)
  • the flag indicating whether or not to divide the block is 0 (false)
  • the flag indicating whether or not to divide into two is set to 1 (true) and encoded (step S1208).
  • step S1209 In the case of the horizontal three-division mode (step S1209: YES), the flag indicating whether or not to divide the block is 1 (true), the flag indicating whether or not to divide the block is 0 (false), and whether or not to divide vertically.
  • the flag indicating whether or not to divide (horizontally divided) is set to 0 (false)
  • the flag indicating whether or not to divide into two is set to 0 (false) and encoded (step S1210).
  • the division mode is 4-division, vertical 2-division, vertical 3-division, horizontal 2-division, or horizontal 3-division
  • the size of the divided luminance block becomes 4 ⁇ 4, 8 ⁇ 4, 4 ⁇ 8 pixels which is 32 pixel blocks or less), and it is determined that the size is not more than a predetermined size (S1212: YES). ..
  • the color difference block non-split flag chroma_non_split_flag is encoded (step S1213). However, even if the color difference block non-split flag chroma_non_split_flag is not encoded, it is not encoded if it can be derived on the decoding side.
  • the color difference block undivided flag chroma_non_split_flag can be derived from the block size after division on the decoding side, so the color difference block undivided flag chroma_non_split_flag Does not need to be encoded.
  • the size of the luminance block after division is 16 pixels (4 ⁇ 4 pixels)
  • the color difference block non-division flag chroma_non_split_flag is 1 (true) because the prediction mode is not inter-prediction (MODE_INTER).
  • Color difference block unsplit flag chroma_non_split_flag does not need to be encoded.
  • the prediction mode of all the divided coded blocks is intra prediction (MODE_INTRA) or IBC prediction (MODE_IBC).
  • the size of the divided color difference block is not 8 pixel blocks or less (that is, 2 ⁇ 2,
  • the color difference block undivided flag chroma_non_split_flag is not encoded, and the prediction mode of each divided coded block is encoded by the layer of the coded block. Will be done.
  • each block divided based on the prediction mode is subsequently scanned in a predetermined order, and this block division information code is used.
  • the conversion process is recursively performed (steps S1214 to S1216). Specifically, each block to be divided is scanned in the order of the numbers shown in FIGS. 5A to 5E (hereinafter referred to as division indexes). Numbers 0 to 3 of 601 in FIG. 5A, numbers 0 to 3 of 602 and 604 of FIG. 5D, 603 of FIG. 5C and 0 to 2 of 605 of FIG. 5E are numbers indicating the order of division information coding processing. is there.
  • the coded block division process is recursively performed for each block divided based on the prediction mode (step S1215 in FIG. 9).
  • step S1209 NO
  • the flag indicating whether or not to divide the block is set to 0 (false) and encoded (step S1211), and the coding information code of the coding block described later is used.
  • the conversion process is performed (step S1217).
  • the block division unit 202 divides the tree block by the same processing procedure as the block division unit 101 of the image coding apparatus 100.
  • the block division unit 101 of the image coding apparatus 100 applies an optimization method such as estimation of the optimum shape by image recognition and optimization of the distortion rate to determine the optimum shape of the block division, whereas the image decoding apparatus
  • the block division unit 202 in 200 is different in that the block division shape is determined by decoding the block division information recorded in the coded bit string by the bit string decoding unit 201.
  • FIG. 12 is a flowchart showing an operation of decoding the block division information and dividing the block.
  • the block division information is decoded from the coded bit string.
  • This block division information is information for identifying whether the division mode is 4-division, vertical 2-division, vertical 3-division, horizontal 2-division, horizontal 3-division, or non-division in each layer of block division, and color difference block non-division.
  • the information indicating the block division is decoded (step S1401).
  • step S1402 When the information indicating the block division is 1 (true) (step S1402: YES), the process proceeds to step S1403, and when the information indicating the block division is 0 (false) (step S1402: NO), the division mode is set to the non-division mode. (Step S1405), the coding information decoding process of the coding block described later is performed.
  • step S1403 when the flag indicating whether or not to divide into four is decoded (step S1403) and the flag indicating whether or not to divide into four is 1 (true) (step S1404: YES), the division mode of the layer is divided into four.
  • step S1405 When the mode is set (step S1405) and the flag indicating whether or not to divide into four is 0 (false) (step S1404: NO), the process proceeds to step S1406.
  • step S1406 the flag indicating whether or not it is vertically divided is decoded
  • step S1407 the flag indicating whether or not it is divided into two is decoded
  • step S1408 When the flag indicating whether or not to divide vertically is 1 (true) (step S1408: YES) and the flag indicating whether or not to divide into 2 is 1 (true) (step S1409: YES), the division mode of the layer is vertical 2.
  • the split mode is set (step S1410).
  • step S1408 When the flag indicating whether or not to divide vertically is 1 (true) (step S1408: YES) and the flag indicating whether or not to divide into 2 is 0 (false) (step S1409: NO), the division mode of the layer is vertical 3.
  • the split mode is set (step S1410).
  • step S1408 NO
  • the flag indicating whether or not to divide into two is 1 (true)
  • step S1412 YES
  • the division mode of the layer is horizontal 2.
  • the split mode is set (step S1413).
  • step S1408: NO When the flag indicating whether or not to divide vertically is 0 (false) (step S1408: NO) and the flag indicating whether or not to divide into two is 0 (false) (step S1412: NO), the division mode of the layer is horizontal 3.
  • the split mode is set (step S1414).
  • Step S1416 it is determined whether or not the divided blocks have a predetermined size or less based on the division mode set in steps S1405, S1410, S1411, S1413, and S1414.
  • the size of the divided color difference block is 2 ⁇ 2, 4 ⁇ 2, 2 ⁇ 4 pixels which is 8 pixel blocks or less (that is, when the color difference format is 4: 2: 0, the division target
  • the size of the divided luminance block becomes 4 ⁇ 4, 8 ⁇ 4, 4 ⁇ 8 pixels which is 32 pixel blocks or less), and it is determined that the size is not more than a predetermined size (S1416: YES).
  • the color difference block non-split flag chroma_non_split_flag is decoded or derived (step S1417). However, if the color difference block unsplit flag chroma_non_split_flag can be derived on the decoding side without decoding it, the non-split flag chroma_non_split_flag is not encoded and is derived.
  • the prediction mode is not inter-prediction (MODE_INTER), so if the divided blocks are smaller than a predetermined size, the color difference block non-division flag chroma_non_split_flag is set to 1 (true) without decoding.
  • the prediction mode is not inter-prediction (MODE_INTER), so the color difference block non-division flag chroma_non_split_flag is not decoded and the color difference is achieved.
  • the block non-split flag chroma_non_split_flag is 1 (true).
  • the color difference block non-split flag chroma_non_split_flag is 1 (true) (step S1419: YES)
  • the color difference block is not divided (step S1420).
  • the prediction modes of the coded blocks of the divided luminance signal and the coded blocks of the undivided color difference signal are all set to intra prediction (MODE_INTRA) or IBC prediction (MODE_IBC).
  • the value of the color difference block non-split flag chroma_non_split_flag is 0 (false) (step S1419: NO)
  • the color difference block is also split based on the split mode (step S1421).
  • the prediction mode of all the divided coded blocks is inter-prediction (MODE_INTER).
  • the size of the divided color difference block is not 8 pixel blocks or less (that is, not 2 ⁇ 2, 4 ⁇ 2, 2 ⁇ 4 pixels) as a result of dividing the color difference block to be divided (step S1416: NO).
  • the color difference block is also divided based on the division mode (step S1421). At this time, the prediction mode of each divided coded block is decoded by the layer of the coded block.
  • each of the divided blocks is scanned in a predetermined order (steps S1422 to S1424), and the block division information decoding and the coded block division processing are performed hierarchically and recursively (step S1423).
  • each of the divided blocks is scanned in the order of the numbers shown in FIGS. 5A to 5E (hereinafter referred to as the divided index).
  • Numbers 0 to 3 of 601 in FIG. 5A, numbers 0 to 1 of 602 and 604 of FIG. 5D, 603 of FIG. 5C and 0 to 2 of 605 of FIG. 5E are numbers indicating the order of division processing.
  • the block division information decoding and the coded block division processing are performed hierarchically and recursively (step S1423 in FIG. 12).
  • the intra prediction method according to the embodiment is carried out by the intra prediction unit 103 of the image coding device of FIG. 1 and the inter prediction unit 203 of the image decoding device of FIG.
  • the intra prediction method according to the embodiment will be described with reference to the drawings.
  • the intra prediction method is carried out in either coding or decoding processing in units of coded blocks.
  • FIG. 41 is a diagram showing a detailed configuration of the intra prediction unit 103 of the image coding device of FIG. 1.
  • the intra prediction unit 103 usually includes an intra prediction unit 351 and an intra block copy prediction unit 352.
  • the intra prediction unit 351 corresponds to the prediction processing when the prediction mode of the coded block is intra prediction (MODE_INTRA)
  • the intra block copy prediction unit 352 predicts when the prediction mode of the coded block is IBC prediction (MODE_IBC).
  • MODE_INTRA intra prediction mode of the coded block
  • IBC prediction IBC prediction
  • the normal intra prediction unit 351 generates a prediction image signal by normal intra prediction from decoded pixels adjacent to a coded block to be processed, selects a suitable intra prediction mode from a plurality of intra prediction modes, and selects the appropriate intra prediction mode.
  • the predicted intra prediction mode selected and the predicted image signal corresponding to the selected intra prediction mode are supplied to the prediction method determination unit 105.
  • 10A-B show an example of normal intra-prediction.
  • FIG. 10A shows the correspondence between the prediction direction of the normal intra-prediction and the intra-prediction mode number.
  • the intra prediction mode 18 is horizontal prediction, and an intra prediction image is generated by copying pixels in the horizontal direction.
  • the intra prediction mode 50 is vertical prediction, and an intra prediction image is generated by copying pixels in the vertical direction.
  • the intra prediction mode 66 is an oblique prediction, and an intra prediction image is generated by copying pixels in an oblique 45 degree direction.
  • the intra prediction mode 1 is an average value prediction (DC) mode, and is a mode in which all the pixel values of the processing target block are set as the average value of the reference pixels.
  • the intra prediction mode 0 is a plane prediction (Planar) mode, which is a mode for creating a two-dimensional intra prediction image from reference pixels in the vertical and horizontal directions.
  • FIG. 10B is an example of generating an intra prediction image in the case of the intra prediction mode 40. For each pixel of the block to be processed, the value of the reference pixel in the direction indicated by the intra prediction mode is copied. When the reference pixel in the intra prediction mode is not an integer position, the reference pixel value is determined by interpolation from the reference pixel values at the surrounding integer positions.
  • the intra-block copy prediction unit 352 acquires a decoded area of the same image signal as the coded block to be processed from the decoded image memory 104, generates a prediction image signal by the intra-block copy prediction processing, and determines the prediction method. Supply to 105. The detailed configuration and processing of the intra-block copy prediction unit 352 will be described later.
  • FIG. 42 is a diagram showing a detailed configuration of the intra prediction unit 204 of the image decoding apparatus of FIG.
  • the intra prediction unit 204 usually includes an intra prediction unit 361 and an intra block copy prediction unit 362.
  • the normal intra prediction unit 361 corresponds to the normal intra prediction processing when the prediction mode of the coded block is intra prediction (MODE_INTRA), and the intra block copy prediction unit 362 has the prediction mode of the coded block intra block copy prediction (MODE_IBC).
  • MODE_INTRA intra prediction mode of the coded block intra block copy prediction
  • MODE_IBC prediction mode of the coded block intra block copy prediction
  • the normal intra prediction unit 361 generates a prediction image signal by normal intra prediction from decoded pixels adjacent to a coded block to be processed, selects a suitable intra prediction mode from a plurality of intra prediction modes, and selects the appropriate intra prediction mode.
  • the predicted image signal corresponding to the selected intra prediction mode and the selected intra prediction mode is obtained.
  • This predicted image signal is supplied to the decoded image signal superimposing unit 207 via the switch 364. Since the processing of the normal intra prediction unit 361 of FIG. 42 corresponds to the normal intra prediction unit 351 of FIG. 41, detailed description thereof will be omitted.
  • the intra-block copy prediction unit 362 acquires a decoded area of the same image signal as the coded block to be processed from the decoded image memory 208, and obtains the predicted image signal by the intra-block copy processing. This predicted image signal is supplied to the decoded image signal superimposing unit 207 via the switch 364. The detailed configuration and processing of the intra-block copy prediction unit 362 will be described later.
  • FIG. 57 is a flowchart showing an operation of encoding the coding information of the coding block.
  • the coding information for each coding block determined by the prediction method determination unit 105 is encoded.
  • PRED_INTER inter-prediction
  • Inter-prediction (PRED_ INTER) is not used in the I-slice, which is equivalent to setting that inter-prediction (PRED_ INTER) is not used for each picture or slice.
  • the prediction mode information indicating that the prediction mode of the coding block is any of intra prediction (PRED_INTRA), IBC prediction (PRED_IBC), and inter prediction (PRED_INTER) is encoded (steps S1501 to S1504).
  • a flag indicating whether the prediction mode is intra-prediction (PRED_INTRA) is encoded (step S1502)
  • a flag indicating whether the prediction mode is IBC prediction (PRED_IBC) (step S1504) is encoded.
  • step S1501 it is determined whether or not to encode a flag indicating whether or not the prediction mode of the coded block is intra prediction (PRED_INTRA) (step S1501).
  • PRED_INTRA intra-prediction
  • step S1502: YES a flag indicating whether the prediction mode of the coded block is intra-prediction (PRED_INTRA) is coded.
  • Step S1502 the prediction mode is intra prediction (PRED_INTRA)
  • the coding block is encoded by setting the flag indicating whether the prediction mode of the coded block is intra prediction (PRED_INTRA) to 1 (true), and the prediction mode is not intra prediction (PRED_INTRA).
  • the flag indicating whether the prediction mode of the coded block is intra prediction is set to 0 (false). To become.
  • step S1503 it is determined whether or not to encode the flag indicating whether or not the prediction mode of the coding block is IBC prediction (PRED_IBC) (step S1503). If IBC prediction (PRED_IBC) is not used for each sequence, picture, or slice, or if inter-prediction (PRED_INTER) is not used for each sequence, picture, or slice, in the parent block of the coded block to be processed. , When the color difference block non-split flag chroma_non_split_flag is set to 0 (false) and encoded, the flag indicating whether the prediction mode of the coding block is IBC prediction (PRED_IBC) is not encoded.
  • a flag indicating whether the prediction mode of the coded block is IBC prediction (PRED_IBC) is coded. (Step S1504).
  • the prediction mode is IBC prediction (PRED_IBC)
  • the flag indicating whether the prediction mode of the coding block is IBC prediction (PRED_IBC) is set to 1 (true) for coding, and the prediction mode is not IBC prediction (PRED_IBC).
  • the flag indicating whether the prediction mode of the coding block is IBC prediction is set to 0 (false) for coding.
  • the color difference block to be divided in the parent block of the coded block to be processed, in the intra prediction or the IBC prediction, the color difference block to be divided is not divided based on the division mode, and the color difference coded block is used.
  • the prediction mode of the luminance signal coding block at the same position as the color difference signal coding block is set to the color difference signal coding block. Prediction mode.
  • the luminance signal coding block at the same position as the color difference signal coding block when specifying the luminance signal coding block at the same position as the color difference signal coding block, it corresponds to the lower right pixel in the center of the color difference signal coding block in the image space of the color difference signal.
  • a luminance signal coding block containing pixels at the same position in the image space of the luminance signal is defined as a luminance signal coding block at the same position as the color difference signal coding block.
  • FIG. 13A shows a coded block of an 8 ⁇ 8 pixel luminance signal
  • FIG. 13B shows a coded block of a 4 ⁇ 4 pixel color difference signal at the same position corresponding to the 8 ⁇ 8 pixel luminance signal coded block. ..
  • the pixels at the same position in the image space of the luminance signal corresponding to the lower right pixel in the center of the coded block of the color difference signal in the image space of the luminance signal are the lower right pixels in the center of the encoded block of the luminance signal. is there.
  • FIG. 39A shows a coded block of a luminance signal in which a luminance block of 8 ⁇ 8 pixels to be divided is divided into four, and the size of each coded block is 4 ⁇ 4 pixels.
  • FIG. 39B shows a 4 ⁇ 4 pixel color difference block at the same position corresponding to the 8 ⁇ 8 pixel luminance block to be divided, and in the present embodiment, the 2 ⁇ 2 pixel color difference signal coding block is prohibited. It becomes a color difference signal coding block without being divided into four.
  • the luminance signal coding block including the pixels at the same position in the luminance signal image space corresponding to the lower right pixel in the center of the color difference signal coding block in the color difference signal image space is the third from 0. That is, the last (lower right) coding block.
  • This coded block is used as a coded block for the luminance signal at the same position as the coded block for the color difference signal.
  • FIG. 40A shows a coding block of a luminance signal in which the luminance block of 8 ⁇ 8 pixels to be divided is vertically divided into two, and the size of each coding block is 4 ⁇ 8 pixels.
  • FIG. 40B shows a color difference block of 4 ⁇ 4 pixels at the same position corresponding to the luminance block of 8 ⁇ 8 pixels to be divided, and in the present embodiment, the coding block of the color difference signal of 2 ⁇ 4 pixels is prohibited. It becomes a color difference signal coding block without being vertically divided into two.
  • the luminance signal coding block including the pixels at the same position in the luminance signal image space corresponding to the lower right pixel in the center of the color difference signal coding block in the color difference signal image space is the first one counting from 0. That is, the last (right side) coding block.
  • This coded block is used as a coded block for the luminance signal at the same position as the coded block for the color difference signal.
  • FIG. 59A shows a coded block of a luminance signal in which the luminance block of 8 ⁇ 8 pixels to be divided is vertically divided into three, and the size of each encoded block is 2 ⁇ 8 pixels.
  • FIG. 59B shows a 4 ⁇ 4 pixel color difference block at the same position corresponding to the 8 ⁇ 8 pixel luminance block to be divided, and in the present embodiment, the 1 ⁇ 4 pixel color difference signal coding block is prohibited. It becomes a color difference signal coding block without being vertically divided into three.
  • the luminance signal coding block including the pixels at the same position in the luminance signal image space corresponding to the lower right pixel in the center of the color difference signal coding block in the color difference signal image space is the first one counting from 0. That is, the coding block in the middle.
  • This coded block is used as a coded block for the luminance signal at the same position as the coded block for the color difference signal.
  • step S1505 when the prediction mode is intra-prediction (PRED_INTRA) (step S1505: YES), the information regarding the intra-luminance prediction mode of the luminance signal coding block is encoded (step S1506).
  • the coding of the information regarding the intra-luminance prediction mode of the luminance signal coding block will be described later.
  • step S1507 it is determined whether or not to encode the information regarding the intra color difference prediction mode of the color difference signal coding block.
  • the color difference block to be divided is divided into the color difference coded block based on the division mode, that is, the color difference block non-division flag chroma_non_split_flag is not set to 1 (true).
  • the information regarding the intra color difference prediction mode is encoded in all the coded blocks to be processed.
  • the prediction mode is intra prediction (MODE_INTRA)
  • the coding block of the color difference signal of 2 ⁇ 2, 4 ⁇ 2, 2 ⁇ 4 pixels is prohibited in the present embodiment, so that the parent of the coded block to be processed
  • the color difference block non-division flag chroma_non_split_flag is set to 1 (true).
  • step S1507: YES the information about the intra-color difference prediction mode is encoded in the last divided coded block (step S1508), and in the other coded blocks (step S1507: NO), Do not encode information about intracolor difference prediction modes.
  • the division mode in the parent block is the 4-division mode (601 in FIG. 5A)
  • the information regarding the intra color difference prediction mode is encoded in the third coding block counting from the 0th, which is the last (step S1508).
  • the division mode in the parent block is the vertical 2-division mode or the horizontal 2-division mode (602 in FIG. 5B, 604 in FIG.
  • the intra-color difference in the first coded block counting from the last 0th is encoded (step S1508), and the information regarding the intra color difference prediction mode is not encoded in the 0th coding block.
  • the division mode in the parent block is the vertical 3-division mode or the horizontal 3-division mode (603 in FIG. 5C, 605 in FIG. 5E)
  • the intra color difference is in the second coding block counting from the 0th last.
  • the information regarding the prediction mode is encoded (step S1508), and the information regarding the intra color difference prediction mode is not encoded in the 0th to 1st coding blocks.
  • the prediction mode is IBC prediction (PRED_IBC) (step S1509: YES)
  • the coding information related to IBC prediction (PRED_IBC) is encoded (step S1510). Specifically, a flag for determining whether or not it is in merge mode, a merge index for merge mode, a predicted block vector index for not in merge mode, a difference block vector, and other coding information are specified in the specified syntax (of the coded bit string). Encode according to the syntax rules).
  • the prediction mode is inter-prediction (PRED_INTER) (step S1509: NO)
  • the coding information related to inter-prediction (PRED_INTER) is encoded (step S1511).
  • Flag to determine whether it is in merge mode sub-block merge flag, merge index in merge mode, inter-prediction mode, predicted motion vector index in non-merge mode, information about differential motion vector, sub-block predicted motion vector flag, etc.
  • the coding information of is encoded according to the specified syntax (the syntax rule of the encoding bit string).
  • step 1512 the information regarding the residual signal derived by the orthogonal conversion / quantization unit 107 is encoded (step 1512), and the coding information coding procedure of the present coding block is completed.
  • step 1513 it is determined whether or not to encode the information regarding the residual signal of the color difference signal (step 1513).
  • the determination of whether or not to encode the information regarding the residual signal of the color difference signal in step 1513 is the same as determining whether or not to encode the information regarding the intra color difference prediction mode of the coding block of the color difference signal in step S1507.
  • it is determined that the information regarding the intra-color difference prediction mode of the coded block is encoded it is determined that the information regarding the residual signal of the color difference signal is also encoded, and it is determined that the information regarding the intra-color difference prediction mode of the coded block is not encoded. If so, it is determined that the information regarding the residual signal of the color difference signal is also not encoded.
  • step S1513: YES when it is determined to encode the information regarding the residual signal of the color difference signal (step S1513: YES), the information regarding the residual signal of the color difference signal generated by the orthogonal conversion / quantization unit 107 is encoded (step S1513: YES). Step S1514).
  • FIG. 58 is a flowchart showing an operation of decoding the coding information of the coding block.
  • the coding information for each coding block is decoded from the coding bit string encoded on the coding side.
  • IBC prediction PRED_IBC
  • PRED_INTER inter-prediction
  • the prediction mode information indicating that the prediction mode of the coding block is any of intra prediction (PRED_INTRA), IBC prediction (PRED_IBC), and inter prediction (PRED_INTER) is decoded (steps S1601 to S1604).
  • the flag indicating whether the prediction mode is intra prediction (PRED_INTRA) is decoded (step S1602)
  • the flag indicating whether the prediction mode is IBC prediction (PRED_IBC) is decoded.
  • step S1601 it is determined whether or not to decode the flag indicating whether or not the prediction mode of the coded block is intra prediction (PRED_INTRA) (step S1601).
  • PRED_INTRA intra prediction
  • step S1602 the flag indicating whether the prediction mode of the coded block is intra prediction (PRED_INTRA) is decoded.
  • the flag indicating whether the prediction mode of the encoded block is intra prediction is 1 (true), and when the prediction mode is not intra prediction (PRED_INTRA), that is, When the prediction mode is IBC prediction (PRED_IBC) or inter prediction (PRED_INTER), the flag indicating whether the prediction mode of the coded block is intra prediction (PRED_INTRA) is 0 (false).
  • step S1603 it is determined whether or not to decode the flag indicating whether or not the prediction mode of the coded block is IBC prediction (PRED_IBC) (step S1603). If IBC prediction (PRED_IBC) is not used for each sequence, picture, or slice, or if inter-prediction (PRED_INTER) is not used for each sequence, picture, or slice, in the parent block of the coded block to be processed. , When the color difference block non-split flag chroma_non_split_flag is set to 0 (false) and encoded, the flag indicating whether the prediction mode of the coding block is IBC prediction (PRED_IBC) is not decoded.
  • the flag indicating whether the prediction mode of the coding block is IBC prediction (PRED_IBC) is decoded. (Step S1604).
  • the prediction mode is IBC prediction (PRED_IBC)
  • the flag indicating whether the prediction mode of the coded block is IBC prediction (PRED_IBC) is 1 (true)
  • the prediction mode is not IBC prediction (PRED_IBC)
  • the flag indicating whether the prediction mode of the coded block is IBC prediction (PRED_IBC) is 0 (false).
  • step S1605 when the prediction mode is intra-prediction (PRED_INTRA) (step S1605: YES), the information regarding the intra-luminance prediction mode of the luminance signal coding block is decoded (step S1606). Decoding of information regarding the intra-luminance prediction mode of the luminance signal coding block will be described later.
  • step S1607 it is determined whether or not to decode the information regarding the intra color difference prediction mode of the coded block of the color difference signal (step S1607).
  • the prediction mode is intra prediction (MODE_INTRA)
  • the coding block of the color difference signal of 2 ⁇ 2, 4 ⁇ 2, 2 ⁇ 4 pixels is prohibited, so that the parent block of the coded block to be processed .
  • Intra prediction, or IBC prediction when it is determined that the color difference block to be divided is not divided based on the division mode and is a color difference coding block, that is, the color difference block non-division flag chroma_non_split_flag is set to 1 (true).
  • step S1607: YES the information regarding the intra color difference prediction mode is decoded in the last divided coded block (step S1608), and in the other coded blocks (step S1607: NO), the intra color difference Do not decode information about predictive mode.
  • the division mode in the parent block is the 4-division mode (601 in FIG. 5A)
  • the information regarding the intra color difference prediction mode is decoded in the third coding block counting from the 0th, which is the last (step S1608).
  • the division mode in the parent block is the vertical 2-division mode or the horizontal 2-division mode (602 in FIG.
  • the intra-color difference in the first coded block counting from the last 0th the intra-color difference in the first coded block counting from the last 0th.
  • the information regarding the prediction mode is decoded (step S1608), and the information regarding the intra color difference prediction mode is not decoded at the 0th coding block.
  • the division mode in the parent block is the vertical 3-division mode or the horizontal 3-division mode (603 in FIG. 5C, 605 in FIG. 5E)
  • the intra color difference is in the second coding block counting from the 0th last.
  • the information regarding the prediction mode is decoded (step S1608), and the information regarding the intra color difference prediction mode is not decoded in the 0th to 1st coding blocks.
  • the color difference block undivided flag chroma_non_split_flag is not set to 1 (true) in the parent block of the coded block to be processed, the information regarding the intra color difference prediction mode is decoded in the coded block to be processed.
  • the prediction mode is IBC prediction (PRED_IBC) (step S1609: YES)
  • the coding information related to IBC prediction (PRED_IBC) is decoded (step S1610). Specifically, a flag for determining whether or not it is in merge mode, a merge index if it is in merge mode, a predicted block vector index if it is not in merge mode, a difference block vector, and other coding information are specified in the syntax (coded bit string). Decrypt according to the syntax rules).
  • step S1609 when the prediction mode is inter-prediction (PRED_INTER) (step S1609: NO), the coding information related to inter-prediction (PRED_INTER) is decoded (step S1611).
  • flag to determine whether it is in merge mode sub-block merge flag, merge index in merge mode, inter-prediction mode, predicted motion vector index in non-merge mode, information about differential motion vector, sub-block predicted motion vector flag, etc.
  • the encoding information of is decoded according to the specified syntax (the syntax rule of the coded bit string).
  • step 1612 the information regarding the residual signal is decoded (step 1612), and the present encoded information decoding process is completed.
  • the prediction mode (PredMode) of the coded block is intra-prediction (MODE_INTRA)
  • the values of the syntax elements related to the intra-luminance prediction mode of the coded block of the luminance signal are respectively.
  • the syntax element related to the intra-luminance prediction mode is the syntax element intra_luma_mpm_flag [x0] [y0], which is a flag indicating whether or not it can be predicted from the intra-luminance prediction mode of the surrounding blocks, and the thin index, which indicates the coding block of the prediction source.
  • x0, y0 are coordinates indicating the position of the coded block.
  • the intra-luminance prediction mode of the peripheral blocks is used by using the correlation with the intra-luminance prediction mode of the peripheral blocks stored in the coding information storage memory 111.
  • the syntax element intra_luma_mpm_idx which is an index indicating the encoding block of the prediction source.
  • the value of the syntax element intra_chroma_pred_mode [x0] [y0] relating to the intra color difference prediction mode of the coded block of the color difference signal is calculated and encoded (step S1508).
  • the intra-luminance prediction mode uses the correlation between the coded block of the color difference signal and the coded block of the luminance signal at the same position as the intra-luminance prediction mode.
  • the intra-luminance prediction mode value is predicted from the intra-luminance prediction mode value, and the intra-luminance prediction mode is used to predict the intra-luminance prediction mode.
  • the intra prediction modes typical of the intra color difference prediction mode are 0 (plane prediction), 1 (average value prediction), 18 (horizontal prediction), 50 (vertical prediction), 66 (diagonal prediction). The amount of code is reduced by using a mechanism for setting one of the values of.
  • the mode for predicting the value of the intra-color difference prediction mode from the value of the intra-luminance prediction mode of the luminance signal coding block at the same position as the color difference signal coding block is set to DM mode, and the syntax element intra_chroma_pred_mode [x0] [y0] When is a predetermined value, it indicates the DM mode.
  • ⁇ Intra prediction mode decoding> In the bit string decoding unit 201 on the decoding side, when the prediction mode (PredMode) of the coded block is intra prediction (MODE_INTRA), the syntax element intra_luma_mpm_flag [x0] relating to the intra-luminance prediction mode of the coded block of the luminance signal from the bit string. Decrypt [y0], intra_luma_mpm_idx [x0] [y0], intra_luma_mpm_remainder [x0] [y0] to derive the intra-luminance prediction mode, and decode the syntax element intra_chroma_pred_mode [x0] [y0] for the intra-color difference prediction mode.
  • the value of the intra-color difference prediction mode is derived.
  • the value of intra_chroma_pred_mode [x0] [y0] indicates the DM mode
  • the value of the intra-color difference prediction mode is set to the intra-luminance of the luminance signal coding block at the same position as the luminance signal coding block. Set to the same value as the prediction mode.
  • the lower right pixel in the center of the coded block of the color difference signal in the image space of the color difference signal when specifying the coded block of the luminance signal at the same position as the coded block of the color difference signal, the lower right pixel in the center of the coded block of the color difference signal in the image space of the color difference signal.
  • the luminance signal coding block containing the pixels at the same position in the image space of the luminance signal corresponding to is the luminance signal coding block at the same position as the color difference signal coding block, but is the same as the color difference signal coding block. Coding of a luminance signal containing pixels at the same position in the image space of the luminance signal corresponding to the upper left pixel of the coding block of the luminance signal in the image space of the color difference signal when identifying the coding block of the luminance signal at the position.
  • the block may be a coded block of the luminance signal at the same position as the coded block of the color difference signal.
  • the inter-prediction method according to the embodiment is carried out by the inter-prediction unit 102 of the image coding device of FIG. 1 and the inter-prediction unit 203 of the image decoding device of FIG.
  • the inter-prediction method according to the embodiment will be described with reference to the drawings.
  • the inter-prediction method is performed in either coding or decoding processing in units of coded blocks.
  • FIG. 16 is a diagram showing a detailed configuration of the inter-prediction unit 102 of the image coding apparatus of FIG.
  • the normal predicted motion vector mode derivation unit 301 derives a plurality of normal predicted motion vector candidates, selects a predicted motion vector, and calculates a difference vector between the selected predicted motion vector and the detected motion vector.
  • the detected inter-prediction mode, reference index, motion vector, and calculated difference vector become the inter-prediction information of the normal prediction motion vector mode.
  • This inter-prediction information is supplied to the inter-prediction mode determination unit 305.
  • the detailed configuration and processing of the normal prediction motion vector mode derivation unit 301 will be described later.
  • the normal merge mode derivation unit 302 derives a plurality of normal merge candidates, selects the normal merge candidates, and obtains the inter-prediction information of the normal merge mode. This inter-prediction information is supplied to the inter-prediction mode determination unit 305. The detailed configuration and processing of the normal merge mode derivation unit 302 will be described later.
  • the sub-block prediction motion vector mode derivation unit 303 derives a plurality of sub-block prediction motion vector candidates, selects a sub-block prediction motion vector, and selects a difference motion vector between the selected sub-block prediction motion vector and the detected motion vector. calculate.
  • the detected inter-prediction mode, reference index, motion vector, and calculated difference motion vector become the inter-prediction information of the sub-block prediction motion vector mode. This inter-prediction information is supplied to the inter-prediction mode determination unit 305.
  • the detailed configuration and processing of the sub-block prediction motion vector mode derivation unit 303 will be described later.
  • the sub-block merge mode derivation unit 304 derives a plurality of sub-block merge candidates, selects the sub-block merge candidates, and obtains the inter-prediction information of the sub-block merge mode. This inter-prediction information is supplied to the inter-prediction mode determination unit 305. The detailed configuration and processing of the subblock merge mode derivation unit 304 will be described later.
  • the inter-prediction mode determination unit 305 is based on the inter-prediction information supplied from the normal prediction motion vector mode derivation unit 301, the normal merge mode derivation unit 302, the sub-block prediction motion vector mode derivation unit 303, and the sub-block merge mode derivation unit 304. , Determine the inter-prediction mode.
  • Inter-prediction mode determination unit 305 supplies inter-prediction information according to the determination result to motion compensation prediction unit 306.
  • the motion compensation prediction unit 306 performs inter-prediction for the reference image signal stored in the decoded image memory 104 based on the determined inter-prediction information. The detailed configuration and processing of the motion compensation prediction unit 306 will be described later.
  • FIG. 22 is a diagram showing a detailed configuration of the inter-prediction unit 203 of the image decoding apparatus of FIG.
  • the normal predicted motion vector mode derivation unit 401 derives a plurality of normal predicted motion vector candidates, selects a predicted motion vector, calculates an added value between the selected predicted motion vector and the decoded differential motion vector, and moves. Let it be a vector.
  • the derived inter-prediction mode, reference index, and motion vector are the inter-prediction information of the normal prediction motion vector mode. This inter-prediction information is supplied to the motion compensation prediction unit 406 via the switch 408. The detailed configuration and processing of the normal predicted motion vector mode derivation unit 401 will be described later.
  • the normal merge mode derivation unit 402 derives a plurality of normal merge candidates, selects the normal merge candidates, and obtains the inter-prediction information of the normal merge mode. This inter-prediction information is supplied to the motion compensation prediction unit 406 via the switch 408. The detailed configuration and processing of the normal merge mode derivation unit 402 will be described later.
  • the sub-block prediction motion vector mode derivation unit 403 derives a plurality of sub-block prediction motion vector candidates, selects a sub-block prediction motion vector, and calculates the sum of the selected sub-block prediction motion vector and the decoded difference vector. And make it a motion vector.
  • the derived inter-prediction mode, reference index, and motion vector are the inter-prediction information of the sub-block prediction motion vector mode. This inter-prediction information is supplied to the motion compensation prediction unit 406 via the switch 408.
  • the sub-block merge mode derivation unit 404 derives a plurality of sub-block merge candidates, selects the sub-block merge candidates, and obtains the inter-prediction information of the sub-block merge mode. This inter-prediction information is supplied to the motion compensation prediction unit 406 via the switch 408.
  • the motion compensation prediction unit 406 performs inter-prediction for the reference image signal stored in the decoded image memory 208 based on the determined inter-prediction information.
  • the detailed configuration and processing of the motion compensation prediction unit 406 are the same as those of the motion compensation prediction unit 306 on the coding side.
  • the normal prediction motion vector mode derivation unit 301 of FIG. 17 includes a spatial prediction motion vector candidate derivation unit 321, a time prediction motion vector candidate derivation unit 322, a history prediction motion vector candidate derivation unit 323, a prediction motion vector candidate replenishment unit 325, and a normal motion. It includes a vector detection unit 326, a predicted motion vector candidate selection unit 327, and a motion vector subtraction unit 328.
  • the normal prediction motion vector mode derivation unit 401 of FIG. 23 includes a space prediction motion vector candidate derivation unit 421, a time prediction motion vector candidate derivation unit 422, a history prediction motion vector candidate derivation unit 423, a prediction motion vector candidate replenishment unit 425, and a prediction motion. It includes a vector candidate selection unit 426 and a motion vector addition unit 427.
  • FIG. 19 is a flowchart showing a normal motion vector mode derivation processing procedure by the normal motion vector mode derivation unit 301 on the coding side
  • FIG. 25 is a normal motion vector mode derivation process by the normal motion vector mode derivation unit 401 on the decoding side. It is a flowchart which shows a procedure.
  • the normal motion vector detection unit 326 detects the normal motion vector for each inter-prediction mode and reference index (step S100 in FIG. 19).
  • the difference motion vector of the motion vector used in the inter-prediction of the normal prediction motion vector mode is calculated for each of L0 and L1, respectively (steps S101 to S106 in FIG. 19).
  • the prediction mode PredMode of the block to be processed is inter-prediction (MODE_INTER) and the inter-prediction mode is L0 prediction (Pred_L0)
  • the prediction motion vector candidate list mvpListL0 of L0 is calculated and the prediction motion vector mvpL0 is selected.
  • the difference motion vector mvdL0 of the motion vector mvL0 of L0 is calculated.
  • the inter-prediction mode of the block to be processed is L1 prediction (Pred_L1)
  • the prediction motion vector candidate list mvpListL1 of L1 is calculated, the prediction motion vector mvpL1 is selected, and the difference motion vector mvdL1 of the motion vector mvL1 of L1 is calculated. ..
  • the prediction motion vector candidate list mvpList L0 of L0 is calculated, the prediction motion vector mvpL0 of L0 is selected, and L0.
  • the motion vector mvL0 of the motion vector mvL0 is calculated, the predicted motion vector candidate list mvpListL1 of L1 is calculated, the predicted motion vector mvpL1 of L1 is calculated, and the differential motion vector mvdL1 of the motion vector mvL1 of L1 is calculated. To do.
  • L0 and L1 are represented as a common LX.
  • X of LX is 0, and in the process of calculating the differential motion vector of L1, X of LX is 1.
  • the other list is represented as LY.
  • step S102 When the LX motion vector mvLX is used (step S102: YES in FIG. 19), the LX predicted motion vector candidates are calculated and the LX predicted motion vector candidate list mvpListLX is constructed (step S103 in FIG. 19). Multiple predicted motions in the space predicted motion vector candidate derived section 321 in the normal predicted motion vector mode derived section 301, the time predicted motion vector candidate derived section 322, the historical predicted motion vector candidate derived section 323, and the predicted motion vector candidate supplement section 325. Derivation of vector candidates and construction of predicted motion vector candidate list mvpListLX. The detailed processing procedure of step S103 of FIG. 19 will be described later with reference to the flowchart of FIG.
  • the predicted motion vector candidate selection unit 327 selects the LX predicted motion vector mvpLX from the LX predicted motion vector candidate list mvpListLX (step S104 in FIG. 19).
  • the predicted motion vector candidate list mvpListLX one element (the i-th element counting from 0) is represented as mvpListLX [i].
  • mvpListLX [i] the difference motion vector, which is the difference between the motion vector mvLX and the candidate mvpListLX [i] of each predicted motion vector stored in the predicted motion vector candidate list mvpListLX.
  • the code amount when these difference motion vectors are encoded is calculated for each element (predicted motion vector candidate) of the predicted motion vector candidate list mvpListLX.
  • the predicted motion vector candidate mvpListLX [i] having the minimum sign amount for each candidate of the predicted motion vector is selected as the predicted motion vector mvpLX, and the candidate mvpListLX [i] is selected.
  • the index i in the predicted motion vector candidate list mvpListLX is represented by a small number. Select the candidate mvpListLX [i] as the optimal predicted motion vector mvpLX and get its index i.
  • the motion vector subtraction unit 328 subtracts the selected LX predicted motion vector mvpLX from the LX motion vector mvLX.
  • mvdLX mvLX --mvpLX
  • the difference motion vector mvdLX of LX is calculated as (step S105 in FIG. 19).
  • the prediction motion vector candidate list mvpListL0 of L0 is calculated and the prediction motion is predicted. Select the vector mvpL0 and calculate the motion vector mvL0 of L0.
  • the inter-prediction mode of the block to be processed is L1 prediction (Pred_L1)
  • the prediction motion vector candidate list mvpListL1 of L1 is calculated, the prediction motion vector mvpL1 is selected, and the motion vector mvL1 of L1 is calculated.
  • the prediction motion vector candidate list mvpList L0 of L0 is calculated, the prediction motion vector mvpL0 of L0 is selected, and L0.
  • the motion vector mvL0 of L1 is calculated, the predicted motion vector candidate list mvpList L1 of L1 is calculated, the predicted motion vector mvpL1 of L1 is calculated, and the motion vector mvL1 of L1 is calculated respectively.
  • L0 and L1 are represented as a common LX.
  • LX represents an inter-prediction mode used for inter-prediction of the coded block to be processed.
  • X is 0 in the process of calculating the motion vector of L0, and X is 1 in the process of calculating the motion vector of L1.
  • the other reference list is represented as LY.
  • step S202 When the LX motion vector mvLX is used (step S202: YES in FIG. 25), the LX predicted motion vector candidates are calculated and the LX predicted motion vector candidate list mvpListLX is constructed (step S203 in FIG. 25). Multiple predicted motions in the space predicted motion vector candidate derived section 421, the time predicted motion vector candidate derived section 422, the historical predicted motion vector candidate derived section 423, and the predicted motion vector candidate supplement section 425 in the normal predicted motion vector mode derivation section 401. Calculate vector candidates and build a predicted motion vector candidate list mvpListLX. The detailed processing procedure of step S203 of FIG. 25 will be described later using the flowchart of FIG.
  • the predicted motion vector candidate selection unit 426 selects the predicted motion vector candidate mvpListLX [mvpIdxLX] corresponding to the index mvpIdxLX of the predicted motion vector decoded and supplied by the bit string decoding unit 201 from the predicted motion vector candidate list mvpListLX. It is taken out as the predicted motion vector mvpLX (step S204 in FIG. 25).
  • the motion vector addition unit 427 adds the LX differential motion vector mvdLX and the LX predicted motion vector mvpLX, which are decoded and supplied by the bit string decoding unit 201.
  • mvLX mvpLX + mvdLX
  • the motion vector mvLX of LX is calculated as (step S205 in FIG. 25).
  • FIG. 20 shows a normal predicted motion vector mode derivation having a function common to the normal predicted motion vector mode derivation unit 301 of the image coding device and the normal predicted motion vector mode derivation unit 401 of the image decoding device according to the embodiment of the present invention. It is a flowchart which shows the processing procedure of processing.
  • the normal prediction motion vector mode derivation unit 301 and the normal prediction motion vector mode derivation unit 401 include a prediction motion vector candidate list mvpListLX.
  • the predicted motion vector candidate list mvpListLX has a list structure, and is provided with a storage area for storing the predicted motion vector index indicating the location inside the predicted motion vector candidate list and the predicted motion vector candidate corresponding to the index as elements. .. The number of the predicted motion vector index starts from 0, and the predicted motion vector candidate is stored in the storage area of the predicted motion vector candidate list mvpListLX.
  • the predicted motion vector candidate list mvpListLX can register at least two predicted motion vector candidates (inter-prediction information). Further, 0 is set in the variable numCurrMvpCand indicating the number of predicted motion vector candidates registered in the predicted motion vector candidate list mvpListLX.
  • Spatial prediction motion vector candidate derivation units 321 and 421 derive prediction motion vector candidates from blocks (A0 or A1 in FIG. 11) adjacent to the left side.
  • the predicted motion vector mvLXA is derived and derived by referring to the inter-prediction information of the block adjacent to the left side, that is, the flag availableFlagLXA indicating whether or not the predicted motion vector candidate can be used, and the motion vector, reference index, etc.
  • Add mvLXA to the predicted motion vector candidate list mvpListLX (step S301 in FIG. 20).
  • X is 0 in the case of L0 prediction
  • X is 1 in the case of L1 prediction (the same applies hereinafter).
  • the spatial prediction motion vector candidate derivation units 321 and 421 derive the prediction motion vector candidates from the blocks (B0, B1, or B2 in FIG. 11) adjacent to the upper side.
  • the inter-prediction information of the adjacent blocks on the upper side that is, the flag availableFlagLXB indicating whether or not the predicted motion vector candidate can be used, and the predicted motion vector mvLXB are derived by referring to the motion vector, the reference index, etc. If the derived mvLXA and mvLXB are not equal, mvLXB is added to the predicted motion vector candidate list mvpListLX (step S302 in FIG. 20). The processing of steps S301 and S302 in FIG.
  • the reference index refIdxN (N indicates A or B, and so on) is derived.
  • the time prediction motion vector candidate derivation units 322 and 422 derive candidates for the prediction motion vector from the block in the picture whose time is different from the current processing target picture.
  • the flags availableFlagLXCol indicating whether the predicted motion vector candidates of the coded blocks of the pictures at different times are available, the motion vector mvLXCol, the reference index refIdxCol, and the reference list listCol are derived, and the mvLXCol is predicted as the motion vector candidate. Add to list mvpListLX (step S303 in FIG. 20).
  • time prediction motion vector candidate derivation unit 322 and 422 can be omitted in units of sequence (SPS), picture (PPS), or slice.
  • the history prediction motion vector candidate derivation units 323 and 423 add the history prediction motion vector candidates registered in the history prediction motion vector candidate list HmvpCandList to the prediction motion vector candidate list mvpListLX. (Step S304 in FIG. 20). The details of the registration processing procedure in step S304 will be described later with reference to the flowchart of FIG.
  • the predicted motion vector candidate supplementing units 325 and 425 add the predicted motion vector candidates having a predetermined value such as (0,0) until the predicted motion vector candidate list mvpListLX is satisfied (S305 in FIG. 20).
  • the normal merge mode derivation unit 302 of FIG. 18 includes a spatial merge candidate derivation unit 341, a time merge candidate derivation unit 342, an average merge candidate derivation unit 344, a history merge candidate derivation unit 345, a merge candidate replenishment unit 346, and a merge candidate selection unit 347. including.
  • the normal merge mode derivation unit 402 of FIG. 24 includes a spatial merge candidate derivation unit 441, a time merge candidate derivation unit 442, an average merge candidate derivation unit 444, a history merge candidate derivation unit 445, a merge candidate replenishment unit 446, and a merge candidate selection unit 447. including.
  • FIG. 21 describes a procedure of the normal merge mode derivation process having a function common to the normal merge mode derivation unit 302 of the image coding device and the normal merge mode derivation unit 402 of the image decoding device according to the embodiment of the present invention. It is a flowchart.
  • the normal merge mode derivation unit 302 and the normal merge mode derivation unit 402 include a merge candidate list mergeCandList.
  • Merge candidate list The mergeCandList has a list structure, and has a merge index indicating the location inside the merge candidate list and a storage area for storing the merge candidates corresponding to the indexes as elements. The number of the merge index starts from 0, and the merge candidates are stored in the storage area of the merge candidate list mergeCandList.
  • the merge candidate of the merge index i registered in the merge candidate list mergeCandList is represented by mergeCandList [i].
  • the merge candidate list mergeCandList can register at least 6 merge candidates (inter-prediction information). Further, 0 is set in the variable numCurrMergeCand indicating the number of merge candidates registered in the merge candidate list mergeCandList.
  • the processing target block is obtained from the coding information stored in the coding information storage memory 111 of the image coding device or the coding information storage memory 205 of the image decoding device.
  • Spatial merge candidates from each block (B1, A1, B0, A0, B2 in FIG. 11) adjacent to the block are derived in the order of B1, A1, B0, A0, B2, and the derived spatial merge candidates are derived as merge candidates.
  • Register in the list mergeCandList (step S401 in FIG. 21).
  • N indicating any of B1, A1, B0, A0, B2 or the time merge candidate Col is defined.
  • Flags availableFlagN indicating whether the inter-prediction information of block N can be used as a spatial merge candidate, reference index refIdxL0N of L0 of spatial merge candidate N and reference index refIdxL1N of L1, L0 prediction indicating whether L0 prediction is performed.
  • the merge candidate is derived without referring to the inter-prediction information of the block included in the coded block to be processed
  • the inter-prediction information of the block included in the coded block to be processed is derived. Spatial merge candidates using is not derived.
  • the time merge candidate derivation unit 342 and the time merge candidate derivation unit 442 derive the time merge candidates from the pictures at different times and register the derived time merge candidates in the merge candidate list mergeCandList (FIG. 21).
  • Step S402 Flags availableFlagCol indicating whether time merge candidates are available, L0 prediction flags predFlag L0Col indicating whether L0 prediction of time merge candidates is performed, and L1 prediction flags predFlagL1Col indicating whether L1 prediction is performed, and L0.
  • the motion vector mvL0Col and the motion vector mvL1Col of L1 are derived.
  • time merge candidate derivation unit 342 and the time merge candidate derivation unit 442 can be omitted in units of sequence (SPS), picture (PPS), or slice.
  • the history merge candidate derivation unit 345 and the history merge candidate derivation unit 445 register the history prediction motion vector candidates registered in the history prediction motion vector candidate list HmvpCandList in the merge candidate list mergeCandList (step S403 in FIG. 21). .. If the number of merge candidates numCurrMergeCand registered in the merge candidate list mergeCandList is smaller than the maximum number of merge candidates MaxNumMergeCand, the number of merge candidates registered in the merge candidate list mergeCandList numCurrMergeCand is limited to the maximum number of merge candidates MaxNumMergeCand. Historical merge candidates are derived and registered in the merge candidate list mergeCandList.
  • the average merge candidate derivation unit 344 and the average merge candidate derivation unit 444 derive the average merge candidate from the merge candidate list mergeCandList and add the derived average merge candidate to the merge candidate list mergeCandList (step of FIG. 21). S404). If the number of merge candidates numCurrMergeCand registered in the merge candidate list mergeCandList is smaller than the maximum number of merge candidates MaxNumMergeCand, the number of merge candidates registered in the merge candidate list mergeCandList numCurrMergeCand is limited to the maximum number of merge candidates MaxNumMergeCand.
  • the average merge candidate is derived and registered in the merge candidate list mergeCandList.
  • the average merge candidate has a motion vector obtained by averaging the motion vectors of the first merge candidate and the second merge candidate registered in the merge candidate list mergeCandList for each L0 prediction and L1 prediction. It is a good merge candidate.
  • the merge candidate replenishment unit 346 and the merge candidate replenishment unit 446 if the number of merge candidates numCurrMergeCand registered in the merge candidate list mergeCandList is smaller than the maximum number of merge candidates MaxNumMergeCand, they are registered in the merge candidate list mergeCandList.
  • the existing number of merge candidates numCurrMergeCand derives additional merge candidates up to the maximum number of merge candidates MaxNumMergeCand and registers them in the merge candidate list mergeCandList (step S405 in FIG. 21).
  • merge candidates whose motion vector has a value of (0,0) and whose prediction mode is L0 prediction (Pred_L0) are added.
  • a merge candidate whose motion vector has a value of (0,0) and whose prediction mode is bi-prediction (Pred_BI) is added.
  • the reference index when adding a merge candidate is different from the reference index already added.
  • the merge candidate selection unit 347 and the merge candidate selection unit 447 select the merge candidate from the merge candidates registered in the merge candidate list mergeCandList.
  • the merge candidate selection unit 347 on the coding side selects the merge candidate by calculating the code amount and the strain amount, and sets the merge index indicating the selected merge candidate and the inter-prediction information of the merge candidate in the inter-prediction mode determination unit. It is supplied to the motion compensation prediction unit 306 via the 305.
  • the merge candidate selection unit 447 on the decoding side selects the merge candidate based on the decoded merge index, and supplies the selected merge candidate to the motion compensation prediction unit 406.
  • FIG. 26 is a flowchart illustrating a procedure for initializing / updating the history prediction motion vector candidate list.
  • the history prediction motion vector candidate list HmvpCandList is updated by the coded information storage memory 111 and the coded information storage memory 205.
  • the history prediction motion vector candidate list update unit may be installed in the inter prediction unit 102 and the inter prediction unit 203 to update the history prediction motion vector candidate list HmvpCandList.
  • the history prediction motion vector candidate list HmvpCandList is set when the normal prediction motion vector mode or the normal merge mode is selected by the prediction method determination unit 105.
  • the history prediction motion vector candidate list HmvpCandList is updated when the prediction information decoded by the bit string decoding unit 201 is in the normal prediction motion vector mode or the normal merge mode.
  • the inter-prediction information used when performing inter-prediction in the normal prediction motion vector mode or the normal merge mode is registered in the history prediction motion vector candidate list HmvpCandList as the inter-prediction information candidate hMvpCand.
  • the inter-prediction information candidate hMvpCand includes the reference index refIdxL0 of L0 and the reference index refIdxL1 of L1, the L0 prediction flag predFlag L0 indicating whether L0 prediction is performed, and the L1 prediction flag predFlag L1 indicating whether L1 prediction is performed.
  • the motion vector mvL0 of L0 and the motion vector mvL1 of L1 are included.
  • Inter-prediction information candidate among the elements that is, inter-prediction information registered in the history prediction motion vector candidate list HmvpCandList provided in the coding information storage memory 111 on the coding side and the coding information storage memory 205 on the decoding side. If the inter-prediction information with the same value as hMvpCand exists, delete the element from the historical prediction motion vector candidate list HmvpCandList. On the other hand, if there is no inter-prediction information with the same value as the inter-prediction information candidate hMvpCand, the first element of the historical prediction motion vector candidate list HmvpCandList is deleted, and the inter-prediction information candidate is at the end of the historical prediction motion vector candidate list HmvpCandList. Add hMvpCand.
  • the number of elements of the history prediction motion vector candidate list HmvpCandList provided in the coding information storage memory 111 on the coding side and the coding information storage memory 205 on the decoding side of the present invention is 6.
  • the history prediction motion vector candidate list HmvpCandList for each slice is initialized (step S2101 in FIG. 26). Empty all elements of the history prediction motion vector candidate list HmvpCandList at the beginning of the slice, and the number of history prediction motion vector candidates registered in the history prediction motion vector candidate list HmvpCandList (current number of candidates) The value of NumHmvpCand becomes 0. Set.
  • the initialization of the history prediction motion vector candidate list HmvpCandList is performed in slice units (first coded block of slices), it may be performed in picture units, tile units, or tree block line units.
  • a FALSE (false) value is set in the flag electricalCandExist indicating whether or not the same candidate exists, and 0 is set in the removal target index removeIdx indicating the deletion target candidate (step S2103 in FIG. 26).
  • Step S2104 in FIG. 26 Determine whether or not the inter-prediction information candidate hMvpCand to be registered exists (step S2104 in FIG. 26).
  • the prediction method determination unit 105 on the coding side determines the normal prediction motion vector mode or the normal merge mode, or when the bit string decoding unit 201 on the decoding side decodes the decoding as the normal prediction motion vector mode or the normal merge mode.
  • the inter-prediction information be the inter-prediction information candidate hMvpCand to be registered.
  • the coding side prediction method determination unit 105 determines the intra prediction mode, subblock prediction motion vector mode or subblock merge mode, or the decoding side bit string decoding unit 201 determines the intra prediction mode, subblock prediction motion vector mode.
  • step S2104 NO in FIG. 26. If the inter-prediction information candidate hMvpCand to be registered exists, the process of step S2105 or less is performed (step S2104: YES in FIG. 26).
  • FIG. 27 is a flowchart of the same element confirmation processing procedure. Number of history prediction motion vector candidates When the value of NumHmvpCand is 0 (step S2121: NO in FIG. 27), the history prediction motion vector candidate list HmvpCandList is empty and the same candidate does not exist, so steps S2122 to S2125 in FIG. 27 are skipped. Then, the same element confirmation processing procedure is terminated.
  • step S2123 When the value of the number of historically predicted motion vector candidates NumHmvpCand is larger than 0 (YES in step S2121 in FIG. 27), the process of step S2123 is repeated from 0 to NumHmvpCand-1 in the historical predicted motion vector index hMvpIdx (step in FIG. 27). S2122 to S2125). First, it is compared whether or not the hMvpCandList [hMvpIdx], which is the xth element of the historical prediction motion vector candidate list counting from 0, is the same as the inter-prediction information candidate hMvpCand (step S2123 in FIG. 27). If they are the same (step S2123: YES in FIG.
  • a TRUE (true) value is set in the flag electricalCandExist indicating whether or not the same candidate exists, and the removal target index removeIdx indicating the position of the element to be deleted is currently set.
  • FIG. 28 is a flowchart of the element shift / addition processing procedure of the history prediction motion vector candidate list HmvpCandList in step S2106 of FIG.
  • First it is determined whether to remove the elements stored in the historical prediction motion vector candidate list HmvpCandList and then add a new element, or to add a new element without removing the elements. Specifically, whether or not TRUE (true) or NumHmvpCand is 6 is compared with the flag identicalCandExist indicating whether or not the same candidate exists (step S2141 in FIG. 28).
  • step S2141 YES in FIG. 28
  • the historical prediction motion vector candidate list HmvpCandList Add a new element after removing the element stored in.
  • Set the initial value of index i to the value of removeIdx + 1.
  • the element shift process in step S2143 is repeated from this initial value to NumHmvpCand. (Steps S2142 to S2144 in FIG. 28).
  • the element is shifted forward (step S2143 in FIG.
  • step S2142 the inter-prediction information candidate hMvpCand is added to the (NumHmvpCand-1) th HmvpCandList [NumHmvpCand-1] counting from 0, which corresponds to the end of the history prediction motion vector candidate list (step S2145 in FIG. 28), and this history prediction is performed.
  • the element shift / addition process of the motion vector candidate list HmvpCandList is completed.
  • TRUE (true) and NumHmvpCand do not satisfy any of the conditions 6 in the flag electricalCandExist indicating whether or not the same candidate exists (step S2141: NO in FIG.
  • the historical prediction motion vector candidate list HmvpCandList it is stored in the historical prediction motion vector candidate list HmvpCandList.
  • the inter-prediction information candidate hMvpCand is added to the end of the history prediction motion vector candidate list without excluding the elements (step S2146 in FIG. 28).
  • the last of the historical prediction motion vector candidate list is the HmvpCandList [NumHmvpCand] which is the NumHmvpCand th from 0.
  • NuMHmvpCand is incremented by 1, and the element shift and additional processing of this history prediction motion vector candidate list HmvpCandList are completed.
  • FIGS. 31A to 31C are diagrams for explaining an example of the update process of the history prediction motion vector candidate list.
  • Fig. 1 When adding a new element to the registered history prediction motion vector candidate list HmvpCandList with 6 elements (inter-prediction information), compare it with the new inter-prediction information in order from the element before the history prediction motion vector candidate list HmvpCandList.
  • HMVP2 deletes the element HMVP2 from the history prediction motion vector candidate list HmvpCandList and the rear element HMVP3 ⁇ Shift (copy) HMVP5 forward one by one, add a new element to the end of the history prediction motion vector candidate list HmvpCandList (Fig. 31B), and complete the update of the history prediction motion vector candidate list HmvpCandList (Fig. 31C). ).
  • FIG. 29 is a flowchart illustrating a history prediction motion vector candidate derivation processing procedure.
  • step S2201 in FIG. 29 When the current number of predicted motion vector candidates numCurrMvpCand is less than 2, which is the maximum number of elements in the predicted motion vector candidate list mvpListLX, and when the value of the number of historical predicted motion vector candidates NumHmvpCand is greater than 0 (step S2201 in FIG. 29). YES), the processes of steps S2202 to S2209 of FIG. 29 are performed.
  • steps S2203 to S2208 of FIG. 29 are repeated until the index i is 1 to 4 and the number of historical prediction motion vector candidates numCheckedHMVPCand, whichever is smaller (steps S2202 to S2209 of FIG. 29).
  • the current number of predicted motion vector candidates numCurrMvpCand is 2 or more, which is the maximum number of elements of the predicted motion vector candidate list mvpListLX (steps S2203: NO in FIG. 29)
  • the processing of steps S2204 to S2209 in FIG. 29 is omitted.
  • the history prediction motion vector candidate derivation processing procedure ends.
  • step S2203 When the current number of predicted motion vector candidates numCurrMvpCand is smaller than 2, which is the maximum number of elements of the predicted motion vector candidate list mvpListLX (step S2203: YES in FIG. 29), the processes after step S2204 in FIG. 29 are performed.
  • steps S2205 to S2207 are performed for Y's 0 and 1 (L0 and L1), respectively (steps S2204 to S2208 in FIG. 29).
  • the processing of steps S2206 to S2209 in FIG. 29 is omitted.
  • the history prediction motion vector candidate derivation processing procedure ends.
  • step S2205 YES in FIG. 29
  • the processes after step S2206 in FIG. 29 are performed.
  • Step S2206 add the LY motion vector of the historical prediction motion vector candidate HmvpCandList [NumHmvpCand-i] to the numCurrMvpCand th element mvpListLX [numCurrMvpCand] counting from 0 in the predicted motion vector candidate list (step in FIG. 29).
  • step S2207 the number of current predicted motion vector candidates numCurrMvpCand is incremented by 1.
  • the additional processing of step S2207 is skipped.
  • steps S2205 to S2207 of FIG. 29 are performed at both L0 and L1 (steps S2204 to S2208 of FIG. 29).
  • the processes after step S2203 are performed again (steps S2202 to S2209 in FIG. 29).
  • step S403 in FIG. 21 which is a process common to the history merge candidate derivation unit 345 of the normal merge mode derivation unit 302 on the coding side and the history merge candidate derivation unit 445 of the normal merge mode derivation unit 402 on the decoding side.
  • the procedure for deriving the history merge candidate from the history merge candidate list HmvpCandList will be described in detail.
  • FIG. 30 is a flowchart illustrating a history merge candidate derivation processing procedure.
  • the initialization process is performed (step S2301 in FIG. 30).
  • the initial value of the index hMvpIdx is set to 1, and the additional processing from step S2303 to step S2310 in FIG. 30 is repeated from this initial value to NuMHmvpCand (steps S2302 to S2311 in FIG. 30). If the number of elements registered in the current merge candidate list numCurrMergeCand is not less than or equal to (maximum number of merge candidates MaxNumMergeCand-1), merge candidates have been added to all elements in the merge candidate list, so this history merge candidate derivation The process ends (NO in step S2303 in FIG. 30).
  • step S2304 If the number of elements registered in the current merge candidate list numCurrMergeCand is (maximum number of merge candidates MaxNumMergeCand-1) or less, the processing in step S2304 and subsequent steps is performed. A FALSE value is set in sameMotion (step S2304 in FIG. 30). Subsequently, the initial value of the index i is set to 0, and the processes of steps S2306 and S2307 of FIG. 30 are performed from this initial value to numOrigMergeCand-1 (S2305 to S2308 of FIG. 30).
  • step S2309 in FIG. 30 when sameMotion is FALSE (false) (step S2309 in FIG. 30). YES), that is, the element HmvpCandList [NumHmvpCand --hMvpIdx] of the (NumHmvpCand --hMvpIdx) th element in the history prediction motion vector candidate list does not exist in the mergeCandList, so the mergeCandList [numCurrMergeCand] of the merge candidate list Add the (NumHmvpCand --hMvpIdx) th element HmvpCandList [NumHmvpCand --hMvpIdx] counting from 0 in the motion vector candidate list, and increment numCurrMergeCand by 1 (step S2310 in FIG.
  • the index hMvpIdx is incremented by 1 (step S2302 in FIG. 30), and the iterative processing of steps S2302 to S2311 in FIG. 30 is repeated.
  • step S404 of FIG. 21 which is a process common to the average merge candidate derivation unit 344 of the normal merge mode derivation unit 302 on the coding side and the average merge candidate derivation unit 444 of the normal merge mode derivation unit 402 on the decoding side.
  • the method of deriving the average merge candidate which is a procedure, will be described in detail.
  • FIG. 38 is a flowchart illustrating a procedure for deriving the average merge candidate.
  • the initialization process is performed (step S1301 in FIG. 38).
  • Step S1302 to S1303 in FIG. 38 If the number of elements registered in the current merge candidate list numCurrMergeCand is not less than or equal to (maximum number of merge candidates MaxNumMergeCand-1), merge candidates have been added to all elements in the merge candidate list, so this history merge candidate derivation The process ends (step S1304 in FIG. 38). If the number of elements registered in the current merge candidate list numCurrMergeCand is (maximum number of merge candidates MaxNumMergeCand-1) or less, the processing of step S1305 and subsequent steps is performed.
  • step S1305 in FIG. 38 It is determined whether or not the i-th motion information mergeCandList [i] of the merge candidate list and the j-th motion information mergeCandList [j] of the merge candidate list are both invalid (step S1305 in FIG. 38), and both are invalid. In that case, move on to the next element without deriving the average merge candidates of mergeCandList [i] and mergeCandList [j]. If both mergeCandList [i] and mergeCandList [j] are not invalid, the following processing is repeated with X as 0 and 1 (steps S1306 to 1314 in FIG. 38).
  • step S1309 the average merge candidate of the LX prediction having the motion vector of the LX prediction obtained by averaging the movement vectors of the LX prediction of [j] and the reference index of the LX prediction of mergeCandList [i] is derived and set to the LX prediction of the averageCand, and the averageCand Enable LX prediction (step S1309 in FIG. 38).
  • step S1308 of FIG. the average merge candidate of the LX prediction having the motion vector of the LX prediction obtained by averaging the movement vectors of the LX prediction of [j] and the reference index of the LX prediction of mergeCandList [i] is derived and set to the LX prediction of the averageCand, and the averageCand Enable LX prediction (step S1309 in FIG. 38).
  • mergeCandList [i] The average merge candidate of the LX prediction having the motion vector and the reference index of the LX prediction is derived and set to the LX prediction of the averageCand, and the LX prediction of the averageCand is valid (step S1310 in FIG. 38). If the LX prediction of mergeCandList [i] is not valid in step S1307 of FIG. 38, it is determined whether or not the LX prediction of mergeCandList [j] is valid (step S1311 of FIG. 38).
  • step S1312 the LX prediction of mergeCandList [j] is valid, that is, if the LX prediction of mergeCandList [i] is invalid and the LX prediction of mergeCandList [j] is valid, then the motion vector of the LX prediction of mergeCandList [j]
  • the average merge candidate of the LX prediction having the reference index is derived and set to the LX prediction of the averageCand, and the LX prediction of the averageCand is enabled (step S1312 in FIG. 38). In step S1311 of FIG.
  • the average merge candidate averageCand of the L0 prediction, L1 prediction or bi-prediction generated as described above is added to the mergeCandList [numCurrMergeCand] of the numCurrMergeCand th numCurrMergeCand of the merge candidate list, and the numCurrMergeCand is incremented by 1 (step S1315 in FIG. 38). This completes the process of deriving the average merge candidate.
  • the average merge candidate is averaged for each of the horizontal component of the motion vector and the vertical component of the motion vector.
  • the motion compensation prediction unit 306 acquires the position and size of the block currently subject to prediction processing in coding. Further, the motion compensation prediction unit 306 acquires the inter prediction information from the inter prediction mode determination unit 305. The reference index and motion vector are derived from the acquired inter-prediction information, and the reference picture specified by the reference index in the decoded image memory 104 is moved from the same position as the image signal of the coded block by the motion vector. A prediction signal is generated after acquiring the image signal of.
  • the inter-prediction mode in inter-prediction is prediction from a single reference picture such as L0 prediction or L1 prediction
  • the prediction signal acquired from one reference picture is used as the motion compensation prediction signal
  • the inter-prediction mode is dual.
  • the prediction mode is prediction from two reference pictures such as prediction
  • the weighted average of the prediction signals acquired from the two reference pictures is used as the motion compensation prediction signal
  • the motion compensation prediction signal is used to determine the prediction method.
  • Supply to unit 105 the ratio of the weighted averages of the biprediction is 1: 1, but weighted averages may be performed using other ratios.
  • the weighting ratio may be increased as the distance between the picture to be predicted and the reference picture is closer. Further, the weighting ratio may be calculated by using the correspondence table between the combination of picture intervals and the weighting ratio.
  • the motion compensation prediction unit 406 has the same function as the motion compensation prediction unit 306 on the coding side.
  • the motion compensation prediction unit 406 transfers the inter-prediction information from the normal prediction motion vector mode derivation unit 401, the normal merge mode derivation unit 402, the subblock prediction motion vector mode derivation unit 403, and the subblock merge mode derivation unit 404 to switch 408. Get through.
  • the motion compensation prediction unit 406 supplies the obtained motion compensation prediction signal to the decoded image signal superimposition unit 207.
  • ⁇ About inter-prediction mode The process of making a prediction from a single reference picture is defined as a simple prediction, and in the case of a single prediction, either one of the two reference pictures registered in the reference lists L0 and L1, which is L0 prediction or L1 prediction, is used. Make a prediction.
  • FIG. 33 is a simple prediction and shows a case where the reference picture (RefL0Pic) of L0 is at a time before the picture to be processed (CurPic).
  • FIG. 34 shows a case where the reference picture of the L0 prediction is at a time after the processing target picture in the simple prediction.
  • the reference picture for the L0 prediction in FIGS. 33 and 34 can be replaced with the reference picture for the L1 prediction (RefL1Pic) to perform simple prediction.
  • FIG. 35 shows a case where the reference picture of the L0 prediction is at a time before the processing target picture and the reference picture of the L1 prediction is at a time after the processing target picture in the bi-prediction.
  • FIG. 36 shows a case where the reference picture of the L0 prediction and the reference picture of the L1 prediction are at a time before the processing target picture in the bi-prediction.
  • FIG. 37 shows a case where the reference picture of the L0 prediction and the reference picture of the L1 prediction are at a time after the processing target picture in the bi-prediction.
  • L0 prediction and L1 prediction may be performed using the same reference picture. It should be noted that the determination of whether the motion compensation prediction is performed by simple prediction or double prediction is determined based on, for example, information (for example, a flag) indicating whether or not to use L0 prediction and whether or not to use L1 prediction. To.
  • ⁇ About reference index> In the embodiment of the present invention, in order to improve the accuracy of motion compensation prediction, it is possible to select the optimum reference picture from a plurality of reference pictures in motion compensation prediction. Therefore, the reference picture used in the motion compensation prediction is used as the reference index, and the reference index is encoded in the bit stream together with the difference vector.
  • the motion compensation prediction unit 306 is used when the inter prediction information by the normal prediction motion vector mode derivation unit 301 is selected in the inter prediction mode determination unit 305. Acquires this inter-prediction information from the inter-prediction mode determination unit 305, derives the inter-prediction mode, reference index, and motion vector of the block currently being processed, and generates a motion compensation prediction signal. The generated motion compensation prediction signal is supplied to the prediction method determination unit 105.
  • the motion compensation prediction unit 406 is normally used when the switch 408 is connected to the normal prediction motion vector mode derivation unit 401 in the process of decoding, as shown by the inter prediction unit 203 on the decoding side of FIG.
  • the inter-prediction information by the prediction motion vector mode derivation unit 401 is acquired, the inter-prediction mode, the reference index, and the motion vector of the block currently being processed are derived, and the motion compensation prediction signal is generated.
  • the generated motion compensation prediction signal is supplied to the decoded image signal superimposing unit 207.
  • the motion compensation prediction unit 306 is used when the inter-prediction information by the normal merge mode derivation unit 302 is selected in the inter-prediction mode determination unit 305.
  • This inter-prediction information is acquired from the inter-prediction mode determination unit 305, the inter-prediction mode, reference index, and motion vector of the block currently being processed are derived, and a motion compensation prediction signal is generated.
  • the generated motion compensation prediction signal is supplied to the prediction method determination unit 105.
  • the motion compensation prediction unit 406 is in the normal merge mode when the switch 408 is connected to the normal merge mode derivation unit 402 in the decoding process, as shown by the inter prediction unit 203 on the decoding side in FIG.
  • the inter-prediction information by the derivation unit 402 is acquired, the inter-prediction mode, the reference index, and the motion vector of the block currently being processed are derived, and the motion compensation prediction signal is generated.
  • the generated motion compensation prediction signal is supplied to the decoded image signal superimposing unit 207.
  • ⁇ Motion compensation processing based on subblock prediction motion vector mode> In the motion compensation prediction unit 306, as shown by the inter prediction unit 102 on the coding side of FIG. 16, when the inter prediction information by the subblock prediction motion vector mode derivation unit 303 is selected in the inter prediction mode determination unit 305.
  • the inter-prediction information is acquired from the inter-prediction mode determination unit 305, the inter-prediction mode, the reference index, and the motion vector of the block currently being processed are derived, and the motion compensation prediction signal is generated.
  • the generated motion compensation prediction signal is supplied to the prediction method determination unit 105.
  • the motion compensation prediction unit 406 as shown by the inter-prediction unit 203 on the decoding side of FIG. 22, when the switch 408 is connected to the subblock prediction motion vector mode derivation unit 403 in the decoding process,
  • the sub-block prediction motion vector mode derivation unit 403 acquires the inter-prediction information, derives the inter-prediction mode, the reference index, and the motion vector of the block currently being processed, and generates a motion compensation prediction signal.
  • the generated motion compensation prediction signal is supplied to the decoded image signal superimposing unit 207.
  • the motion compensation prediction unit 306 is used when the inter-prediction information by the sub-block merge mode derivation unit 304 is selected in the inter-prediction mode determination unit 305. , This inter-prediction information is acquired from the inter-prediction mode determination unit 305, the inter-prediction mode, reference index, and motion vector of the block currently being processed are derived, and the motion compensation prediction signal is generated. The generated motion compensation prediction signal is supplied to the prediction method determination unit 105.
  • the motion compensation prediction unit 406 is a subblock when the switch 408 is connected to the subblock merge mode derivation unit 404 in the decoding process, as shown by the inter prediction unit 203 on the decoding side of FIG.
  • the inter-prediction information by the merge mode derivation unit 404 is acquired, the inter-prediction mode, the reference index, and the motion vector of the block currently being processed are derived, and the motion compensation prediction signal is generated.
  • the generated motion compensation prediction signal is supplied to the decoded image signal superimposing unit 207.
  • motion compensation by the affine model can be used based on the following flags.
  • the following flags are reflected in the following flags based on the inter-prediction conditions determined by the inter-prediction mode determination unit 305 in the coding process, and are encoded in the bit stream.
  • Sps_affine_enabled_flag indicates whether or not motion compensation by the affine model can be used in inter-prediction. If sps_affine_enabled_flag is 0, it is suppressed so that it is not motion compensation by the affine model in sequence units. Also, inter_affine_flag and cu_affine_type_flag are not transmitted in the CU (encoded block) syntax of the encoded video sequence. If sps_affine_enabled_flag is 1, motion compensation by the affine model can be used in the coded video sequence.
  • Sps_affine_type_flag indicates whether or not motion compensation by the 6-parameter affine model can be used in inter-prediction. If sps_affine_type_flag is 0, it is suppressed so that it is not motion compensation by the 6-parameter affine model. Also, cu_affine_type_flag is not transmitted in the CU syntax of the encoded video sequence. If sps_affine_type_flag is 1, motion compensation by the 6-parameter affine model can be used in the coded video sequence. If sps_affine_type_flag does not exist, it shall be 0.
  • inter_affine_flag When decoding P or B slices, if inter_affine_flag is 1 in the CU currently being processed, an affine model is used to generate a motion compensation prediction signal for the CU currently being processed. Motion compensation is used. If inter_affine_flag is 0, the affine model is not used for the CU currently being processed. If inter_affine_flag does not exist, it shall be 0.
  • the motion compensation prediction signal is generated using the reference index and motion vector to be processed in subblock units.
  • the 4-parameter affine model is a mode in which the motion vector of a subblock is derived from the four parameters of the horizontal component and the vertical component of the motion vector of each of the two control points, and the motion is compensated for each subblock.
  • FIG. 32A is an example in which the effective reference area is determined by using the coded tree block unit as the intra-block copy reference block.
  • Reference numerals 500, 501, 502, 503, and 504 in FIG. 32A are coded tree blocks, and 504 is a coded tree block to be processed.
  • Reference numeral 505 is a coded block to be processed.
  • the processing order of the coded tree blocks is 500, 501, 502, 503, 504.
  • the three coding tree blocks 501, 502, and 503 processed immediately before the coding tree block 504 including the processing target coding block 505 are set as effective reference areas of the processing target coding block 505.
  • FIG. 32B is an example in which the effective reference area is determined by using the unit obtained by dividing the coded tree block into four as the intra-block copy reference block.
  • Reference numerals 515 and 516 in FIG. 32B are coded tree blocks, and 516 is a coded tree block to be processed.
  • the coded tree block 515 is divided into 506, 507, 508, and 509, and 516 is divided into 510, 511, 512, and 513.
  • Reference numeral 514 is a coded block to be processed.
  • the processing order of the intra-block copy reference block is 506, 507, 508, 509, 510, 511, 512, 513.
  • the three intra-block copy reference blocks 508, 509, and 510 processed immediately before the intra-block copy reference block 511 including the processing target coding block 514 are set as the effective reference area of the processing target coding block 514.
  • Intrablock copy Intrablock copy including the coded tree block processed before the reference block 508 and the coded block 514 to be processed, regardless of whether the processing is completed before the coded block 514 to be processed. All the areas included in the reference block 511 are invalid reference areas.
  • FIG. 43 is a block diagram for explaining the configuration of the intra-block copy prediction unit 352 on the coding side.
  • the intra block copy prediction unit 352 of FIG. 43 is at least an IBC space block vector candidate derivation unit 371, an IBC history block vector candidate derivation unit 372, an IBC prediction block vector replenishment unit 373, an IBC merge candidate selection unit 374, and an IBC block vector detection unit.
  • IBC prediction block vector candidate selection unit 376, IBC prediction mode determination unit 377, block vector subtraction unit 378 are included.
  • the intra-block copy prediction unit 352 of FIG. 43 may further include a reference position correction unit 380 and a block vector subtraction unit 381.
  • FIG. 44 is a block diagram for explaining the configuration of the intra-block copy prediction unit 362 on the decoding side.
  • the intra-block copy prediction unit 362 of FIG. 44 has at least an IBC space block vector candidate derivation unit 471, an IBC history block vector candidate derivation unit 472, an IBC prediction block vector replenishment unit 473, an IBC merge candidate selection unit 474, a switch 475, and an IBC prediction. It includes a block vector candidate selection unit 476, a block copy unit 477, and a block vector addition unit 478.
  • intra-block copy prediction unit 362 of FIG. 44 may further include a reference position correction unit 480.
  • the IBC spatial block vector candidate derivation units 371 and 471 derive the candidates for the predicted block vector in the spatial direction that have been decoded and can be referred to in the intra block copy, and construct the predicted block vector candidate list.
  • the IBC history block vector candidate derivation units 372 and 472 derive the prediction block vector candidates from the history block vector candidates registered in the history block vector candidate list, and construct the prediction block vector candidate list.
  • the IBC prediction block vector replenishment units 373 and 473 build a prediction block vector candidate list by adding block vectors having predetermined values until the prediction block vector candidate list is satisfied (0,0).
  • the IBC merge candidate selection units 374 and 474 select one from the intra-block merge candidates registered in the intra-block merge candidate list.
  • the IBC block vector detection unit 375 detects the block vector from the decoded and referenceable area in the intra block copy.
  • the IBC prediction block vector candidate selection units 376 and 476 select the prediction block vector from the prediction block vector candidate list.
  • the IBC prediction mode determination unit 377 selects the prediction mode by calculating the code amount and the strain amount.
  • the prediction mode can be selected from the prediction intra-block copy mode and the merge intra-block copy mode.
  • the predictive merge intra-block copy mode may be selectable.
  • the block vector subtraction units 378 and 381 acquire the block vector and the predicted block vector, and calculate the difference block vector.
  • the reference position correction units 380 and 480 perform processing for correcting the reference position when the prediction block vector to be processed is trying to refer to the outside of the referenceable area.
  • Switch 475 selects the supply destination of various information to be supplied according to the prediction mode in the intra-block copy processing.
  • the block vector addition unit 478 acquires the predicted block vector and the difference block vector, and calculates the block vector.
  • the block copy unit 477 acquires the decoded image at the reference position from the decoded image memory based on the block vector and supplies it.
  • Predictive intra-block copy processing is realized by configuring with each of the above parts. A more detailed description of the intra-block copy prediction units 352 and 362 will be described later.
  • the block vector detection unit 375 detects the block vector mvL, which is the motion vector of the luminance block (step S4500 in FIG. 45).
  • the difference block vector of the block vector used in the predicted block vector mode is calculated (steps S4501 to S4503 in FIG. 45).
  • step S4501 in FIG. 45 Calculate the candidates for the predicted block vector and construct the block vector candidate list mvpList (step S4501 in FIG. 45).
  • a plurality of prediction block vector candidates are derived by the IBC space block vector candidate derivation unit 371, the IBC history block vector candidate derivation unit 372, and the IBC prediction block vector candidate supplementation unit 373 in FIG. 43 to construct a prediction block vector candidate list mvpList. ..
  • the detailed processing procedure of step S4501 of FIG. 45 will be described later using the flowchart of FIG. 48.
  • the IBC prediction block vector candidate selection unit 376 of FIG. 43 selects the prediction block vector mvpL from the prediction block vector candidate list mvpListL (step S4502 of FIG. 45). Calculate each difference block vector which is the difference between the block vector mvL and the candidate mvpListL [i] of each prediction block vector stored in the prediction block vector candidate list mvpListL. The amount of code when these difference block vectors are encoded is calculated for each element of the predicted block vector candidate list mvpListL.
  • the prediction block vector candidate mvpListL [i] having the minimum sign amount for each candidate of the prediction block vector is selected as the prediction block vector mvpL, and the candidate mvpListL [i] is selected.
  • Get index i When there are multiple candidates for the predicted block vector that is the smallest generated code amount in the predicted block vector candidate list mvpListL, the predicted block vector whose index i in the predicted block vector candidate list mvpListL is represented by a small number.
  • the candidate mvpListL [i] of is selected as the optimal prediction block vector mvpL, and its index i is acquired.
  • the block vector subtraction unit 378 of FIG. 43 subtracts the predicted block vector mvpL selected from the block vector mvL.
  • mvdL mvL --mvpL
  • the difference block vector mvdL is calculated as (step S4503 in FIG. 45).
  • the prediction block vector mode processing procedure on the decoding side will be described with reference to FIGS. 44 and 46.
  • the IBC space prediction block vector candidate derivation unit 471, the IBC history block vector candidate derivation unit 472, and the IBC prediction block vector replenishment unit 473 of FIG. 44 calculate the block vector used in the prediction block vector mode (FIG. 46). Steps S4600 to S4602). Specifically, the prediction block vector candidate list mvpListL is calculated, the prediction block vector mvpL is selected, and the block vector mvL is calculated.
  • Prediction block vector candidates are calculated and a prediction block vector candidate list mvpListL is constructed (step S4601 in FIG. 46).
  • IBC space block vector candidate derivation unit 471, IBC history block vector candidate derivation unit 472, and IBC block vector replenishment unit 473 in the intra block copy prediction unit 362 calculate multiple prediction block vector candidates, and the prediction block vector candidate list. Build mvpListL.
  • the IBC prediction block vector candidate selection unit 476 obtains the prediction block vector candidate mvpListL [mvpIdxL] corresponding to the prediction block vector index mvpIdxL decoded and supplied by the bit string decoding unit 201 from the prediction block vector candidate list mvpListL. Extracted as the selected predicted block vector mvpL (step S4601 in FIG. 46).
  • FIG. 48 shows a processing procedure of the prediction intra-block copy mode derivation process having a function common to the intra-block copy prediction unit 352 of the image coding device and the intra-block copy prediction unit 362 of the image decoding device according to the embodiment of the present invention. It is a flowchart showing.
  • the intra-block copy prediction unit 352 and the intra-block copy prediction unit 362 include a prediction block vector candidate list mvpListL.
  • the predicted block vector candidate list mvpListL has a list structure, and is provided with a predicted block vector index indicating the location inside the predicted block vector candidate list and a storage area for storing the predicted block vector candidates corresponding to the index as elements.
  • the number of the prediction block vector index starts from 0, and the prediction block vector candidate is stored in the storage area of the prediction block vector candidate list mvpListL.
  • the prediction block vector candidate list mvpListL can register three prediction block vector candidates. Further, 0 is set in the variable numCurrMvpIbcCand indicating the number of predicted block vector candidates registered in the predicted block vector candidate list mvpListL.
  • the IBC spatial block vector candidate derivation units 371 and 471 derive candidates for the predicted block vector from the blocks adjacent to the left side (step S4801 in FIG. 48).
  • the flag availableFlagLA indicating whether or not the predicted block vector candidate of the block (A0 or A1) adjacent to the left side is available and the block vector mvLA are derived, and mvLA is added to the predicted block vector candidate list mvpListL.
  • the IBC spatial block vector candidate derivation units 371 and 471 derive candidates for the predicted block vector from the blocks (B0, B1 or B2) adjacent to the upper side (step S4802 in FIG. 48).
  • the flag availableFlagLB indicating whether the predicted motion vector candidates of the adjacent blocks on the upper side are available and the block vector mvLB are derived, and if mvLA and mvLB are not equal, mvLB is added to the predicted block vector candidate list mvpListL. to add.
  • the processing of steps S4801 and S4802 of FIG. 48 is common except that the position and number of adjacent blocks to be referred to are different, and the flag availableFlagLN indicating whether or not the predicted block vector candidate of the coded block can be used, and the motion vector mvLN (N is A or B, and so on) is derived.
  • the IBC history block vector candidate derivation units 372 and 472 add the history block vector candidates registered in the history block vector candidate list HmvpIbcCandList to the prediction block vector candidate list mvpListL. (Step S4803 in FIG. 48).
  • the motion vector is the block vector
  • the reference index list is L0
  • the history prediction motion vector candidate list HmvpCandList is the history block vector candidate list. Since it is sufficient if the operation is the same as that of HmvpIbcCandList, the description is omitted.
  • the IBC prediction block vector replenishment units 373 and 473 add block vectors having predetermined values, such as until the prediction block vector candidate list mvpListL is satisfied (0,0) (step S4804 in FIG. 48).
  • the intra-block copy prediction unit 352 of FIG. 43 includes an IBC space block vector candidate derivation unit 371, an IBC history block vector candidate derivation unit 372, an IBC block vector replenishment unit 373, a reference position correction unit 380, an IBC merge candidate selection unit 374, and an IBC. Prediction mode determination unit 377 is included.
  • the intra-block copy prediction unit 362 of FIG. 44 includes an IBC space block vector candidate derivation unit 471, an IBC history block vector candidate derivation unit 472, an IBC block vector replenishment unit 473, an IBC merge candidate selection unit 474, a reference position correction unit 480, and a block. Includes copy section 477.
  • FIG. 47 shows a procedure for merging intra-block copy mode derivation processing having a function common to the intra-block copy prediction unit 352 of the image coding device and the intra-block copy prediction unit 362 of the image decoding device according to the embodiment of the present invention. It is a flowchart to explain.
  • the intra-block copy prediction unit 352 and the intra-block copy prediction unit 362 include a merge intra-block copy candidate list mergeIbcCandList.
  • Merge intra-block copy candidate list mergeIbcCandList has a list structure, and has a merge index indicating the location inside the merge intra-block copy candidate and a storage area for storing the merge intra-block copy candidate corresponding to the index as an element.
  • the numbers in the merge index start from 0, and the merge intrablock copy candidates are stored in the storage area of the mergeIbcCandList merge intrablock copy candidate list.
  • the merge candidate of the merge index i registered in the merge intra-block copy candidate list mergeIbcCandList is represented by mergeIbcCandList [i].
  • the merge candidate list mergeCandList can register at least three merge intra-block copy candidates. Further, 0 is set in the variable numCurrMergeIbcCand indicating the number of merge intrablock copy candidates registered in the mergeIbcCandList merge intrablock copy candidate list.
  • the IBC space block vector candidate derivation unit 371 and the IBC space block vector candidate derivation unit 471 from the coding information stored in the coding information storage memory 111 of the image coding device or the coding information storage memory 205 of the image decoding device, Spatial merge candidates A and B from blocks adjacent to the left and upper sides of the block to be processed are derived, and the derived spatial merge candidates are registered in the merge intra-block copy candidate list mergeIbcCandList (step S4701 in FIG. 47).
  • N indicating either one of the spatial merge candidates A and B is defined.
  • the flag availableFlagN and the block vector mvL indicating whether or not the intra-block copy prediction information of the block N can be used as the spatial block vector merge candidate N are derived.
  • the block vector merge candidate is derived without referring to other coded blocks included in the block including the coded block to be processed, the block including the coded block to be processed is derived. Spatial block vector merge candidates included in are not derived.
  • the IBC history block vector candidate derivation unit 372 and the IBC history block vector candidate derivation unit 472 add the history prediction block vector candidates registered in the history prediction block vector candidate list HmvpIbcCandList to the merge intrablock copy candidate list mergeIbcCandList. (Step S4702 in FIG. 47).
  • the block vector already added to the mergeIbcCandList and the block vector of the history prediction block vector candidate have the same value, the block vector is not added to the mergeIbcCandList.
  • the IBC prediction block vector replenishment unit 373 and the IBC prediction block vector replenishment unit 473 The number of merge candidates registered in the mergeIbcCandList merge intra-block copy candidate list numCurrMergeIbcCand adds up to the maximum number of merge candidates MaxNumMergeIbcCand Derives the intra-block merge candidates and registers them in the merge-intra-block copy candidate list mergeIbcCandList (Fig. 47). Step S4703). Up to the maximum number of merge candidates MaxNumMergeIbcCand, a block vector with a value of (0,0) is added to the mergeintra block copy candidate list mergeIbcCandList.
  • the IBC merge candidate selection unit 374 and the IBC merge candidate selection unit 474 select one from the merge intrablock copy candidates registered in the intrablock merge candidate list mergeIbcCandList (step S4704 in FIG. 47).
  • the IBC merge candidate selection unit 374 selects a merge candidate by acquiring the decoded image at the reference position from the decoded image memory 104 and calculating the code amount and the strain amount, and sets a merge index indicating the selected intra-block merge candidate. It is supplied to the IBC prediction mode determination unit 377.
  • the IBC prediction mode determination unit 377 selects whether or not it is in the merge mode by calculating the code amount and the strain amount, and supplies the result to the prediction method determination unit 105.
  • the IBC merge candidate selection unit 474 on the decoding side selects an intra-block merge candidate based on the decoded merge index, and supplies the selected intra-block merge candidate to the reference position correction unit 480.
  • the block copy unit 477 copies the luminance component and the color difference component.
  • the reference position correction unit 380 and the reference position correction unit 480 perform a process of correcting the reference position for the intra-block merge candidate (step S4705 in FIG. 47). Details of the processing of the reference position correction unit 380 and the reference position correction unit 480 will be described later.
  • the block copy unit 477 acquires the decoded image at the reference position from the decoded image memory 208 and supplies it to the decoded image signal superimposing unit 207.
  • the block vector mvL indicates the brightness block vector.
  • the color difference block vector mvC is when the color difference format is 4: 2: 0.
  • mvC ((mvL >> (3 + 2))) * 32 Will be. According to the above equation, each of the x and y components of mvC is processed.
  • the color difference block to be divided in the parent block of the coded block to be processed, in the intra prediction or the IBC prediction, the color difference block to be divided is not divided based on the division mode, and the color difference coded block is used.
  • the color difference block undivided flag chroma_non_split_flag is set to 1 (true)
  • the block vector mvC of the coded block of the luminance signal is calculated by the formula.
  • the lower right pixel in the center of the color difference signal coding block in the image space of the color difference signal when specifying the luminance signal coding block at the same position as the color difference signal coding block, the lower right pixel in the center of the color difference signal coding block in the image space of the color difference signal.
  • a luminance signal coding block containing pixels at the same position in the image space of the luminance signal corresponding to is defined as a luminance signal coding block at the same position as the color difference signal coding block.
  • FIG. 49 is a flowchart illustrating the processing of the reference position correction unit 380 and the reference position correction unit 480. Now, it is assumed that the unit of the intra-block copy reference block is the coded tree block (CTU), and its size is not 128x128 pixels.
  • CTU coded tree block
  • the position of the coded block to be processed is (xCb, yCb), the block vector is (mvL [0], mvL [1]), the width of the coded block to be processed is cbWidth, and the height is cbHeight.
  • step S6002 it is determined whether or not the size of the CTU is 128x128 pixels (step S6002). Since the size is not 128x128 pixels (step S6002: NO), the upper left and lower right positions of the referenceable area are calculated (step S6003).
  • the size of CTU is CtbLog2SizeY.
  • step S6004 it is determined whether or not the reference position of the reference block in the x direction is smaller than the upper left of the referenceable area (step S6004). If the determination is false (step S6004: NO), the process proceeds to the next process (step S6006). On the other hand, if the determination is true (step S6004: YES), the reference position in the x direction is corrected according to the upper left of the referenceable area (step S6005).
  • FIG. 50 is a diagram showing how the reference position is corrected.
  • 6001 indicates a processing target coding tree block
  • 6002 indicates a processing target coding block
  • 6003 indicates a referenceable area.
  • the reference block r2 is located at 6011
  • xRefBR xRefTL + cbWidth-1 as in S6001
  • xRefBR is also corrected as xRefTL is corrected.
  • the block vector mvL [0] may be corrected.
  • mvL [0] (xAvlTL-xCb) ⁇ 4 To correct.
  • xRefTL xAvlTL, so the reference position can be corrected.
  • the intra-block copy prediction unit 352 It is assumed that some block vectors in the block vector candidate list constructed by the intra-block copy prediction unit 352 are outside the referenceable area. If the reference position is not corrected, those block vectors cannot be used as candidates for the IBC merge mode because they cannot be referenced by the block vectors. On the other hand, when the reference position is corrected in the present invention, all the block vectors of the constructed block vector candidate list are inside the referenceable area. Therefore, it is possible to all the block vectors, and all the block vectors can be candidates for the IBC merge mode. Therefore, in the IBC merge mode selection unit 374, the optimum prediction mode can be selected from the candidates of each IBC merge mode corresponding to all the block vectors, so that the coding efficiency is improved.
  • the merge index indicating the IBC merge mode using those block vectors operates as unencoded. However, due to malfunction or the like, such a merge index may be encoded to generate a bitstream. Alternatively, a part of the bitstream may be missing due to packet loss or the like, and the decryption result may become such a merge index.
  • the decoding result may differ depending on the decoding device, or the decoding process may stop.
  • the reference position is corrected in the present invention, all the block vectors of the constructed block vector candidate list are inside the referenceable area. Therefore, even if such an incomplete bit stream is decoded, the reference position is corrected inside the referenceable area and reference is possible. By correcting the reference position in this way, the memory access range is guaranteed. As a result, the decoding result becomes the same depending on the decoding device, and the decoding process can be continued, so that the robustness of the decoding device can be improved.
  • the target is the brightness block vector.
  • the color difference block vector is calculated from the luminance block vector. That is, if the luminance block vector is corrected, the color difference block vector is also corrected. Therefore, it is not necessary to correct the reference position again in the color difference. Compared with the need to determine whether or not reference is possible based on both the luminance and the color difference when the block vector is not corrected, the amount of processing can be reduced.
  • the corrected block vector is stored in the coding information storage memory 111 or the coding information storage memory 205 as the block vector of the coded block to be processed. That is, the corrected reference position and the position pointed to by the block vector are the same.
  • a deblocking filter process may be performed when the decoding result is saved in the decoded image memory. In this filtering process, the strength of the filter is controlled by the difference between the block vectors of the two blocks facing the block boundary. When the block vector is not corrected, the corrected reference position and the position pointed to by the block vector are different, and the filter strength is more appropriate, so that the coding efficiency can be improved.
  • step S6006 it is determined whether or not the reference position of the reference block in the y direction is smaller than the upper left of the referenceable area. If the determination is false (step S6006: NO), the process proceeds to the next process (step S6008). On the other hand, if the determination is true (step S6006: YES), the reference position in the y direction is corrected according to the upper left of the referenceable area (step S6007).
  • step S6006 YES
  • yRefBR yRefTL + cbHeight-1 as in step S6001
  • yRefBR is also corrected as yRefTL is corrected.
  • the block vector mvL [1] may be corrected.
  • mvL [1] (yAvlTL --yCb) ⁇ 4 To correct.
  • yRefTL yAvlTL, so the reference position can be corrected.
  • step S6008 it is determined whether or not the reference position of the reference block in the x direction is larger than the lower right of the referenceable area. If the determination is false (step S6008: NO), the process proceeds to the next process (step S6010). On the other hand, if the determination is true (step S6008: YES), the reference position in the x direction is corrected according to the lower right of the referenceable area (step S6009).
  • xRefBR xRefTL + cbWidth-1 as in step S6001
  • xRefTL xRefBR- (cbWidth-1)
  • xRefTL is also corrected as xRefBR is corrected.
  • the block vector mvL [0] may be corrected.
  • step S6010 it is determined whether or not the reference position of the reference block in the y direction is larger than the lower right of the referenceable area (step S6010). If the determination is false (step S6010: NO), the process ends. On the other hand, if the determination is true (step S6010: YES), the reference position in the y direction is corrected according to the lower right of the referenceable area (step S6011).
  • yRefBR yRefTL + cbHeight-1 as in step S6001
  • yRefTL yRefBR- (cbHeight-1)
  • yRefTL is also corrected as yRefBR is corrected.
  • the block vector mvL [1] may be corrected.
  • mvL [1] (yAvlBR-(yCb + cbHeitght --1)) ⁇ 4 To correct.
  • yRefBR yAvlBR, so the reference position can be corrected.
  • the reference block r1 is located at 6051.
  • the reference position in the x direction is corrected as in the case where the reference block is r2.
  • the reference position in the y direction is corrected as in the case where the reference block is r4.
  • the reference block r1 is located at 6052, which is inside the referenceable area.
  • each reference block is located inside the referenceable area.
  • step S6002 the upper left and lower right positions when the referenceable area is rectangular are calculated (step S6012).
  • 51A to 51D are diagrams for explaining the upper left and lower right positions when the referenceable area is rectangular.
  • the coded tree block 6101 to be processed is divided into four, and the coded block 6102 to be processed is located at the upper left of the division.
  • the referenceable area has an inverted L shape like the shaded area in 6103.
  • the range is 6103.
  • FIG. 52 is a flowchart illustrating a process of correcting a reference position in a portion where the referenceable area is not rectangular.
  • step S6023 it is determined whether or not the difference between the reference block and the referenceable area in the x direction is smaller than the difference between the reference block and the referenceable area in the y direction (step S6023). If the determination is true (step S6023: YES), the reference position in the x direction is corrected (step S6024). On the other hand, when the determination is false (step S6023: NO), the reference position in the y direction is corrected (step S6025).
  • FIG. 53A is a diagram showing how the reference position is corrected in step S6024 and step S6025.
  • blk_idx 0.
  • the difference between the reference block and the referenceable area in the x direction is smaller than the difference between the reference block and the referenceable area in the y direction (step S6023: YES).
  • xRefBR xRefTL + cbWidth-1 as in step S6001
  • xRefBR is also corrected as xRefTL is corrected.
  • the block vector mvL [0] may be corrected.
  • mvL [0] (xAvlTL + NL-xCb) ⁇ 4 To correct.
  • xRefTL xAvlTL + NL, so the reference position can be corrected.
  • Step S6022 YES
  • yRefBR yRefTL + cbHeight-1 as in step S6001
  • yRefBR is also corrected as yRefTL is corrected.
  • the block vector mvL [0] may be corrected.
  • mvL [1] (yAvlTL + 64 --yCb) ⁇ 4 To correct.
  • yRefTL yAvlTL + 64, so the reference position can be corrected.
  • the reference block r3 is located at 6205.
  • the difference between the reference block and the referenceable area in the x direction is smaller than the difference between the reference block and the referenceable area in the y direction (step S6023: YES). Therefore, it is located at 6206 by correcting the reference position in the x direction in the same manner as the reference block r1 (step S6024). At this point, the reference block is outside the referenceable area. However, the reference position in the y direction is corrected by the processing of steps S6006 and S6007 described later. After all, the reference block is inside the referenceable area.
  • step S6028 it is determined whether or not the difference between the reference block and the referenceable area in the x direction is smaller than the difference between the reference block and the referenceable area in the y direction (step S6028). If the determination is true (step S6028: YES), the reference position in the x direction is corrected (step S6029). On the other hand, when the determination is false (step S6028: NO), the reference position in the y direction is corrected (step S6030).
  • FIG. 53B is a diagram showing how the reference position is corrected in step S6029 and step S6030.
  • blk_idx 3.
  • the reference block r1 is located at 6211
  • the lower right corner of the reference block is located in a region larger than X4 (x direction of 6114) and Y3 (y direction of 6113) (step).
  • S6027 YES).
  • the difference between the reference block and the referenceable area in the x direction is smaller than the difference between the reference block and the referenceable area in the y direction (step S6028: YES).
  • xRefBR xRefTL + cbWidth-1 as in step S6001
  • xRefTL xRefBR- (cbWidth-1)
  • xRefTL is also corrected as xRefBR is corrected.
  • the block vector mvL [0] may be corrected.
  • mvL [0] (xAvlBR --NR-(xCb + cbWitdh --1)) ⁇ 4 To correct.
  • xRefBR xAvlBR, so the reference position can be corrected.
  • Step S6027 YES
  • step S6028 NO
  • yRefBR yRefTL + cbHeight-1 as in step S6001
  • yRefTL yRefBR- (cbHeight-1)
  • yRefTL is also corrected as yRefBR is corrected.
  • the block vector mvL [1] may be corrected.
  • mvL [1] (yAvlBR --64-(yCb + cbHeight --1)) ⁇ 4 To correct.
  • yRefBR yAvlBR, so the reference position can be corrected.
  • the reference block r3 is located at 6215.
  • the difference between the reference block and the referenceable area in the x direction is not smaller than the difference between the reference block and the referenceable area in the y direction (step S6028: NO). Therefore, it is located at 6216 by correcting the reference position in the y direction in the same manner as the reference block r2 (step S6030). At this point, the reference block is outside the referenceable area. However, the reference position in the x direction is corrected by the processing of step S6008 and step S6009 described later. After all, the reference block is inside the referenceable area.
  • step S6013 After the process of correcting the reference position of the portion where the referenceable area is not rectangular (step S6013), the processes of steps S6004 to S6011 are performed. With the above, the processing when the size of CTU is 128x128 pixels is completed.
  • step S6024 the process of correcting the reference position in the x direction according to the upper left of the referenceable area. Then, since the reference position of the reference block in the x direction is not smaller than the upper left of the referenceable area, the determination in step S6004 is always false (step S6004: NO). Therefore, when the process of step S6024 is performed, the processes of step S6004 and step S6005 may not be performed.
  • step S6025 when the processing of step S6025 is performed, the processing of steps S6006 and S6007 may be omitted, and when the processing of step S6029 is performed, the processing of steps S6008 and S6009 may not be performed.
  • step S6030 When the process of step S6030 is performed, the processes of step S6010 and step S6011 may not be performed.
  • step S6023 may be omitted and the configuration may be such that step S6024 is always executed, or the configuration may be such that step S6025 is always executed.
  • step S6028 may be omitted, and the configuration may be such that step S6029 is always executed, or the configuration may be such that step S6030 is always executed.
  • the reference position can be corrected by a simple process.
  • the reference position is corrected by using the processes of S6012, S6013 and S6004 to S6011. Instead of this, as shown in FIG. 54, it can also be realized by a process of decomposing the referenceable area into two and correcting each reference position (S6101 in FIG. 54).
  • FIG. 56 is a flowchart illustrating a process (S6101) of decomposing the referenceable area into two and correcting each reference position.
  • S6101 the same process as in FIG. 49 is assigned the same step number, and the description thereof will be omitted.
  • the upper left and lower right positions of the referenceable area A are calculated (S6111).
  • the reference position can be corrected and the reference can be made. Further, by decomposing the referenceable area into two and correcting each reference position, the processing can be simplified and the amount of calculation can be reduced.
  • one referenceable area (6301) is designated as a referenceable area A
  • the other referenceable area (6302) is designated as a referenceable area B.
  • the referenceable area A and the referenceable area B may be exchanged so that one referenceable area (6301) becomes the referenceable area B and the other referenceable area (6302) is treated as the referenceable area A. ..
  • the processing is switched. This may determine whether the intra-block copy reference block is a unit obtained by dividing the coded tree block into four, or whether the size of the CTU is larger than the maximum size of the coded block. You may do so.
  • the bitstream output by the image coding apparatus has a specific data format so that it can be decoded according to the coding method used in the embodiment.
  • the bit stream may be recorded and provided on a recording medium that can be read by a computer such as an HDD, SSD, flash memory, or optical disk, or may be provided from a server via a wired or wireless network. Therefore, the image decoding device corresponding to this image coding device can decode the bit stream of this specific data format regardless of the providing means.
  • the bitstream may be converted and transmitted in a data format suitable for the transmission form of the communication path.
  • a transmission device that converts the bitstream output by the image encoding device into encoded data in a data format suitable for the transmission form of the communication path and transmits it to the network, and a transmission device that receives the encoded data from the network and sends the bitstream.
  • a receiving device that restores the data and supplies it to the image decoding device is provided.
  • the transmitting device includes a memory for buffering a bit stream output by the image coding device, a packet processing unit for packetizing the bit stream, and a transmitting unit for transmitting the encoded data packetized via the network.
  • the receiving device receives the encoded data packetized via the network, a memory for buffering the received encoded data, and packet-processes the encoded data to generate a bit stream for image decoding. Includes a packet processing unit provided to the device.
  • a relay device for supplying to the receiving device may be provided.
  • the relay device includes a receiving unit that receives the packetized encoded data transmitted by the transmitting device, a memory that buffers the received encoded data, and a transmitting unit that transmits the packetized encoded data to the network. Including. Further, the relay device includes a received packet processing unit that packet-processes the packetized encoded data to generate a bit stream, a recording medium that stores the bit stream, and a transmission packet processing unit that packets the bit stream. But it's okay.
  • the display device may be used.
  • the display unit reads the decoded image signal generated by the decoded image signal superimposing unit 207 and stored in the decoded image memory 208 and displays it on the screen.
  • the image pickup device may be used.
  • the image pickup unit inputs the captured image signal to the block division unit 101.
  • FIG. 60 shows an example of the hardware configuration of the coding / decoding device of this embodiment.
  • the coding / decoding device includes the configuration of the image coding device and the image decoding device according to the embodiment of the present invention.
  • the coding / decoding device 9000 includes a CPU 9001, a codec IC 9002, an I / O interface 9003, a memory 9004, an optical disk drive 9005, a network interface 9006, and a video interface 9009, and each part is connected by a bus 9010.
  • the image coding unit 9007 and the image decoding unit 9008 are typically implemented as a codec IC9002.
  • the image coding process of the image coding device according to the embodiment of the present invention is executed by the image coding unit 9007, and the image decoding process in the image decoding device according to the embodiment of the present invention is performed by the image decoding unit 9008.
  • the I / O interface 9003 is realized by, for example, a USB interface, and is connected to an external keyboard 9104, mouse 9105, or the like.
  • the CPU 9001 controls the coding / decoding device 9000 so as to execute the operation desired by the user based on the user operation input via the I / O interface 9003.
  • User operations using the keyboard 9104, mouse 9105, and the like include selection of which function to execute, coding or decoding, setting of coding quality, bitstream input / output destination, image input / output destination, and the like.
  • the optical disc drive 9005 When the user desires an operation of reproducing an image recorded on the disc recording medium 9100, the optical disc drive 9005 reads a bit stream from the inserted disc recording medium 9100 and reads the read bit stream via the bus 9010. It is sent to the image decoding unit 9008 of the codec IC9002.
  • the image decoding unit 9008 executes the image decoding process in the image decoding device according to the embodiment of the present invention on the input bit stream, and sends the decoded image to the external monitor 9103 via the video interface 9009.
  • the coding / decoding device 9000 has a network interface 9006 and can be connected to an external distribution server 9106 or a mobile terminal 9107 via the network 9101.
  • the network interface 9006 is used from the input disc recording medium 9100. Instead of reading the bitstream, it gets the bitstream from network 9101. Further, when the user desires to reproduce the image recorded in the memory 9004, the image decoding process in the image decoding device according to the embodiment of the present invention is executed on the bit stream recorded in the memory 9004. To do.
  • the video interface 9009 inputs an image from the camera 9102, and the image coding unit 9007 of the codec IC 9002 via the bus 9010. Send to.
  • the image coding unit 9007 executes the image coding process in the image coding device according to the embodiment of the present invention on the image input via the video interface 9009 to create a bit stream. Then, the bit stream is sent to the memory 9004 via the bus 9010. If the user desires to record the bitstream on the disc recording medium 9100 instead of the memory 9004, the optical disc drive 9005 writes the bitstream to the inserted disc recording medium 9100.
  • Such a hardware configuration is realized, for example, by replacing the codec IC9002 with an image coding unit 9007 or an image decoding unit 9008, respectively.
  • the above processing related to coding and decoding may be realized as a transmission, storage, and reception device using hardware, and is stored in a ROM (read-only memory), a flash memory, or the like. It may be realized by firmware or software such as a computer.
  • the firmware program and software program may be recorded on a recording medium readable by a computer or the like and provided, or may be provided from a server via a wired or wireless network, or terrestrial or satellite digital broadcasting data broadcasting. May be provided as.
  • the present invention can be used in an image coding and decoding technique for dividing an image into blocks and performing prediction.
  • 100 image encoding device 101 block division unit, 102 inter-prediction unit, 103 intra-prediction unit, 104 decoded image memory, 105 prediction method determination unit, 106 residual signal generation unit, 107 orthogonal conversion / quantization unit, 108 bit string code Chemical unit, 109 inverse quantization / inverse orthogonal conversion unit, 110 decoded image signal superimposition unit, 111 coded information storage memory, 200 image decoding device, 201 bit string decoding unit, 202 block division unit, 203 inter prediction unit 204 intra prediction unit. , 205 Coding information storage memory 206 Inverse quantization / inverse orthogonal conversion section, 207 Decoded image signal superimposition section, 208 Decoded image memory.

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Abstract

This image coding device for coding an image in blocks into which each picture of the image is divided is provided with a block division unit which divides each picture of an image into blocks, and an intra prediction unit which predicts a block with reference to, as a predicted value, a decoded pixel in a screen, in accordance with an intra prediction mode. The block division unit performs division recursively in accordance with a common division mode, with a luminance block and a color-difference block being synchronized with each other, and, during intra prediction, prohibits a color-difference coding block smaller than or equal to a predetermined minimum size of a color-difference coding block.

Description

画像符号化装置、画像符号化方法、及び画像符号化プログラム、画像復号装置、画像復号方法及び画像復号プログラムImage coding device, image coding method, and image coding program, image decoding device, image decoding method, and image decoding program.
　本発明は、画像をブロックに分割し、予測を行う画像符号化及び復号技術に関する。 The present invention relates to an image coding and decoding technique for dividing an image into blocks and performing prediction.
　画像の符号化及び復号では、処理の対象となる画像を所定数の画素の集合であるブロックに分割し、ブロック単位で処理をする。適切なブロックに分割し、画面内予測（イントラ予測）、画面間予測（インター予測）を適切に設定することにより、符号化効率が向上する。 In image coding and decoding, the image to be processed is divided into blocks which are a set of a predetermined number of pixels, and processing is performed in block units. Coding efficiency is improved by dividing into appropriate blocks and appropriately setting in-screen prediction (intra prediction) and inter-screen prediction (inter prediction).
　特許文献１には符号化・復号対象のブロックに隣接する復号済みの画素を用いて予測画像を得るイントラ予測技術が開示されている。 Patent Document 1 discloses an intra-prediction technique for obtaining a predicted image using decoded pixels adjacent to a block to be encoded / decoded.
特開２００９－２４６９７５号公報Japanese Unexamined Patent Publication No. 2009-246975
　しかしながら、特許文献１の技術は符号化・復号対象のブロックに隣接する復号済みの画素のみを予測に用いるものであり、予測効率が悪い。 However, the technique of Patent Document 1 uses only the decoded pixels adjacent to the block to be encoded / decoded for prediction, and the prediction efficiency is poor.
　上記課題を解決する本発明のある態様では、画像の各ピクチャを分割したブロック単位で前記画像が符号化された符号化ビット列を復号する画像復号装置は、画像の各ピクチャを分割したブロック単位に分割するブロック分割部と、イントラ予測モードに応じて画面内の復号済の画素を予測値として参照してブロックを予測するイントラ予測部とを備える。前記ブロック分割部は、輝度ブロックと色差ブロックが互いに同期して共通の分割モードにしたがって再帰的に分割され、イントラ予測において、所定の色差符号化ブロック最小サイズ以下の色差の符号化ブロックを禁止し、色差フォーマットが４：２：０で、輝度ブロックを再帰的に分割し、それに対応する色差ブロックが分割する際に所定の色差符号化ブロック最小サイズよりも小さい色差の符号化ブロックとなる場合は、色差ブロックを分割しないものとした場合に、分割対象ブロックを３分割する３分割モードにおいて、輝度信号の分割対象ブロックを第１の輝度信号の符号化ブロック、第２の輝度信号の符号化ブロック、第３の輝度信号の符号化ブロックに分割されるとともに、色差信号の分割対象ブロックを分割せずに１つの色差信号の符号化ブロックとし、前記イントラ予測部は、色差信号の符号化ブロックの中心の右下の画素の位置に対応する色差信号の画素を含む符号化ブロックのイントラ輝度予測モードの値を色差信号の符号化ブロックのイントラ色差予測モードの値としてイントラ予測を行う。 In one aspect of the present invention that solves the above problems, an image decoding device that decodes a coded bit string in which each picture of an image is encoded is divided into block units of each picture of the image. It includes a block division unit for dividing and an intra prediction unit that predicts a block by referring to a decoded pixel in the screen as a prediction value according to an intra prediction mode. In the block division unit, the luminance block and the color difference block are synchronized with each other and recursively divided according to a common division mode, and in the intra prediction, the color difference coding block having a predetermined color difference coding block minimum size or less is prohibited. , When the color difference format is 4: 2: 0 and the luminance block is recursively divided, and the corresponding color difference block becomes a color difference coding block smaller than the predetermined color difference coding block minimum size when divided. , When the color difference block is not divided, in the three-division mode in which the division target block is divided into three, the division target block of the luminance signal is the first luminance signal coding block and the second luminance signal coding block. , The third luminance signal coding block is divided, and the color difference signal division target block is not divided into one color difference signal coding block, and the intra prediction unit is a color difference signal coding block. Intra-prediction is performed by using the value of the intra-luminance prediction mode of the coded block including the pixel of the color difference signal corresponding to the position of the lower right pixel of the center as the value of the intra-luminance prediction mode of the coded block of the color difference signal.
　本発明によれば、高効率な画像符号化・復号処理を低負荷で実現することができる。 According to the present invention, highly efficient image coding / decoding processing can be realized with a low load.
本発明の実施の形態に係る画像符号化装置のブロック図である。It is a block diagram of the image coding apparatus which concerns on embodiment of this invention. 本発明の実施の形態に係る画像復号装置のブロック図である。It is a block diagram of the image decoding apparatus which concerns on embodiment of this invention. 画像の色差フォーマット４：２：０を説明する図である。It is a figure explaining the color difference format 4: 2: 0 of an image. 画像の色差フォーマット４：２：２を説明する図である。It is a figure explaining the color difference format 4: 2: 2 of an image. 画像の色差フォーマット４：４：４を説明する図である。It is a figure explaining the color difference format 4: 4: 4 of an image. 画像の色差フォーマットをモノクロ説明する図である。It is a figure explaining the color difference format of an image in monochrome. 画像の色差フォーマット４：２：０を説明する図である。It is a figure explaining the color difference format 4: 2: 0 of an image. 入力された画像をツリーブロックおよび符号化ブロックに分割する様子を示す図である。It is a figure which shows the mode that the input image is divided into a tree block and a coded block. ブロックの分割形状を示す図である。It is a figure which shows the division shape of a block. ブロックの分割形状を示す図である。It is a figure which shows the division shape of a block. ブロックの分割形状を示す図である。It is a figure which shows the division shape of a block. ブロックの分割形状を示す図である。It is a figure which shows the division shape of a block. ブロックの分割形状を示す図である。It is a figure which shows the division shape of a block. 画像をツリーブロックに分割し、各ツリーブロックをさらに符号化ブロックに分割する動作を説明するためのフローチャートである。It is a flowchart for demonstrating the operation which divides an image into tree blocks, and further divides each tree block into coded blocks. ブロックを分割する動作を説明するためのフローチャートである。It is a flowchart for demonstrating the operation which divides a block. イントラ予測またはＩＢＣ予測において所定のサイズ以下の色差符号化ブロックを禁止するか否かを説明する図である。It is a figure explaining whether or not the color difference coding block of a predetermined size or less is prohibited in intra prediction or IBC prediction. イントラ予測またはＩＢＣ予測において所定のサイズ以下の色差符号化ブロックを禁止するか否かを説明する図である。It is a figure explaining whether or not the color difference coding block of a predetermined size or less is prohibited in intra prediction or IBC prediction. イントラ予測またはＩＢＣ予測において所定のサイズ以下の色差符号化ブロックを禁止するか否かを説明する図である。It is a figure explaining whether or not the color difference coding block of a predetermined size or less is prohibited in intra prediction or IBC prediction. イントラ予測またはＩＢＣ予測において所定のサイズ以下の色差符号化ブロックを禁止するか否かを説明する図である。It is a figure explaining whether or not the color difference coding block of a predetermined size or less is prohibited in intra prediction or IBC prediction. イントラ予測またはＩＢＣ予測において所定のサイズ以下の色差符号化ブロックを禁止するか否かを説明する図である。It is a figure explaining whether or not the color difference coding block of a predetermined size or less is prohibited in intra prediction or IBC prediction. ブロック分割情報を符号化する動作を示すフローチャートである。It is a flowchart which shows the operation which encodes a block division information. イントラ予測を説明するための図である。It is a figure for demonstrating an intra prediction. イントラ予測を説明するための図である。It is a figure for demonstrating an intra prediction. インター予測の参照ブロックを説明するための図である。It is a figure for demonstrating the reference block of an inter-prediction. ブロック分割情報を復号し、ブロックを分割する動作を示すフローチャートである。It is a flowchart which shows the operation of decoding a block division information and dividing a block. 色差フォーマットが４：２：０の際の、色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックを説明するための図である。It is a figure for demonstrating the coding block of the luminance signal at the same position as the coding block of the color difference signal when the color difference format is 4: 2: 0. 色差フォーマットが４：２：０の際の、色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックを説明するための図である。It is a figure for demonstrating the coding block of the luminance signal at the same position as the coding block of the color difference signal when the color difference format is 4: 2: 0. 制御点２点のアフィン変換動き補償を説明するための図である。It is a figure for demonstrating the affine transformation motion compensation of two control points. 制御点３点のアフィン変換動き補償を説明するための図である。It is a figure for demonstrating the affine transformation motion compensation of three control points. 図１のインター予測部１０２の詳細な構成のブロック図である。It is a block diagram of the detailed structure of the inter prediction unit 102 of FIG. 図１６の通常予測動きベクトルモード導出部３０１の詳細な構成のブロック図である。It is a block diagram of the detailed structure of the normal prediction motion vector mode derivation unit 301 of FIG. 図１６の通常マージモード導出部３０２の詳細な構成のブロック図である。It is a block diagram of the detailed structure of the normal merge mode derivation part 302 of FIG. 図１６の通常予測動きベクトルモード導出部３０１の通常予測動きベクトルモード導出処理の処理手順を説明するためのフローチャートである。It is a flowchart for demonstrating the processing procedure of the normal prediction motion vector mode derivation process of the normal prediction motion vector mode derivation unit 301 of FIG. 通常予測動きベクトルモード導出処理の処理手順を表すフローチャートである。It is a flowchart which shows the processing procedure of the normal prediction motion vector mode derivation processing. 通常マージモード導出処理の処理手順を説明するフローチャートである。It is a flowchart explaining the processing procedure of the normal merge mode derivation process. 図２のインター予測部２０３の詳細な構成のブロック図である。It is a block diagram of the detailed structure of the inter-prediction unit 203 of FIG. 図２２の通常予測動きベクトルモード導出部４０１の詳細な構成のブロック図である。It is a block diagram of the detailed structure of the normal prediction motion vector mode derivation unit 401 of FIG. 図２２の通常マージモード導出部４０２の詳細な構成のブロック図である。It is a block diagram of the detailed structure of the normal merge mode derivation part 402 of FIG. 図２２の通常予測動きベクトルモード導出部４０１の通常予測動きベクトルモード導出処理の処理手順を説明するためのフローチャートである。It is a flowchart for demonstrating the processing procedure of the normal prediction motion vector mode derivation processing of the normal prediction motion vector mode derivation unit 401 of FIG. 履歴予測動きベクトル候補リスト初期化・更新処理の処理手順を説明するためのフローチャートである。It is a flowchart for demonstrating the processing procedure of the history prediction motion vector candidate list initialization / update process. 履歴予測動きベクトル候補リスト初期化・更新処理における、同一要素確認処理の処理手順を説明するためのフローチャートである。It is a flowchart for demonstrating the processing procedure of the same element confirmation processing in the history prediction motion vector candidate list initialization / update processing. 履歴予測動きベクトル候補リスト初期化・更新処理における、要素シフト処理の処理手順を説明するためのフローチャートである。It is a flowchart for demonstrating the processing procedure of element shift processing in the history prediction motion vector candidate list initialization / update processing. 履歴予測動きベクトル候補導出処理の処理手順を説明するためのフローチャートである。It is a flowchart for demonstrating the processing procedure of the history prediction motion vector candidate derivation processing. 履歴マージ候補導出処理の処理手順を説明するためのフローチャートである。It is a flowchart for demonstrating the processing procedure of the history merge candidate derivation process. 履歴予測動きベクトル候補リスト更新処理の一例を説明するための図である。It is a figure for demonstrating an example of the history prediction motion vector candidate list update processing. 履歴予測動きベクトル候補リスト更新処理の一例を説明するための図である。It is a figure for demonstrating an example of the history prediction motion vector candidate list update processing. 履歴予測動きベクトル候補リスト更新処理の一例を説明するための図である。It is a figure for demonstrating an example of the history prediction motion vector candidate list update processing. イントラブロックコピーの有効参照領域を説明する図である。It is a figure explaining the effective reference area of an intrablock copy. イントラブロックコピーの有効参照領域を説明する図である。It is a figure explaining the effective reference area of an intrablock copy. Ｌ０予測であってＬ０の参照ピクチャ（ＲｅｆＬ０Ｐｉｃ）が処理対象ピクチャ（ＣｕｒＰｉｃ）より前の時刻にある場合の動き補償予測を説明するための図である。It is a figure for demonstrating the motion compensation prediction at the time of L0 prediction, and the reference picture (RefL0Pic) of L0 is at the time before the processing target picture (CurPic). Ｌ０予測であってＬ０予測の参照ピクチャが処理対象ピクチャより後の時刻にある場合の動き補償予測を説明するための図である。It is a figure for demonstrating motion compensation prediction at the time of L0 prediction, and the reference picture of L0 prediction is at the time after the processing target picture. 双予測であってＬ０予測の参照ピクチャが処理対象ピクチャより前の時刻にあって、Ｌ１予測の参照ピクチャが処理対象ピクチャより後の時刻にある場合の動き補償予測の予測方向を説明するための図である。To explain the prediction direction of the motion compensation prediction when the reference picture of the L0 prediction is in the time before the processing target picture in the bi-prediction and the reference picture of the L1 prediction is in the time after the processing target picture. It is a figure. 双予測であってＬ０予測の参照ピクチャとＬ１予測の参照ピクチャが処理対象ピクチャより前の時刻にある場合の動き補償予測の予測方向を説明するための図である。It is a figure for demonstrating the prediction direction of the motion compensation prediction at the time when the reference picture of L0 prediction and the reference picture of L1 prediction are at the time before the picture to be processed in the bi-prediction. 双予測であってＬ０予測の参照ピクチャとＬ１予測の参照ピクチャが処理対象ピクチャより後の時刻にある場合の動き補償予測の予測方向を説明するための図である。It is a figure for demonstrating the prediction direction of the motion compensation prediction at the time when the reference picture of L0 prediction and the reference picture of L1 prediction are at the time after the processing target picture in the bi-prediction. 平均マージ候補導出処理の処理手順を説明するためのフローチャートである。It is a flowchart for demonstrating the processing procedure of the average merge candidate derivation process. 色差フォーマットが４：２：０の際の、色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックを説明するための図である。It is a figure for demonstrating the coding block of the luminance signal at the same position as the coding block of the color difference signal when the color difference format is 4: 2: 0. 色差フォーマットが４：２：０の際の、色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックを説明するための図である。It is a figure for demonstrating the coding block of the luminance signal at the same position as the coding block of the color difference signal when the color difference format is 4: 2: 0. 色差フォーマットが４：２：０の際の、色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックを説明するための図である。It is a figure for demonstrating the coding block of the luminance signal at the same position as the coding block of the color difference signal when the color difference format is 4: 2: 0. 色差フォーマットが４：２：０の際の、色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックを説明するための図である。It is a figure for demonstrating the coding block of the luminance signal at the same position as the coding block of the color difference signal when the color difference format is 4: 2: 0. 図１のイントラ予測部１０３の詳細な構成のブロック図である。It is a block diagram of the detailed structure of the intra prediction unit 103 of FIG. 図２のイントラ予測部２０４の詳細な構成のブロック図である。It is a block diagram of the detailed structure of the intra prediction unit 204 of FIG. イントラブロックコピー予測部３５２のブロック図である。It is a block diagram of an intra block copy prediction unit 352. イントラブロックコピー予測部３６２のブロック図である。It is a block diagram of an intra block copy prediction unit 362. イントラブロックコピー予測部３５２の予測イントラブロックコピー処理の処理手順を説明するためのフローチャートである。It is a flowchart for demonstrating the processing procedure of the prediction intra block copy processing of the intra block copy prediction unit 352. イントラブロックコピー予測部３６２の予測イントラブロックコピー処理の処理手順を説明するためのフローチャートである。It is a flowchart for demonstrating the processing procedure of the prediction intra block copy processing of the intra block copy prediction unit 362. マージイントラブロックコピー処理の処理手順を説明するためのフローチャートである。It is a flowchart for demonstrating the processing procedure of the merge intra block copy processing. 予測イントラブロックコピーのブロックベクトルモード導出処理の処理手順を表すフローチャートである。It is a flowchart which shows the processing procedure of the block vector mode derivation processing of the prediction intra block copy. 参照位置補正部３８０及び参照位置補正部４８０の処理の処理手順を説明するためのフローチャートである。It is a flowchart for demonstrating the processing procedure of the process of the reference position correction unit 380 and the reference position correction unit 480. 参照位置を補正する様子を示す図である。It is a figure which shows the state of correcting a reference position. 参照可能領域を矩形状とした場合の左上および右下の位置を説明する図である。It is a figure explaining the position of the upper left and the lower right when the referenceable area is rectangular. 参照可能領域を矩形状とした場合の左上および右下の位置を説明する図である。It is a figure explaining the position of the upper left and the lower right when the referenceable area is rectangular. 参照可能領域を矩形状とした場合の左上および右下の位置を説明する図である。It is a figure explaining the position of the upper left and the lower right when the referenceable area is rectangular. 参照可能領域を矩形状とした場合の左上および右下の位置を説明する図である。It is a figure explaining the position of the upper left and the lower right when the referenceable area is rectangular. 参照可能領域が矩形でない部分の参照位置を補正する処理の処理手順を説明するためのフローチャートである。It is a flowchart for demonstrating the processing procedure of the process of correcting the reference position of the part where a referenceable area is not rectangular. 参照位置を補正する様子を示す図である。It is a figure which shows the state of correcting a reference position. 参照位置を補正する様子を示す図である。It is a figure which shows the state of correcting a reference position. 参照位置補正部３８０及び参照位置補正部４８０の処理の処理手順を説明するためのフローチャートである。It is a flowchart for demonstrating the processing procedure of the process of the reference position correction unit 380 and the reference position correction unit 480. 参照可能領域を２つに分解する様子を説明する図である。It is a figure explaining a mode that the referenceable area is decomposed into two. 参照可能領域を２つに分解する様子を説明する図である。It is a figure explaining a mode that the referenceable area is decomposed into two. 参照可能領域を２つに分解する様子を説明する図である。It is a figure explaining a mode that the referenceable area is decomposed into two. 参照可能領域を２つに分解する様子を説明する図である。It is a figure explaining a mode that the referenceable area is decomposed into two. 参照可能領域を２つに分解し、それぞれの参照位置を補正する処理の処理手順を説明するフローチャートである。It is a flowchart explaining the processing procedure of the process of decomposing the referenceable area into two and correcting each reference position. 符号化ブロックの符号化情報を符号化する動作を示すフローチャートである。It is a flowchart which shows the operation which encodes the coding information of a coding block. 符号化ブロックの符号化情報を復号する動作を示すフローチャートである。It is a flowchart which shows the operation of decoding the coding information of a coding block. 色差フォーマットが４：２：０の際の、色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックを説明するための図である。It is a figure for demonstrating the coding block of the luminance signal at the same position as the coding block of the color difference signal when the color difference format is 4: 2: 0. 色差フォーマットが４：２：０の際の、色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックを説明するための図である。It is a figure for demonstrating the coding block of the luminance signal at the same position as the coding block of the color difference signal when the color difference format is 4: 2: 0. 本発明の実施の形態の符号化復号装置のハードウェア構成の一例を説明するための図である。It is a figure for demonstrating an example of the hardware structure of the coding / decoding apparatus of embodiment of this invention.
　本実施の形態において使用する技術、及び技術用語を定義する。 Define the technology and technical terms used in this embodiment.
　＜色差フォーマット＞
　色差フォーマットは１つの輝度情報と２つの色差情報の３つの信号の標本化された画素数の比率をＸ：Ｙ：Ｚで表す。画像の色差フォーマットは４：２：０、４：２：２、４：４：４、モノクロ等がある。
　図３Ａ～Ｅは画像の各色差フォーマットを説明する図である。×は画像の画面平面上での輝度信号の画素の位置を示し、○は色差信号の画素の位置を示す。
　図３Ａに示す４：２：０は、輝度信号に対して色差信号が水平、垂直の両方向に２分の１の密度で標本化された色差フォーマットである。即ち、４：２：０は輝度信号と色差信号の画素のアスペクト比が同じである。なお、４：２：０は図３Ｅに示す位置で色差信号が標本化される場合もある。
　図３Ｂに示す４：２：２は、輝度信号に対して色差信号が水平方向に２分の１の密度、垂直方向に同じ密度で標本化された色差フォーマットである。即ち、４：２：２は輝度信号と色差信号の画素のアスペクト比が異なる。
　図３Ｃに示す４：４：４は輝度信号、色差信号ともに同じ密度で標本化された色差フォーマットである。即ち、４：４：４は輝度信号と色差信号の画素のアスペクト比が同じである。
　図３Ｄに示すモノクロは色差信号が無く、輝度信号だけで構成される色差フォーマットである。
　本実施の形態においては、特に記載のない場合、色差フォーマットが４：２：０であるものとして説明する。 <Color difference format>
The color difference format represents the ratio of the number of sampled pixels of three signals of one luminance information and two color difference information by X: Y: Z. The color difference format of the image includes 4: 2: 0, 4: 2: 2, 4: 4: 4, monochrome, and the like.
3A to 3E are diagrams for explaining each color difference format of the image. X indicates the position of the pixel of the luminance signal on the screen plane of the image, and ◯ indicates the position of the pixel of the color difference signal.
4: 2: 0 shown in FIG. 3A is a color difference format in which the color difference signal is sampled at a density of half in both the horizontal and vertical directions with respect to the luminance signal. That is, 4: 2: 0 has the same aspect ratio of the pixels of the luminance signal and the color difference signal. At 4: 2: 0, the color difference signal may be sampled at the position shown in FIG. 3E.
4: 2: 2 shown in FIG. 3B is a color difference format in which the color difference signal is sampled at half the density in the horizontal direction and the same density in the vertical direction with respect to the luminance signal. That is, the aspect ratios of the pixels of the luminance signal and the color difference signal are different in 4: 2: 2.
4: 4: 4 shown in FIG. 3C is a color difference format in which both the luminance signal and the color difference signal are sampled at the same density. That is, in 4: 4: 4, the aspect ratios of the pixels of the luminance signal and the color difference signal are the same.
Monochrome shown in FIG. 3D is a color difference format composed only of a luminance signal without a color difference signal.
In the present embodiment, unless otherwise specified, the color difference format is assumed to be 4: 2: 0.
　＜ツリーブロック＞
　実施の形態では、図４に太線で示されるように、画面内を任意の同一サイズの正方の矩形の単位にて均等分割する。この単位をツリーブロックと定義し、画像内での処理対象（符号化においては符号化対象、復号においては復号対象）のブロックを特定するためのアドレス管理の基本単位とする。モノクロを除きツリーブロックは１つの輝度信号と２つの色差信号で構成される。ツリーブロックのサイズはピクチャサイズや画面内のテクスチャに応じて、２のべき乗のサイズで自由に設定することができるものとする。 <Tree block>
In the embodiment, as shown by a thick line in FIG. 4, the inside of the screen is evenly divided in units of arbitrary rectangular rectangles of the same size. This unit is defined as a tree block, and is used as a basic unit of address management for specifying a block of a processing target (encoding target in coding, decoding target in decoding) in an image. Except for monochrome, the tree block is composed of one luminance signal and two color difference signals. The size of the tree block can be freely set to the power of 2 according to the picture size and the texture in the screen.
　＜符号化ブロック＞
　ツリーブロックは画面内のテクスチャに応じて、符号化処理を最適にすべく、必要に応じてツリーブロック内の輝度信号、及び色差信号を階層的（再帰的）に４分割、垂直２分割、垂直３分割、水平２分割または水平３分割して、サイズの小さいブロックにすることができる。このブロックをそれぞれ符号化ブロックと定義し、符号化及び復号を行う際の処理の基本単位とする。モノクロを除き１つの輝度信号の符号化ブロックと２つの色差信号の符号化ブロックで構成される。符号化ブロックの最大サイズはツリーブロックのサイズと同一である。符号化ブロックの最小のサイズとなる符号化ブロックを最小符号化ブロックと呼び、自由に設定することができるものとする。 <Coded block>
The tree block divides the luminance signal and color difference signal in the tree block into four hierarchically (recursively), vertically into two, and vertically as necessary in order to optimize the coding process according to the texture in the screen. It can be divided into three, two horizontal or three horizontal to make a small block. Each of these blocks is defined as a coded block, and is used as a basic unit of processing when encoding and decoding. Except for monochrome, it is composed of one luminance signal coding block and two color difference signal coding blocks. The maximum size of the coded block is the same as the size of the tree block. The coded block having the minimum size of the coded block is called the minimum coded block and can be freely set.
　図５Ａ～Ｅは符号化ブロックの分割モードの一例について説明する図である。ブロックの分割モードには、ブロックを幅及び高さをそれぞれ１：１比率で均等に４分割する４分割モード（図５Ａの６０１）、ブロックの幅を１：１の比率で左右に垂直２分割して断面が垂直方向となる垂直２分割モード（図５Ｂの６０２）、ブロックの幅を１：２：１の比率で左中右に垂直３分割して断面が垂直方向となる垂直３分割モード（図５Ｃの６０３）、ブロックの高さを１：１の比率で上下に水平２分割して断面が水平方向となる水平２分割モード（図５Ｄの６０４）、ブロックの高さを１：２：１の比率で上中下に水平３分割して断面が水平方向となる水平３分割モード（図５Ｅの６０５）がある。 5A to 5E are diagrams for explaining an example of the division mode of the coded block. The block division mode is a 4-division mode (601 in FIG. 5A) in which the block is evenly divided into 4 parts at a ratio of 1: 1 and the width and height of the block are divided into 2 vertically at a ratio of 1: 1. Vertical 2-division mode in which the cross section is in the vertical direction (602 in FIG. 5B), and vertical 3-division mode in which the block width is vertically divided into left, middle, and right at a ratio of 1: 2: 1 and the cross section is in the vertical direction. (603 in FIG. 5C), the block height is divided into two vertically at a ratio of 1: 1 and the cross section is in the horizontal direction (604 in FIG. 5D), and the block height is 1: 2. There is a horizontal three-division mode (605 in FIG. 5E) in which the cross section is in the horizontal direction by horizontally dividing the upper, middle, and lower parts at a ratio of 1.
　図４においては、符号化ブロックＡは、ツリーブロックを分割せず、１つの符号化ブロックとしたものである。符号化ブロックＢは、ツリーブロックを４分割してできた符号化ブロックである。符号化ブロックＣは、ツリーブロックを４分割してできたブロックをさらに４分割してできた符号化ブロックである。符号化ブロックＤは、ツリーブロックを４分割してできたブロックをさらに階層的に２度４分割してできた符号化ブロックである。 In FIG. 4, the coded block A is a single coded block without dividing the tree block. The coding block B is a coding block formed by dividing a tree block into four parts. The coded block C is a coded block formed by further dividing a block formed by dividing a tree block into four. The coded block D is a coded block formed by dividing a tree block into four and further hierarchically dividing the block into four.
　符号化ブロックＥは、ツリーブロックを４分割してできたブロックをさらに垂直２分割してできた符号化ブロックである。符号化ブロックＦは、ツリーブロックを４分割してできたブロックをさらに垂直３分割してできた符号化ブロックである。符号化ブロックＧは、ツリーブロックを４分割してできたブロックをさらに水平方向に垂直２分割してできた符号化ブロックである。符号化ブロックＨは、ツリーブロックを４分割してできたブロックをさらに水平３分割してできた符号化ブロックである。 The coded block E is a coded block formed by further dividing a block formed by dividing a tree block into four and further dividing it into two vertically. The coded block F is a coded block formed by further dividing a block formed by dividing a tree block into four and further dividing the block into three vertically. The coded block G is a coded block formed by further dividing a block formed by dividing a tree block into four and further dividing it into two vertically in the horizontal direction. The coded block H is a coded block formed by further dividing a block formed by dividing a tree block into four and further dividing the block into three horizontally.
　実施の形態の説明においては、色差フォーマットが４：２：０で、ツリーブロックのサイズを輝度信号で６４×６４画素、色差信号で３２×３２画素と設定し、最小の符号化ブロックのサイズを輝度信号で８×８画素、色差信号で４×４画素と設定するものとする。図４では、符号化ブロックＡのサイズは輝度信号で６４×６４画素、色差信号で３２×３２画素となり、符号化ブロックＢのサイズは輝度信号で３２×３２画素、色差信号で１６×１６画素となり、符号化ブロックＣのサイズは輝度信号で１６×１６画素、色差信号で８×８画素となり、符号化ブロックＤのサイズは輝度信号で８×８画素、色差信号で４×４画素となる。なお、色差フォーマットが４：４：４の場合、各符号化ブロックの輝度信号と色差信号のサイズが等しくなる。色差フォーマットが４：２：２の場合、符号化ブロックＡのサイズは色差信号で３２×６４画素となり、符号化ブロックＢのサイズは色差信号で１６×３２画素となり、符号化ブロックＣのサイズは色差信号で８×１６画素となり、最小の符号化ブロックである符号化ブロックＤのサイズは色差信号で４×８画素となる。
　なお、あるブロックを分割した場合、分割前のブロックを親ブロックと呼び、分割後の各ブロックを子ブロックと呼ぶ。 In the description of the embodiment, the color difference format is 4: 2: 0, the size of the tree block is set to 64 × 64 pixels for the luminance signal and 32 × 32 pixels for the color difference signal, and the size of the minimum coded block is set. It is assumed that the luminance signal is set to 8 × 8 pixels and the color difference signal is set to 4 × 4 pixels. In FIG. 4, the size of the coding block A is 64 × 64 pixels for the luminance signal and 32 × 32 pixels for the color difference signal, and the size of the coding block B is 32 × 32 pixels for the luminance signal and 16 × 16 pixels for the color difference signal. The size of the coded block C is 16 × 16 pixels for the luminance signal and 8 × 8 pixels for the color difference signal, and the size of the coded block D is 8 × 8 pixels for the luminance signal and 4 × 4 pixels for the color difference signal. .. When the color difference format is 4: 4: 4, the size of the luminance signal and the color difference signal of each coded block are equal. When the color difference format is 4: 2: 2, the size of the coded block A is 32 × 64 pixels for the color difference signal, the size of the coded block B is 16 × 32 pixels for the color difference signal, and the size of the coded block C is The color difference signal has 8 × 16 pixels, and the size of the coded block D, which is the smallest coded block, is 4 × 8 pixels for the color difference signal.
When a certain block is divided, the block before the division is called a parent block, and each block after the division is called a child block.
　＜予測モード＞
　処理対象符号化ブロック単位で、処理対象画像の処理済み（符号化処理においては符号化が完了した信号を復号した画像、画像信号、ツリーブロック、ブロック、符号化ブロック等に用い、復号処理においては復号が完了した画像、画像信号、ツリーブロック、ブロック、符号化ブロック等に用いる。）の周囲の画像信号から予測を行うイントラ予測（MODE_INTRA）及びＩＢＣ（イントラブロックコピー）予測（MODE_IBC）、及び処理済み画像の画像信号から予測を行うインター予測（MODE_INTER）を切り替える。このイントラ予測（MODE_INTRA）、ＩＢＣ予測（MODE_IBC）とインター予測（MODE_INTER）を識別するモードを予測モード（CuPredMode）と定義する。予測モード（CuPredMode）はイントラ予測（MODE_INTRA）、ＩＢＣ予測（MODE_IBC）、またはインター予測（MODE_INTER）を値として持つ。 <Prediction mode>
Processed image to be processed in units of coded blocks to be processed (in the coding process, the coded signal is used for the decoded image, image signal, tree block, block, coded block, etc., and in the decoding process Intra-prediction (MODE_INTRA) and IBC (intra-block copy) prediction (MODE_IBC), and processing that make predictions from image signals around the image, image signal, tree block, block, coded block, etc. that have been decoded. Switch the inter-prediction (MODE_INTER) that makes a prediction from the image signal of the completed image. The mode for discriminating between the intra prediction (MODE_INTRA), the IBC prediction (MODE_IBC) and the inter prediction (MODE_INTER) is defined as the prediction mode (CuPredMode). The prediction mode (CuPredMode) has an intra prediction (MODE_INTRA), an IBC prediction (MODE_IBC), or an inter prediction (MODE_INTER) as values.
　＜イントラブロックコピー予測＞
　ＩＢＣ（イントラブロックコピー）予測は、処理対象ピクチャにおける復号済みの画素（ブロック）を予測値として参照して、処理対象ブロックを予測し、処理対象ブロックを符号化／復号する処理である。そして、処理対象ブロックから参照する画素までの距離は、ブロックベクトルで表す。ブロックベクトルは処理対象ピクチャを参照し、参照ピクチャは一意に定まるため、参照インデックスは不要である。ブロックベクトルと動きベクトルの違いは、参照するピクチャが処理対象ピクチャか、異なる時間の処理済みピクチャかである。また、ブロックベクトルは、適応動きベクトル解像度（AMVR）を用いて、1画素精度または4画素精度を選択できる。 <Intrablock copy prediction>
The IBC (intra-block copy) prediction is a process of predicting a processing target block by referring to a decoded pixel (block) in the processing target picture as a prediction value, and encoding / decoding the processing target block. Then, the distance from the processing target block to the reference pixel is represented by a block vector. Since the block vector refers to the picture to be processed and the reference picture is uniquely determined, the reference index is unnecessary. The difference between the block vector and the motion vector is whether the referenced picture is a processed picture or a processed picture at a different time. In addition, the block vector can be selected from 1-pixel accuracy or 4-pixel accuracy using the adaptive motion vector resolution (AMVR).
　イントラブロックコピーでは、予測イントラブロックコピーモードと、マージイントラブロックコピーモードの２つのモードを選択可能である。 For intra block copy, two modes can be selected: predicted intra block copy mode and merge intra block copy mode.
　予測イントラブロックコピーモードは、処理済みの情報から導出する予測ブロックベクトルと、差分ブロックベクトルから、処理対象ブロックのブロックベクトルを決定するモードである。予測ブロックベクトルは、処理対象ブロックに隣接する処理済みブロックと、予測ブロックベクトルを特定するためのインデックスから導出する。予測ブロックベクトルを特定するためのインデックス、差分ブロックベクトルはビットストリームで伝送する。
　マージイントラブロックコピーモードは、差分動きベクトルを伝送せずに、処理対象ブロックに隣接する処理済みブロックのイントラブロックコピー予測情報から、処理対象ブロックのイントラブロックコピー予測情報を導出するモードである。 The prediction intra-block copy mode is a mode in which the block vector of the block to be processed is determined from the prediction block vector derived from the processed information and the difference block vector. The prediction block vector is derived from the processed block adjacent to the processing target block and the index for identifying the prediction block vector. The index and difference block vector for specifying the predicted block vector are transmitted as a bit stream.
The merge intra-block copy mode is a mode in which the intra-block copy prediction information of the processing target block is derived from the intra-block copy prediction information of the processed block adjacent to the processing target block without transmitting the differential motion vector.
　＜インター予測＞
　処理済み画像の画像信号から予測を行うインター予測では、複数の処理済み画像を参照ピクチャとして用いることができる。複数の参照ピクチャを管理するため、Ｌ０（参照リスト０）とＬ１（参照リスト１）の２種類の参照リストを定義し、それぞれ参照インデックスを用いて参照ピクチャを特定する。ＰスライスではＬ０予測（Pred_L0）が利用可能である。ＢスライスではＬ０予測（Pred_L0）、Ｌ１予測（Pred_L1）、双予測（Pred_BI）が利用可能である。Ｌ０予測（Pred_L0）はＬ０で管理されている参照ピクチャを参照するインター予測であり、Ｌ１予測（Pred_L1）はＬ１で管理されている参照ピクチャを参照するインター予測である。双予測（Pred_BI）はＬ０予測とＬ１予測が共に行われ、Ｌ０とＬ１のそれぞれで管理されている１つずつの参照ピクチャを参照するインター予測である。Ｌ０予測、Ｌ１予測、双予測を特定する情報を、インター予測モードと定義する。以降の処理において出力に添え字ＬＸが付いている定数、変数に関しては、Ｌ０、Ｌ１ごとに処理が行われることを前提とする。 <Inter prediction>
In the inter-prediction that predicts from the image signal of the processed image, a plurality of processed images can be used as reference pictures. In order to manage a plurality of reference pictures, two types of reference lists, L0 (reference list 0) and L1 (reference list 1), are defined, and the reference pictures are specified by using the reference indexes of each. L0 prediction (Pred_L0) is available for P-slices. For B slices, L0 prediction (Pred_L0), L1 prediction (Pred_L1), and dual prediction (Pred_BI) can be used. The L0 prediction (Pred_L0) is an inter-prediction that refers to a reference picture managed by L0, and the L1 prediction (Pred_L1) is an inter-prediction that refers to a reference picture managed by L1. The bi-prediction (Pred_BI) is an inter-prediction in which both L0 prediction and L1 prediction are performed, and one reference picture managed in each of L0 and L1 is referred to. Information that identifies L0 prediction, L1 prediction, and bi-prediction is defined as an inter-prediction mode. In the subsequent processing, it is assumed that the constants and variables with the subscript LX attached to the output are processed for each L0 and L1.
　＜予測動きベクトルモード＞
　予測動きベクトルモードは、予測動きベクトルを特定するためのインデックス、差分動きベクトル、インター予測モード、参照インデックスを伝送し、処理対象ブロックのインター予測情報を決定するモードである。予測動きベクトルは、処理対象ブロックに隣接する処理済みブロック、または処理済み画像に属するブロックで処理対象ブロックと同一位置またはその付近（近傍）に位置するブロックから導出した予測動きベクトル候補と、予測動きベクトルを特定するためのインデックスから導出する。 <Predicted motion vector mode>
The predicted motion vector mode is a mode in which an index for specifying a predicted motion vector, a differential motion vector, an inter-prediction mode, and a reference index are transmitted to determine inter-prediction information of a block to be processed. The predicted motion vector is a predicted motion vector candidate derived from a processed block adjacent to the processing target block or a block belonging to the processed image and located at the same position as or near (near) the processing target block, and a predicted motion. Derived from the index to identify the vector.
　＜マージモード＞
　マージモードは、差分動きベクトル、参照インデックスを伝送せずに、処理対象ブロックに隣接する処理済みブロック、または処理済み画像に属するブロックで処理対象ブロックと同一位置またはその付近（近傍）に位置するブロックのインター予測情報から、処理対象ブロックのインター予測情報を導出するモードである。 <Merge mode>
In the merge mode, the processed block adjacent to the processed block or the block belonging to the processed image and located at the same position as or near (near) the processed block without transmitting the differential motion vector and the reference index. In this mode, the inter-prediction information of the block to be processed is derived from the inter-prediction information of.
　処理対象ブロックに隣接する処理済みブロック、およびその処理済みブロックのインター予測情報を空間マージ候補と定義する。処理済み画像に属するブロックで処理対象ブロックと同一位置またはその付近（近傍）に位置するブロック、およびそのブロックのインター予測情報から導出されるインター予測情報を時間マージ候補と定義する。各マージ候補はマージ候補リストに登録され、マージインデックスにより、処理対象ブロックの予測で使用するマージ候補を特定する。 The processed block adjacent to the processing target block and the inter-prediction information of the processed block are defined as spatial merge candidates. Blocks that belong to the processed image and are located at the same position as or near (near) the block to be processed, and inter-prediction information derived from the inter-prediction information of that block are defined as time merge candidates. Each merge candidate is registered in the merge candidate list, and the merge index identifies the merge candidate used in the prediction of the block to be processed.
　＜隣接ブロック＞
　図１１は、予測動きベクトルモード、マージモードで、インター予測情報を導出するために参照する参照ブロックを説明する図である。Ａ０，Ａ１，Ａ２，Ｂ０，Ｂ１，Ｂ２，Ｂ３は、処理対象ブロックに隣接する処理済みブロックである。Ｔ０は、処理済み画像に属するブロックで、処理対象画像における処理対象ブロックと同一位置またはその付近（近傍）に位置するブロックである。 <Adjacent block>
FIG. 11 is a diagram illustrating a reference block referred to for deriving inter-prediction information in the predicted motion vector mode and the merge mode. A0, A1, A2, B0, B1, B2, and B3 are processed blocks adjacent to the processing target block. T0 is a block belonging to the processed image, and is a block located at the same position as or near (near) the processing target block in the processing target image.
　Ａ１，Ａ２は、処理対象符号化ブロックの左側に位置し、処理対象符号化ブロックに隣接するブロックである。Ｂ１，Ｂ３は、処理対象符号化ブロックの上側に位置し、処理対象符号化ブロックに隣接するブロックである。Ａ０，Ｂ０，Ｂ２はそれぞれ、処理対象符号化ブロックの左下、右上、左上に位置するブロックである。 A1 and A2 are blocks located on the left side of the processing target coding block and adjacent to the processing target coding block. B1 and B3 are blocks located above the processing target coding block and adjacent to the processing target coding block. A0, B0, and B2 are blocks located at the lower left, upper right, and upper left of the coded block to be processed, respectively.
　予測動きベクトルモード、マージモードにおいて隣接ブロックをどのように扱うかの詳細については後述する。 Details on how to handle adjacent blocks in the predicted motion vector mode and merge mode will be described later.
　＜アフィン変換動き補償＞
　アフィン変換動き補償は、符号化ブロックを所定単位のサブブロックに分割し、分割された各サブブロックに対して個別に動きベクトルを決定して動き補償を行うものである。各サブブロックの動きベクトルは、処理対象ブロックに隣接する処理済みブロック、または処理済み画像に属するブロックで処理対象ブロックと同一位置またはその付近（近傍）に位置するブロックのインター予測情報から導出する１つ以上の制御点に基づき導出する。本実施の形態では、サブブロックのサイズを４ｘ４画素とするが、サブブロックのサイズはこれに限定されるものではないし、画素単位で動きベクトルを導出してもよい。 <Affine transformation motion compensation>
In the affine transformation motion compensation, the coded block is divided into subblocks of a predetermined unit, and the motion vector is individually determined for each of the divided subblocks to perform the motion compensation. The motion vector of each sub-block is derived from the inter-prediction information of the processed block adjacent to the processing target block or the block belonging to the processed image and located at the same position as or near (near) the processing target block. Derived based on one or more control points. In the present embodiment, the size of the subblock is 4x4 pixels, but the size of the subblock is not limited to this, and the motion vector may be derived in pixel units.
　図１４に、制御点が２つの場合のアフィン変換動き補償の例を示す。この場合、２つの制御点が水平方向成分、垂直方向成分の２つのパラメータを有する。このため、制御点が２つの場合のアフィン変換を、４パラメータアフィン変換と呼称する。図１４のＣＰ１、ＣＰ２が制御点である。
　図１５に、制御点が３つの場合のアフィン変換動き補償の例を示す。この場合、３つの制御点が水平方向成分、垂直方向成分の２つのパラメータを有する。このため、制御点が３つの場合のアフィン変換を、６パラメータアフィン変換と呼称する。図１５のＣＰ１、ＣＰ２、ＣＰ３が制御点である。 FIG. 14 shows an example of affine transformation motion compensation when there are two control points. In this case, the two control points have two parameters, a horizontal component and a vertical component. Therefore, the affine transformation when there are two control points is called a four-parameter affine transformation. CP1 and CP2 in FIG. 14 are control points.
FIG. 15 shows an example of affine transformation motion compensation when there are three control points. In this case, the three control points have two parameters, a horizontal component and a vertical component. Therefore, the affine transformation when there are three control points is called a 6-parameter affine transformation. CP1, CP2, and CP3 in FIG. 15 are control points.
　アフィン変換動き補償は、予測動きベクトルモードおよびマージモードのいずれのモードにおいても利用可能である。予測動きベクトルモードでアフィン変換動き補償を適用するモードをサブブロック予測動きベクトルモードと定義し、マージモードでアフィン変換動き補償を適用するモードをサブブロックマージモードと定義する。 Affine transformation motion compensation can be used in both the predicted motion vector mode and the merge mode. The mode in which the affine transformation motion compensation is applied in the predicted motion vector mode is defined as the subblock predicted motion vector mode, and the mode in which the affine transformation motion compensation is applied in the merge mode is defined as the subblock merge mode.
　＜ＰＯＣ＞
　ＰＯＣ（Picture Order Count）は符号化されるピクチャに関連付けられる変数であり、ピクチャの出力順序に応じた１ずつ増加する値が設定される。ＰＯＣの値によって、同じピクチャであるかを判別したり、出力順序でのピクチャ間の前後関係を判別したり、ピクチャ間の距離を導出したりすることができる。例えば、２つのピクチャのＰＯＣが同じ値を持つ場合、同一のピクチャであると判断できる。２つのピクチャのＰＯＣが違う値を持つ場合、ＰＯＣの値が小さいピクチャのほうが、先に出力されるピクチャであると判断でき、２つのピクチャのＰＯＣの差が時間軸方向でのピクチャ間距離を示す。 <POC>
The POC (Picture Order Count) is a variable associated with the encoded picture, and a value that increases by 1 according to the output order of the picture is set. Depending on the value of POC, it is possible to determine whether the pictures are the same, determine the context between the pictures in the output order, and derive the distance between the pictures. For example, if the POCs of the two pictures have the same value, it can be determined that they are the same picture. If the POCs of the two pictures have different values, it can be determined that the picture with the smaller POC value is the picture to be output first, and the difference between the POCs of the two pictures is the distance between the pictures in the time axis direction. Shown.
（第１の実施の形態）
　本発明の第１の実施の形態に係る画像符号化装置１００及び画像復号装置２００について説明する。 (First Embodiment)
The image coding device 100 and the image decoding device 200 according to the first embodiment of the present invention will be described.
　図１は、第１の実施の形態に係る画像符号化装置１００のブロック図である。実施の形態の画像符号化装置１００は、ブロック分割部１０１、インター予測部１０２、イントラ予測部１０３、復号画像メモリ１０４、予測方法決定部１０５、残差信号生成部１０６、直交変換・量子化部１０７、ビット列符号化部１０８、逆量子化・逆直交変換部１０９、復号画像信号重畳部１１０、および符号化情報格納メモリ１１１を備える。 FIG. 1 is a block diagram of the image coding device 100 according to the first embodiment. The image coding device 100 of the embodiment includes a block division unit 101, an inter prediction unit 102, an intra prediction unit 103, a decoded image memory 104, a prediction method determination unit 105, a residual signal generation unit 106, and an orthogonal conversion / quantization unit. It includes 107, a bit string coding unit 108, an inverse quantization / inverse orthogonal conversion unit 109, a decoded image signal superimposing unit 110, and a coding information storage memory 111.
　ブロック分割部１０１は、入力した画像をツリーブロックに分割し、各ツリーブロックをさらに再帰的かつ階層的に符号化ブロックに分割する。ブロック分割部１０１は、各階層においては、４分割、垂直２分割、垂直３分割、水平２分割、水平３分割による分割を行い、ブロック分割情報をインター予測部１０２、イントラ予測部１０３および予測方法決定部に供給する。さらに、生成した処理対象符号化ブロックの画像信号を、インター予測部１０２、イントラ予測部１０３および残差信号生成部１０６に供給する。また、ブロック分割部１０１は、決定した再帰分割構造を示す情報をビット列符号化部１０８に供給する。ブロック分割部１０１の詳細な動作は後述する。 The block division unit 101 divides the input image into tree blocks, and further recursively and hierarchically divides each tree block into coded blocks. In each layer, the block division unit 101 divides by four divisions, vertical two divisions, vertical three divisions, horizontal two divisions, and horizontal three divisions, and blocks division information is divided into an inter prediction unit 102, an intra prediction unit 103, and a prediction method. Supply to the decision section. Further, the generated image signal of the coded block to be processed is supplied to the inter prediction unit 102, the intra prediction unit 103, and the residual signal generation unit 106. Further, the block division unit 101 supplies information indicating the determined recursive division structure to the bit string coding unit 108. The detailed operation of the block dividing unit 101 will be described later.
　インター予測部１０２は、処理対象符号化ブロックのインター予測を行う。インター予測部１０２は、符号化情報格納メモリ１１１に格納されているインター予測情報と、復号画像メモリ１０４に格納されている復号済みの画像信号とから、複数のインター予測情報の候補を導出し、導出した複数の候補の中から適したインター予測モードを選択し、選択されたインター予測モード、及び選択されたインター予測モードに応じた予測画像信号を予測方法決定部１０５に供給する。インター予測部１０２の詳細な構成と動作は後述する。 The inter-prediction unit 102 performs inter-prediction of the coded block to be processed. The inter-prediction unit 102 derives a plurality of inter-prediction information candidates from the inter-prediction information stored in the coded information storage memory 111 and the decoded image signal stored in the decoded image memory 104. A suitable inter-prediction mode is selected from the plurality of derived candidates, and the selected inter-prediction mode and the prediction image signal corresponding to the selected inter-prediction mode are supplied to the prediction method determination unit 105. The detailed configuration and operation of the inter-prediction unit 102 will be described later.
　イントラ予測部１０３は、処理対象符号化ブロックのイントラ予測およびイントラブロックコピー予測を行う。イントラ予測およびイントラブロックコピー予測は、復号画像メモリ１０４に格納されている処理対象符号化ブロックと同一の画像信号、すなわち処理対象画像の、復号済みの領域から予測画像信号を作成し、予測方法決定部１０５に供給する。イントラ予測部１０３の詳細な構成と動作は後述する。 The intra prediction unit 103 performs intra prediction and intra block copy prediction of the coded block to be processed. In the intra prediction and the intra block copy prediction, a prediction image signal is created from the same image signal as the processing target coded block stored in the decoded image memory 104, that is, the decoded area of the processing target image, and the prediction method is determined. Supply to unit 105. The detailed configuration and operation of the intra prediction unit 103 will be described later.
　復号画像メモリ１０４は、復号画像信号重畳部１１０で生成した復号画像を格納する。復号画像メモリ１０４は、格納している復号画像を、インター予測部１０２、イントラ予測部１０３に供給する。 The decoded image memory 104 stores the decoded image generated by the decoded image signal superimposing unit 110. The decoded image memory 104 supplies the stored decoded image to the inter prediction unit 102 and the intra prediction unit 103.
　予測方法決定部１０５は、各予測に対して、符号化情報及び残差信号の符号量、予測画像信号と処理対象画像信号との間の歪量等を用いて評価することにより、ブロック分割の各階層において、ブロックを分割するか否か、ブロック分割する場合、４分割、垂直２分割、垂直３分割、水平２分割、水平３分割のいずれかを決定する。さらに、符号化ブロックにおいて、処理対象の符号化ブロックの最適な予測モードCuPredModeがイントラ予測モード（MODE_INTRA）、ＩＢＣ予測モード（MODE_IBC）、インター予測モード（MODE_INTER）のいずれであるかを決定する。イントラ予測（MODE_INTRA）の場合、イントラ輝度予測モード、イントラ色差予測モードを決定する。ＩＢＣ予測（MODE_IBC）の場合、マージモード情報、ブロックベクトル等のＩＢＣ予測（MODE_IBC）に関する符号化情報を決定する。インター予測（MODE_INTER）の場合は、マージモード情報、インター予測モード、参照ピクチャ、動きベクトル等のインター予測（MODE_INTER）に関する符号化情報を決定する。決定した符号化情報をビット列符号化部１０８、符号化情報格納メモリ１１１に供給する。予測方法決定部１０５は、残差信号生成部１０６及び予測画像信号を復号画像信号重畳部１１０に供給する。 The prediction method determination unit 105 divides each prediction into blocks by evaluating each prediction using the coding information, the code amount of the residual signal, the amount of distortion between the predicted image signal and the image signal to be processed, and the like. In each layer, it is determined whether or not to divide the block, and when the block is divided, one of 4 division, vertical 2 division, vertical 3 division, horizontal 2 division, and horizontal 3 division is determined. Further, in the coded block, it is determined whether the optimum prediction mode CuPredMode of the coded block to be processed is the intra prediction mode (MODE_INTRA), the IBC prediction mode (MODE_IBC), or the inter prediction mode (MODE_INTER). In the case of intra prediction (MODE_INTRA), the intra brightness prediction mode and the intra color difference prediction mode are determined. In the case of IBC prediction (MODE_IBC), the coding information related to IBC prediction (MODE_IBC) such as merge mode information and block vector is determined. In the case of inter-prediction (MODE_INTER), the coding information related to inter-prediction (MODE_INTER) such as merge mode information, inter-prediction mode, reference picture, and motion vector is determined. The determined coding information is supplied to the bit string coding unit 108 and the coding information storage memory 111. The prediction method determination unit 105 supplies the residual signal generation unit 106 and the prediction image signal to the decoded image signal superimposition unit 110.
　残差信号生成部１０６は、処理対象の画像信号から予測画像信号を減ずることにより残差信号を生成し、直交変換・量子化部１０７に供給する。 The residual signal generation unit 106 generates a residual signal by subtracting the predicted image signal from the image signal to be processed, and supplies the residual signal to the orthogonal transformation / quantization unit 107.
　直交変換・量子化部１０７は、残差信号に対して量子化パラメータに応じて直交変換及び量子化を行い直交変換・量子化された残差信号を生成し、生成した残差信号をビット列符号化部１０８と逆量子化・逆直交変換部１０９に供給する。 The orthogonal conversion / quantization unit 107 performs orthogonal conversion and quantization on the residual signal according to the quantization parameter, generates an orthogonal conversion / quantization residual signal, and uses the generated residual signal as a bit string code. It is supplied to the conversion unit 108 and the inverse quantization / inverse orthogonal conversion unit 109.
　ビット列符号化部１０８は、シーケンス、ピクチャ、スライス単位の情報に加えて、予測方法決定部１０５によって決定されたブロック分割情報、符号化ブロック毎の予測方法に応じた符号化情報を符号化する。具体的には、ブロック分割の各階層において、ブロック分割を示す情報、例えばブロックを分割するか否かを示すフラグ、４分割するか否かを示すフラグ、２分割または３分割するか否かを示すフラグ、垂直に分割するか水平に分割するかを示すフラグ、２分割するか３分割するかを示すフラグ等を符号化する。さらに、符号化ブロック毎の予測モードCuPredModeを示す情報を符号化する。例えば、ビット列符号化部１０８は、符号化ブロック毎の予測モードがインター予測か否かを示すフラグPredModeを符号化する。さらに、インター予測でない場合、すなわち、イントラ予測（MODE_INTRA）またはＩＢＣ予測（MODE_IBC）の場合、イントラブロックコピーか否かを判別するフラグpred_mode_ibc_flagを符号化する。さらに、予測モードがイントラ予測（MODE_INTRA）の場合は、イントラ輝度予測モード、イントラ色差予測モードに関する情報を符号化し、第１の符号化ビット列とする。予測モードがＩＢＣ予測（MODE_IBC）の場合は、マージモードか否かを判別するフラグ、マージモードならばマージインデックス、マージモードでないならば予測ブロックベクトルインデックス、差分ブロックベクトル等の符号化情報を符号化し、第１の符号化ビット列とする。予測モードがインター予測（MODE_INTER）の場合、マージモードか否かを判別するフラグ、サブブロックマージフラグ、マージモードの場合はマージインデックス、マージモードでない場合はインター予測モード、予測動きベクトルインデックス、差分動きベクトルに関する情報、サブブロック予測動きベクトルフラグ等の符号化情報を規定のシンタックス（符号化ビット列の構文規則）に従って符号化し、第１の符号化ビット列とする。また、ビット列符号化部１０８は、直交変換及び量子化された残差信号を規定のシンタックスに従ってエントロピー符号化して第２の符号化ビット列を生成する。第１の符号化ビット列と第２の符号化ビット列を規定のシンタックスに従って多重化し、ビットストリームを出力する。 The bit string coding unit 108 encodes the block division information determined by the prediction method determination unit 105 and the coding information according to the prediction method for each coding block, in addition to the sequence, picture, and slice unit information. Specifically, in each layer of block division, information indicating block division, for example, a flag indicating whether or not to divide the block, a flag indicating whether or not to divide into four, and whether or not to divide into two or three A flag indicating, a flag indicating whether to divide vertically or horizontally, a flag indicating whether to divide into two or three, and the like are encoded. Further, the information indicating the prediction mode CuPredMode for each coding block is encoded. For example, the bit string coding unit 108 encodes a flag PredMode indicating whether or not the prediction mode for each coding block is inter-prediction. Further, in the case of non-inter-prediction, that is, intra-prediction (MODE_INTRA) or IBC prediction (MODE_IBC), the flag pred_mode_ibc_flag for determining whether or not it is an intra-block copy is encoded. Further, when the prediction mode is intra prediction (MODE_INTRA), the information regarding the intra-luminance prediction mode and the intra-color difference prediction mode is encoded and used as the first coded bit string. When the prediction mode is IBC prediction (MODE_IBC), a flag for determining whether or not the merge mode is used, a merge index for the merge mode, a prediction block vector index for the non-merge mode, and a difference block vector are encoded. , The first coded bit string. If the prediction mode is inter-prediction (MODE_INTER), a flag that determines whether or not it is in merge mode, a subblock merge flag, a merge index if it is in merge mode, an inter-prediction mode if it is not in merge mode, a prediction motion vector index, and a differential motion. Coded information such as vector information and subblock predicted motion vector flags are coded according to the specified syntax (coded bit string syntax rules) to be the first coded bit string. Further, the bit string coding unit 108 entropy-encodes the orthogonal conversion and the quantized residual signal according to the specified syntax to generate a second coded bit string. The first coded bit string and the second coded bit string are multiplexed according to the specified syntax, and a bit stream is output.
　逆量子化・逆直交変換部１０９は、直交変換・量子化部１０７から供給された直交変換・量子化された残差信号を逆量子化及び逆直交変換して残差信号を算出し、算出した残差信号を復号画像信号重畳部１１０に供給する。 The inverse quantization / inverse orthogonal conversion unit 109 calculates and calculates the residual signal by inversely quantizing and inversely orthogonalizing the orthogonal conversion / quantization residual signal supplied from the orthogonal conversion / quantization unit 107. The generated residual signal is supplied to the decoded image signal superimposing unit 110.
　復号画像信号重畳部１１０は、予測方法決定部１０５による決定に応じた予測画像信号と逆量子化・逆直交変換部１０９で逆量子化及び逆直交変換された残差信号を重畳して復号画像を生成し、復号画像メモリ１０４に格納する。なお、復号画像信号重畳部１１０は、復号画像に対して符号化によるブロック歪等の歪を減少させるフィルタリング処理を施した後、復号画像メモリ１０４に格納してもよい。 The decoded image signal superimposition unit 110 superimposes the predicted image signal according to the determination by the prediction method determination unit 105 and the residual signal that has been inversely quantized and inversely orthogonally converted by the inverse quantization / inverse orthogonal conversion unit 109 to obtain the decoded image. Is generated and stored in the decoded image memory 104. The decoded image signal superimposing unit 110 may store the decoded image in the decoded image memory 104 after performing a filtering process on the decoded image to reduce distortion such as block distortion due to coding.
　符号化情報格納メモリ１１１は、予測方法決定部１０５で決定した、予測モード（イントラ予測、ＩＢＣ予測、またはインター予測）等の符号化情報を格納する。符号化情報格納メモリ１１１が格納する符号化情報は、イントラ予測の場合は、決定したイントラ輝度予測モード、イントラ色差予測モード等のイントラ予測情報である。ＩＢＣ予測の場合は、決定したブロックベクトル等のＩＢＣ情報である。インター予測の場合は、決定した動きベクトル、参照リスト、参照インデックス等のインター予測情報である。符号化情報格納メモリ１１１で管理される履歴候補リストの構築については後述する。 The coded information storage memory 111 stores coded information such as a prediction mode (intra prediction, IBC prediction, or inter prediction) determined by the prediction method determination unit 105. In the case of intra-prediction, the coding information stored in the coding information storage memory 111 is intra-prediction information such as the determined intra-luminance prediction mode and intra-color difference prediction mode. In the case of IBC prediction, it is IBC information such as a determined block vector. In the case of inter-prediction, it is inter-prediction information such as a determined motion vector, a reference list, and a reference index. The construction of the history candidate list managed by the coded information storage memory 111 will be described later.
　図２は、図１の画像符号化装置に対応した本発明の実施の形態に係る画像復号装置の構成を示すブロックである。実施の形態の画像復号装置は、ビット列復号部２０１、ブロック分割部２０２、インター予測部２０３、イントラ予測部２０４、符号化情報格納メモリ２０５、逆量子化・逆直交変換部２０６、復号画像信号重畳部２０７、および復号画像メモリ２０８を備える。 FIG. 2 is a block showing a configuration of an image decoding device according to an embodiment of the present invention corresponding to the image coding device of FIG. The image decoding device of the embodiment includes a bit string decoding unit 201, a block division unit 202, an inter prediction unit 203, an intra prediction unit 204, a coded information storage memory 205, an inverse quantization / inverse orthogonal conversion unit 206, and a decoded image signal superimposition. A unit 207 and a decoded image memory 208 are provided.
　図２の画像復号装置の復号処理は、図１の画像符号化装置の内部に設けられている復号処理に対応するものであるから、図２の符号化情報格納メモリ２０５、逆量子化・逆直交変換部２０６、復号画像信号重畳部２０７、および復号画像メモリ２０８の各構成は、図１の画像符号化装置の符号化情報格納メモリ１１１、逆量子化・逆直交変換部１０９、復号画像信号重畳部１１０、および復号画像メモリ１０４の各構成とそれぞれ対応する機能を有する。 Since the decoding process of the image decoding device of FIG. 2 corresponds to the decoding process provided inside the image coding device of FIG. 1, the coding information storage memory 205 of FIG. 2 and the inverse quantization / reverse Each configuration of the orthogonal conversion unit 206, the decoded image signal superimposing unit 207, and the decoded image memory 208 includes the coding information storage memory 111 of the image coding apparatus of FIG. 1, the inverse quantization / inverse orthogonal conversion unit 109, and the decoded image signal. It has a function corresponding to each configuration of the superimposing unit 110 and the decoded image memory 104.
　ビット列復号部２０１はビット列復号部２０１に供給されるビットストリームを規定のシンタックスの規則に従って第１の符号化ビット列、第２の符号化ビット列に分離する。ビット列復号部２０１は分離された第１の符号化ビット列を復号し、シーケンス、ピクチャ、スライス、ブロック分割の情報、及び、符号化ブロック単位の符号化情報を得る。具体的には、ブロック分割の各階層において、ブロック分割を示す情報、例えばブロックを分割するか否かを示すフラグ、４分割するか否かを示すフラグ、２分割または３分割するか否かを示すフラグ、垂直に分割するか水平に分割するかを示すフラグ、２分割するか３分割するかを示すフラグ等を復号する。さらに、符号化ブロック単位で予測モードCuPredModeを示す情報を復号する。具体的には、ビット列符号化部１０８は、符号化ブロック毎の予測モードがインター予測か否かを示すフラグPredModeを復号する。さらに、インター予測でない場合、すなわち、イントラ予測（MODE_INTRA）またはＩＢＣ予測（MODE_IBC）の場合、イントラブロックコピーか否かを判別するフラグpred_mode_ibc_flagを復号する。さらに、予測モードがイントラ予測（MODE_INTRA）の場合は、イントラ輝度予測モード、イントラ色差予測モード等のイントラ予測情報を復号する。ＩＢＣ（MODE_IBC）の場合は、マージモードか否かを判別するフラグ、マージモードならばマージインデックス、マージモードでないならば予測ブロックベクトルインデックス、差分ブロックベクトル等の符号化情報を規定のシンタックス（符号化ビット列の構文規則）に従って復号し、符号化情報をイントラ予測部２０４、および符号化情報格納メモリ２０５に供給する。インター予測（MODE_INTER）の場合、マージモードか否かを判別するフラグ、マージモードの場合はマージインデックス、サブブロックマージフラグ、予測動きベクトルモードである場合はインター予測モード、予測動きベクトルインデックス、差分動きベクトル、サブブロック予測動きベクトルフラグ等に関する符号化情報を規定のシンタックスに従って復号し、符号化情報をインター予測部２０３、および符号化情報格納メモリ２０５に供給する。さらに、ビット列復号部２０１は分離された第２の符号化ビット列を復号して直交変換・量子化された残差信号を算出し、直交変換・量子化された残差信号を逆量子化・逆直交変換部２０６に供給する。 The bit string decoding unit 201 separates the bit stream supplied to the bit string decoding unit 201 into a first coded bit string and a second coded bit string according to a predetermined syntax rule. The bit string decoding unit 201 decodes the separated first coded bit string to obtain sequence, picture, slice, block division information, and coded block unit coding information. Specifically, in each layer of block division, information indicating block division, for example, a flag indicating whether or not to divide the block, a flag indicating whether or not to divide into four, and whether or not to divide into two or three The flag indicating, the flag indicating whether to divide vertically or horizontally, the flag indicating whether to divide into two or three, and the like are decoded. Further, the information indicating the prediction mode CuPredMode is decoded for each coded block. Specifically, the bit string coding unit 108 decodes the flag PredMode indicating whether or not the prediction mode for each coding block is inter-prediction. Further, in the case of non-inter-prediction, that is, intra-prediction (MODE_INTRA) or IBC prediction (MODE_IBC), the flag pred_mode_ibc_flag for determining whether or not it is an intra-block copy is decoded. Further, when the prediction mode is the intra prediction (MODE_INTRA), the intra prediction information such as the intra brightness prediction mode and the intra color difference prediction mode is decoded. In the case of IBC (MODE_IBC), the specified syntax (code) is the coding information such as the flag that determines whether or not it is in merge mode, the merge index if it is in merge mode, the predicted block vector index if it is not in merge mode, and the difference block vector. Decoding is performed according to the syntax rule of the coded bit string), and the coded information is supplied to the intra prediction unit 204 and the coded information storage memory 205. In the case of inter-prediction (MODE_INTER), the flag that determines whether or not it is in merge mode, in the case of merge mode, the merge index, subblock merge flag, in the case of predictive motion vector mode, the inter-prediction mode, predicted motion vector index, differential motion. The coded information related to the vector, the sub-block prediction motion vector flag, etc. is decoded according to the specified syntax, and the coded information is supplied to the inter-prediction unit 203 and the coded information storage memory 205. Further, the bit string decoding unit 201 decodes the separated second coded bit string, calculates the orthogonally converted / quantized residual signal, and dequantizes / reverses the orthogonally converted / quantized residual signal. It is supplied to the orthogonal conversion unit 206.
　インター予測部２０３は、処理対象の符号化ブロックの予測モードPredModeがインター予測（MODE_INTER）で予測動きベクトルモードである時に、符号化情報格納メモリ２０５に記憶されている既に復号された画像信号の符号化情報を用いて、複数の予測動きベクトルの候補を導出して、導出した複数の予測動きベクトルの候補を、後述する予測動きベクトル候補リストに登録する。インター予測部２０３は、予測動きベクトル候補リストに登録された複数の予測動きベクトルの候補の中から、ビット列復号部２０１で復号され供給される予測動きベクトルインデックスに応じた予測動きベクトルを選択し、ビット列復号部２０１で復号された差分動きベクトルと選択された予測動きベクトルから動きベクトルを算出し、算出した動きベクトルを他の符号化情報とともに符号化情報格納メモリ２０５に格納する。ここで供給・格納する符号化ブロックの符号化情報は、予測モードPredMode、分割モードPartMode、Ｌ０予測、及びＬ１予測を利用するか否かを示すフラグpredFlagL0[xP][yP], predFlagL1[xP][yP]、Ｌ０、Ｌ１の参照インデックスrefIdxL0[xP][yP], refIdxL1[xP][yP]、Ｌ０、Ｌ１の動きベクトルmvL0[xP][yP], mvL1[xP][yP]等である。ここで、xP、yPはピクチャ内での符号化ブロックの左上の画素の位置を示すインデックスである。予測モードPredModeがインター予測（MODE_INTER）で、インター予測モードがＬ０予測（Pred_L0）の場合、Ｌ０予測を利用するか否かを示すフラグpredFlagL0は１、Ｌ１予測を利用するか否かを示すフラグpredFlagL1は０である。インター予測モードがＬ１予測（Pred_L1）の場合、Ｌ０予測を利用するか否かを示すフラグpredFlagL0は０、Ｌ１予測を利用するか否かを示すフラグpredFlagL1は１である。インター予測モードが双予測（Pred_BI）の場合、Ｌ０予測を利用するか否かを示すフラグpredFlagL0、Ｌ１予測を利用するか否かを示すフラグpredFlagL1は共に１である。さらに、処理対象の符号化ブロックの予測モードPredModeがインター予測（MODE_INTER）でマージモードの時に、マージ候補を導出する。符号化情報格納メモリ２０５に記憶されている既に復号された符号化ブロックの符号化情報を用いて、複数のマージの候補を導出して後述するマージ候補リストに登録し、マージ候補リストに登録された複数のマージ候補の中からビット列復号部２０１で復号され供給されるマージインデックスに対応したマージ候補を選択し、選択されたマージ候補のＬ０予測、及びＬ１予測を利用するか否かを示すフラグpredFlagL0[xP][yP], predFlagL1[xP][yP]、Ｌ０、Ｌ１の参照インデックスrefIdxL0[xP][yP], refIdxL1[xP][yP]、Ｌ０、Ｌ１の動きベクトルmvL0[xP][yP], mvL1[xP][yP]等のインター予測情報を符号化情報格納メモリ２０５に格納する。ここで、xP、yPはピクチャ内での符号化ブロックの左上の画素の位置を示すインデックスである。インター予測部２０３の詳細な構成と動作は後述する。 The inter-prediction unit 203 describes the code of the already decoded image signal stored in the coding information storage memory 205 when the prediction mode PredMode of the coded block to be processed is inter-prediction (MODE_INTER) and the prediction motion vector mode. A plurality of predicted motion vector candidates are derived using the conversion information, and the derived candidates for the plurality of predicted motion vectors are registered in the predicted motion vector candidate list described later. The inter-prediction unit 203 selects a predicted motion vector according to the predicted motion vector index decoded and supplied by the bit string decoding unit 201 from a plurality of predicted motion vector candidates registered in the predicted motion vector candidate list. A motion vector is calculated from the differential motion vector decoded by the bit string decoding unit 201 and the selected predicted motion vector, and the calculated motion vector is stored in the coding information storage memory 205 together with other coding information. The coding information of the coding block supplied and stored here is the flag predFlagL0 [xP] [yP], predFlagL1 [xP] indicating whether or not to use the prediction mode PredMode, the division mode PartMode, the L0 prediction, and the L1 prediction. Reference indexes of [yP], L0, L1 refIdxL0 [xP] [yP], refIdxL1 [xP] [yP], motion vectors of L0, L1 mvL0 [xP] [yP], mvL1 [xP] [yP], etc. .. Here, xP and yP are indexes indicating the positions of the upper left pixels of the coded block in the picture. When the prediction mode PredMode is inter-prediction (MODE_INTER) and the inter-prediction mode is L0 prediction (Pred_L0), the flag predFlagL0 indicating whether to use L0 prediction is 1, and the flag predFlagL1 indicating whether to use L1 prediction. Is 0. When the inter-prediction mode is L1 prediction (Pred_L1), the flag predFlagL0 indicating whether or not to use the L0 prediction is 0, and the flag predFlag L1 indicating whether or not to use the L1 prediction is 1. When the inter-prediction mode is bi-prediction (Pred_BI), the flag predFlagL0 indicating whether or not to use the L0 prediction and the flag predFlag L1 indicating whether or not to use the L1 prediction are both 1. Further, when the prediction mode PredMode of the coded block to be processed is inter-prediction (MODE_INTER) and the merge mode is set, merge candidates are derived. Using the coding information of the already decoded coding block stored in the coding information storage memory 205, a plurality of merge candidates are derived, registered in the merge candidate list described later, and registered in the merge candidate list. A flag indicating whether or not to use the L0 prediction and the L1 prediction of the selected merge candidate by selecting the merge candidate corresponding to the merge index decoded and supplied by the bit string decoding unit 201 from the plurality of merge candidates. PredFlagL0 [xP] [yP], predFlagL1 [xP] [yP], reference index refIdxL0 [xP] [yP], refIdxL1 [xP] [yP], L0, L1 motion vector mvL0 [xP] [yP] ], MvL1 [xP] [yP] and other inter-prediction information is stored in the coded information storage memory 205. Here, xP and yP are indexes indicating the positions of the upper left pixels of the coded block in the picture. The detailed configuration and operation of the inter-prediction unit 203 will be described later.
　イントラ予測部２０４は、処理対象の符号化ブロックの予測モードPredModeがイントラ予測（MODE_INTRA）の時に、イントラ予測を行い、ＩＢＣ予測（MODE_IBC）の時に、イントラブロックコピー予測を行う。イントラ予測（MODE_INTRA）の時には、ビット列復号部２０１から供給される符号化情報にはイントラ輝度予測モード、イントラ色差予測モードが含まれており、イントラ輝度予測モード、イントラ色差予測モードに応じて、復号画像メモリ２０８に格納されている復号済みの画像信号からイントラ予測により予測画像信号を生成し、予測画像信号を復号画像信号重畳部２０７に供給する。ＩＢＣ予測（MODE_IBC）の時には、ビット列復号部２０１から供給されるＩＢＣ予測（MODE_IBC）に関する符号化情報に基づいて、ブロックベクトルを導出し、イントラブロックコピー予測を行う。イントラ予測部２０４は、画像符号化装置１００のイントラ予測部１０３に対応するものであるから、イントラ予測部１０３と同様の処理を行う。イントラ予測部２０４の詳細な構成と動作は後述する。 The intra prediction unit 204 performs intra prediction when the prediction mode PredMode of the coded block to be processed is intra prediction (MODE_INTRA), and performs intra block copy prediction when IBC prediction (MODE_IBC). At the time of intra prediction (MODE_INTRA), the coding information supplied from the bit string decoding unit 201 includes an intra luminance prediction mode and an intra color difference prediction mode, and decodes according to the intra luminance prediction mode and the intra color difference prediction mode. A predicted image signal is generated by intra-prediction from the decoded image signal stored in the image memory 208, and the predicted image signal is supplied to the decoded image signal superimposing unit 207. At the time of IBC prediction (MODE_IBC), a block vector is derived and intra-block copy prediction is performed based on the coding information regarding the IBC prediction (MODE_IBC) supplied from the bit string decoding unit 201. Since the intra prediction unit 204 corresponds to the intra prediction unit 103 of the image coding device 100, the same processing as that of the intra prediction unit 103 is performed. The detailed configuration and operation of the intra prediction unit 204 will be described later.
　逆量子化・逆直交変換部２０６は、ビット列復号部２０１で復号された直交変換・量子化された残差信号に対して逆直交変換及び逆量子化を行い、逆直交変換・逆量子化された残差を得る。 The inverse quantization / anti-orthogonal conversion unit 206 performs anti-orthogonal conversion and inverse quantization on the orthogonal conversion / quantization residual signal decoded by the bit string decoding unit 201, and is inversely orthogonal conversion / inverse quantization. Get the residuals.
　復号画像信号重畳部２０７は、インター予測部２０３でインター予測された予測画像信号、またはイントラ予測部２０４でイントラ予測された予測画像信号と、逆量子化・逆直交変換部２０６により逆直交変換・逆量子化された残差信号とを重畳することにより、復号画像信号を復号し、復号した復号画像信号を復号画像メモリ２０８に格納する。復号画像メモリ２０８に格納する際には、復号画像信号重畳部２０７は、復号画像に対して符号化によるブロック歪等を減少させるフィルタリング処理を施した後、復号画像メモリ２０８に格納してもよい。 The decoded image signal superimposition unit 207 is inversely quantized and inversely orthogonally converted by the inverse quantization / inverse orthogonal conversion unit 206 with the predicted image signal inter-predicted by the inter-prediction unit 203 or the predicted image signal intra-predicted by the intra prediction unit 204. The decoded image signal is decoded by superimposing the inverse quantized residual signal, and the decoded image signal is stored in the decoded image memory 208. When storing in the decoded image memory 208, the decoded image signal superimposing unit 207 may perform a filtering process on the decoded image to reduce block distortion due to coding and then store in the decoded image memory 208. ..
　＜ブロック分割＞
　次に、画像符号化装置１００におけるブロック分割部１０１の動作について説明する。本実施の形態においては輝度ブロックと色差ブロックを同様の分割方法で同期させて分割するシングルツリーモードについて説明する。図６は、画像をツリーブロックに分割し、各ツリーブロックをさらに符号化ブロックに分割する動作を示すフローチャートである。まず、入力された画像を、所定サイズのツリーブロックに分割する（ステップＳ１００１）。各ツリーブロックについては、所定の順序、すなわちラスタスキャン順に走査し（ステップＳ１００２～Ｓ１００４）、処理対象のツリーブロックの内部を再帰的かつ階層的に分割し、符号化ブロックとする（ステップＳ１００３）。 <Block division>
Next, the operation of the block dividing unit 101 in the image coding apparatus 100 will be described. In the present embodiment, a single tree mode in which the luminance block and the color difference block are synchronized and divided by the same division method will be described. FIG. 6 is a flowchart showing an operation of dividing an image into tree blocks and further dividing each tree block into coded blocks. First, the input image is divided into tree blocks of a predetermined size (step S1001). Each tree block is scanned in a predetermined order, that is, in the order of raster scan (steps S1002 to S1004), and the inside of the tree block to be processed is recursively and hierarchically divided into coded blocks (step S1003).
　図７は、ステップＳ１００３の符号化側の符号化ブロック分割処理の詳細動作を示すフローチャートである。符号化側のブロック分割部１０１では、４分割、垂直２分割、垂直３分割、水平２分割、水平３分割による分割または非分割を行い、（ステップＳ１１０１～Ｓ１１１１）各分割モード及び、それに対応する後述の色差ブロック非分割フラグchroma_non_split_flag等のブロック分割情報をインター予測部１０２、イントラ予測部１０３及び予測方法決定部１０５に供給する。さらに、生成した処理対象符号化ブロックの画像信号を、インター予測部１０２、イントラ予測部１０３および残差信号生成部１０６に供給する。 FIG. 7 is a flowchart showing a detailed operation of the coded block division process on the coded side in step S1003. The block division section 101 on the coding side performs division or non-division by 4 divisions, vertical 2 divisions, vertical 3 divisions, horizontal 2 divisions, and horizontal 3 divisions (steps S1101 to S1111), and corresponds to each division mode. Block division information such as the color difference block non-division flag chroma_non_split_flag, which will be described later, is supplied to the inter prediction unit 102, the intra prediction unit 103, and the prediction method determination unit 105. Further, the generated image signal of the coded block to be processed is supplied to the inter prediction unit 102, the intra prediction unit 103, and the residual signal generation unit 106.
　まず、ステップＳ１１０１～Ｓ１１１１のループが回る毎に、４分割（SPLIT_QT）、垂直２分割（SPLIT_BT_VER）、垂直３分割（SPLIT_TT_VER）、水平２分割（SPLIT_BT_HOR）、水平３分割（SPLIT_TT_HOR）、非分割（SPLIT_NONE）の分割モードを順次設定し、色差ブロック非分割フラグchroma_non_split_flagを０（偽）に初期化する（ステップＳ１１０２）。色差ブロック非分割フラグchroma_non_split_flagについては後述する。 First, every time the loop of steps S1101 to S1111 turns, it is divided into 4 (SPLIT_QT), 2 vertical (SPLIT_BT_VER), 3 vertical (SPLIT_TT_VER), 2 horizontal (SPLIT_BT_HOR), 3 horizontal (SPLIT_TT_HOR), and non-divided (SPLIT_TT_HOR). The division mode of SPLIT_NONE) is sequentially set, and the color difference block non-division flag chroma_non_split_flag is initialized to 0 (false) (step S1102). The color difference block non-split flag chroma_non_split_flag will be described later.
　続いて、ステップＳ１１０２で設定した分割モードが４分割（SPLIT_QT）、垂直２分割（SPLIT_BT_VER）、垂直３分割（SPLIT_TT_VER）、水平２分割（SPLIT_BT_HOR）、または水平３分割（SPLIT_TT_HOR）の場合（ステップＳ１１０３：ＹＥＳ）、分割モードに従って、分割対象の輝度ブロックを分割する（ステップＳ１１０４）。一方、ステップＳ１１０２で設定した分割モードが非分割（SPLIT_NONE）の場合（ステップＳ１１０３：ＮＯ）、ステップＳ１１０４～Ｓ１１１０の分割処理をスキップする。 Subsequently, when the division mode set in step S1102 is 4-division (SPLIT_QT), vertical 2-division (SPLIT_BT_VER), vertical 3-division (SPLIT_TT_VER), horizontal 2-division (SPLIT_BT_HOR), or horizontal 3-division (SPLIT_TT_HOR) (step S1103). : YES), the luminance block to be divided is divided according to the division mode (step S1104). On the other hand, when the division mode set in step S1102 is non-division (SPLIT_NONE) (step S1103: NO), the division processing of steps S1104 to S1110 is skipped.
　続いて、予測モードがイントラ予測（MODE_INTRA）またはＩＢＣ予測（MODE_IBC）において、ステップＳ１１０２で設定した分割モードに基づいて色差ブロックの分割処理を行うか否かを判定する（ステップＳ１１０５）。本実施の形態においては、演算処理量、及びメモリアクセス回数を減らすために、輝度信号の符号化ブロックのサイズが１６画素（４×４、８×２、２×８）画素では、インター予測を禁止し、イントラ予測またはＩＢＣ予測を行う。さらに、色差フォーマットが４：２：０または、４：２：２の場合、演算処理量、及びメモリアクセス回数を減らすために、予測モードがイントラ予測（MODE_INTRA）またはＩＢＣ予測（MODE_IBC）において所定のサイズ以下の色差符号化ブロックを禁止する。本実施の形態では色差ブロックのサイズが８画素以下（または１６画素未満）、すなわち２×２、４×２、２×４画素の色差符号化ブロックを禁止する。ステップＳ１１０２で設定された分割モードで分割対象の色差ブロックを分割した際に、分割された色差ブロックが所定のサイズである８画素以下になる場合は、分割対象の色差ブロックを分割せずに、色差符号化ブロックとする。なお、色差フォーマットが４：２：０では、分割後の輝度ブロックのサイズが３２画素以下、すなわち４×４、８×４、４×８画素の時、色差ブロックの分割を禁止することと等価である。なお、前述の色差ブロック非分割フラグchroma_non_split_flagはイントラ予測、およびIBC予測において、分割モードに基づいて分割対象の色差ブロックを分割せずに、色差符号化ブロックとすることを示すフラグである。 Subsequently, when the prediction mode is intra prediction (MODE_INTRA) or IBC prediction (MODE_IBC), it is determined whether or not to perform the color difference block division processing based on the division mode set in step S1102 (step S1105). In the present embodiment, in order to reduce the amount of arithmetic processing and the number of memory accesses, when the size of the coded block of the luminance signal is 16 pixels (4 × 4, 8 × 2, 2 × 8) pixels, inter-prediction is performed. Prohibit and make intra-prediction or IBC prediction. Further, when the color difference format is 4: 2: 0 or 4: 2: 2, the prediction mode is predetermined in intra prediction (MODE_INTRA) or IBC prediction (MODE_IBC) in order to reduce the amount of arithmetic processing and the number of memory accesses. Prohibit color difference coded blocks smaller than size. In the present embodiment, the color difference coded block having a color difference block size of 8 pixels or less (or less than 16 pixels), that is, 2 × 2, 4 × 2, 2 × 4 pixels is prohibited. When the color difference block to be divided is divided in the division mode set in step S1102, if the divided color difference block is 8 pixels or less, which is a predetermined size, the color difference block to be divided is not divided. It is a color difference coded block. When the color difference format is 4: 2: 0 and the size of the luminance block after division is 32 pixels or less, that is, 4 × 4, 8 × 4, 4 × 8 pixels, it is equivalent to prohibiting the division of the color difference block. Is. The above-mentioned color difference block non-division flag chroma_non_split_flag is a flag indicating that the color difference block to be divided is not divided based on the division mode in the intra prediction and the IBC prediction, but is used as the color difference coding block.
　イントラ予測またはＩＢＣ予測において所定のサイズ以下の色差符号化ブロックを禁止するか否かについて、分割対象の色差ブロックのサイズが８×４を一例として、図８Ａ～Ｅを用いて説明する。図８Ａに示すように、分割モードが垂直２分割モードでは、分割対象の色差ブロックを垂直２分割することができ、分割された色差ブロックのサイズは４×４となる。図８Ｂに示すように、分割モードが水平２分割モードでは、分割対象の色差ブロックを水平２分割することができ、分割された色差ブロックのサイズは８×２となる。 Whether or not to prohibit color difference coded blocks smaller than a predetermined size in intra prediction or IBC prediction will be described with reference to FIGS. 8A to 8E, taking as an example the size of the color difference block to be divided is 8 × 4. As shown in FIG. 8A, when the division mode is the vertical two division mode, the color difference block to be divided can be vertically divided into two, and the size of the divided color difference block is 4 × 4. As shown in FIG. 8B, when the division mode is the horizontal two division mode, the color difference block to be divided can be horizontally divided into two, and the size of the divided color difference block is 8 × 2.
　しかし、図８Ｃに示すように、分割モードが４分割モードでは、分割対象の色差ブロックを分割する際に、分割された色差ブロックのサイズが４×２となるので、分割を行わない。図８Ｄに示すように、分割モードが垂直３分割モードでは、分割対象の色差ブロックを分割すると、分割された左の色差ブロックと右の色差ブロックのサイズが２×４となるので、分割を行わない。図８Ｅに示すように、分割モードが水平３分割モードでは、分割対象の色差ブロックを分割すると、上の色差ブロックと下の色差ブロックが８×１となるので、分割を行わない。 However, as shown in FIG. 8C, when the division mode is the 4-division mode, when the color difference block to be divided is divided, the size of the divided color difference block is 4 × 2, so the division is not performed. As shown in FIG. 8D, when the division mode is the vertical 3-division mode, when the color difference block to be divided is divided, the size of the divided left color difference block and the right color difference block becomes 2 × 4, so the division is performed. Absent. As shown in FIG. 8E, when the division mode is the horizontal 3-division mode, when the color difference block to be divided is divided, the upper color difference block and the lower color difference block become 8 × 1, so the division is not performed.
　イントラ予測（MODE_INTRA）またはＩＢＣ予測（MODE_IBC）において、色差ブロックの分割処理を行うと判定された場合（ステップＳ１１０５：ＹＥＳ）、ステップＳ１１０２で設定された分割モードで分割対象の色差ブロックを分割する（ステップＳ１１０７）。 When it is determined in the intra prediction (MODE_INTRA) or the IBC prediction (MODE_IBC) that the color difference block is to be divided (step S1105: YES), the color difference block to be divided is divided in the division mode set in step S1102 (step S1105: YES). Step S1107).
　イントラ予測（MODE_INTRA）またはＩＢＣ予測（MODE_IBC）において、色差ブロックの分割処理を行うと判定されなかった場合（ステップＳ１１０５：ＮＯ）、ステップＳ１１０２で設定された分割モードで分割対象の色差ブロックの分割を行わずに、色差符号化ブロックとし、色差ブロック非分割フラグchroma_non_split_flagを１（真）とする（ステップＳ１１０６）。 If it is not determined in the intra prediction (MODE_INTRA) or IBC prediction (MODE_IBC) that the color difference block division processing is to be performed (step S1105: NO), the color difference block to be divided is divided in the division mode set in step S1102. Instead, the color difference coded block is used, and the color difference block non-split flag chroma_non_split_flag is set to 1 (true) (step S1106).
　続いて、分割した各ブロックについて、所定の順に走査し、本符号化ブロック分割処理を再帰的に行う（ステップＳ１１０８～Ｓ１１１０）。具体的には、分割された各ブロックについて、図５Ａ～Ｅに示す番号（以下、分割インデックスとする）順に走査する。図５Ａの６０１の番号０～３、図５Ｂの６０２および図５Ｄの６０４の番号０～１、図５Ｃの６０３および図５Ｅの６０５の０～２は分割処理の順番を示す番号である。分割された各ブロックについて、本符号化ブロック分割処理を再帰的に行う（図７のステップＳ１１１９）。 Subsequently, each of the divided blocks is scanned in a predetermined order, and the main coded block division process is recursively performed (steps S1108 to S1110). Specifically, each of the divided blocks is scanned in the order of the numbers shown in FIGS. 5A to 5E (hereinafter referred to as the divided index). Numbers 0 to 3 of 601 in FIG. 5A, numbers 0 to 1 of 602 and 604 of FIG. 5D, 603 of FIG. 5C and 0 to 2 of 605 of FIG. 5E are numbers indicating the order of division processing. The coded block division process is recursively performed for each of the divided blocks (step S1119 in FIG. 7).
　以上、４分割、垂直２分割、垂直３分割、水平２分割、水平３分割、非分割による分割処理が完了したら（ステップＳ１１０１～Ｓ１１１０）、本符号化ブロック分割処理を終了する。 When the division processing by 4 division, vertical 2 division, vertical 3 division, horizontal 2 division, horizontal 3 division, and non-division is completed (steps S1101 to S1110), the present coding block division process is completed.
　ここで説明した再帰的なブロック分割は、分割する回数、または、分割対象のブロックのサイズ等により、分割要否を制限してもよい。分割要否を制限する情報は、符号化装置と復号化装置の間で予め取り決めを行うことで、情報の伝達を行わない構成で実現してもよいし、符号化装置が分割要否を制限する情報を決定し、符号化ビット列に記録することにより、復号化装置に伝達する構成で実現してもよい。 In the recursive block division described here, the necessity of division may be limited depending on the number of divisions, the size of the block to be divided, and the like. The information that limits the necessity of division may be realized in a configuration that does not transmit information by making an agreement in advance between the coding device and the decoding device, or the coding device limits the necessity of division. It may be realized by the configuration which transmits to the decoding apparatus by determining the information to be performed and recording it in the coded bit string.
　あるブロックを分割したとき、分割前のブロックを親ブロックと呼び、分割後の各ブロックを子ブロックと呼ぶ。 When a certain block is divided, the block before division is called the parent block, and each block after division is called the child block.
　なお、本実施の形態においては、色差フォーマットが４：２：０または、４：２：２の場合、演算処理量、及びメモリアクセス回数を減らすために、イントラ予測（MODE_INTRA）またはＩＢＣ予測（MODE_IBC）において所定のサイズ以下の色差符号化ブロックを禁止するとしたが、所定のサイズ未満の色差符号化ブロックを禁止してもよい。例えば、所定の最小色差符号化ブロックサイズを１６画素（４×４、８×２、２×８）とし、ステップＳ１１０２で設定された分割モードで分割対象の色差ブロックを分割した際に、分割された色差ブロックが最小色差符号化ブロックサイズ未満になる場合は、分割対象の色差ブロックを分割せずに、色差符号化ブロックとする。 In the present embodiment, when the color difference format is 4: 2: 0 or 4: 2: 2, intra prediction (MODE_INTRA) or IBC prediction (MODE_IBC) is used in order to reduce the amount of arithmetic processing and the number of memory accesses. ), The color difference coded block smaller than the predetermined size is prohibited, but the color difference coded block smaller than the predetermined size may be prohibited. For example, when the predetermined minimum color difference coded block size is 16 pixels (4 × 4, 8 × 2, 2 × 8) and the color difference block to be divided is divided in the division mode set in step S1102, it is divided. If the color difference block is smaller than the minimum color difference coded block size, the color difference block to be divided is not divided and is used as the color difference coded block.
　また、本符号化ブロック分割処理においては、イントラ予測（MODE_INTRA）またはＩＢＣ予測（MODE_IBC）を中心に説明したが、インター予測（MODE_INTER）において、２×２、４×２、２×４の色差符号化ブロックを禁止しない場合は、イントラ予測（MODE_INTRA）またはＩＢＣ予測（MODE_IBC）用の処理（ステップＳ１１０５～Ｓ１１１０）に加えて、インター予測（MODE_INTER）用にステップＳ１１０６、Ｓ１１０８～Ｓ１１１０の処理も行う。 Further, in this coded block division process, the intra prediction (MODE_INTRA) or the IBC prediction (MODE_IBC) has been mainly described, but in the inter prediction (MODE_INTER), the color difference code of 2 × 2, 4 × 2, 2 × 4 When the conversion block is not prohibited, in addition to the processing for intra prediction (MODE_INTRA) or IBC prediction (MODE_IBC) (steps S1105 to S1110), the processing of steps S1106 and S1108 to S1110 for inter prediction (MODE_INTER) is also performed.
　＜ブロック分割情報符号化＞
　次に、画像符号化装置１００におけるビット列符号化部１０８においてブロック分割情報を符号化する動作について説明する。図９は、ブロック分割情報を符号化する動作を示すフローチャートである。符号化側では、予測方法決定部１０５によって決定されたブロック分割情報を符号化する。このブロック分割情報はブロック分割の各階層において、分割モードが４分割、垂直２分割、垂直３分割、水平２分割、水平３分割、非分割のいずれであるかを識別する情報、および色差ブロック非分割フラグchroma_non_split_flag等である。例えばブロックを分割するか否かを示すフラグ、４分割するか否かを示すフラグ、２分割または３分割するか否かを示すフラグ、垂直に分割するか否か（垂直に分割するか水平に分割するか）を示すフラグ、２分割するか否か（２分割するか３分割するか）を示すフラグ等を符号化する。分割モードが４分割モードの場合（ステップＳ１２０１：ＹＥＳ）、ブロックを分割するか否かを示すフラグを１（真）、４分割するか否かを示すフラグを１（真）に設定して符号化する（ステップＳ１２０２）。分割モードが垂直２分割モードの場合（ステップＳ１２０３：ＹＥＳ）、ブロックを分割するか否かを示すフラグを１（真）、４分割するか否かを示すフラグを０（偽）、垂直に分割するか否か（水平に分割するか）を示すフラグを１（真）、２分割するか否か（３分割するか）を示すフラグを１（真）に設定して符号化する（ステップＳ１２０４）。分割モードが、垂直３分割モードの場合（ステップＳ１２０５：ＹＥＳ）、ブロックを分割するか否かを示すフラグを１（真）、４分割するか否かを示すフラグを０（偽）、垂直に分割するか否か（水平に分割するか）を示すフラグを１（真）、２分割するか否か（３分割するか）を示すフラグを０（偽）に設定して符号化する（ステップＳ１２０６）。水平２分割モードの場合（ステップＳ１２０７：ＹＥＳ）、ブロックを分割するか否かを示すフラグを１（真）、４分割するか否かを示すフラグを０（偽）、垂直に分割するか否か（水平に分割するか）を示すフラグを０（偽）、２分割するか否か（３分割するか）を示すフラグを１（真）に設定して符号化する（ステップＳ１２０８）。水平３分割モードの場合（ステップＳ１２０９：ＹＥＳ）、ブロックを分割するか否かを示すフラグを１（真）、４分割するか否かを示すフラグを０（偽）、垂直に分割するか否か（水平に分割するか）を示すフラグを０（偽）、２分割するか否か（３分割するか）を示すフラグを０（偽）に設定して符号化する（ステップＳ１２１０）。 <Block division information coding>
Next, the operation of encoding the block division information in the bit string coding unit 108 in the image coding apparatus 100 will be described. FIG. 9 is a flowchart showing an operation of encoding the block division information. On the coding side, the block division information determined by the prediction method determination unit 105 is encoded. This block division information is information for identifying whether the division mode is 4-division, vertical 2-division, vertical 3-division, horizontal 2-division, horizontal 3-division, or non-division in each layer of block division, and color difference block non-division. Split flag chroma_non_split_flag etc. For example, a flag indicating whether or not to divide a block, a flag indicating whether or not to divide into four, a flag indicating whether or not to divide into two or three, and whether or not to divide vertically (vertically or horizontally). A flag indicating whether to divide into two or not (whether to divide into two or three) is encoded. When the division mode is the 4-division mode (step S1201: YES), the flag indicating whether or not to divide the block is set to 1 (true), and the flag indicating whether or not to divide the block is set to 1 (true). (Step S1202). When the division mode is the vertical 2-division mode (step S1203: YES), the flag indicating whether or not to divide the block is 1 (true), the flag indicating whether or not to divide the block is 0 (false), and the block is vertically divided. The flag indicating whether to divide (divided horizontally) is set to 1 (true), and the flag indicating whether to divide into 2 (divided into 3) is set to 1 (true) and encoded (step S1204). ). When the division mode is the vertical 3-division mode (step S1205: YES), the flag indicating whether or not to divide the block is 1 (true), and the flag indicating whether or not to divide the block is 0 (false), vertically. The flag indicating whether to divide (divided horizontally) is set to 1 (true), and the flag indicating whether to divide into 2 (divided into 3) is set to 0 (false) and encoded (step). S1206). In the case of the horizontal 2-split mode (step S1207: YES), the flag indicating whether or not to divide the block is 1 (true), the flag indicating whether or not to divide the block is 0 (false), and whether or not to divide vertically. The flag indicating whether or not to divide (horizontally divided) is set to 0 (false), and the flag indicating whether or not to divide into two (whether to divide into three) is set to 1 (true) and encoded (step S1208). In the case of the horizontal three-division mode (step S1209: YES), the flag indicating whether or not to divide the block is 1 (true), the flag indicating whether or not to divide the block is 0 (false), and whether or not to divide vertically. The flag indicating whether or not to divide (horizontally divided) is set to 0 (false), and the flag indicating whether or not to divide into two (whether to divide into three) is set to 0 (false) and encoded (step S1210).
　分割モードが４分割、垂直２分割、垂直３分割、水平２分割、水平３分割の場合は続いて、分割モードに基づいて分割されたブロックが所定のサイズ以下かどうかを判定する（ステップＳ１２１２）。具体的には、分割された色差ブロックのサイズが８画素ブロック以下である２×２、４×２、２×４画素になる場合（すなわち、色差フォーマットが４：２：０において、分割対象の輝度ブロックを分割した結果、分割された輝度ブロックのサイズが３２画素ブロック以下である４×４、８×４、４×８画素になる場合）、所定のサイズ以下と判定する（Ｓ１２１２：ＹＥＳ）。所定サイズ以下の場合、色差ブロック非分割フラグchroma_non_split_flagを符号化する（ステップＳ１２１３）。ただし、色差ブロック非分割フラグchroma_non_split_flagを符号化しなくても、復号側で導出できる場合は符号化しない。例えば、Ｉスライスでは、予測モードがインター予測（MODE_INTER）は使われないので、分割後のブロックサイズから復号側で色差ブロック非分割フラグchroma_non_split_flagを導出することが可能なため、色差ブロック非分割フラグchroma_non_split_flagを符号化する必要はない。また、分割後の輝度ブロックのサイズが１６画素（４×４画素）になる場合も、予測モードがインター予測（MODE_INTER）は行われないので、色差ブロック非分割フラグchroma_non_split_flagが１（真）であり、色差ブロック非分割フラグchroma_non_split_flagを符号化する必要はない。 When the division mode is 4-division, vertical 2-division, vertical 3-division, horizontal 2-division, or horizontal 3-division, it is subsequently determined whether or not the divided blocks based on the division mode have a predetermined size or less (step S1212). .. Specifically, when the size of the divided color difference block is 2 × 2, 4 × 2, 2 × 4 pixels which is 8 pixel blocks or less (that is, when the color difference format is 4: 2: 0, the division target As a result of dividing the luminance block, the size of the divided luminance block becomes 4 × 4, 8 × 4, 4 × 8 pixels which is 32 pixel blocks or less), and it is determined that the size is not more than a predetermined size (S1212: YES). .. If the size is less than or equal to the predetermined size, the color difference block non-split flag chroma_non_split_flag is encoded (step S1213). However, even if the color difference block non-split flag chroma_non_split_flag is not encoded, it is not encoded if it can be derived on the decoding side. For example, in I-slice, since the prediction mode is not inter-prediction (MODE_INTER), the color difference block undivided flag chroma_non_split_flag can be derived from the block size after division on the decoding side, so the color difference block undivided flag chroma_non_split_flag Does not need to be encoded. Also, when the size of the luminance block after division is 16 pixels (4 × 4 pixels), the color difference block non-division flag chroma_non_split_flag is 1 (true) because the prediction mode is not inter-prediction (MODE_INTER). , Color difference block unsplit flag chroma_non_split_flag does not need to be encoded.
　本実施の形態においては、色差ブロック非分割フラグchroma_non_split_flagが１（真）の場合、分割された符号化ブロックはすべて予測モードがイントラ予測（MODE_INTRA）またはＩＢＣ予測（MODE_IBC）とする。色差フォーマットが４：２：０において、分割対象の輝度ブロックを分割した結果、分割対象の色差ブロックを分割した結果、分割された色差ブロックのサイズが８画素ブロック以下でない（すなわち、２×２、４×２、２×４画素でない）場合（ステップＳ１２１２：ＮＯ）、色差ブロック非分割フラグchroma_non_split_flagを符号化せず、分割された各符号化ブロックの予測モードは符号化ブロックのレイヤーでそれぞれ符号化される。 In the present embodiment, when the color difference block non-split flag chroma_non_split_flag is 1 (true), the prediction mode of all the divided coded blocks is intra prediction (MODE_INTRA) or IBC prediction (MODE_IBC). When the color difference format is 4: 2: 0, as a result of dividing the brightness block to be divided, as a result of dividing the color difference block to be divided, the size of the divided color difference block is not 8 pixel blocks or less (that is, 2 × 2, In the case of (not 4 × 2, 2 × 4 pixels) (step S1212: NO), the color difference block undivided flag chroma_non_split_flag is not encoded, and the prediction mode of each divided coded block is encoded by the layer of the coded block. Will be done.
　分割モードが４分割、垂直２分割、垂直３分割、水平２分割、水平３分割の場合は続いて、予測モードに基づいて分割される各ブロックについて、所定の順に走査し、本ブロック分割情報符号化処理を再帰的に行う（ステップＳ１２１４～Ｓ１２１６）。具体的には、分割される各ブロックについて、図５Ａ～Ｅに示す番号（以下、分割インデックスとする）順に走査する。図５Ａの６０１の番号０～３、図５Ｂの６０２および図５Ｄの６０４の番号０～１、図５Ｃの６０３および図５Ｅの６０５の０～２は分割情報符号化処理の順番を示す番号である。予測モードに基づいて分割される各ブロックについて、本符号化ブロック分割処理を再帰的に行う（図９のステップＳ１２１５）。 When the division mode is 4-division, vertical 2-division, vertical 3-division, horizontal 2-division, or horizontal 3-division, each block divided based on the prediction mode is subsequently scanned in a predetermined order, and this block division information code is used. The conversion process is recursively performed (steps S1214 to S1216). Specifically, each block to be divided is scanned in the order of the numbers shown in FIGS. 5A to 5E (hereinafter referred to as division indexes). Numbers 0 to 3 of 601 in FIG. 5A, numbers 0 to 3 of 602 and 604 of FIG. 5D, 603 of FIG. 5C and 0 to 2 of 605 of FIG. 5E are numbers indicating the order of division information coding processing. is there. The coded block division process is recursively performed for each block divided based on the prediction mode (step S1215 in FIG. 9).
　一方、非分割モードの場合（ステップＳ１２０９：ＮＯ）、ブロックを分割するか否かを示すフラグを０（偽）に設定して符号化し（ステップＳ１２１１）、後述する符号化ブロックの符号化情報符号化処理を行う（ステップＳ１２１７）。 On the other hand, in the non-division mode (step S1209: NO), the flag indicating whether or not to divide the block is set to 0 (false) and encoded (step S1211), and the coding information code of the coding block described later is used. The conversion process is performed (step S1217).
　＜ブロック分割情報復号・ブロック分割＞
　次に、画像復号装置２００におけるビット列復号部２０１、およびブロック分割部２０２の動作について説明する。ブロック分割部２０２は、画像符号化装置１００のブロック分割部１０１と同様の処理手順でツリーブロックを分割するものである。ただし、画像符号化装置１００のブロック分割部１０１では、画像認識による最適形状の推定や歪レート最適化等最適化手法を適用し、最適なブロック分割の形状を決定するのに対し、画像復号装置２００におけるブロック分割部２０２は、ビット列復号部２０１で符号化ビット列に記録されたブロック分割情報を復号することにより、ブロック分割形状を決定する点が異なる。 <Block division information decoding / block division>
Next, the operations of the bit string decoding unit 201 and the block division unit 202 in the image decoding device 200 will be described. The block division unit 202 divides the tree block by the same processing procedure as the block division unit 101 of the image coding apparatus 100. However, the block division unit 101 of the image coding apparatus 100 applies an optimization method such as estimation of the optimum shape by image recognition and optimization of the distortion rate to determine the optimum shape of the block division, whereas the image decoding apparatus The block division unit 202 in 200 is different in that the block division shape is determined by decoding the block division information recorded in the coded bit string by the bit string decoding unit 201.
　図１２は、ブロック分割情報を復号し、ブロックを分割する動作を示すフローチャートである。復号側では、符号化ビット列からブロック分割情報を復号する。このブロック分割情報はブロック分割の各階層において、分割モードが４分割、垂直２分割、垂直３分割、水平２分割、水平３分割、非分割のいずれであるかを識別する情報、および色差ブロック非分割フラグchroma_non_split_flag等である。まず、ブロック分割を示す情報を復号する（ステップＳ１４０１）。ブロック分割を示す情報が１（真）の場合（ステップＳ１４０２：ＹＥＳ）、ステップＳ１４０３に進み、ブロック分割を示す情報が０（偽）の場合（ステップＳ１４０２：ＮＯ）、分割モードを非分割モードとし（ステップＳ１４０５）、後述する符号化ブロックの符号化情報復号処理を行う。 FIG. 12 is a flowchart showing an operation of decoding the block division information and dividing the block. On the decoding side, the block division information is decoded from the coded bit string. This block division information is information for identifying whether the division mode is 4-division, vertical 2-division, vertical 3-division, horizontal 2-division, horizontal 3-division, or non-division in each layer of block division, and color difference block non-division. Split flag chroma_non_split_flag etc. First, the information indicating the block division is decoded (step S1401). When the information indicating the block division is 1 (true) (step S1402: YES), the process proceeds to step S1403, and when the information indicating the block division is 0 (false) (step S1402: NO), the division mode is set to the non-division mode. (Step S1405), the coding information decoding process of the coding block described later is performed.
　続いて、４分割するか否かを示すフラグを復号し（ステップＳ１４０３）、４分割か否かを示すフラグが１（真）の場合（ステップＳ１４０４：ＹＥＳ）、当該階層の分割モードは４分割モードとし（ステップＳ１４０５）、４分割するか否かを示すフラグが０（偽）の場合（ステップＳ１４０４：ＮＯ）、ステップＳ１４０６に進む。 Subsequently, when the flag indicating whether or not to divide into four is decoded (step S1403) and the flag indicating whether or not to divide into four is 1 (true) (step S1404: YES), the division mode of the layer is divided into four. When the mode is set (step S1405) and the flag indicating whether or not to divide into four is 0 (false) (step S1404: NO), the process proceeds to step S1406.
　続いて、垂直分割か否かを示すフラグを復号し（ステップＳ１４０６）、２分割か否かを示すフラグを復号する（ステップＳ１４０７）。 Subsequently, the flag indicating whether or not it is vertically divided is decoded (step S1406), and the flag indicating whether or not it is divided into two is decoded (step S1407).
　垂直分割否かを示すフラグが１（真）で（ステップＳ１４０８：ＹＥＳ）、２分割か否かを示すフラグが１（真）の場合（ステップＳ１４０９：ＹＥＳ）、当該階層の分割モードは垂直２分割モードとする（ステップＳ１４１０）。 When the flag indicating whether or not to divide vertically is 1 (true) (step S1408: YES) and the flag indicating whether or not to divide into 2 is 1 (true) (step S1409: YES), the division mode of the layer is vertical 2. The split mode is set (step S1410).
　垂直分割否かを示すフラグが１（真）で（ステップＳ１４０８：ＹＥＳ）、２分割か否かを示すフラグが０（偽）の場合（ステップＳ１４０９：ＮＯ）、当該階層の分割モードは垂直３分割モードとする（ステップＳ１４１０）。 When the flag indicating whether or not to divide vertically is 1 (true) (step S1408: YES) and the flag indicating whether or not to divide into 2 is 0 (false) (step S1409: NO), the division mode of the layer is vertical 3. The split mode is set (step S1410).
　垂直分割否かを示すフラグが０（偽）で（ステップＳ１４０８：ＮＯ）、２分割か否かを示すフラグが１（真）の場合（ステップＳ１４１２：ＹＥＳ）、当該階層の分割モードは水平２分割モードとする（ステップＳ１４１３）。 When the flag indicating whether or not to divide vertically is 0 (false) (step S1408: NO) and the flag indicating whether or not to divide into two is 1 (true) (step S1412: YES), the division mode of the layer is horizontal 2. The split mode is set (step S1413).
　垂直分割否かを示すフラグが０（偽）で（ステップＳ１４０８：ＮＯ）、２分割か否かを示すフラグが０（偽）の場合（ステップＳ１４１２：ＮＯ）、当該階層の分割モードは水平３分割モードとする（ステップＳ１４１４）。 When the flag indicating whether or not to divide vertically is 0 (false) (step S1408: NO) and the flag indicating whether or not to divide into two is 0 (false) (step S1412: NO), the division mode of the layer is horizontal 3. The split mode is set (step S1414).
　続いて、符号化側のブロック分割処理で説明したのと同様に、ステップＳ１４０５、Ｓ１４１０、Ｓ１４１１、Ｓ１４１３、Ｓ１４１４で設定した分割モードに基づいて分割されたブロックが所定のサイズ以下かどうかを判定する（ステップＳ１４１６）。具体的には、分割された色差ブロックのサイズが８画素ブロック以下である２×２、４×２、２×４画素になる場合（すなわち、色差フォーマットが４：２：０において、分割対象の輝度ブロックを分割した結果、分割された輝度ブロックのサイズが３２画素ブロック以下である４×４、８×４、４×８画素になる場合）、所定のサイズ以下と判定する（Ｓ１４１６：ＹＥＳ）。所定サイズ以下の場合、色差ブロック非分割フラグchroma_non_split_flagを復号または導出する（ステップＳ１４１７）。ただし、色差ブロック非分割フラグchroma_non_split_flagを復号しなくても、復号側で導出できる場合は、非分割フラグchroma_non_split_flagは符号化されていないので、導出する。例えば、Ｉスライスでは、予測モードがインター予測（MODE_INTER）は使われないので、分割されたブロックが所定のサイズ以下では、色差ブロック非分割フラグchroma_non_split_flagは復号せずに１（真）とする。また、分割後の輝度ブロックのサイズが１６画素（４×４画素）になる場合も、予測モードがインター予測（MODE_INTER）は行われないので、色差ブロック非分割フラグchroma_non_split_flagを復号せずに、色差ブロック非分割フラグchroma_non_split_flagが１（真）とする。 Subsequently, as described in the block division process on the coding side, it is determined whether or not the divided blocks have a predetermined size or less based on the division mode set in steps S1405, S1410, S1411, S1413, and S1414. (Step S1416). Specifically, when the size of the divided color difference block is 2 × 2, 4 × 2, 2 × 4 pixels which is 8 pixel blocks or less (that is, when the color difference format is 4: 2: 0, the division target As a result of dividing the luminance block, the size of the divided luminance block becomes 4 × 4, 8 × 4, 4 × 8 pixels which is 32 pixel blocks or less), and it is determined that the size is not more than a predetermined size (S1416: YES). .. If the size is less than or equal to the predetermined size, the color difference block non-split flag chroma_non_split_flag is decoded or derived (step S1417). However, if the color difference block unsplit flag chroma_non_split_flag can be derived on the decoding side without decoding it, the non-split flag chroma_non_split_flag is not encoded and is derived. For example, in the I slice, the prediction mode is not inter-prediction (MODE_INTER), so if the divided blocks are smaller than a predetermined size, the color difference block non-division flag chroma_non_split_flag is set to 1 (true) without decoding. Also, when the size of the luminance block after division is 16 pixels (4 x 4 pixels), the prediction mode is not inter-prediction (MODE_INTER), so the color difference block non-division flag chroma_non_split_flag is not decoded and the color difference is achieved. The block non-split flag chroma_non_split_flag is 1 (true).
　色差ブロック非分割フラグchroma_non_split_flagが１（真）の場合（ステップＳ１４１９：ＹＥＳ）、色差ブロックを分割しない（ステップＳ１４２０）。この時、分割された輝度信号の符号化ブロックと分割されない色差信号の符号化ブロックはすべて予測モードがイントラ予測（MODE_INTRA）またはＩＢＣ予測（MODE_IBC）とする。一方、色差ブロック非分割フラグchroma_non_split_flagの値が０（偽）の場合（ステップＳ１４１９：ＮＯ）、分割モードに基づいて色差ブロックも分割する（ステップＳ１４２１）。分割された符号化ブロックはすべて予測モードがインター予測（MODE_INTER）とする。 When the color difference block non-split flag chroma_non_split_flag is 1 (true) (step S1419: YES), the color difference block is not divided (step S1420). At this time, the prediction modes of the coded blocks of the divided luminance signal and the coded blocks of the undivided color difference signal are all set to intra prediction (MODE_INTRA) or IBC prediction (MODE_IBC). On the other hand, when the value of the color difference block non-split flag chroma_non_split_flag is 0 (false) (step S1419: NO), the color difference block is also split based on the split mode (step S1421). The prediction mode of all the divided coded blocks is inter-prediction (MODE_INTER).
　また、分割対象の色差ブロックを分割した結果、分割された色差ブロックのサイズが８画素ブロック以下でない（すなわち、２×２、４×２、２×４画素でない）場合（ステップＳ１４１６：ＮＯ）、分割モードに基づいて色差ブロックも分割する（ステップＳ１４２１）。このとき、分割された各符号化ブロックの予測モードは符号化ブロックのレイヤーでそれぞれ復号される。 Further, when the size of the divided color difference block is not 8 pixel blocks or less (that is, not 2 × 2, 4 × 2, 2 × 4 pixels) as a result of dividing the color difference block to be divided (step S1416: NO). The color difference block is also divided based on the division mode (step S1421). At this time, the prediction mode of each divided coded block is decoded by the layer of the coded block.
　続いて、分割した各ブロックについて、所定の順に走査し（ステップＳ１４２２～Ｓ１４２４）、本ブロック分割情報復号、及び符号化ブロック分割処理を階層的かつ再帰的に行う（ステップＳ１４２３）。具体的には、分割された各ブロックについて、図５Ａ～Ｅに示す番号（以下、分割インデックスとする）順に走査する。図５Ａの６０１の番号０～３、図５Ｂの６０２および図５Ｄの６０４の番号０～１、図５Ｃの６０３および図５Ｅの６０５の０～２は分割処理の順番を示す番号である。分割された各ブロックについて、本ブロック分割情報復号、及び符号化ブロック分割処理を階層的かつ再帰的に行う（図１２のステップＳ１４２３）。 Subsequently, each of the divided blocks is scanned in a predetermined order (steps S1422 to S1424), and the block division information decoding and the coded block division processing are performed hierarchically and recursively (step S1423). Specifically, each of the divided blocks is scanned in the order of the numbers shown in FIGS. 5A to 5E (hereinafter referred to as the divided index). Numbers 0 to 3 of 601 in FIG. 5A, numbers 0 to 1 of 602 and 604 of FIG. 5D, 603 of FIG. 5C and 0 to 2 of 605 of FIG. 5E are numbers indicating the order of division processing. For each of the divided blocks, the block division information decoding and the coded block division processing are performed hierarchically and recursively (step S1423 in FIG. 12).
　＜イントラ予測＞
　実施の形態に係るイントラ予測方法は、図１の画像符号化装置のイントラ予測部１０３および図２の画像復号装置のインター予測部２０３において実施される。 <Intra forecast>
The intra prediction method according to the embodiment is carried out by the intra prediction unit 103 of the image coding device of FIG. 1 and the inter prediction unit 203 of the image decoding device of FIG.
　実施の形態によるイントラ予測方法について、図面を用いて説明する。イントラ予測方法は符号化ブロック単位で符号化及び復号の処理の何れでも実施される。 The intra prediction method according to the embodiment will be described with reference to the drawings. The intra prediction method is carried out in either coding or decoding processing in units of coded blocks.
　＜符号化側のイントラ予測部１０３の説明＞
　図４１は図１の画像符号化装置のイントラ予測部１０３の詳細な構成を示す図である。イントラ予測部１０３は通常イントラ予測部３５１、およびイントラブロックコピー予測部３５２を備える。通常イントラ予測部３５１は符号化ブロックの予測モードがイントラ予測（MODE_INTRA）の際の予測処理に対応し、イントラブロックコピー予測部３５２は符号化ブロックの予測モードがＩＢＣ予測（MODE_IBC）の際の予測処理に対応する。 <Explanation of Intra Prediction Unit 103 on the Encoding Side>
FIG. 41 is a diagram showing a detailed configuration of the intra prediction unit 103 of the image coding device of FIG. 1. The intra prediction unit 103 usually includes an intra prediction unit 351 and an intra block copy prediction unit 352. Normally, the intra prediction unit 351 corresponds to the prediction processing when the prediction mode of the coded block is intra prediction (MODE_INTRA), and the intra block copy prediction unit 352 predicts when the prediction mode of the coded block is IBC prediction (MODE_IBC). Corresponds to processing.
　通常イントラ予測部３５１は、処理対象の符号化ブロックに隣接する復号済み画素から、通常イントラ予測により予測画像信号を生成し、複数のイントラ予測モードの中から適したイントラ予測モードを選択し、選択されたイントラ予測モード、及び選択されたイントラ予測モードに応じた予測画像信号を予測方法決定部１０５に供給する。図１０Ａ～Ｂに通常イントラ予測の例を示す。図１０Ａは、通常イントラ予測の予測方向とイントラ予測モード番号の対応を示したものである。例えば、イントラ予測モード１８は、水平予測であり、水平方向に画素をコピーすることによりイントラ予測画像を生成する。イントラ予測モード５０は、垂直予測であり、垂直方向に画素をコピーすることによりイントラ予測画像を生成する。イントラ予測モード６６は、斜め予測であり、斜め４５度方向に画素をコピーすることによりイントラ予測画像を生成する。イントラ予測モード１は、平均値予測（ＤＣ）モードであり、処理対象ブロックのすべての画素値を参照画素の平均値とするモードである。イントラ予測モード０は平面予測（Ｐｌａｎａｒ）モードであり、垂直方向・水平方向の参照画素から２次元的なイントラ予測画像を作成するモードである。図１０Ｂは、イントラ予測モード４０の場合のイントラ予測画像を生成する例である。処理対象ブロックの各画素に対し、イントラ予測モードの示す方向の参照画素の値をコピーする。イントラ予測モードの参照画素が整数位置でない場合には、周辺の整数位置の参照画素値から補間により参照画素値を決定する。 The normal intra prediction unit 351 generates a prediction image signal by normal intra prediction from decoded pixels adjacent to a coded block to be processed, selects a suitable intra prediction mode from a plurality of intra prediction modes, and selects the appropriate intra prediction mode. The predicted intra prediction mode selected and the predicted image signal corresponding to the selected intra prediction mode are supplied to the prediction method determination unit 105. 10A-B show an example of normal intra-prediction. FIG. 10A shows the correspondence between the prediction direction of the normal intra-prediction and the intra-prediction mode number. For example, the intra prediction mode 18 is horizontal prediction, and an intra prediction image is generated by copying pixels in the horizontal direction. The intra prediction mode 50 is vertical prediction, and an intra prediction image is generated by copying pixels in the vertical direction. The intra prediction mode 66 is an oblique prediction, and an intra prediction image is generated by copying pixels in an oblique 45 degree direction. The intra prediction mode 1 is an average value prediction (DC) mode, and is a mode in which all the pixel values of the processing target block are set as the average value of the reference pixels. The intra prediction mode 0 is a plane prediction (Planar) mode, which is a mode for creating a two-dimensional intra prediction image from reference pixels in the vertical and horizontal directions. FIG. 10B is an example of generating an intra prediction image in the case of the intra prediction mode 40. For each pixel of the block to be processed, the value of the reference pixel in the direction indicated by the intra prediction mode is copied. When the reference pixel in the intra prediction mode is not an integer position, the reference pixel value is determined by interpolation from the reference pixel values at the surrounding integer positions.
　イントラブロックコピー予測部３５２は、復号画像メモリ１０４から処理対象の符号化ブロックと同一の画像信号の復号済み領域を取得し、イントラブロックコピー予測処理により、予測画像信号を生成し、予測方法決定部１０５に供給する。イントラブロックコピー予測部３５２の詳細な構成と処理については後述する。 The intra-block copy prediction unit 352 acquires a decoded area of the same image signal as the coded block to be processed from the decoded image memory 104, generates a prediction image signal by the intra-block copy prediction processing, and determines the prediction method. Supply to 105. The detailed configuration and processing of the intra-block copy prediction unit 352 will be described later.
　＜復号側のイントラ予測部２０４の説明＞
　図４２は図２の画像復号装置のイントラ予測部２０４の詳細な構成を示す図である。イントラ予測部２０４は通常イントラ予測部３６１、およびイントラブロックコピー予測部３６２を備える。通常イントラ予測部３６１は符号化ブロックの予測モードがイントラ予測（MODE_INTRA）の際の通常イントラ予測処理に対応し、イントラブロックコピー予測部３６２は符号化ブロックの予測モードがイントラブロックコピー予測（MODE_IBC）の際のイントラブロックコピー予測処理に対応する。 　通常イントラ予測部３６１は、処理対象の符号化ブロックに隣接する復号済み画素から、通常イントラ予測により予測画像信号を生成し、複数のイントラ予測モードの中から適したイントラ予測モードを選択し、選択されたイントラ予測モード、及び選択されたイントラ予測モードに応じた予測画像信号を得る。この予測画像信号がスイッチ３６４を経由して復号画像信号重畳部２０７に供給される。図４２の通常イントラ予測部３６１の処理は、図４１の通常イントラ予測部３５１に対応するものであるため、詳細の説明を省略する。 <Explanation of Intra Prediction Unit 204 on the Decoding Side>
FIG. 42 is a diagram showing a detailed configuration of the intra prediction unit 204 of the image decoding apparatus of FIG. The intra prediction unit 204 usually includes an intra prediction unit 361 and an intra block copy prediction unit 362. The normal intra prediction unit 361 corresponds to the normal intra prediction processing when the prediction mode of the coded block is intra prediction (MODE_INTRA), and the intra block copy prediction unit 362 has the prediction mode of the coded block intra block copy prediction (MODE_IBC). Corresponds to the intra-block copy prediction processing at the time of. The normal intra prediction unit 361 generates a prediction image signal by normal intra prediction from decoded pixels adjacent to a coded block to be processed, selects a suitable intra prediction mode from a plurality of intra prediction modes, and selects the appropriate intra prediction mode. The predicted image signal corresponding to the selected intra prediction mode and the selected intra prediction mode is obtained. This predicted image signal is supplied to the decoded image signal superimposing unit 207 via the switch 364. Since the processing of the normal intra prediction unit 361 of FIG. 42 corresponds to the normal intra prediction unit 351 of FIG. 41, detailed description thereof will be omitted.
　イントラブロックコピー予測部３６２は、復号画像メモリ２０８から処理対象の符号化ブロックと同一の画像信号の復号済み領域を取得し、イントラブロックコピー処理により、予測画像信号を得る。この予測画像信号がスイッチ３６４を経由して復号画像信号重畳部２０７に供給される。イントラブロックコピー予測部３６２の詳細な構成と処理については後述する。 The intra-block copy prediction unit 362 acquires a decoded area of the same image signal as the coded block to be processed from the decoded image memory 208, and obtains the predicted image signal by the intra-block copy processing. This predicted image signal is supplied to the decoded image signal superimposing unit 207 via the switch 364. The detailed configuration and processing of the intra-block copy prediction unit 362 will be described later.
　＜符号化ブロックの符号化情報符号化＞
　次に、画像符号化装置１００におけるビット列符号化部１０８において符号化ブロックの符号化情報を符号化する動作について説明する。図５７は、符号化ブロックの符号化情報を符号化する動作を示すフローチャートである。符号化側では、予測方法決定部１０５によって決定された符号化ブロック毎の符号化情報を符号化する。本実施の形態においては、シーケンス、ピクチャ、またはスライス単位で、ＩＢＣ予測（PRED_IBC）を用いるかどうかを設定できるものとする。さらに、シーケンス、ピクチャまたはスライス単位で、インター予測（PRED_ INTER）を用いるかどうかを設定できるものとする。Ｉスライスではインター予測（PRED_ INTER）が使われないておらず、ピクチャまたはスライス単位で、インター予測（PRED_ INTER）を用いないと設定されているのと等価である。 <Coded information coding of coded block>
Next, an operation of encoding the coding information of the coding block in the bit string coding unit 108 in the image coding apparatus 100 will be described. FIG. 57 is a flowchart showing an operation of encoding the coding information of the coding block. On the coding side, the coding information for each coding block determined by the prediction method determination unit 105 is encoded. In the present embodiment, it is possible to set whether to use IBC prediction (PRED_IBC) for each sequence, picture, or slice. Furthermore, it shall be possible to set whether to use inter-prediction (PRED_INTER) for each sequence, picture or slice. Inter-prediction (PRED_ INTER) is not used in the I-slice, which is equivalent to setting that inter-prediction (PRED_ INTER) is not used for each picture or slice.
　まず、符号化ブロックの予測モードが、イントラ予測（PRED_INTRA）、ＩＢＣ予測（PRED_IBC）、インター予測（PRED_INTER）のいずれかを示す予測モード情報を符号化する（ステップＳ１５０１～Ｓ１５０４）。例えば、予測モードがイントラ予測（PRED_INTRA）か否かを示すフラグを符号化し（ステップＳ１５０２）、さらに、予測モードがＩＢＣ予測（PRED_IBC）か否かを示すフラグ（ステップＳ１５０４）を符号化する。 First, the prediction mode information indicating that the prediction mode of the coding block is any of intra prediction (PRED_INTRA), IBC prediction (PRED_IBC), and inter prediction (PRED_INTER) is encoded (steps S1501 to S1504). For example, a flag indicating whether the prediction mode is intra-prediction (PRED_INTRA) is encoded (step S1502), and a flag indicating whether the prediction mode is IBC prediction (PRED_IBC) (step S1504) is encoded.
　まず、符号化ブロックの予測モードがイントラ予測（PRED_INTRA）か否かを示すフラグを符号化するか否かを判定する（ステップＳ１５０１）。符号化ブロックの予測モードがイントラ予測（PRED_INTRA）か否かを示すフラグを符号化する場合（ステップＳ１５０１：ＹＥＳ）、符号化ブロックの予測モードがイントラ予測（PRED_INTRA）か否かを示すフラグを符号化する（ステップＳ１５０２）。予測モードがイントラ予測（PRED_INTRA）の場合、符号化ブロックの予測モードがイントラ予測（PRED_INTRA）か否かを示すフラグを１（真）に設定して符号化し、予測モードがイントラ予測（PRED_INTRA）でない場合、すなわち、予測モードがＩＢＣ予測（PRED_IBC）、またはインター予測（PRED_INTER）の場合、符号化ブロックの予測モードがイントラ予測（PRED_INTRA）か否かを示すフラグを０（偽）に設定して符号化する。 First, it is determined whether or not to encode a flag indicating whether or not the prediction mode of the coded block is intra prediction (PRED_INTRA) (step S1501). When encoding a flag indicating whether the prediction mode of the coded block is intra-prediction (PRED_INTRA) (step S1501: YES), a flag indicating whether the prediction mode of the coded block is intra-prediction (PRED_INTRA) is coded. (Step S1502). When the prediction mode is intra prediction (PRED_INTRA), the coding block is encoded by setting the flag indicating whether the prediction mode of the coded block is intra prediction (PRED_INTRA) to 1 (true), and the prediction mode is not intra prediction (PRED_INTRA). In the case, that is, when the prediction mode is IBC prediction (PRED_IBC) or inter prediction (PRED_INTER), the flag indicating whether the prediction mode of the coded block is intra prediction (PRED_INTRA) is set to 0 (false). To become.
　続いて、符号化ブロックの予測モードがＩＢＣ予測（PRED_IBC）か否かを示すフラグを符号化するか否かを判定する（ステップＳ１５０３）。シーケンス、ピクチャ、またはスライス単位で、ＩＢＣ予測（PRED_IBC）を用いない場合、または、シーケンス、ピクチャ、またはスライス単位で、インター予測（PRED_INTER）を用いない場合、処理対象の符号化ブロックの親ブロックにおいて、色差ブロック非分割フラグchroma_non_split_flagが０（偽）に設定されて符号化されている場合などは、符号化ブロックの予測モードがＩＢＣ予測（PRED_IBC）か否かを示すフラグを符号化しない。符号化ブロックの予測モードがＩＢＣ予測（PRED_IBC）か否かを示すフラグを符号化する場合（ステップＳ１５０３：ＹＥＳ）、符号化ブロックの予測モードがＩＢＣ予測（PRED_IBC）か否かを示すフラグを符号化する（ステップＳ１５０４）。予測モードがＩＢＣ予測（PRED_IBC）の場合、符号化ブロックの予測モードがＩＢＣ予測（PRED_IBC）か否かを示すフラグを１（真）に設定して符号化し、予測モードがＩＢＣ予測（PRED_IBC）でない場合、すなわち、予測モードがインター予測（PRED_INTER）の場合、符号化ブロックの予測モードがＩＢＣ予測（PRED_IBC）か否かを示すフラグを０（偽）に設定して符号化する。 Subsequently, it is determined whether or not to encode the flag indicating whether or not the prediction mode of the coding block is IBC prediction (PRED_IBC) (step S1503). If IBC prediction (PRED_IBC) is not used for each sequence, picture, or slice, or if inter-prediction (PRED_INTER) is not used for each sequence, picture, or slice, in the parent block of the coded block to be processed. , When the color difference block non-split flag chroma_non_split_flag is set to 0 (false) and encoded, the flag indicating whether the prediction mode of the coding block is IBC prediction (PRED_IBC) is not encoded. When encoding a flag indicating whether the prediction mode of the coded block is IBC prediction (PRED_IBC) (step S1503: YES), a flag indicating whether the prediction mode of the coded block is IBC prediction (PRED_IBC) is coded. (Step S1504). When the prediction mode is IBC prediction (PRED_IBC), the flag indicating whether the prediction mode of the coding block is IBC prediction (PRED_IBC) is set to 1 (true) for coding, and the prediction mode is not IBC prediction (PRED_IBC). In the case, that is, when the prediction mode is inter-prediction (PRED_INTER), the flag indicating whether the prediction mode of the coding block is IBC prediction (PRED_IBC) is set to 0 (false) for coding.
　ここで、本実施の形態においては、処理対象の符号化ブロックの親ブロックにおいて、イントラ予測、またはIBC予測において、分割モードに基づいて分割対象の色差ブロックを分割せずに、色差符号化ブロックとすると判断した場合、すなわち色差ブロック非分割フラグchroma_non_split_flagが１（真）に設定された場合は、色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックの予測モードを色差信号の符号化ブロックの予測モードとする。 Here, in the present embodiment, in the parent block of the coded block to be processed, in the intra prediction or the IBC prediction, the color difference block to be divided is not divided based on the division mode, and the color difference coded block is used. When it is determined that the color difference block is not divided, that is, when the chroma_non_split_flag flag is set to 1 (true), the prediction mode of the luminance signal coding block at the same position as the color difference signal coding block is set to the color difference signal coding block. Prediction mode.
　本実施の形態においては、色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックを特定する際に、色差信号の画像空間における色差信号の符号化ブロックの中央の右下の画素に対応する輝度信号の画像空間で同じ位置の画素を含む輝度信号の符号化ブロックを色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックとする。 In the present embodiment, when specifying the luminance signal coding block at the same position as the color difference signal coding block, it corresponds to the lower right pixel in the center of the color difference signal coding block in the image space of the color difference signal. A luminance signal coding block containing pixels at the same position in the image space of the luminance signal is defined as a luminance signal coding block at the same position as the color difference signal coding block.
　色差フォーマットが４：２：０の際の、イントラ色差予測モードが色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックについて図１３Ａ～Ｂ、図３９Ａ～Ｂ、図４０Ａ～Ｂ、図５９Ａ～Ｂを用いて説明する。 13A-B, 39A-B, 40A-B, FIGS. 13A-B, 39A-B, 40A-B, for the luminance signal coding block at the same position as the color-difference signal coding block in the intra-color difference prediction mode when the color difference format is 4: 2: 0. This will be described with reference to 59A to B.
　図１３Ａは８×８画素の輝度信号の符号化ブロックを示し、図１３Ｂは８×８画素の輝度信号の符号化ブロックに対応する同じ位置の４×４画素の色差信号の符号化ブロックを示す。この際、色差信号の画像空間における色差信号の符号化ブロックの中央の右下の画素に対応する輝度信号の画像空間で同じ位置の画素は輝度信号の符号化ブロックの中央の右下の画素である。 FIG. 13A shows a coded block of an 8 × 8 pixel luminance signal, and FIG. 13B shows a coded block of a 4 × 4 pixel color difference signal at the same position corresponding to the 8 × 8 pixel luminance signal coded block. .. At this time, the pixels at the same position in the image space of the luminance signal corresponding to the lower right pixel in the center of the coded block of the color difference signal in the image space of the luminance signal are the lower right pixels in the center of the encoded block of the luminance signal. is there.
　図３９Ａは分割対象の８×８画素の輝度ブロックが４分割された輝度信号の符号化ブロックを示し、各符号化ブロックのサイズは４×４画素である。図３９Ｂは分割対象の８×８画素の輝度ブロックに対応する同じ位置の４×４画素の色差ブロックを示し、本実施の形態では２×２画素の色差信号の符号化ブロックを禁止するので、４分割されずに色差信号の符号化ブロックとなる。この際、色差信号の画像空間における色差信号の符号化ブロックの中央の右下の画素に対応する輝度信号の画像空間で同じ位置の画素を含む輝度信号の符号化ブロックは０から数えて３番目、すなわち最後（右下）の符号化ブロックである。この符号化ブロックを色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックとする。 FIG. 39A shows a coded block of a luminance signal in which a luminance block of 8 × 8 pixels to be divided is divided into four, and the size of each coded block is 4 × 4 pixels. FIG. 39B shows a 4 × 4 pixel color difference block at the same position corresponding to the 8 × 8 pixel luminance block to be divided, and in the present embodiment, the 2 × 2 pixel color difference signal coding block is prohibited. It becomes a color difference signal coding block without being divided into four. At this time, the luminance signal coding block including the pixels at the same position in the luminance signal image space corresponding to the lower right pixel in the center of the color difference signal coding block in the color difference signal image space is the third from 0. That is, the last (lower right) coding block. This coded block is used as a coded block for the luminance signal at the same position as the coded block for the color difference signal.
　図４０Ａは分割対象の８×８画素の輝度ブロックが垂直２分割された輝度信号の符号化ブロックを示し、各符号化ブロックのサイズは４×８画素である。図４０Ｂは分割対象の８×８画素の輝度ブロックに対応する同じ位置の４×４画素の色差ブロックを示し、本実施の形態では２×４画素の色差信号の符号化ブロックを禁止するので、垂直２分割されずに色差信号の符号化ブロックとなる。この際、色差信号の画像空間における色差信号の符号化ブロックの中央の右下の画素に対応する輝度信号の画像空間で同じ位置の画素を含む輝度信号の符号化ブロックは０から数えて１番目、すなわち最後（右側）の符号化ブロックである。この符号化ブロックを色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックとする。 FIG. 40A shows a coding block of a luminance signal in which the luminance block of 8 × 8 pixels to be divided is vertically divided into two, and the size of each coding block is 4 × 8 pixels. FIG. 40B shows a color difference block of 4 × 4 pixels at the same position corresponding to the luminance block of 8 × 8 pixels to be divided, and in the present embodiment, the coding block of the color difference signal of 2 × 4 pixels is prohibited. It becomes a color difference signal coding block without being vertically divided into two. At this time, the luminance signal coding block including the pixels at the same position in the luminance signal image space corresponding to the lower right pixel in the center of the color difference signal coding block in the color difference signal image space is the first one counting from 0. That is, the last (right side) coding block. This coded block is used as a coded block for the luminance signal at the same position as the coded block for the color difference signal.
　図５９Ａは分割対象の８×８画素の輝度ブロックが垂直３分割された輝度信号の符号化ブロックを示し、各符号化ブロックのサイズは２×８画素である。図５９Ｂは分割対象の８×８画素の輝度ブロックに対応する同じ位置の４×４画素の色差ブロックを示し、本実施の形態では１×４画素の色差信号の符号化ブロックを禁止するので、垂直３分割されずに色差信号の符号化ブロックとなる。この際、色差信号の画像空間における色差信号の符号化ブロックの中央の右下の画素に対応する輝度信号の画像空間で同じ位置の画素を含む輝度信号の符号化ブロックは０から数えて１番目、すなわち真ん中の符号化ブロックである。この符号化ブロックを色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックとする。 FIG. 59A shows a coded block of a luminance signal in which the luminance block of 8 × 8 pixels to be divided is vertically divided into three, and the size of each encoded block is 2 × 8 pixels. FIG. 59B shows a 4 × 4 pixel color difference block at the same position corresponding to the 8 × 8 pixel luminance block to be divided, and in the present embodiment, the 1 × 4 pixel color difference signal coding block is prohibited. It becomes a color difference signal coding block without being vertically divided into three. At this time, the luminance signal coding block including the pixels at the same position in the luminance signal image space corresponding to the lower right pixel in the center of the color difference signal coding block in the color difference signal image space is the first one counting from 0. That is, the coding block in the middle. This coded block is used as a coded block for the luminance signal at the same position as the coded block for the color difference signal.
　続いて、予測モードがイントラ予測（PRED_INTRA）の場合は（ステップＳ１５０５：ＹＥＳ）、輝度信号の符号化ブロックのイントラ輝度予測モードに関する情報を符号化する（ステップＳ１５０６）。輝度信号の符号化ブロックのイントラ輝度予測モードに関する情報の符号化については後述する。 Subsequently, when the prediction mode is intra-prediction (PRED_INTRA) (step S1505: YES), the information regarding the intra-luminance prediction mode of the luminance signal coding block is encoded (step S1506). The coding of the information regarding the intra-luminance prediction mode of the luminance signal coding block will be described later.
　続いて、色差信号の符号化ブロックのイントラ色差予測モードに関する情報を符号化するか否かを判断する（ステップＳ１５０７）。処理対象の符号化ブロックの親ブロックにおいて、分割モードに基づいて分割対象の色差ブロックを分割して色差符号化ブロックとした場合、すなわち色差ブロック非分割フラグchroma_non_split_flagが１（真）に設定されていない場合は、すべての処理対象の符号化ブロックにおいてイントラ色差予測モードに関する情報を符号化する。また、予測モードがイントラ予測（MODE_INTRA）の場合、本実施の形態では２×２、４×２、２×４画素の色差信号の符号化ブロックを禁止するので、処理対象の符号化ブロックの親ブロックにおいて、イントラ予測、またはIBC予測において、分割モードに基づいて分割対象の色差ブロックを分割せずに、色差符号化ブロックとすると判断した場合、すなわち色差ブロック非分割フラグchroma_non_split_flagが１（真）に設定された場合は（ステップＳ１５０７：ＹＥＳ）、分割された最後の符号化ブロックにおいてイントラ色差予測モードに関する情報を符号化し（ステップＳ１５０８）、それ以外の符号化ブロックにおいては（ステップＳ１５０７：ＮＯ）、イントラ色差予測モードに関する情報を符号化しない。例えば、親ブロックでの分割モードが４分割モードの場合（図５Ａの６０１）、最後である０番目から数えて３番目の符号化ブロックにおいて、イントラ色差予測モードに関する情報を符号化し（ステップＳ１５０８）、０～２番目の符号化ブロックにおいてはイント色差予測モードに関する情報を符号化しない。また、親ブロックでの分割モードが垂直２分割モードまたは水平２分割モードの場合（図５Ｂの６０２、図５Ｄの６０４）、最後である０番目から数えて１番目の符号化ブロックにおいて、イントラ色差予測モードに関する情報を符号化し（ステップＳ１５０８）、０番目の符号化ブロックにおいてはイントラ色差予測モードに関する情報を符号化しない。また、親ブロックでの分割モードが垂直３分割モードまたは水平３分割モードの場合（図５Ｃの６０３、図５Ｅの６０５）、最後である０番目から数えて２番目の符号化ブロックにおいて、イントラ色差予測モードに関する情報を符号化し（ステップＳ１５０８）、０～１番目の符号化ブロックにおいてはイントラ色差予測モードに関する情報を符号化しない。 Subsequently, it is determined whether or not to encode the information regarding the intra color difference prediction mode of the color difference signal coding block (step S1507). In the parent block of the coded block to be processed, when the color difference block to be divided is divided into the color difference coded block based on the division mode, that is, the color difference block non-division flag chroma_non_split_flag is not set to 1 (true). In the case, the information regarding the intra color difference prediction mode is encoded in all the coded blocks to be processed. Further, when the prediction mode is intra prediction (MODE_INTRA), the coding block of the color difference signal of 2 × 2, 4 × 2, 2 × 4 pixels is prohibited in the present embodiment, so that the parent of the coded block to be processed In the block, in the intra prediction or IBC prediction, when it is determined that the color difference block to be divided is not divided based on the division mode and is a color difference coded block, that is, the color difference block non-division flag chroma_non_split_flag is set to 1 (true). If set (step S1507: YES), the information about the intra-color difference prediction mode is encoded in the last divided coded block (step S1508), and in the other coded blocks (step S1507: NO), Do not encode information about intracolor difference prediction modes. For example, when the division mode in the parent block is the 4-division mode (601 in FIG. 5A), the information regarding the intra color difference prediction mode is encoded in the third coding block counting from the 0th, which is the last (step S1508). In the 0th to 2nd coding blocks, the information regarding the into color difference prediction mode is not encoded. Further, when the division mode in the parent block is the vertical 2-division mode or the horizontal 2-division mode (602 in FIG. 5B, 604 in FIG. 5D), the intra-color difference in the first coded block counting from the last 0th. The information regarding the prediction mode is encoded (step S1508), and the information regarding the intra color difference prediction mode is not encoded in the 0th coding block. Further, when the division mode in the parent block is the vertical 3-division mode or the horizontal 3-division mode (603 in FIG. 5C, 605 in FIG. 5E), the intra color difference is in the second coding block counting from the 0th last. The information regarding the prediction mode is encoded (step S1508), and the information regarding the intra color difference prediction mode is not encoded in the 0th to 1st coding blocks.
　一方、予測モードがＩＢＣ予測（PRED_IBC）の場合（ステップＳ１５０９：ＹＥＳ）、ＩＢＣ予測（PRED_IBC）に関する符号化情報を符号化する（ステップＳ１５１０）。具体的には、マージモードか否かを判別するフラグ、マージモードならばマージインデックス、マージモードでないならば予測ブロックベクトルインデックス、差分ブロックベクトル等の符号化情報を規定のシンタックス（符号化ビット列の構文規則）に従って符号化する。 On the other hand, when the prediction mode is IBC prediction (PRED_IBC) (step S1509: YES), the coding information related to IBC prediction (PRED_IBC) is encoded (step S1510). Specifically, a flag for determining whether or not it is in merge mode, a merge index for merge mode, a predicted block vector index for not in merge mode, a difference block vector, and other coding information are specified in the specified syntax (of the coded bit string). Encode according to the syntax rules).
　一方、予測モードがインター予測（PRED_INTER）の場合（ステップＳ１５０９：ＮＯ）、インター予測（PRED_INTER）に関する符号化情報を符号化する（ステップＳ１５１１）。マージモードか否かを判別するフラグ、サブブロックマージフラグ、マージモードの場合はマージインデックス、マージモードでない場合はインター予測モード、予測動きベクトルインデックス、差分動きベクトルに関する情報、サブブロック予測動きベクトルフラグ等の符号化情報を規定のシンタックス（符号化ビット列の構文規則）に従って符号化する。 On the other hand, when the prediction mode is inter-prediction (PRED_INTER) (step S1509: NO), the coding information related to inter-prediction (PRED_INTER) is encoded (step S1511). Flag to determine whether it is in merge mode, sub-block merge flag, merge index in merge mode, inter-prediction mode, predicted motion vector index in non-merge mode, information about differential motion vector, sub-block predicted motion vector flag, etc. The coding information of is encoded according to the specified syntax (the syntax rule of the encoding bit string).
　続いて、直交変換・量子化部１０７で導出された残差信号に関する情報を符号化し（ステップ１５１２）、本符号化ブロックの符号化情報符号化手順を終了する。 Subsequently, the information regarding the residual signal derived by the orthogonal conversion / quantization unit 107 is encoded (step 1512), and the coding information coding procedure of the present coding block is completed.
　続いて、色差信号の残差信号に関する情報を符号化するかどうかを判断する（ステップ１５１３）。ステップ１５１３の色差信号の残差信号に関する情報を符号化するかどうかの判断はステップＳ１５０７の色差信号の符号化ブロックのイントラ色差予測モードに関する情報を符号化するか否かを判断すると同一であり、符号化ブロックのイントラ色差予測モードに関する情報を符号化すると判断した場合は、色差信号の残差信号に関する情報も符号化すると判断し、符号化ブロックのイントラ色差予測モードに関する情報を符号化しないと判断した場合は、色差信号の残差信号に関する情報も符号化しないと判断する。 Subsequently, it is determined whether or not to encode the information regarding the residual signal of the color difference signal (step 1513). The determination of whether or not to encode the information regarding the residual signal of the color difference signal in step 1513 is the same as determining whether or not to encode the information regarding the intra color difference prediction mode of the coding block of the color difference signal in step S1507. When it is determined that the information regarding the intra-color difference prediction mode of the coded block is encoded, it is determined that the information regarding the residual signal of the color difference signal is also encoded, and it is determined that the information regarding the intra-color difference prediction mode of the coded block is not encoded. If so, it is determined that the information regarding the residual signal of the color difference signal is also not encoded.
　続いて、色差信号の残差信号に関する情報を符号化すると判断した場合は（ステップＳ１５１３：ＹＥＳ）、直交変換・量子化部１０７で生成された色差信号の残差信号に関する情報を符号化する（ステップＳ１５１４）。 Subsequently, when it is determined to encode the information regarding the residual signal of the color difference signal (step S1513: YES), the information regarding the residual signal of the color difference signal generated by the orthogonal conversion / quantization unit 107 is encoded (step S1513: YES). Step S1514).
　＜符号化ブロックの符号化情報復号＞
　次に、画像復号装置２００におけるビット列復号部２０１において符号化ブロックの符号化情報を復号する動作について説明する。図５８は、符号化ブロックの符号化情報を復号する動作を示すフローチャートである。復号側では、符号化側で符号化された符号化ビット列から符号化ブロック毎の符号化情報を復号する。本実施の形態においては、符号化側で説明したようにシーケンス、ピクチャ、またはスライス単位で、ＩＢＣ予測（PRED_IBC）を用いるかどうかを設定できるものとする。さらに、シーケンス、ピクチャまたはスライス単位で、インター予測（PRED_ INTER）を用いるかどうかを設定できるものとする。 <Decoding the coded information of the coded block>
Next, the operation of decoding the coding information of the coding block in the bit string decoding unit 201 of the image decoding device 200 will be described. FIG. 58 is a flowchart showing an operation of decoding the coding information of the coding block. On the decoding side, the coding information for each coding block is decoded from the coding bit string encoded on the coding side. In the present embodiment, it is possible to set whether or not to use IBC prediction (PRED_IBC) for each sequence, picture, or slice as described on the coding side. Furthermore, it shall be possible to set whether to use inter-prediction (PRED_INTER) for each sequence, picture or slice.
　まず、符号化ブロックの予測モードが、イントラ予測（PRED_INTRA）、ＩＢＣ予測（PRED_IBC）、インター予測（PRED_INTER）のいずれかを示す予測モード情報を復号する（ステップＳ１６０１～Ｓ１６０４）。例えば、予測モードがイントラ予測（PRED_INTRA）か否かを示すフラグを復号し（ステップＳ１６０２）、さらに、予測モードがＩＢＣ予測（PRED_IBC）か否かを示すフラグ（ステップＳ１６０４）を復号する。 First, the prediction mode information indicating that the prediction mode of the coding block is any of intra prediction (PRED_INTRA), IBC prediction (PRED_IBC), and inter prediction (PRED_INTER) is decoded (steps S1601 to S1604). For example, the flag indicating whether the prediction mode is intra prediction (PRED_INTRA) is decoded (step S1602), and the flag indicating whether the prediction mode is IBC prediction (PRED_IBC) (step S1604) is decoded.
　まず、符号化ブロックの予測モードがイントラ予測（PRED_INTRA）か否かを示すフラグを復号するか否かを判定する（ステップＳ１６０１）。符号化ブロックの予測モードがイントラ予測（PRED_INTRA）か否かを示すフラグを復号する場合（ステップＳ１６０１：ＹＥＳ）、符号化ブロックの予測モードがイントラ予測（PRED_INTRA）か否かを示すフラグを復号する（ステップＳ１６０２）。予測モードがイントラ予測（PRED_INTRA）の場合、符号化ブロックの予測モードがイントラ予測（PRED_INTRA）か否かを示すフラグは１（真）であり、予測モードがイントラ予測（PRED_INTRA）でない場合、すなわち、予測モードがＩＢＣ予測（PRED_IBC）、またはインター予測（PRED_INTER）の場合、符号化ブロックの予測モードがイントラ予測（PRED_INTRA）か否かを示すフラグは０（偽）である。 First, it is determined whether or not to decode the flag indicating whether or not the prediction mode of the coded block is intra prediction (PRED_INTRA) (step S1601). When decoding the flag indicating whether the prediction mode of the coded block is intra prediction (PRED_INTRA) (step S1601: YES), the flag indicating whether the prediction mode of the coded block is intra prediction (PRED_INTRA) is decoded. (Step S1602). When the prediction mode is intra prediction (PRED_INTRA), the flag indicating whether the prediction mode of the encoded block is intra prediction (PRED_INTRA) is 1 (true), and when the prediction mode is not intra prediction (PRED_INTRA), that is, When the prediction mode is IBC prediction (PRED_IBC) or inter prediction (PRED_INTER), the flag indicating whether the prediction mode of the coded block is intra prediction (PRED_INTRA) is 0 (false).
　続いて、符号化ブロックの予測モードがＩＢＣ予測（PRED_IBC）か否かを示すフラグを復号するか否かを判定する（ステップＳ１６０３）。シーケンス、ピクチャ、またはスライス単位で、ＩＢＣ予測（PRED_IBC）を用いない場合、または、シーケンス、ピクチャ、またはスライス単位で、インター予測（PRED_INTER）を用いない場合、処理対象の符号化ブロックの親ブロックにおいて、色差ブロック非分割フラグchroma_non_split_flagが０（偽）に設定されて符号化されている場合などは、符号化ブロックの予測モードがＩＢＣ予測（PRED_IBC）か否かを示すフラグを復号しない。符号化ブロックの予測モードがＩＢＣ予測（PRED_IBC）か否かを示すフラグを復号する場合（ステップＳ１６０３：ＹＥＳ）、符号化ブロックの予測モードがＩＢＣ予測（PRED_IBC）か否かを示すフラグを復号する（ステップＳ１６０４）。予測モードがＩＢＣ予測（PRED_IBC）の場合、符号化ブロックの予測モードがＩＢＣ予測（PRED_IBC）か否かを示すフラグは１（真）であり、予測モードがＩＢＣ予測（PRED_IBC）でない場合、すなわち、予測モードがインター予測（PRED_INTER）の場合、符号化ブロックの予測モードがＩＢＣ予測（PRED_IBC）か否かを示すフラグは０（偽）である。 Subsequently, it is determined whether or not to decode the flag indicating whether or not the prediction mode of the coded block is IBC prediction (PRED_IBC) (step S1603). If IBC prediction (PRED_IBC) is not used for each sequence, picture, or slice, or if inter-prediction (PRED_INTER) is not used for each sequence, picture, or slice, in the parent block of the coded block to be processed. , When the color difference block non-split flag chroma_non_split_flag is set to 0 (false) and encoded, the flag indicating whether the prediction mode of the coding block is IBC prediction (PRED_IBC) is not decoded. When decoding the flag indicating whether the prediction mode of the coding block is IBC prediction (PRED_IBC) (step S1603: YES), the flag indicating whether the prediction mode of the coding block is IBC prediction (PRED_IBC) is decoded. (Step S1604). When the prediction mode is IBC prediction (PRED_IBC), the flag indicating whether the prediction mode of the coded block is IBC prediction (PRED_IBC) is 1 (true), and when the prediction mode is not IBC prediction (PRED_IBC), that is, When the prediction mode is inter-prediction (PRED_INTER), the flag indicating whether the prediction mode of the coded block is IBC prediction (PRED_IBC) is 0 (false).
　続いて、予測モードがイントラ予測（PRED_INTRA）の場合は（ステップＳ１６０５：ＹＥＳ）、輝度信号の符号化ブロックのイントラ輝度予測モードに関する情報を復号する（ステップＳ１６０６）。輝度信号の符号化ブロックのイントラ輝度予測モードに関する情報の復号については後述する。 Subsequently, when the prediction mode is intra-prediction (PRED_INTRA) (step S1605: YES), the information regarding the intra-luminance prediction mode of the luminance signal coding block is decoded (step S1606). Decoding of information regarding the intra-luminance prediction mode of the luminance signal coding block will be described later.
　続いて、色差信号の符号化ブロックのイントラ色差予測モードに関する情報を復号するか否かを判断する（ステップＳ１６０７）。予測モードがイントラ予測（MODE_INTRA）の場合、本実施の形態では２×２、４×２、２×４画素の色差信号の符号化ブロックを禁止するので、処理対象の符号化ブロックの親ブロックにおいて、イントラ予測、またはIBC予測において、分割モードに基づいて分割対象の色差ブロックを分割せずに、色差符号化ブロックとすると判断した場合、すなわち色差ブロック非分割フラグchroma_non_split_flagが１（真）に設定された場合は（ステップＳ１６０７：ＹＥＳ）、分割された最後の符号化ブロックにおいてイントラ色差予測モードに関する情報を復号し（ステップＳ１６０８）、それ以外の符号化ブロックにおいては（ステップＳ１６０７：ＮＯ）、イントラ色差予測モードに関する情報を復号しない。例えば、親ブロックでの分割モードが４分割モードの場合（図５Ａの６０１）、最後である０番目から数えて３番目の符号化ブロックにおいて、イントラ色差予測モードに関する情報を復号し（ステップＳ１６０８）、０～２番目の符号化ブロックにおいてはイント色差予測モードに関する情報を復号しない。また、親ブロックでの分割モードが垂直２分割モードまたは水平２分割モードの場合（図５Ｂの６０２、図５Ｄの６０４）、最後である０番目から数えて１番目の符号化ブロックにおいて、イントラ色差予測モードに関する情報を復号し（ステップＳ１６０８）、０番目の符号化ブロックにおいてはイントラ色差予測モードに関する情報を復号しない。また、親ブロックでの分割モードが垂直３分割モードまたは水平３分割モードの場合（図５Ｃの６０３、図５Ｅの６０５）、最後である０番目から数えて２番目の符号化ブロックにおいて、イントラ色差予測モードに関する情報を復号し（ステップＳ１６０８）、０～１番目の符号化ブロックにおいてはイントラ色差予測モードに関する情報を復号しない。なお、処理対象の符号化ブロックの親ブロックにおいて、色差ブロック非分割フラグchroma_non_split_flagが１（真）に設定されていない場合は、処理対象の符号化ブロックにおいてイントラ色差予測モードに関する情報を復号する。 Subsequently, it is determined whether or not to decode the information regarding the intra color difference prediction mode of the coded block of the color difference signal (step S1607). When the prediction mode is intra prediction (MODE_INTRA), in the present embodiment, the coding block of the color difference signal of 2 × 2, 4 × 2, 2 × 4 pixels is prohibited, so that the parent block of the coded block to be processed , Intra prediction, or IBC prediction, when it is determined that the color difference block to be divided is not divided based on the division mode and is a color difference coding block, that is, the color difference block non-division flag chroma_non_split_flag is set to 1 (true). If (step S1607: YES), the information regarding the intra color difference prediction mode is decoded in the last divided coded block (step S1608), and in the other coded blocks (step S1607: NO), the intra color difference Do not decode information about predictive mode. For example, when the division mode in the parent block is the 4-division mode (601 in FIG. 5A), the information regarding the intra color difference prediction mode is decoded in the third coding block counting from the 0th, which is the last (step S1608). , In the 0th to 2nd coding blocks, the information regarding the into color difference prediction mode is not decoded. Further, when the division mode in the parent block is the vertical 2-division mode or the horizontal 2-division mode (602 in FIG. 5B, 604 in FIG. 5D), the intra-color difference in the first coded block counting from the last 0th. The information regarding the prediction mode is decoded (step S1608), and the information regarding the intra color difference prediction mode is not decoded at the 0th coding block. Further, when the division mode in the parent block is the vertical 3-division mode or the horizontal 3-division mode (603 in FIG. 5C, 605 in FIG. 5E), the intra color difference is in the second coding block counting from the 0th last. The information regarding the prediction mode is decoded (step S1608), and the information regarding the intra color difference prediction mode is not decoded in the 0th to 1st coding blocks. If the color difference block undivided flag chroma_non_split_flag is not set to 1 (true) in the parent block of the coded block to be processed, the information regarding the intra color difference prediction mode is decoded in the coded block to be processed.
　一方、予測モードがＩＢＣ予測（PRED_IBC）の場合（ステップＳ１６０９：ＹＥＳ）、ＩＢＣ予測（PRED_IBC）に関する符号化情報を復号する（ステップＳ１６１０）。具体的には、マージモードか否かを判別するフラグ、マージモードならばマージインデックス、マージモードでないならば予測ブロックベクトルインデックス、差分ブロックベクトル等の符号化情報を規定のシンタックス（符号化ビット列の構文規則）に従って復号する。 On the other hand, when the prediction mode is IBC prediction (PRED_IBC) (step S1609: YES), the coding information related to IBC prediction (PRED_IBC) is decoded (step S1610). Specifically, a flag for determining whether or not it is in merge mode, a merge index if it is in merge mode, a predicted block vector index if it is not in merge mode, a difference block vector, and other coding information are specified in the syntax (coded bit string). Decrypt according to the syntax rules).
　一方、予測モードがインター予測（PRED_INTER）の場合（ステップＳ１６０９：ＮＯ）、インター予測（PRED_INTER）に関する符号化情報を復号する（ステップＳ１６１１）。マージモードか否かを判別するフラグ、サブブロックマージフラグ、マージモードの場合はマージインデックス、マージモードでない場合はインター予測モード、予測動きベクトルインデックス、差分動きベクトルに関する情報、サブブロック予測動きベクトルフラグ等の符号化情報を規定のシンタックス（符号化ビット列の構文規則）に従って復号する。 On the other hand, when the prediction mode is inter-prediction (PRED_INTER) (step S1609: NO), the coding information related to inter-prediction (PRED_INTER) is decoded (step S1611). Flag to determine whether it is in merge mode, sub-block merge flag, merge index in merge mode, inter-prediction mode, predicted motion vector index in non-merge mode, information about differential motion vector, sub-block predicted motion vector flag, etc. The encoding information of is decoded according to the specified syntax (the syntax rule of the coded bit string).
　続いて、残差信号に関する情報を復号し（ステップ１６１２）、本符号化情報復号処理を終了する。 Subsequently, the information regarding the residual signal is decoded (step 1612), and the present encoded information decoding process is completed.
　＜イントラ予測モード符号化＞
　次に、図１のビット列符号化部１０８で行われるイントラ予測モードの符号化処理、図２のビット列復号部２０１で行われるイントラ予測モードの復号処理について説明する。 <Intra-prediction mode coding>
Next, the coding process of the intra prediction mode performed by the bit string coding unit 108 of FIG. 1 and the decoding process of the intra prediction mode performed by the bit string decoding unit 201 of FIG. 2 will be described.
　符号化側のビット列符号化部１０８においては、符号化ブロックの予測モード（PredMode）がイントラ予測（MODE_INTRA）の場合に、輝度信号の符号化ブロックのイントラ輝度予測モードに関するシンタックス要素の値をそれぞれ算出して符号化する（ステップＳ１５０６）。イントラ輝度予測モードに関するシンタックス要素は周辺のブロックのイントラ輝度予測モードから予測できるかどうかを示すフラグであるシンタックス要素intra_luma_mpm_flag [ x0 ][ y0 ]、予測元の符号化ブロックを指し示すインデックスであるシンタックス要素intra_luma_mpm_idx [ x0 ][ y0 ]、及び符号化ブロック単位のイントラ輝度予測モードを示すシンタックス要素intra_luma_mpm_remainder [ x0 ][ y0 ]である。なお、x0, 及びy0は符号化ブロックの位置を示す座標である。イントラ輝度予測モードに関するシンタックス要素の値の算出においては、符号化情報格納メモリ１１１に格納されている周辺のブロックのイントラ輝度予測モードとの相関性を利用し、周辺のブロックのイントラ輝度予測モードから予測できる場合はその値を用いることを示すフラグであるシンタックス要素intra_luma_mpm_flag [ x0 ][ y0 ]を１（真）に設定して、予測元の符号化ブロックを指し示すインデックスであるシンタックス要素intra_luma_mpm_idx [ x0 ][ y0 ]に参照先を特定する値を設定し、予測できない場合には、intra_luma_mpm_flag [ x0 ][ y0 ]を０（偽）に設定して、符号化するイントラ輝度予測モードを示すシンタックス要素intra_luma_mpm_remainder [ x0 ][ y0 ]にイントラ輝度予測モードを特定する値を設定する。 In the bit string coding unit 108 on the coding side, when the prediction mode (PredMode) of the coded block is intra-prediction (MODE_INTRA), the values of the syntax elements related to the intra-luminance prediction mode of the coded block of the luminance signal are respectively. Calculate and encode (step S1506). The syntax element related to the intra-luminance prediction mode is the syntax element intra_luma_mpm_flag [x0] [y0], which is a flag indicating whether or not it can be predicted from the intra-luminance prediction mode of the surrounding blocks, and the thin index, which indicates the coding block of the prediction source. The tax element intra_luma_mpm_idx [x0] [y0], and the syntax element intra_luma_mpm_remainder [x0] [y0] indicating the intra-luminance prediction mode for each coded block. Note that x0, y0 are coordinates indicating the position of the coded block. In the calculation of the value of the syntax element related to the intra-luminance prediction mode, the intra-luminance prediction mode of the peripheral blocks is used by using the correlation with the intra-luminance prediction mode of the peripheral blocks stored in the coding information storage memory 111. If it can be predicted from, the syntax element intra_luma_mpm_flag [x0] [y0], which is a flag indicating that the value is used, is set to 1 (true), and the syntax element intra_luma_mpm_idx, which is an index indicating the encoding block of the prediction source, is set. Set a value to specify the reference destination in [x0] [y0], and if it cannot be predicted, set intra_luma_mpm_flag [x0] [y0] to 0 (false) to indicate the intra-brightness prediction mode to be encoded. Set the tax element intra_luma_mpm_remainder [x0] [y0] to a value that specifies the intra-brightness prediction mode.
　さらに、符号化側のビット列符号化部１０８においては、色差信号の符号化ブロックのイントラ色差予測モードに関するシンタックス要素intra_chroma_pred_mode[ x0 ][ y0 ]の値を算出して符号化する（ステップＳ１５０８）。イントラ色差予測モードに関するシンタックス要素の値の算出においては、色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックのイントラ輝度予測モードとの相関性を利用し、イントラ色差予測モードが色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックのイントラ輝度予測モードから予測できる場合はイントラ輝度予測モードの値からイントラ色差予測モードの値を予測し、イントラ輝度予測モードからイントラ色差予測モードを予測できない場合に、イントラ色差予測モードに代表的なイントラ予測モードである０（平面予測）、１（平均値予測）、１８（水平予測）、５０（垂直予測）、６６（斜め予測）のいずれかの値を設定する仕組みを用いることにより、符号量を削減する。色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックのイントラ輝度予測モードの値からイントラ色差予測モードの値を予測するモードをＤＭモードととし、シンタックス要素intra_chroma_pred_mode[ x0 ][ y0 ]が所定の値の時、ＤＭモードを示すものとする。 Further, in the bit string coding unit 108 on the coding side, the value of the syntax element intra_chroma_pred_mode [x0] [y0] relating to the intra color difference prediction mode of the coded block of the color difference signal is calculated and encoded (step S1508). In calculating the value of the syntax element related to the intra-color difference prediction mode, the intra-luminance prediction mode uses the correlation between the coded block of the color difference signal and the coded block of the luminance signal at the same position as the intra-luminance prediction mode. If it can be predicted from the intra-luminance prediction mode of the luminance signal coding block at the same position as the signal coding block, the intra-luminance prediction mode value is predicted from the intra-luminance prediction mode value, and the intra-luminance prediction mode is used to predict the intra-luminance prediction mode. When the mode cannot be predicted, the intra prediction modes typical of the intra color difference prediction mode are 0 (plane prediction), 1 (average value prediction), 18 (horizontal prediction), 50 (vertical prediction), 66 (diagonal prediction). The amount of code is reduced by using a mechanism for setting one of the values of. The mode for predicting the value of the intra-color difference prediction mode from the value of the intra-luminance prediction mode of the luminance signal coding block at the same position as the color difference signal coding block is set to DM mode, and the syntax element intra_chroma_pred_mode [x0] [y0] When is a predetermined value, it indicates the DM mode.
　＜イントラ予測モード復号＞
　復号側のビット列復号部２０１においては、符号化ブロックの予測モード（PredMode）がイントラ予測（MODE_INTRA）の場合に、ビット列から輝度信号の符号化ブロックのイントラ輝度予測モードに関するシンタックス要素intra_luma_mpm_flag [ x0 ][ y0 ]、intra_luma_mpm_idx [ x0 ][ y0 ]、intra_luma_mpm_remainder [ x0 ][ y0 ]を復号して、イントラ輝度予測モードを導出し、イントラ色差予測モードに関するシンタックス要素intra_chroma_pred_mode[ x0 ][ y0 ]を復号して、イントラ色差予測モードの値を導出する。イントラ色差予測モードに関するシンタックス要素intra_chroma_pred_mode[ x0 ][ y0 ]の値がＤＭモードを示す場合、イントラ色差予測モードの値を色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックのイントラ輝度予測モードと同じ値とする。 <Intra prediction mode decoding>
In the bit string decoding unit 201 on the decoding side, when the prediction mode (PredMode) of the coded block is intra prediction (MODE_INTRA), the syntax element intra_luma_mpm_flag [x0] relating to the intra-luminance prediction mode of the coded block of the luminance signal from the bit string. Decrypt [y0], intra_luma_mpm_idx [x0] [y0], intra_luma_mpm_remainder [x0] [y0] to derive the intra-luminance prediction mode, and decode the syntax element intra_chroma_pred_mode [x0] [y0] for the intra-color difference prediction mode. Then, the value of the intra-color difference prediction mode is derived. When the value of intra_chroma_pred_mode [x0] [y0] indicates the DM mode, the value of the intra-color difference prediction mode is set to the intra-luminance of the luminance signal coding block at the same position as the luminance signal coding block. Set to the same value as the prediction mode.
　なお、本実施の形態においては、色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックを特定する際に、色差信号の画像空間における色差信号の符号化ブロックの中央の右下の画素に対応する輝度信号の画像空間で同じ位置の画素を含む輝度信号の符号化ブロックを色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックとしたが、色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックを特定する際に、色差信号の画像空間における色差信号の符号化ブロックの左上の画素に対応する輝度信号の画像空間で同じ位置の画素を含む輝度信号の符号化ブロックを色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックとしてもよい。 In the present embodiment, when specifying the coded block of the luminance signal at the same position as the coded block of the color difference signal, the lower right pixel in the center of the coded block of the color difference signal in the image space of the color difference signal. The luminance signal coding block containing the pixels at the same position in the image space of the luminance signal corresponding to is the luminance signal coding block at the same position as the color difference signal coding block, but is the same as the color difference signal coding block. Coding of a luminance signal containing pixels at the same position in the image space of the luminance signal corresponding to the upper left pixel of the coding block of the luminance signal in the image space of the color difference signal when identifying the coding block of the luminance signal at the position. The block may be a coded block of the luminance signal at the same position as the coded block of the color difference signal.
　＜インター予測＞
　実施の形態に係るインター予測方法は、図１の画像符号化装置のインター予測部１０２および図２の画像復号装置のインター予測部２０３において実施される。 <Inter prediction>
The inter-prediction method according to the embodiment is carried out by the inter-prediction unit 102 of the image coding device of FIG. 1 and the inter-prediction unit 203 of the image decoding device of FIG.
　実施の形態によるインター予測方法について、図面を用いて説明する。インター予測方法は符号化ブロック単位で符号化及び復号の処理の何れでも実施される。 The inter-prediction method according to the embodiment will be described with reference to the drawings. The inter-prediction method is performed in either coding or decoding processing in units of coded blocks.
　＜符号化側のインター予測部１０２の説明＞
　図１６は図１の画像符号化装置のインター予測部１０２の詳細な構成を示す図である。通常予測動きベクトルモード導出部３０１は、複数の通常予測動きベクトル候補を導出して予測動きベクトルを選択し、選択された予測動きベクトルと、検出された動きベクトルとの差分ベクトルを算出する。検出されたインター予測モード、参照インデックス、動きベクトル、算出された差分ベクトルが通常予測動きベクトルモードのインター予測情報となる。このインター予測情報がインター予測モード判定部３０５に供給される。通常予測動きベクトルモード導出部３０１の詳細な構成と処理については後述する。 <Explanation of Inter Prediction Unit 102 on the Encoding Side>
FIG. 16 is a diagram showing a detailed configuration of the inter-prediction unit 102 of the image coding apparatus of FIG. The normal predicted motion vector mode derivation unit 301 derives a plurality of normal predicted motion vector candidates, selects a predicted motion vector, and calculates a difference vector between the selected predicted motion vector and the detected motion vector. The detected inter-prediction mode, reference index, motion vector, and calculated difference vector become the inter-prediction information of the normal prediction motion vector mode. This inter-prediction information is supplied to the inter-prediction mode determination unit 305. The detailed configuration and processing of the normal prediction motion vector mode derivation unit 301 will be described later.
　通常マージモード導出部３０２では複数の通常マージ候補を導出して通常マージ候補を選択し、通常マージモードのインター予測情報を得る。このインター予測情報がインター予測モード判定部３０５に供給される。通常マージモード導出部３０２の詳細な構成と処理については後述する。 The normal merge mode derivation unit 302 derives a plurality of normal merge candidates, selects the normal merge candidates, and obtains the inter-prediction information of the normal merge mode. This inter-prediction information is supplied to the inter-prediction mode determination unit 305. The detailed configuration and processing of the normal merge mode derivation unit 302 will be described later.
　サブブロック予測動きベクトルモード導出部３０３では複数のサブブロック予測動きベクトル候補を導出してサブブロック予測動きベクトルを選択し、選択したサブブロック予測動きベクトルと、検出した動きベクトルとの差分動きベクトルを算出する。検出されたインター予測モード、参照インデックス、動きベクトル、算出された差分動きベクトルがサブブロック予測動きベクトルモードのインター予測情報となる。このインター予測情報がインター予測モード判定部３０５に供給される。サブブロック予測動きベクトルモード導出部３０３の詳細な構成と処理については後述する。 The sub-block prediction motion vector mode derivation unit 303 derives a plurality of sub-block prediction motion vector candidates, selects a sub-block prediction motion vector, and selects a difference motion vector between the selected sub-block prediction motion vector and the detected motion vector. calculate. The detected inter-prediction mode, reference index, motion vector, and calculated difference motion vector become the inter-prediction information of the sub-block prediction motion vector mode. This inter-prediction information is supplied to the inter-prediction mode determination unit 305. The detailed configuration and processing of the sub-block prediction motion vector mode derivation unit 303 will be described later.
　サブブロックマージモード導出部３０４では複数のサブブロックマージ候補を導出してサブブロックマージ候補を選択し、サブブロックマージモードのインター予測情報を得る。このインター予測情報がインター予測モード判定部３０５に供給される。サブブロックマージモード導出部３０４の詳細な構成と処理については後述する。 The sub-block merge mode derivation unit 304 derives a plurality of sub-block merge candidates, selects the sub-block merge candidates, and obtains the inter-prediction information of the sub-block merge mode. This inter-prediction information is supplied to the inter-prediction mode determination unit 305. The detailed configuration and processing of the subblock merge mode derivation unit 304 will be described later.
　インター予測モード判定部３０５では通常予測動きベクトルモード導出部３０１、通常マージモード導出部３０２、サブブロック予測動きベクトルモード導出部３０３、サブブロックマージモード導出部３０４から供給されるインター予測情報に基づいて、インター予測モードを判定する。インター予測モード判定部３０５から判定結果に応じたインター予測情報が動き補償予測部３０６に供給される。 The inter-prediction mode determination unit 305 is based on the inter-prediction information supplied from the normal prediction motion vector mode derivation unit 301, the normal merge mode derivation unit 302, the sub-block prediction motion vector mode derivation unit 303, and the sub-block merge mode derivation unit 304. , Determine the inter-prediction mode. Inter-prediction mode determination unit 305 supplies inter-prediction information according to the determination result to motion compensation prediction unit 306.
　動き補償予測部３０６では判定されたインター予測情報に基づいて、復号画像メモリ１０４に格納されている参照画像信号に対してインター予測を行う。動き補償予測部３０６の詳細な構成と処理については後述する。 The motion compensation prediction unit 306 performs inter-prediction for the reference image signal stored in the decoded image memory 104 based on the determined inter-prediction information. The detailed configuration and processing of the motion compensation prediction unit 306 will be described later.
　＜復号側のインター予測部２０３の説明＞
　図２２は図２の画像復号装置のインター予測部２０３の詳細な構成を示す図である。 <Explanation of inter-prediction unit 203 on the decoding side>
FIG. 22 is a diagram showing a detailed configuration of the inter-prediction unit 203 of the image decoding apparatus of FIG.
　通常予測動きベクトルモード導出部４０１は複数の通常予測動きベクトル候補を導出して予測動きベクトルを選択し、選択された予測動きベクトルと、復号された差分動きベクトルとの加算値を算出して動きベクトルとする。導出されたインター予測モード、参照インデックス、動きベクトルが通常予測動きベクトルモードのインター予測情報となる。このインター予測情報がスイッチ４０８を経由して動き補償予測部４０６に供給される。通常予測動きベクトルモード導出部４０１の詳細な構成と処理については後述する。 The normal predicted motion vector mode derivation unit 401 derives a plurality of normal predicted motion vector candidates, selects a predicted motion vector, calculates an added value between the selected predicted motion vector and the decoded differential motion vector, and moves. Let it be a vector. The derived inter-prediction mode, reference index, and motion vector are the inter-prediction information of the normal prediction motion vector mode. This inter-prediction information is supplied to the motion compensation prediction unit 406 via the switch 408. The detailed configuration and processing of the normal predicted motion vector mode derivation unit 401 will be described later.
　通常マージモード導出部４０２では複数の通常マージ候補を導出して通常マージ候補を選択し、通常マージモードのインター予測情報を得る。このインター予測情報がスイッチ４０８を経由して動き補償予測部４０６に供給される。通常マージモード導出部４０２の詳細な構成と処理については後述する。 The normal merge mode derivation unit 402 derives a plurality of normal merge candidates, selects the normal merge candidates, and obtains the inter-prediction information of the normal merge mode. This inter-prediction information is supplied to the motion compensation prediction unit 406 via the switch 408. The detailed configuration and processing of the normal merge mode derivation unit 402 will be described later.
　サブブロック予測動きベクトルモード導出部４０３では複数のサブブロック予測動きベクトル候補を導出してサブブロック予測動きベクトルを選択し、選択したサブブロック予測動きベクトルと、復号した差分ベクトルとの加算値を算出して動きベクトルとする。導出されたインター予測モード、参照インデックス、動きベクトルがサブブロック予測動きベクトルモードのインター予測情報となる。このインター予測情報がスイッチ４０８を経由して動き補償予測部４０６に供給される。 The sub-block prediction motion vector mode derivation unit 403 derives a plurality of sub-block prediction motion vector candidates, selects a sub-block prediction motion vector, and calculates the sum of the selected sub-block prediction motion vector and the decoded difference vector. And make it a motion vector. The derived inter-prediction mode, reference index, and motion vector are the inter-prediction information of the sub-block prediction motion vector mode. This inter-prediction information is supplied to the motion compensation prediction unit 406 via the switch 408.
　サブブロックマージモード導出部４０４では複数のサブブロックマージ候補を導出してサブブロックマージ候補を選択し、サブブロックマージモードのインター予測情報を得る。このインター予測情報がスイッチ４０８を経由して動き補償予測部４０６に供給される。 The sub-block merge mode derivation unit 404 derives a plurality of sub-block merge candidates, selects the sub-block merge candidates, and obtains the inter-prediction information of the sub-block merge mode. This inter-prediction information is supplied to the motion compensation prediction unit 406 via the switch 408.
　動き補償予測部４０６では判定されたインター予測情報に基づいて、復号画像メモリ２０８に格納されている参照画像信号に対してインター予測を行う。動き補償予測部４０６の詳細な構成と処理については符号化側の動き補償予測部３０６と同様である。 The motion compensation prediction unit 406 performs inter-prediction for the reference image signal stored in the decoded image memory 208 based on the determined inter-prediction information. The detailed configuration and processing of the motion compensation prediction unit 406 are the same as those of the motion compensation prediction unit 306 on the coding side.
　＜通常予測動きベクトルモード導出部（通常AMVP）＞
　図１７の通常予測動きベクトルモード導出部３０１は、空間予測動きベクトル候補導出部３２１、時間予測動きベクトル候補導出部３２２、履歴予測動きベクトル候補導出部３２３、予測動きベクトル候補補充部３２５、通常動きベクトル検出部３２６、予測動きベクトル候補選択部３２７、動きベクトル減算部３２８を含む。 <Normal prediction motion vector mode derivation unit (normal AMVP)>
The normal prediction motion vector mode derivation unit 301 of FIG. 17 includes a spatial prediction motion vector candidate derivation unit 321, a time prediction motion vector candidate derivation unit 322, a history prediction motion vector candidate derivation unit 323, a prediction motion vector candidate replenishment unit 325, and a normal motion. It includes a vector detection unit 326, a predicted motion vector candidate selection unit 327, and a motion vector subtraction unit 328.
　図２３の通常予測動きベクトルモード導出部４０１は、空間予測動きベクトル候補導出部４２１、時間予測動きベクトル候補導出部４２２、履歴予測動きベクトル候補導出部４２３、予測動きベクトル候補補充部４２５、予測動きベクトル候補選択部４２６、動きベクトル加算部４２７を含む。 The normal prediction motion vector mode derivation unit 401 of FIG. 23 includes a space prediction motion vector candidate derivation unit 421, a time prediction motion vector candidate derivation unit 422, a history prediction motion vector candidate derivation unit 423, a prediction motion vector candidate replenishment unit 425, and a prediction motion. It includes a vector candidate selection unit 426 and a motion vector addition unit 427.
　符号化側の通常予測動きベクトルモード導出部３０１および復号側の通常予測動きベクトルモード導出部４０１の処理手順について、それぞれ図１９、図２５のフローチャートを用いて説明する。図１９は符号化側の通常動きベクトルモード導出部３０１による通常予測動きベクトルモード導出処理手順を示すフローチャートであり、図２５は復号側の通常動きベクトルモード導出部４０１による通常予測動きベクトルモード導出処理手順を示すフローチャートである。 The processing procedures of the normal prediction motion vector mode derivation unit 301 on the coding side and the normal prediction motion vector mode derivation unit 401 on the decoding side will be described with reference to the flowcharts of FIGS. 19 and 25, respectively. FIG. 19 is a flowchart showing a normal motion vector mode derivation processing procedure by the normal motion vector mode derivation unit 301 on the coding side, and FIG. 25 is a normal motion vector mode derivation process by the normal motion vector mode derivation unit 401 on the decoding side. It is a flowchart which shows a procedure.
　＜通常予測動きベクトルモード導出部（通常AMVP）：符号化側の説明＞
　図１９を参照して符号化側の通常予測動きベクトルモード導出処理手順を説明する。図１９の処理手順の説明において、図１９に示した通常という言葉を省略することがある。 <Normal prediction motion vector mode derivation unit (normal AMVP): Explanation on the coding side>
The procedure for deriving the normal predicted motion vector mode on the coding side will be described with reference to FIG. In the description of the processing procedure of FIG. 19, the word "normal" shown in FIG. 19 may be omitted.
　まず、通常動きベクトル検出部３２６でインター予測モードおよび参照インデックス毎に通常動きベクトルを検出する（図１９のステップＳ１００）。 First, the normal motion vector detection unit 326 detects the normal motion vector for each inter-prediction mode and reference index (step S100 in FIG. 19).
　続いて、空間予測動きベクトル候補導出部３２１、時間予測動きベクトル候補導出部３２２、履歴予測動きベクトル候補導出部３２３、予測動きベクトル候補補充部３２５、予測動きベクトル候補選択部３２７、動きベクトル減算部３２８で、通常予測動きベクトルモードのインター予測で用いる動きベクトルの差分動きベクトルをＬ０、Ｌ１毎にそれぞれ算出する（図１９のステップＳ１０１～Ｓ１０６）。具体的には処理対象ブロックの予測モードPredModeがインター予測（MODE_INTER）で、インター予測モードがＬ０予測（Pred_L0）の場合、Ｌ０の予測動きベクトル候補リストmvpListL0を算出して、予測動きベクトルmvpL0を選択し、Ｌ０の動きベクトルmvL0の差分動きベクトルmvdL0を算出する。処理対象ブロックのインター予測モードがＬ１予測（Pred_L1）の場合、Ｌ１の予測動きベクトル候補リストmvpListL1を算出して、予測動きベクトルmvpL1を選択し、Ｌ１の動きベクトルmvL1の差分動きベクトルmvdL1を算出する。処理対象ブロックのインター予測モードが双予測（Pred_BI）の場合、Ｌ０予測とＬ１予測が共に行われ、Ｌ０の予測動きベクトル候補リストmvpListL0を算出して、Ｌ０の予測動きベクトルmvpL0を選択し、Ｌ０の動きベクトルmvL0の差分動きベクトルmvdL0を算出するとともに、Ｌ１の予測動きベクトル候補リストmvpListL1を算出して、Ｌ１の予測動きベクトルmvpL1を算出し、Ｌ１の動きベクトルmvL1の差分動きベクトルmvdL1をそれぞれ算出する。 Subsequently, the spatial prediction motion vector candidate derivation unit 321, the time prediction motion vector candidate derivation unit 322, the history prediction motion vector candidate derivation unit 323, the prediction motion vector candidate supplementation unit 325, the prediction motion vector candidate selection unit 327, and the motion vector subtraction unit. At 328, the difference motion vector of the motion vector used in the inter-prediction of the normal prediction motion vector mode is calculated for each of L0 and L1, respectively (steps S101 to S106 in FIG. 19). Specifically, when the prediction mode PredMode of the block to be processed is inter-prediction (MODE_INTER) and the inter-prediction mode is L0 prediction (Pred_L0), the prediction motion vector candidate list mvpListL0 of L0 is calculated and the prediction motion vector mvpL0 is selected. Then, the difference motion vector mvdL0 of the motion vector mvL0 of L0 is calculated. When the inter-prediction mode of the block to be processed is L1 prediction (Pred_L1), the prediction motion vector candidate list mvpListL1 of L1 is calculated, the prediction motion vector mvpL1 is selected, and the difference motion vector mvdL1 of the motion vector mvL1 of L1 is calculated. .. When the inter-prediction mode of the block to be processed is bi-prediction (Pred_BI), both L0 prediction and L1 prediction are performed, the prediction motion vector candidate list mvpList L0 of L0 is calculated, the prediction motion vector mvpL0 of L0 is selected, and L0. The motion vector mvL0 of the motion vector mvL0 is calculated, the predicted motion vector candidate list mvpListL1 of L1 is calculated, the predicted motion vector mvpL1 of L1 is calculated, and the differential motion vector mvdL1 of the motion vector mvL1 of L1 is calculated. To do.
　Ｌ０、Ｌ１それぞれについて、差分動きベクトル算出処理を行うが、Ｌ０、Ｌ１ともに共通の処理となる。したがって、以下の説明においてはＬ０、Ｌ１を共通のＬＸとして表す。Ｌ０の差分動きベクトルを算出する処理ではＬＸのＸが０であり、Ｌ１の差分動きベクトルを算出する処理ではＬＸのＸが１である。また、ＬＸの差分動きベクトルを算出する処理中に、ＬＸではなく、もう一方のリストの情報を参照する場合、もう一方のリストをＬＹとして表す。 The difference motion vector calculation process is performed for each of L0 and L1, but both L0 and L1 are common processes. Therefore, in the following description, L0 and L1 are represented as a common LX. In the process of calculating the differential motion vector of L0, X of LX is 0, and in the process of calculating the differential motion vector of L1, X of LX is 1. Further, when the information of the other list is referred to instead of the LX during the process of calculating the differential motion vector of the LX, the other list is represented as LY.
　ＬＸの動きベクトルmvLXを使用する場合（図１９のステップＳ１０２：ＹＥＳ）、ＬＸの予測動きベクトルの候補を算出してＬＸの予測動きベクトル候補リストmvpListLXを構築する（図１９のステップＳ１０３）。通常予測動きベクトルモード導出部３０１の中の空間予測動きベクトル候補導出部３２１、時間予測動きベクトル候補導出部３２２、履歴予測動きベクトル候補導出部３２３、予測動きベクトル候補補充部３２５で複数の予測動きベクトルの候補を導出して予測動きベクトル候補リストmvpListLXを構築する。図１９のステップＳ１０３の詳細な処理手順については図２０のフローチャートを用いて後述する。 When the LX motion vector mvLX is used (step S102: YES in FIG. 19), the LX predicted motion vector candidates are calculated and the LX predicted motion vector candidate list mvpListLX is constructed (step S103 in FIG. 19). Multiple predicted motions in the space predicted motion vector candidate derived section 321 in the normal predicted motion vector mode derived section 301, the time predicted motion vector candidate derived section 322, the historical predicted motion vector candidate derived section 323, and the predicted motion vector candidate supplement section 325. Derivation of vector candidates and construction of predicted motion vector candidate list mvpListLX. The detailed processing procedure of step S103 of FIG. 19 will be described later with reference to the flowchart of FIG.
　続いて、予測動きベクトル候補選択部３２７により、ＬＸの予測動きベクトル候補リストmvpListLXからＬＸの予測動きベクトルmvpLXを選択する（図１９のステップＳ１０４）。ここで、予測動きベクトル候補リストmvpListLXの中で、ある１つの要素（０から数えてｉ番目の要素）をmvpListLX[i]として表す。動きベクトルmvLXと予測動きベクトル候補リストmvpListLXの中に格納された各予測動きベクトルの候補mvpListLX[i]との差分であるそれぞれの差分動きベクトルを算出する。それら差分動きベクトルを符号化したときの符号量を予測動きベクトル候補リストmvpListLXの要素（予測動きベクトル候補）ごとに算出する。そして、予測動きベクトル候補リストmvpListLXに登録された各要素の中で、予測動きベクトルの候補毎の符号量が最小となる予測動きベクトルの候補mvpListLX[i]を予測動きベクトルmvpLXとして選択し、そのインデックスiを取得する。予測動きベクトル候補リストmvpListLXの中で最小の発生符号量となる予測動きベクトルの候補が複数存在する場合には、予測動きベクトル候補リストmvpListLXの中のインデックスiが小さい番号で表される予測動きベクトルの候補mvpListLX[i]を最適な予測動きベクトルmvpLXとして選択し、そのインデックスiを取得する。 Subsequently, the predicted motion vector candidate selection unit 327 selects the LX predicted motion vector mvpLX from the LX predicted motion vector candidate list mvpListLX (step S104 in FIG. 19). Here, in the predicted motion vector candidate list mvpListLX, one element (the i-th element counting from 0) is represented as mvpListLX [i]. Calculate each difference motion vector, which is the difference between the motion vector mvLX and the candidate mvpListLX [i] of each predicted motion vector stored in the predicted motion vector candidate list mvpListLX. The code amount when these difference motion vectors are encoded is calculated for each element (predicted motion vector candidate) of the predicted motion vector candidate list mvpListLX. Then, among the elements registered in the predicted motion vector candidate list mvpListLX, the predicted motion vector candidate mvpListLX [i] having the minimum sign amount for each candidate of the predicted motion vector is selected as the predicted motion vector mvpLX, and the candidate mvpListLX [i] is selected. Get index i. When there are multiple candidates for the predicted motion vector that is the smallest generated code in the predicted motion vector candidate list mvpListLX, the index i in the predicted motion vector candidate list mvpListLX is represented by a small number. Select the candidate mvpListLX [i] as the optimal predicted motion vector mvpLX and get its index i.
　続いて、動きベクトル減算部３２８で、ＬＸの動きベクトルmvLXから選択されたＬＸの予測動きベクトルmvpLXを減算し、
　　mvdLX = mvLX - mvpLX
としてＬＸの差分動きベクトルmvdLXを算出する（図１９のステップＳ１０５）。 Subsequently, the motion vector subtraction unit 328 subtracts the selected LX predicted motion vector mvpLX from the LX motion vector mvLX.
mvdLX = mvLX --mvpLX
The difference motion vector mvdLX of LX is calculated as (step S105 in FIG. 19).
　＜通常予測動きベクトルモード導出部（通常AMVP）：復号側の説明＞
　次に、図２５を参照して復号側の通常予測動きベクトルモード処理手順を説明する。復号側では、空間予測動きベクトル候補導出部４２１、時間予測動きベクトル候補導出部４２２、履歴予測動きベクトル候補導出部４２３、予測動きベクトル候補補充部４２５で、通常予測動きベクトルモードのインター予測で用いる動きベクトルをＬ０，Ｌ１毎にそれぞれ算出する（図２５のステップＳ２０１～Ｓ２０６）。具体的には処理対象ブロックの予測モードPredModeがインター予測（MODE_INTER）で、処理対象ブロックのインター予測モードがＬ０予測（Pred_L0）の場合、Ｌ０の予測動きベクトル候補リストmvpListL0を算出して、予測動きベクトルmvpL0を選択し、Ｌ０の動きベクトルmvL0を算出する。処理対象ブロックのインター予測モードがＬ１予測（Pred_L1）の場合、Ｌ１の予測動きベクトル候補リストmvpListL1を算出して、予測動きベクトルmvpL1を選択し、Ｌ１の動きベクトルmvL1を算出する。処理対象ブロックのインター予測モードが双予測（Pred_BI）の場合、Ｌ０予測とＬ１予測が共に行われ、Ｌ０の予測動きベクトル候補リストmvpListL0を算出して、Ｌ０の予測動きベクトルmvpL0を選択し、Ｌ０の動きベクトルmvL0を算出するとともに、Ｌ１の予測動きベクトル候補リストmvpListL1を算出して、Ｌ１の予測動きベクトルmvpL1を算出し、Ｌ１の動きベクトルmvL1をそれぞれ算出する。 <Normal prediction motion vector mode derivation unit (normal AMVP): Explanation on the decoding side>
Next, the normal predicted motion vector mode processing procedure on the decoding side will be described with reference to FIG. On the decoding side, the spatial prediction motion vector candidate derivation unit 421, the time prediction motion vector candidate derivation unit 422, the history prediction motion vector candidate derivation unit 423, and the prediction motion vector candidate replenishment unit 425 are used for inter-prediction in the normal prediction motion vector mode. The motion vector is calculated for each L0 and L1 (steps S201 to S206 in FIG. 25). Specifically, when the prediction mode PredMode of the processing target block is inter-prediction (MODE_INTER) and the inter-prediction mode of the processing target block is L0 prediction (Pred_L0), the prediction motion vector candidate list mvpListL0 of L0 is calculated and the prediction motion is predicted. Select the vector mvpL0 and calculate the motion vector mvL0 of L0. When the inter-prediction mode of the block to be processed is L1 prediction (Pred_L1), the prediction motion vector candidate list mvpListL1 of L1 is calculated, the prediction motion vector mvpL1 is selected, and the motion vector mvL1 of L1 is calculated. When the inter-prediction mode of the block to be processed is bi-prediction (Pred_BI), both L0 prediction and L1 prediction are performed, the prediction motion vector candidate list mvpList L0 of L0 is calculated, the prediction motion vector mvpL0 of L0 is selected, and L0. The motion vector mvL0 of L1 is calculated, the predicted motion vector candidate list mvpList L1 of L1 is calculated, the predicted motion vector mvpL1 of L1 is calculated, and the motion vector mvL1 of L1 is calculated respectively.
　符号化側と同様に、復号側でもＬ０、Ｌ１それぞれについて、動きベクトル算出処理を行うが、Ｌ０、Ｌ１ともに共通の処理となる。したがって、以下の説明においてはＬ０、Ｌ１を共通のＬＸとして表す。ＬＸは処理対象の符号化ブロックのインター予測に用いるインター予測モードを表す。Ｌ０の動きベクトルを算出する処理ではＸが０であり、Ｌ１の動きベクトルを算出する処理ではＸが１である。また、ＬＸの動きベクトルを算出する処理中に、算出対象のＬＸと同じ参照リストではなく、もう一方の参照リストの情報を参照する場合、もう一方の参照リストをＬＹとして表す。 Similar to the coding side, the decoding side also performs motion vector calculation processing for each of L0 and L1, but both L0 and L1 are common processing. Therefore, in the following description, L0 and L1 are represented as a common LX. LX represents an inter-prediction mode used for inter-prediction of the coded block to be processed. X is 0 in the process of calculating the motion vector of L0, and X is 1 in the process of calculating the motion vector of L1. Further, when the information of the other reference list is referred to instead of the same reference list as the LX to be calculated during the process of calculating the motion vector of the LX, the other reference list is represented as LY.
　ＬＸの動きベクトルmvLXを使用する場合（図２５のステップＳ２０２：ＹＥＳ）、ＬＸの予測動きベクトルの候補を算出してＬＸの予測動きベクトル候補リストmvpListLXを構築する（図２５のステップＳ２０３）。通常予測動きベクトルモード導出部４０１の中の空間予測動きベクトル候補導出部４２１、時間予測動きベクトル候補導出部４２２、履歴予測動きベクトル候補導出部４２３、予測動きベクトル候補補充部４２５で複数の予測動きベクトルの候補を算出し、予測動きベクトル候補リストmvpListLXを構築する。図２５のステップＳ２０３の詳細な処理手順については図２０のフローチャートを用いて後述する。 When the LX motion vector mvLX is used (step S202: YES in FIG. 25), the LX predicted motion vector candidates are calculated and the LX predicted motion vector candidate list mvpListLX is constructed (step S203 in FIG. 25). Multiple predicted motions in the space predicted motion vector candidate derived section 421, the time predicted motion vector candidate derived section 422, the historical predicted motion vector candidate derived section 423, and the predicted motion vector candidate supplement section 425 in the normal predicted motion vector mode derivation section 401. Calculate vector candidates and build a predicted motion vector candidate list mvpListLX. The detailed processing procedure of step S203 of FIG. 25 will be described later using the flowchart of FIG.
　続いて、予測動きベクトル候補選択部４２６で予測動きベクトル候補リストmvpListLXからビット列復号部２０１にて復号されて供給される予測動きベクトルのインデックスmvpIdxLXに対応する予測動きベクトルの候補mvpListLX[mvpIdxLX]を選択された予測動きベクトルmvpLXとして取り出す（図２５のステップＳ２０４）。 Subsequently, the predicted motion vector candidate selection unit 426 selects the predicted motion vector candidate mvpListLX [mvpIdxLX] corresponding to the index mvpIdxLX of the predicted motion vector decoded and supplied by the bit string decoding unit 201 from the predicted motion vector candidate list mvpListLX. It is taken out as the predicted motion vector mvpLX (step S204 in FIG. 25).
　続いて、動きベクトル加算部４２７でビット列復号部２０１にて復号されて供給されるＬＸの差分動きベクトルmvdLXとＬＸの予測動きベクトルmvpLXを加算し、
　　mvLX = mvpLX + mvdLX
としてＬＸの動きベクトルmvLXを算出する（図２５のステップＳ２０５）。 Subsequently, the motion vector addition unit 427 adds the LX differential motion vector mvdLX and the LX predicted motion vector mvpLX, which are decoded and supplied by the bit string decoding unit 201.
mvLX = mvpLX + mvdLX
The motion vector mvLX of LX is calculated as (step S205 in FIG. 25).
　＜通常予測動きベクトルモード導出部（通常AMVP）：動きベクトルの予測方法＞
　図２０は本発明の実施の形態に係る画像符号化装置の通常予測動きベクトルモード導出部３０１及び画像復号装置の通常予測動きベクトルモード導出部４０１とで共通する機能を有する通常予測動きベクトルモード導出処理の処理手順を表すフローチャートである。 <Normal prediction motion vector mode derivation unit (normal AMVP): Motion vector prediction method>
FIG. 20 shows a normal predicted motion vector mode derivation having a function common to the normal predicted motion vector mode derivation unit 301 of the image coding device and the normal predicted motion vector mode derivation unit 401 of the image decoding device according to the embodiment of the present invention. It is a flowchart which shows the processing procedure of processing.
　通常予測動きベクトルモード導出部３０１及び通常予測動きベクトルモード導出部４０１では、予測動きベクトル候補リストmvpListLXを備えている。予測動きベクトル候補リストmvpListLXはリスト構造を成し、予測動きベクトル候補リスト内部の所在を示す予測動きベクトルインデックスと、インデックスに対応する予測動きベクトル候補とを要素として格納する記憶領域が設けられている。予測動きベクトルインデックスの数字は０から開始され、予測動きベクトル候補リストmvpListLXの記憶領域に、予測動きベクトル候補が格納される。本実施の形態においては、予測動きベクトル候補リストmvpListLXは少なくとも２個の予測動きベクトル候補（インター予測情報）を登録することができるものとする。さらに、予測動きベクトル候補リストmvpListLXに登録されている予測動きベクトル候補数を示す変数numCurrMvpCandに０を設定する。 The normal prediction motion vector mode derivation unit 301 and the normal prediction motion vector mode derivation unit 401 include a prediction motion vector candidate list mvpListLX. The predicted motion vector candidate list mvpListLX has a list structure, and is provided with a storage area for storing the predicted motion vector index indicating the location inside the predicted motion vector candidate list and the predicted motion vector candidate corresponding to the index as elements. .. The number of the predicted motion vector index starts from 0, and the predicted motion vector candidate is stored in the storage area of the predicted motion vector candidate list mvpListLX. In the present embodiment, the predicted motion vector candidate list mvpListLX can register at least two predicted motion vector candidates (inter-prediction information). Further, 0 is set in the variable numCurrMvpCand indicating the number of predicted motion vector candidates registered in the predicted motion vector candidate list mvpListLX.
　空間予測動きベクトル候補導出部３２１及び４２１は、左側に隣接するブロック（図１１のＡ０またはＡ１）からの予測動きベクトルの候補を導出する。この処理では、左側に隣接するブロックのインター予測情報、すなわち予測動きベクトル候補が利用できるか否かを示すフラグavailableFlagLXA、及び動きベクトル、参照インデックス等を参照して予測動きベクトルmvLXA導出し、導出したmvLXAを予測動きベクトル候補リストmvpListLXに追加する（図２０のステップＳ３０１）。なお、Ｌ０予測のときＸは０、Ｌ１予測のときＸは１とする（以下同様）。続いて、空間予測動きベクトル候補導出部３２１及び４２１は、上側に隣接するブロック（図１１のＢ０，Ｂ１，またはＢ２）からの予測動きベクトルの候補を導出する。この処理では、上側に隣接するブロックのインター予測情報、すなわち予測動きベクトル候補が利用できるか否かを示すフラグavailableFlagLXB、及び動きベクトル、参照インデックス等を参照して予測動きベクトルmvLXBを導出し、それぞれ導出したmvLXAとmvLXBとが等しくなければ、mvLXBを予測動きベクトル候補リストmvpListLXに追加する（図２０のステップＳ３０２）。図２０のステップＳ３０１とＳ３０２の処理は参照する隣接ブロックの位置と数が異なる点以外は共通であり、符号化ブロックの予測動きベクトル候補が利用できるか否かを示すフラグavailableFlagLXN、及び動きベクトルmvLXN、参照インデックスrefIdxN（ＮはＡまたはＢを示す、以下同様）を導出する。 Spatial prediction motion vector candidate derivation units 321 and 421 derive prediction motion vector candidates from blocks (A0 or A1 in FIG. 11) adjacent to the left side. In this process, the predicted motion vector mvLXA is derived and derived by referring to the inter-prediction information of the block adjacent to the left side, that is, the flag availableFlagLXA indicating whether or not the predicted motion vector candidate can be used, and the motion vector, reference index, etc. Add mvLXA to the predicted motion vector candidate list mvpListLX (step S301 in FIG. 20). In addition, X is 0 in the case of L0 prediction, and X is 1 in the case of L1 prediction (the same applies hereinafter). Subsequently, the spatial prediction motion vector candidate derivation units 321 and 421 derive the prediction motion vector candidates from the blocks (B0, B1, or B2 in FIG. 11) adjacent to the upper side. In this process, the inter-prediction information of the adjacent blocks on the upper side, that is, the flag availableFlagLXB indicating whether or not the predicted motion vector candidate can be used, and the predicted motion vector mvLXB are derived by referring to the motion vector, the reference index, etc. If the derived mvLXA and mvLXB are not equal, mvLXB is added to the predicted motion vector candidate list mvpListLX (step S302 in FIG. 20). The processing of steps S301 and S302 in FIG. 20 is common except that the position and number of adjacent blocks to be referred to are different, and the flag availableFlagLXN indicating whether or not the predicted motion vector candidate of the coded block can be used and the motion vector mvLXN , The reference index refIdxN (N indicates A or B, and so on) is derived.
　続いて、時間予測動きベクトル候補導出部３２２及び４２２は、現在の処理対象ピクチャとは時間が異なるピクチャにおけるブロックからの予測動きベクトルの候補を導出する。この処理では、異なる時間のピクチャの符号化ブロックの予測動きベクトル候補が利用できるか否かを示すフラグavailableFlagLXCol、及び動きベクトルmvLXCol、参照インデックスrefIdxCol、参照リストlistColを導出し、mvLXColを予測動きベクトル候補リストmvpListLXに追加する（図２０のステップＳ３０３）。 Subsequently, the time prediction motion vector candidate derivation units 322 and 422 derive candidates for the prediction motion vector from the block in the picture whose time is different from the current processing target picture. In this process, the flags availableFlagLXCol indicating whether the predicted motion vector candidates of the coded blocks of the pictures at different times are available, the motion vector mvLXCol, the reference index refIdxCol, and the reference list listCol are derived, and the mvLXCol is predicted as the motion vector candidate. Add to list mvpListLX (step S303 in FIG. 20).
　なお、シーケンス（ＳＰＳ）、ピクチャ（ＰＰＳ）、またはスライスの単位で時間予測動きベクトル候補導出部３２２及び４２２の処理を省略することができるものとする。 It should be noted that the processing of the time prediction motion vector candidate derivation unit 322 and 422 can be omitted in units of sequence (SPS), picture (PPS), or slice.
　続いて、履歴予測動きベクトル候補導出部３２３及び４２３は履歴予測動きベクトル候補リストHmvpCandListに登録されている履歴予測動きベクトル候補を予測動きベクトル候補リストmvpListLXに追加する。（図２０のステップＳ３０４）。このステップＳ３０４の登録処理手順の詳細については図２９のフローチャートを用いて後述する。 Subsequently, the history prediction motion vector candidate derivation units 323 and 423 add the history prediction motion vector candidates registered in the history prediction motion vector candidate list HmvpCandList to the prediction motion vector candidate list mvpListLX. (Step S304 in FIG. 20). The details of the registration processing procedure in step S304 will be described later with reference to the flowchart of FIG.
　続いて予測動きベクトル候補補充部３２５及び４２５は予測動きベクトル候補リストmvpListLXを満たすまで、（０，０）等の、所定の値の予測動きベクトル候補を追加する（図２０のＳ３０５）。 Subsequently, the predicted motion vector candidate supplementing units 325 and 425 add the predicted motion vector candidates having a predetermined value such as (0,0) until the predicted motion vector candidate list mvpListLX is satisfied (S305 in FIG. 20).
　＜通常マージモード導出部（通常マージ）＞
　図１８の通常マージモード導出部３０２は、空間マージ候補導出部３４１、時間マージ候補導出部３４２、平均マージ候補導出部３４４、履歴マージ候補導出部３４５、マージ候補補充部３４６、マージ候補選択部３４７を含む。 <Normal merge mode derivation section (normal merge)>
The normal merge mode derivation unit 302 of FIG. 18 includes a spatial merge candidate derivation unit 341, a time merge candidate derivation unit 342, an average merge candidate derivation unit 344, a history merge candidate derivation unit 345, a merge candidate replenishment unit 346, and a merge candidate selection unit 347. including.
　図２４の通常マージモード導出部４０２は、空間マージ候補導出部４４１、時間マージ候補導出部４４２、平均マージ候補導出部４４４、履歴マージ候補導出部４４５、マージ候補補充部４４６、マージ候補選択部４４７を含む。 The normal merge mode derivation unit 402 of FIG. 24 includes a spatial merge candidate derivation unit 441, a time merge candidate derivation unit 442, an average merge candidate derivation unit 444, a history merge candidate derivation unit 445, a merge candidate replenishment unit 446, and a merge candidate selection unit 447. including.
　図２１は本発明の実施の形態に係る画像符号化装置の通常マージモード導出部３０２及び画像復号装置の通常マージモード導出部４０２とで共通する機能を有する通常マージモード導出処理の手順を説明するフローチャートである。 FIG. 21 describes a procedure of the normal merge mode derivation process having a function common to the normal merge mode derivation unit 302 of the image coding device and the normal merge mode derivation unit 402 of the image decoding device according to the embodiment of the present invention. It is a flowchart.
　以下、諸過程を順を追って説明する。なお、以下の説明においては特に断りのない限りスライスタイプslice_typeがＢスライスの場合について説明するが、Ｐスライスの場合にも適用できる。ただし、スライスタイプslice_typeがＰスライスの場合、インター予測モードとしてＬ０予測（Pred_L0）だけがあり、Ｌ１予測（Pred_L1）、双予測（Pred_BI）がないので、Ｌ１に纏わる処理を省略することができる。 The various processes will be explained step by step below. In the following description, unless otherwise specified, the case where the slice type slice_type is B slice is described, but it can also be applied to the case of P slice. However, when the slice type slice_type is P slice, there is only L0 prediction (Pred_L0) as the inter-prediction mode, and there is no L1 prediction (Pred_L1) and double prediction (Pred_BI), so that the processing related to L1 can be omitted.
　通常マージモード導出部３０２及び通常マージモード導出部４０２では、マージ候補リストmergeCandListを備えている。マージ候補リストmergeCandListはリスト構造を成し、マージ候補リスト内部の所在を示すマージインデックスと、インデックスに対応するマージ候補を要素として格納する記憶領域が設けられている。マージインデックスの数字は０から開始され、マージ候補リストmergeCandListの記憶領域に、マージ候補が格納される。以降の処理では、マージ候補リストmergeCandListに登録されたマージインデックスｉのマージ候補は、mergeCandList[i]で表すこととする。本実施の形態においては、マージ候補リストmergeCandListは少なくとも６個のマージ候補（インター予測情報）を登録することができるものとする。さらに、マージ候補リストmergeCandListに登録されているマージ候補数を示す変数numCurrMergeCandに０を設定する。 The normal merge mode derivation unit 302 and the normal merge mode derivation unit 402 include a merge candidate list mergeCandList. Merge candidate list The mergeCandList has a list structure, and has a merge index indicating the location inside the merge candidate list and a storage area for storing the merge candidates corresponding to the indexes as elements. The number of the merge index starts from 0, and the merge candidates are stored in the storage area of the merge candidate list mergeCandList. In the subsequent processing, the merge candidate of the merge index i registered in the merge candidate list mergeCandList is represented by mergeCandList [i]. In the present embodiment, the merge candidate list mergeCandList can register at least 6 merge candidates (inter-prediction information). Further, 0 is set in the variable numCurrMergeCand indicating the number of merge candidates registered in the merge candidate list mergeCandList.
　空間マージ候補導出部３４１及び空間マージ候補導出部４４１では、画像符号化装置の符号化情報格納メモリ１１１または画像復号装置の符号化情報格納メモリ２０５に格納されている符号化情報から、処理対象ブロックに隣接するそれぞれのブロック（図１１のＢ１、Ａ１、Ｂ０、Ａ０、Ｂ２）からの空間マージ候補をＢ１、Ａ１、Ｂ０、Ａ０、Ｂ２の順に導出して、導出された空間マージ候補をマージ候補リストmergeCandListに登録する（図２１のステップＳ４０１）。ここで、Ｂ１、Ａ１、Ｂ０、Ａ０、Ｂ２または時間マージ候補Ｃｏｌのいずれかを示すＮを定義する。ブロックＮのインター予測情報が空間マージ候補として利用できるか否かを示すフラグavailableFlagN、空間マージ候補ＮのＬ０の参照インデックスrefIdxL0N及びＬ１の参照インデックスrefIdxL1N、Ｌ０予測が行われるか否かを示すＬ０予測フラグpredFlagL0NおよびＬ１予測が行われるか否かを示すＬ１予測フラグpredFlagL1N、Ｌ０の動きベクトルmvL0N、Ｌ１の動きベクトルmvL1Nを導出する。ただし、本実施の形態においては処理対象となる符号化ブロックに含まれるブロックのインター予測情報を参照せずに、マージ候補を導出するので、処理対象の符号化ブロックに含まれるブロックのインター予測情報を用いる空間マージ候補は導出しない。 In the space merge candidate derivation unit 341 and the space merge candidate derivation unit 441, the processing target block is obtained from the coding information stored in the coding information storage memory 111 of the image coding device or the coding information storage memory 205 of the image decoding device. Spatial merge candidates from each block (B1, A1, B0, A0, B2 in FIG. 11) adjacent to the block are derived in the order of B1, A1, B0, A0, B2, and the derived spatial merge candidates are derived as merge candidates. Register in the list mergeCandList (step S401 in FIG. 21). Here, N indicating any of B1, A1, B0, A0, B2 or the time merge candidate Col is defined. Flags availableFlagN indicating whether the inter-prediction information of block N can be used as a spatial merge candidate, reference index refIdxL0N of L0 of spatial merge candidate N and reference index refIdxL1N of L1, L0 prediction indicating whether L0 prediction is performed. The L1 prediction flags predFlag L1N and L0 motion vectors mvL0N and L1 motion vectors mvL1N, which indicate whether or not the flags predFlag L0N and L1 prediction are performed, are derived. However, in the present embodiment, since the merge candidate is derived without referring to the inter-prediction information of the block included in the coded block to be processed, the inter-prediction information of the block included in the coded block to be processed is derived. Spatial merge candidates using is not derived.
　続いて、時間マージ候補導出部３４２及び時間マージ候補導出部４４２では、異なる時間のピクチャからの時間マージ候補を導出して、導出された時間マージ候補をマージ候補リストmergeCandListに登録する（図２１のステップＳ４０２）。時間マージ候補が利用できるか否かを示すフラグavailableFlagCol、時間マージ候補のＬ０予測が行われるか否かを示すＬ０予測フラグpredFlagL0ColおよびＬ１予測が行われるか否かを示すＬ１予測フラグpredFlagL1Col、及びＬ０の動きベクトルmvL0Col、Ｌ１の動きベクトルmvL1Colを導出する。 Subsequently, the time merge candidate derivation unit 342 and the time merge candidate derivation unit 442 derive the time merge candidates from the pictures at different times and register the derived time merge candidates in the merge candidate list mergeCandList (FIG. 21). Step S402). Flags availableFlagCol indicating whether time merge candidates are available, L0 prediction flags predFlag L0Col indicating whether L0 prediction of time merge candidates is performed, and L1 prediction flags predFlagL1Col indicating whether L1 prediction is performed, and L0. The motion vector mvL0Col and the motion vector mvL1Col of L1 are derived.
　なお、シーケンス（ＳＰＳ）、ピクチャ（ＰＰＳ）、またはスライスの単位で時間マージ候補導出部３４２及び時間マージ候補導出部４４２の処理を省略することができるものとする。 It should be noted that the processing of the time merge candidate derivation unit 342 and the time merge candidate derivation unit 442 can be omitted in units of sequence (SPS), picture (PPS), or slice.
　続いて、履歴マージ候補導出部３４５及び履歴マージ候補導出部４４５では、履歴予測動きベクトル候補リストHmvpCandListに登録されている履歴予測動きベクトル候補をマージ候補リストmergeCandListに登録する（図２１のステップＳ４０３）。
　なお、マージ候補リストmergeCandList内に登録されているマージ候補数numCurrMergeCandが、最大マージ候補数MaxNumMergeCandより小さい場合、マージ候補リストmergeCandList内に登録されているマージ候補数numCurrMergeCandが最大マージ候補数MaxNumMergeCandを上限として履歴マージ候補は導出されて、マージ候補リストmergeCandListに登録される。 Subsequently, the history merge candidate derivation unit 345 and the history merge candidate derivation unit 445 register the history prediction motion vector candidates registered in the history prediction motion vector candidate list HmvpCandList in the merge candidate list mergeCandList (step S403 in FIG. 21). ..
If the number of merge candidates numCurrMergeCand registered in the merge candidate list mergeCandList is smaller than the maximum number of merge candidates MaxNumMergeCand, the number of merge candidates registered in the merge candidate list mergeCandList numCurrMergeCand is limited to the maximum number of merge candidates MaxNumMergeCand. Historical merge candidates are derived and registered in the merge candidate list mergeCandList.
　続いて、平均マージ候補導出部３４４及び平均マージ候補導出部４４４では、マージ候補リストmergeCandListから平均マージ候補を導出して、導出された平均マージ候補をマージ候補リストmergeCandListに追加する（図２１のステップＳ４０４）。
　なお、マージ候補リストmergeCandList内に登録されているマージ候補数numCurrMergeCandが、最大マージ候補数MaxNumMergeCandより小さい場合、マージ候補リストmergeCandList内に登録されているマージ候補数numCurrMergeCandが最大マージ候補数MaxNumMergeCandを上限として平均マージ候補は導出されて、マージ候補リストmergeCandListに登録される。
　ここで、平均マージ候補は、マージ候補リストmergeCandListに登録されている第１のマージ候補と第２のマージ候補の有する動きベクトルをＬ０予測及びＬ１予測毎に平均して得られる動きベクトルを有する新たなマージ候補である。 Subsequently, the average merge candidate derivation unit 344 and the average merge candidate derivation unit 444 derive the average merge candidate from the merge candidate list mergeCandList and add the derived average merge candidate to the merge candidate list mergeCandList (step of FIG. 21). S404).
If the number of merge candidates numCurrMergeCand registered in the merge candidate list mergeCandList is smaller than the maximum number of merge candidates MaxNumMergeCand, the number of merge candidates registered in the merge candidate list mergeCandList numCurrMergeCand is limited to the maximum number of merge candidates MaxNumMergeCand. The average merge candidate is derived and registered in the merge candidate list mergeCandList.
Here, the average merge candidate has a motion vector obtained by averaging the motion vectors of the first merge candidate and the second merge candidate registered in the merge candidate list mergeCandList for each L0 prediction and L1 prediction. It is a good merge candidate.
　続いて、マージ候補補充部３４６及びマージ候補補充部４４６では、マージ候補リストmergeCandList内に登録されているマージ候補数numCurrMergeCandが、最大マージ候補数MaxNumMergeCandより小さい場合、マージ候補リストmergeCandList内に登録されているマージ候補数numCurrMergeCandが最大マージ候補数MaxNumMergeCandを上限として追加マージ候補を導出して、マージ候補リストmergeCandListに登録する（図２１のステップＳ４０５）。最大マージ候補数MaxNumMergeCandを上限として、Ｐスライスでは、動きベクトルが（０，０）の値を持つ予測モードがＬ０予測（Pred_L0）のマージ候補を追加する。Ｂスライスでは、動きベクトルが（０，０）の値を持つ予測モードが双予測（Pred_BI）のマージ候補を追加する。マージ候補を追加する際の参照インデックスは、すでに追加した参照インデックスと異なる。 Subsequently, in the merge candidate replenishment unit 346 and the merge candidate replenishment unit 446, if the number of merge candidates numCurrMergeCand registered in the merge candidate list mergeCandList is smaller than the maximum number of merge candidates MaxNumMergeCand, they are registered in the merge candidate list mergeCandList. The existing number of merge candidates numCurrMergeCand derives additional merge candidates up to the maximum number of merge candidates MaxNumMergeCand and registers them in the merge candidate list mergeCandList (step S405 in FIG. 21). With the maximum number of merge candidates MaxNumMergeCand as the upper limit, in the P slice, merge candidates whose motion vector has a value of (0,0) and whose prediction mode is L0 prediction (Pred_L0) are added. In the B slice, a merge candidate whose motion vector has a value of (0,0) and whose prediction mode is bi-prediction (Pred_BI) is added. The reference index when adding a merge candidate is different from the reference index already added.
　続いて、マージ候補選択部３４７及びマージ候補選択部４４７では、マージ候補リストmergeCandList内に登録されているマージ候補からマージ候補を選択する。符号化側のマージ候補選択部３４７では、符号量とひずみ量を算出することによりマージ候補を選択し、選択されたマージ候補を示すマージインデックス、マージ候補のインター予測情報を、インター予測モード判定部３０５を介して動き補償予測部３０６に供給する。一方、復号側のマージ候補選択部４４７では、復号されたマージインデックスに基づいて、マージ候補を選択し、選択されたマージ候補を動き補償予測部４０６に供給する。 Subsequently, the merge candidate selection unit 347 and the merge candidate selection unit 447 select the merge candidate from the merge candidates registered in the merge candidate list mergeCandList. The merge candidate selection unit 347 on the coding side selects the merge candidate by calculating the code amount and the strain amount, and sets the merge index indicating the selected merge candidate and the inter-prediction information of the merge candidate in the inter-prediction mode determination unit. It is supplied to the motion compensation prediction unit 306 via the 305. On the other hand, the merge candidate selection unit 447 on the decoding side selects the merge candidate based on the decoded merge index, and supplies the selected merge candidate to the motion compensation prediction unit 406.
　＜履歴予測動きベクトル候補リストの更新＞
　次に、符号化側の符号化情報格納メモリ１１１及び復号側の符号化情報格納メモリ２０５に備える履歴予測動きベクトル候補リストHmvpCandListの初期化方法および更新方法について詳細に説明する。図２６は履歴予測動きベクトル候補リスト初期化・更新処理手順を説明するフローチャートである。 <Update of history prediction motion vector candidate list>
Next, an initialization method and an update method of the history prediction motion vector candidate list HmvpCandList provided in the coding information storage memory 111 on the coding side and the coding information storage memory 205 on the decoding side will be described in detail. FIG. 26 is a flowchart illustrating a procedure for initializing / updating the history prediction motion vector candidate list.
　本実施の形態では、履歴予測動きベクトル候補リストHmvpCandListの更新は、符号化情報格納メモリ１１１及び符号化情報格納メモリ２０５で実施されるものとする。インター予測部１０２及びインター予測部２０３の中に履歴予測動きベクトル候補リスト更新部を設置して履歴予測動きベクトル候補リストHmvpCandListの更新を実施させてもよい。 In the present embodiment, the history prediction motion vector candidate list HmvpCandList is updated by the coded information storage memory 111 and the coded information storage memory 205. The history prediction motion vector candidate list update unit may be installed in the inter prediction unit 102 and the inter prediction unit 203 to update the history prediction motion vector candidate list HmvpCandList.
　スライスの先頭で履歴予測動きベクトル候補リストHmvpCandListの初期設定を行い、符号化側では予測方法決定部１０５で通常予測動きベクトルモードまたは通常マージモードが選択された場合に履歴予測動きベクトル候補リストHmvpCandListを更新し、復号側では、ビット列復号部２０１で復号された予測情報が通常予測動きベクトルモードまたは通常マージモードの場合に履歴予測動きベクトル候補リストHmvpCandListを更新する。 Initialize the history prediction motion vector candidate list HmvpCandList at the beginning of the slice, and on the coding side, the history prediction motion vector candidate list HmvpCandList is set when the normal prediction motion vector mode or the normal merge mode is selected by the prediction method determination unit 105. On the decoding side, the history prediction motion vector candidate list HmvpCandList is updated when the prediction information decoded by the bit string decoding unit 201 is in the normal prediction motion vector mode or the normal merge mode.
　通常予測動きベクトルモードまたは通常マージモードでインター予測を行う際に用いるインター予測情報を、インター予測情報候補hMvpCandとして履歴予測動きベクトル候補リストHmvpCandListに登録する。インター予測情報候補hMvpCandには、Ｌ０の参照インデックスrefIdxL0およびＬ１の参照インデックスrefIdxL1、Ｌ０予測が行われるか否かを示すＬ０予測フラグpredFlagL0およびＬ１予測が行われるか否かを示すＬ１予測フラグpredFlagL1、Ｌ０の動きベクトルmvL0、Ｌ１の動きベクトルmvL1が含まれる。 The inter-prediction information used when performing inter-prediction in the normal prediction motion vector mode or the normal merge mode is registered in the history prediction motion vector candidate list HmvpCandList as the inter-prediction information candidate hMvpCand. The inter-prediction information candidate hMvpCand includes the reference index refIdxL0 of L0 and the reference index refIdxL1 of L1, the L0 prediction flag predFlag L0 indicating whether L0 prediction is performed, and the L1 prediction flag predFlag L1 indicating whether L1 prediction is performed. The motion vector mvL0 of L0 and the motion vector mvL1 of L1 are included.
　符号化側の符号化情報格納メモリ１１１及び復号側の符号化情報格納メモリ２０５に備える履歴予測動きベクトル候補リストHmvpCandListに登録されている要素（すなわち、インター予測情報）の中に、インター予測情報候補hMvpCandと同じ値のインター予測情報が存在する場合は、履歴予測動きベクトル候補リストHmvpCandListからその要素を削除する。一方、インター予測情報候補hMvpCandと同じ値のインター予測情報が存在しない場合は、履歴予測動きベクトル候補リストHmvpCandListの先頭の要素を削除し、履歴予測動きベクトル候補リストHmvpCandListの最後に、インター予測情報候補hMvpCandを追加する。 Inter-prediction information candidate among the elements (that is, inter-prediction information) registered in the history prediction motion vector candidate list HmvpCandList provided in the coding information storage memory 111 on the coding side and the coding information storage memory 205 on the decoding side. If the inter-prediction information with the same value as hMvpCand exists, delete the element from the historical prediction motion vector candidate list HmvpCandList. On the other hand, if there is no inter-prediction information with the same value as the inter-prediction information candidate hMvpCand, the first element of the historical prediction motion vector candidate list HmvpCandList is deleted, and the inter-prediction information candidate is at the end of the historical prediction motion vector candidate list HmvpCandList. Add hMvpCand.
　本発明の符号化側の符号化情報格納メモリ１１１及び復号側の符号化情報格納メモリ２０５に備える履歴予測動きベクトル候補リストHmvpCandListの要素の数は６とする。 The number of elements of the history prediction motion vector candidate list HmvpCandList provided in the coding information storage memory 111 on the coding side and the coding information storage memory 205 on the decoding side of the present invention is 6.
　まず、スライス単位での履歴予測動きベクトル候補リストHmvpCandListの初期化を行う（図２６のステップＳ２１０１）。スライスの先頭で履歴予測動きベクトル候補リストHmvpCandListのすべての要素を空にし、履歴予測動きベクトル候補リストHmvpCandListに登録されている履歴予測動きベクトル候補の数（現在の候補数）NumHmvpCandの値は0に設定する。 First, the history prediction motion vector candidate list HmvpCandList for each slice is initialized (step S2101 in FIG. 26). Empty all elements of the history prediction motion vector candidate list HmvpCandList at the beginning of the slice, and the number of history prediction motion vector candidates registered in the history prediction motion vector candidate list HmvpCandList (current number of candidates) The value of NumHmvpCand becomes 0. Set.
　なお、履歴予測動きベクトル候補リストHmvpCandListの初期化をスライス単位（スライスの最初の符号化ブロック）で実施するとしたが、ピクチャ単位、タイル単位やツリーブロック行単位で実施しても良い。 Although the initialization of the history prediction motion vector candidate list HmvpCandList is performed in slice units (first coded block of slices), it may be performed in picture units, tile units, or tree block line units.
　続いて、スライス内の符号化ブロック毎に以下の履歴予測動きベクトル候補リストHmvpCandListの更新処理を繰り返し行なう（図２６のステップＳ２１０２～Ｓ２１０７）。 Subsequently, the following history prediction motion vector candidate list HmvpCandList update process is repeated for each coded block in the slice (steps S2102 to S2107 in FIG. 26).
　まず、符号化ブロック単位での初期設定を行う。同一候補が存在するか否かを示すフラグidenticalCandExistにFALSE（偽）の値を設定し、削除対象の候補を示す削除対象インデックスremoveIdxに０を設定する（図２６のステップＳ２１０３）。 First, make initial settings for each coded block. A FALSE (false) value is set in the flag electricalCandExist indicating whether or not the same candidate exists, and 0 is set in the removal target index removeIdx indicating the deletion target candidate (step S2103 in FIG. 26).
　登録対象のインター予測情報候補hMvpCandが存在するか否かを判定する（図２６のステップＳ２１０４）。符号化側の予測方法決定部１０５で通常予測動きベクトルモードまたは通常マージモードと判定された場合、または復号側のビット列復号部２０１で通常予測動きベクトルモードまたは通常マージモードとして復号された場合、そのインター予測情報を登録対象のインター予測情報候補hMvpCandとする。符号化側の予測方法決定部１０５でイントラ予測モード、サブブロック予測動きベクトルモードまたはサブブロックマージモードと判定された場合、または復号側のビット列復号部２０１でイントラ予測モード、サブブロック予測動きベクトルモードまたはサブブロックマージモードとして復号された場合、履歴予測動きベクトル候補リストHmvpCandListの更新処理を行わず、登録対象のインター予測情報候補hMvpCandは存在しない。登録対象のインター予測情報候補hMvpCandが存在しない場合はステップＳ２１０５～Ｓ２１０６をスキップする（図２６のステップＳ２１０４：ＮＯ）。登録対象のインター予測情報候補hMvpCandが存在する場合はステップＳ２１０５以下の処理を行う（図２６のステップＳ２１０４：ＹＥＳ）。 Determine whether or not the inter-prediction information candidate hMvpCand to be registered exists (step S2104 in FIG. 26). When the prediction method determination unit 105 on the coding side determines the normal prediction motion vector mode or the normal merge mode, or when the bit string decoding unit 201 on the decoding side decodes the decoding as the normal prediction motion vector mode or the normal merge mode. Let the inter-prediction information be the inter-prediction information candidate hMvpCand to be registered. When the coding side prediction method determination unit 105 determines the intra prediction mode, subblock prediction motion vector mode or subblock merge mode, or the decoding side bit string decoding unit 201 determines the intra prediction mode, subblock prediction motion vector mode. Or, when decoded in the sub-block merge mode, the history prediction motion vector candidate list HmvpCandList is not updated, and the inter-prediction information candidate hMvpCand to be registered does not exist. If the inter-prediction information candidate hMvpCand to be registered does not exist, steps S2105 to S2106 are skipped (step S2104: NO in FIG. 26). If the inter-prediction information candidate hMvpCand to be registered exists, the process of step S2105 or less is performed (step S2104: YES in FIG. 26).
　続いて、履歴予測動きベクトル候補リストHmvpCandListの各要素の中に登録対象のインター予測情報候補hMvpCandと同じ値の要素（インター予測情報）、すなわち同一の要素が存在するか否かを判定する（図２６のステップＳ２１０５）。図２７はこの同一要素確認処理手順のフローチャートである。履歴予測動きベクトル候補の数NumHmvpCandの値が０の場合（図２７のステップＳ２１２１：ＮＯ）、履歴予測動きベクトル候補リストHmvpCandListは空で、同一候補は存在しないので図２７のステップＳ２１２２～Ｓ２１２５をスキップし、本同一要素確認処理手順を終了する。履歴予測動きベクトル候補の数NumHmvpCandの値が0より大きい場合（図２７のステップＳ２１２１のＹＥＳ）、履歴予測動きベクトルインデックスhMvpIdxが0からNumHmvpCand-1まで、ステップＳ２１２３の処理を繰り返す（図２７のステップＳ２１２２～Ｓ２１２５）。まず、履歴予測動きベクトル候補リストの０から数えてhMvpIdx番目の要素HmvpCandList[hMvpIdx]がインター予測情報候補hMvpCandと同一か否かを比較する（図２７のステップＳ２１２３）。同一の場合（図２７のステップＳ２１２３：ＹＥＳ）、同一候補が存在するか否かを示すフラグidenticalCandExistにTRUE（真）の値を設定し、削除対象の要素の位置を示す削除対象インデックスremoveIdxに現在の履歴予測動きベクトルインデックスhMvpIdxの値を設定し、本同一要素確認処理を終了する。同一でない場合（図２７のステップＳ２１２３：ＮＯ）、hMvpIdxを1インクリメントし、履歴予測動きベクトルインデックスhMvpIdxがNumHmvpCand-1以下であれば、ステップＳ２１２３以降の処理を行う。 Next, it is determined whether or not each element of the historical prediction motion vector candidate list HmvpCandList has the same value as the inter-prediction information candidate hMvpCand to be registered (inter-prediction information), that is, the same element (Fig.). Step S2105 of 26). FIG. 27 is a flowchart of the same element confirmation processing procedure. Number of history prediction motion vector candidates When the value of NumHmvpCand is 0 (step S2121: NO in FIG. 27), the history prediction motion vector candidate list HmvpCandList is empty and the same candidate does not exist, so steps S2122 to S2125 in FIG. 27 are skipped. Then, the same element confirmation processing procedure is terminated. When the value of the number of historically predicted motion vector candidates NumHmvpCand is larger than 0 (YES in step S2121 in FIG. 27), the process of step S2123 is repeated from 0 to NumHmvpCand-1 in the historical predicted motion vector index hMvpIdx (step in FIG. 27). S2122 to S2125). First, it is compared whether or not the hMvpCandList [hMvpIdx], which is the xth element of the historical prediction motion vector candidate list counting from 0, is the same as the inter-prediction information candidate hMvpCand (step S2123 in FIG. 27). If they are the same (step S2123: YES in FIG. 27), a TRUE (true) value is set in the flag electricalCandExist indicating whether or not the same candidate exists, and the removal target index removeIdx indicating the position of the element to be deleted is currently set. Set the value of the history prediction motion vector index hMvpIdx of, and end this same element confirmation process. If they are not the same (step S2123: NO in FIG. 27), hMvpIdx is incremented by 1, and if the historical prediction motion vector index hMvpIdx is NumHmvpCand-1 or less, the processes after step S2123 are performed.
　再び図２６のフローチャートに戻り、履歴予測動きベクトル候補リストHmvpCandListの要素のシフト及び追加処理を行う（図２６のステップＳ２１０６）。図２８は図２６のステップＳ２１０６の履歴予測動きベクトル候補リストHmvpCandListの要素シフト／追加処理手順のフローチャートである。まず、履歴予測動きベクトル候補リストHmvpCandListに格納されている要素を除いてから新たな要素を追加するか、要素を除かずに新たな要素追加するかを判定する。具体的には同一候補が存在するか否かを示すフラグidenticalCandExistにTRUE（真）またはNumHmvpCandが6か否かを比較する（図２８のステップＳ２１４１）。同一候補が存在するか否かを示すフラグidenticalCandExistにTRUE（真）または現在の候補数NumHmvpCandが6のいずれかの条件を満たす場合（図２８のステップＳ２１４１：ＹＥＳ）、履歴予測動きベクトル候補リストHmvpCandListに格納されている要素を除いてから新たな要素を追加する。インデックスiの初期値をremoveIdx + 1の値に設定する。この初期値からNumHmvpCandまで、ステップＳ２１４３の要素シフト処理を繰り返す。（図２８のステップＳ２１４２～Ｓ２１４４）。HmvpCandList[ i -　1 ]にHmvpCandList[ i ]の要素をコピーすることで要素を前方にシフトし（図２８のステップＳ２１４３）、iを１インクリメントする（図２８のステップＳ２１４２～Ｓ２１４４）。続いて、履歴予測動きベクトル候補リストの最後に相当する０から数えて(NumHmvpCand-1)番目 HmvpCandList[NumHmvpCand-1]にインター予測情報候補hMvpCandを追加し（図２８のステップＳ２１４５）、本履歴予測動きベクトル候補リストHmvpCandListの要素シフト・追加処理を終了する。一方、同一候補が存在するか否かを示すフラグidenticalCandExistにTRUE（真）およびNumHmvpCandが6のいずれの条件も満たさない場合（図２８のステップＳ２１４１：ＮＯ）、履歴予測動きベクトル候補リストHmvpCandListに格納されている要素を除かずに、履歴予測動きベクトル候補リストの最後にインター予測情報候補hMvpCandを追加する（図２８のステップＳ２１４６）。ここで、履歴予測動きベクトル候補リストの最後とは、０から数えてNumHmvpCand番目のHmvpCandList[NumHmvpCand]である。また、NumHmvpCandを１インクリメントして、本履歴予測動きベクトル候補リストHmvpCandListの要素シフトおよび追加処理を終了する。 Returning to the flowchart of FIG. 26 again, the elements of the history prediction motion vector candidate list HmvpCandList are shifted and added (step S2106 of FIG. 26). FIG. 28 is a flowchart of the element shift / addition processing procedure of the history prediction motion vector candidate list HmvpCandList in step S2106 of FIG. First, it is determined whether to remove the elements stored in the historical prediction motion vector candidate list HmvpCandList and then add a new element, or to add a new element without removing the elements. Specifically, whether or not TRUE (true) or NumHmvpCand is 6 is compared with the flag identicalCandExist indicating whether or not the same candidate exists (step S2141 in FIG. 28). If the flag identicalCandExist indicating whether or not the same candidate exists satisfies either TRUE (true) or the current number of candidates NuMHmvpCand satisfies either of 6 (step S2141: YES in FIG. 28), the historical prediction motion vector candidate list HmvpCandList Add a new element after removing the element stored in. Set the initial value of index i to the value of removeIdx + 1. The element shift process in step S2143 is repeated from this initial value to NumHmvpCand. (Steps S2142 to S2144 in FIG. 28). By copying the element of HmvpCandList [i] to HmvpCandList [i-1], the element is shifted forward (step S2143 in FIG. 28) and i is incremented by 1 (steps S2142 to S2144 in FIG. 28). Next, the inter-prediction information candidate hMvpCand is added to the (NumHmvpCand-1) th HmvpCandList [NumHmvpCand-1] counting from 0, which corresponds to the end of the history prediction motion vector candidate list (step S2145 in FIG. 28), and this history prediction is performed. The element shift / addition process of the motion vector candidate list HmvpCandList is completed. On the other hand, when TRUE (true) and NumHmvpCand do not satisfy any of the conditions 6 in the flag electricalCandExist indicating whether or not the same candidate exists (step S2141: NO in FIG. 28), it is stored in the historical prediction motion vector candidate list HmvpCandList. The inter-prediction information candidate hMvpCand is added to the end of the history prediction motion vector candidate list without excluding the elements (step S2146 in FIG. 28). Here, the last of the historical prediction motion vector candidate list is the HmvpCandList [NumHmvpCand] which is the NumHmvpCand th from 0. In addition, NuMHmvpCand is incremented by 1, and the element shift and additional processing of this history prediction motion vector candidate list HmvpCandList are completed.
　図３１Ａ～Ｃは履歴予測動きベクトル候補リストの更新処理の一例を説明する図である。６つの要素（インター予測情報）を登録済みの履歴予測動きベクトル候補リストHmvpCandListに新たな要素を追加する場合、履歴予測動きベクトル候補リストHmvpCandListの前方の要素から順に新たなインター予測情報と比較して（図３１Ａ）、新たな要素が履歴予測動きベクトル候補リストHmvpCandListの先頭から３番目の要素HMVP2と同じ値であれば、履歴予測動きベクトル候補リストHmvpCandListから要素HMVP2を削除して後方の要素HMVP3～HMVP5を前方に１つずつシフト（コピー）し、履歴予測動きベクトル候補リストHmvpCandListの最後に新たな要素を追加して（図３１Ｂ）、履歴予測動きベクトル候補リストHmvpCandListの更新を完了する（図３１Ｃ）。 FIGS. 31A to 31C are diagrams for explaining an example of the update process of the history prediction motion vector candidate list. When adding a new element to the registered history prediction motion vector candidate list HmvpCandList with 6 elements (inter-prediction information), compare it with the new inter-prediction information in order from the element before the history prediction motion vector candidate list HmvpCandList. (Fig. 31A) If the new element has the same value as the third element from the beginning of the history prediction motion vector candidate list HmvpCandList, HMVP2, delete the element HMVP2 from the history prediction motion vector candidate list HmvpCandList and the rear element HMVP3 ~ Shift (copy) HMVP5 forward one by one, add a new element to the end of the history prediction motion vector candidate list HmvpCandList (Fig. 31B), and complete the update of the history prediction motion vector candidate list HmvpCandList (Fig. 31C). ).
　＜履歴予測動きベクトル候補導出処理＞
　次に、符号化側の通常予測動きベクトルモード導出部３０１の履歴予測動きベクトル候補導出部３２３、復号側の通常予測動きベクトルモード導出部４０１の履歴予測動きベクトル候補導出部４２３で共通の処理である図２０のステップＳ３０４の処理手順である履歴予測動きベクトル候補リストHmvpCandListからの履歴予測動きベクトル候補の導出方法について詳細に説明する。図２９は履歴予測動きベクトル候補導出処理手順を説明するフローチャートである。 <History prediction motion vector candidate derivation process>
Next, the history prediction motion vector candidate derivation unit 323 of the normal prediction motion vector mode derivation unit 301 on the coding side and the history prediction motion vector candidate derivation unit 423 of the normal prediction motion vector mode derivation unit 401 on the decoding side perform common processing. A method of deriving the history prediction motion vector candidate from the history prediction motion vector candidate list HmvpCandList, which is the processing procedure of step S304 of FIG. 20, will be described in detail. FIG. 29 is a flowchart illustrating a history prediction motion vector candidate derivation processing procedure.
　現在の予測動きベクトル候補の数numCurrMvpCandが予測動きベクトル候補リストmvpListLXの最大要素数（ここでは２とする）以上または履歴予測動きベクトル候補の数がNumHmvpCandの値が0の場合（図２９のステップＳ２２０１のＮＯ）、図２９のステップＳ２２０２からＳ２２０９の処理を省略し、履歴予測動きベクトル候補導出処理手順を終了する。現在の予測動きベクトル候補の数numCurrMvpCandが予測動きベクトル候補リストmvpListLXの最大要素数である２より小さい場合、かつ履歴予測動きベクトル候補の数NumHmvpCandの値が０より大きい場合（図２９のステップＳ２２０１のＹＥＳ）、図２９のステップＳ２２０２からＳ２２０９の処理を行う。 When the current number of predicted motion vector candidates numCurrMvpCand is equal to or greater than the maximum number of elements in the predicted motion vector candidate list mvpListLX (here, 2) or the number of historical predicted motion vector candidates is 0 in the value of NumHmvpCand (step S2201 in FIG. 29). NO), the process of steps S2202 to S2209 of FIG. 29 is omitted, and the history prediction motion vector candidate derivation process procedure is completed. When the current number of predicted motion vector candidates numCurrMvpCand is less than 2, which is the maximum number of elements in the predicted motion vector candidate list mvpListLX, and when the value of the number of historical predicted motion vector candidates NumHmvpCand is greater than 0 (step S2201 in FIG. 29). YES), the processes of steps S2202 to S2209 of FIG. 29 are performed.
　続いて、インデックスｉが１から、４と履歴予測動きベクトル候補の数numCheckedHMVPCandのいずれか小さい値まで、図２９のステップＳ２２０３からＳ２２０８の処理を繰り返す（図２９のステップＳ２２０２～Ｓ２２０９）。現在の予測動きベクトル候補の数numCurrMvpCandが予測動きベクトル候補リストmvpListLXの最大要素数である２以上の場合（図２９のステップＳ２２０３：ＮＯ）、図２９のステップＳ２２０４からＳ２２０９の処理を省略し、本履歴予測動きベクトル候補導出処理手順を終了する。現在の予測動きベクトル候補の数numCurrMvpCandが予測動きベクトル候補リストmvpListLXの最大要素数である２より小さい場合（図２９のステップＳ２２０３：ＹＥＳ）、図２９のステップＳ２２０４以降の処理を行う。 Subsequently, the processes of steps S2203 to S2208 of FIG. 29 are repeated until the index i is 1 to 4 and the number of historical prediction motion vector candidates numCheckedHMVPCand, whichever is smaller (steps S2202 to S2209 of FIG. 29). When the current number of predicted motion vector candidates numCurrMvpCand is 2 or more, which is the maximum number of elements of the predicted motion vector candidate list mvpListLX (steps S2203: NO in FIG. 29), the processing of steps S2204 to S2209 in FIG. 29 is omitted. The history prediction motion vector candidate derivation processing procedure ends. When the current number of predicted motion vector candidates numCurrMvpCand is smaller than 2, which is the maximum number of elements of the predicted motion vector candidate list mvpListLX (step S2203: YES in FIG. 29), the processes after step S2204 in FIG. 29 are performed.
　続いて、ステップＳ２２０５からＳ２２０７までの処理をＹが０と１（Ｌ０とＬ１）についてそれぞれ行う（図２９のステップＳ２２０４～Ｓ２２０８）。現在の予測動きベクトル候補の数numCurrMvpCandが予測動きベクトル候補リストmvpListLXの最大要素数である２以上の場合（図２９のステップＳ２２０５：ＮＯ）、図２９のステップＳ２２０６からＳ２２０９の処理を省略し、本履歴予測動きベクトル候補導出処理手順を終了する。現在の予測動きベクトル候補の数numCurrMvpCandが予測動きベクトル候補リストmvpListLXの最大要素数である２より小さい場合（図２９のステップＳ２２０５：ＹＥＳ）、図２９のステップＳ２２０６以降の処理を行う。 Subsequently, the processes from steps S2205 to S2207 are performed for Y's 0 and 1 (L0 and L1), respectively (steps S2204 to S2208 in FIG. 29). When the current number of predicted motion vector candidates numCurrMvpCand is 2 or more, which is the maximum number of elements of the predicted motion vector candidate list mvpListLX (steps S2205: NO in FIG. 29), the processing of steps S2206 to S2209 in FIG. 29 is omitted. The history prediction motion vector candidate derivation processing procedure ends. When the current number of predicted motion vector candidates numCurrMvpCand is smaller than 2, which is the maximum number of elements of the predicted motion vector candidate list mvpListLX (step S2205: YES in FIG. 29), the processes after step S2206 in FIG. 29 are performed.
　続いて、履歴予測動きベクトル候補リストHmvpCandListの中に、符号化／復号対象動きベクトルの参照インデックスrefIdxLXと同じ参照インデックスの要素であり、予測動きベクトルリストmvpListLXのどの要素とも異なる要素の場合（図２９のステップＳ２２０６：ＹＥＳ）、予測動きベクトル候補リストの０から数えてnumCurrMvpCand番目の要素mvpListLX[numCurrMvpCand]に履歴予測動きベクトル候補HmvpCandList[NumHmvpCand - i]のLYの動きベクトルを追加し（図２９のステップＳ２２０７）、現在の予測動きベクトル候補の数numCurrMvpCandを１インクリメントする。履歴予測動きベクトル候補リストHmvpCandListの中に、符号化／復号対象動きベクトルの参照インデックスrefIdxLXと同じ参照インデックスの要素であり、予測動きベクトルリストmvpListLXのどの要素とも異なる要素がない場合（図２９のステップＳ２２０６：ＮＯ）、ステップＳ２２０７の追加処理をスキップする。 Next, in the historical prediction motion vector candidate list HmvpCandList, if the element has the same reference index as the reference index refIdxLX of the motion vector to be encoded / decoded and is different from any element of the prediction motion vector list mvpListLX (FIG. 29). Step S2206: YES), add the LY motion vector of the historical prediction motion vector candidate HmvpCandList [NumHmvpCand-i] to the numCurrMvpCand th element mvpListLX [numCurrMvpCand] counting from 0 in the predicted motion vector candidate list (step in FIG. 29). S2207), the number of current predicted motion vector candidates numCurrMvpCand is incremented by 1. When there is no element in the historical predicted motion vector candidate list HmvpCandList that has the same reference index as the reference index refIdxLX of the motion vector to be encoded / decoded and is different from any element of the predicted motion vector list mvpListLX (step in FIG. 29). S2206: NO), the additional processing of step S2207 is skipped.
　以上の図２９のステップＳ２２０５からＳ２２０７の処理をＬ０とＬ１で双方ともに行う（図２９のステップＳ２２０４～Ｓ２２０８）。インデックスｉを１インクリメントし、インデックスｉが４と履歴予測動きベクトル候補の数NumHmvpCandのいずれか小さい値以下の場合、再びステップＳ２２０３以降の処理を行う（図２９のステップＳ２２０２～Ｓ２２０９）。 The above processes of steps S2205 to S2207 of FIG. 29 are performed at both L0 and L1 (steps S2204 to S2208 of FIG. 29). When the index i is incremented by 1 and the index i is 4 or less than the smaller value of the number of historical prediction motion vector candidates NuMHmvpCand, the processes after step S2203 are performed again (steps S2202 to S2209 in FIG. 29).
　＜履歴マージ候補導出処理＞
　次に、符号化側の通常マージモード導出部３０２の履歴マージ候補導出部３４５、復号側の通常マージモード導出部４０２の履歴マージ候補導出部４４５で共通の処理である図２１のステップＳ４０３の処理手順である履歴マージ候補リストHmvpCandListからの履歴マージ候補の導出方法について詳細に説明する。図３０は履歴マージ候補導出処理手順を説明するフローチャートである。 <History merge candidate derivation process>
Next, the process of step S403 in FIG. 21, which is a process common to the history merge candidate derivation unit 345 of the normal merge mode derivation unit 302 on the coding side and the history merge candidate derivation unit 445 of the normal merge mode derivation unit 402 on the decoding side. The procedure for deriving the history merge candidate from the history merge candidate list HmvpCandList will be described in detail. FIG. 30 is a flowchart illustrating a history merge candidate derivation processing procedure.
　まず、初期化処理を行う（図３０のステップＳ２３０１）。isPruned[i]の0から(numCurrMergeCand -1)番目のそれぞれの要素にFALSEの値を設定し、変数numOrigMergeCandに現在のマージ候補リストに登録されている要素の数numCurrMergeCandを設定する。 First, the initialization process is performed (step S2301 in FIG. 30). Set the value of FALSE to each element from 0 to (numCurrMergeCand-1) of isPruned [i], and set the variable numOrigMergeCand to the number of elements registered in the current merge candidate list, numCurrMergeCand.
　続いて、インデックスhMvpIdxの初期値を1に設定し、この初期値からNumHmvpCandまで、図３０のステップＳ２３０３からステップＳ２３１０までの追加処理を繰り返す（図３０のステップＳ２３０２～Ｓ２３１１）。現在のマージ候補リストに登録されている要素の数numCurrMergeCandが(最大マージ候補数MaxNumMergeCand-1)以下でなければ、マージ候補リストのすべての要素にマージ候補が追加されたので、本履歴マージ候補導出処理を終了する（図３０のステップＳ２３０３のＮＯ）。現在のマージ候補リストに登録されている要素の数numCurrMergeCandが(最大マージ候補数MaxNumMergeCand-1)以下の場合、ステップＳ２３０４以降の処理を行う。sameMotionにFALSE（偽）の値を設定する（図３０のステップＳ２３０４）。続いて、インデックスiの初期値を0に設定し、この初期値からnumOrigMergeCand-1まで図３０のステップＳ２３０６、Ｓ２３０７の処理を行う（図３０のＳ２３０５～Ｓ２３０８）。履歴動きベクトル予測候補リストの０から数えて(NumHmvpCand - hMvpIdx)番目の要素HmvpCandList[NumHmvpCand- hMvpIdx]がマージ候補リストの０から数えてi番目の要素mergeCandList[i]と同じ値か否かを比較する（図３０のステップＳ２３０６）。 Subsequently, the initial value of the index hMvpIdx is set to 1, and the additional processing from step S2303 to step S2310 in FIG. 30 is repeated from this initial value to NuMHmvpCand (steps S2302 to S2311 in FIG. 30). If the number of elements registered in the current merge candidate list numCurrMergeCand is not less than or equal to (maximum number of merge candidates MaxNumMergeCand-1), merge candidates have been added to all elements in the merge candidate list, so this history merge candidate derivation The process ends (NO in step S2303 in FIG. 30). If the number of elements registered in the current merge candidate list numCurrMergeCand is (maximum number of merge candidates MaxNumMergeCand-1) or less, the processing in step S2304 and subsequent steps is performed. A FALSE value is set in sameMotion (step S2304 in FIG. 30). Subsequently, the initial value of the index i is set to 0, and the processes of steps S2306 and S2307 of FIG. 30 are performed from this initial value to numOrigMergeCand-1 (S2305 to S2308 of FIG. 30). Compare whether the (NumHmvpCand-hMvpIdx) th element HmvpCandList [NumHmvpCand-hMvpIdx] is the same as the i-th element mergeCandList [i] in the merge candidate list, counting from 0 in the historical motion vector prediction candidate list. (Step S2306 in FIG. 30).
　マージ候補の同じ値とはマージ候補が持つすべての構成要素（インター予測モード、参照インデックス、動きベクトル）の値が同じ場合にマージ候補が同じ値とする。マージ候補が同じ値、かつisPruned[i]がFALSEの場合（図３０のステップＳ２３０６のＹＥＳ）、sameMotionおよびisPruned[i]共にTRUE（真）を設定する（図３０のステップＳ２３０７）。同じ値でない場合（図３０のステップＳ２３０６のＮＯ）、ステップＳ２３０７の処理をスキップする。図３０のステップＳ２３０５からステップＳ２３０８までの繰り返し処理が完了したらsameMotionがFALSE（偽）か否かを比較し（図３０のステップＳ２３０９）、sameMotionが FALSE（偽）の場合（図３０のステップＳ２３０９のＹＥＳ）、すなわち履歴予測動きベクトル候補リストの０から数えて(NumHmvpCand - hMvpIdx)番目の要素HmvpCandList[NumHmvpCand - hMvpIdx]はmergeCandListに存在しないので、マージ候補リストのnumCurrMergeCand番目のmergeCandList[numCurrMergeCand]に履歴予測動きベクトル候補リストの０から数えて(NumHmvpCand - hMvpIdx)番目の要素HmvpCandList[NumHmvpCand - hMvpIdx]を追加し、numCurrMergeCandを1インクリメントする（図３０のステップＳ２３１０）。インデックスhMvpIdxを１インクリメントし（図３０のステップＳ２３０２）、図３０のステップＳ２３０２～Ｓ２３１１の繰り返し処理を行う。
　履歴予測動きベクトル候補リストのすべての要素の確認が完了するか、マージ候補リストのすべての要素にマージ候補が追加されたら、本履歴マージ候補の導出処理を完了する。 What is the same value of the merge candidate? When the values of all the components (inter prediction mode, reference index, motion vector) of the merge candidate are the same, the merge candidates have the same value. When the merge candidates have the same value and isPruned [i] is FALSE (YES in step S2306 of FIG. 30), TRUE (true) is set for both sameMotion and isPruned [i] (step S2307 of FIG. 30). If the values are not the same (NO in step S2306 of FIG. 30), the process of step S2307 is skipped. When the iterative processing from step S2305 to step S2308 in FIG. 30 is completed, it is compared whether or not sameMotion is FALSE (false) (step S2309 in FIG. 30), and when sameMotion is FALSE (false) (step S2309 in FIG. 30). YES), that is, the element HmvpCandList [NumHmvpCand --hMvpIdx] of the (NumHmvpCand --hMvpIdx) th element in the history prediction motion vector candidate list does not exist in the mergeCandList, so the mergeCandList [numCurrMergeCand] of the merge candidate list Add the (NumHmvpCand --hMvpIdx) th element HmvpCandList [NumHmvpCand --hMvpIdx] counting from 0 in the motion vector candidate list, and increment numCurrMergeCand by 1 (step S2310 in FIG. 30). The index hMvpIdx is incremented by 1 (step S2302 in FIG. 30), and the iterative processing of steps S2302 to S2311 in FIG. 30 is repeated.
When the confirmation of all the elements of the history prediction motion vector candidate list is completed or the merge candidates are added to all the elements of the merge candidate list, the derivation process of this history merge candidate is completed.
　＜平均マージ候補導出処理＞
　次に、符号化側の通常マージモード導出部３０２の平均マージ候補導出部３４４、復号側の通常マージモード導出部４０２の平均マージ候補導出部４４４で共通の処理である図２１のステップＳ４０４の処理手順である平均マージ候補の導出方法について詳細に説明する。図３８は平均マージ候補導出処理手順を説明するフローチャートである。 <Average merge candidate derivation process>
Next, the process of step S404 of FIG. 21, which is a process common to the average merge candidate derivation unit 344 of the normal merge mode derivation unit 302 on the coding side and the average merge candidate derivation unit 444 of the normal merge mode derivation unit 402 on the decoding side. The method of deriving the average merge candidate, which is a procedure, will be described in detail. FIG. 38 is a flowchart illustrating a procedure for deriving the average merge candidate.
　まず、初期化処理を行う（図３８のステップＳ１３０１）。変数numOrigMergeCandに現在のマージ候補リストに登録されている要素の数numCurrMergeCandを設定する。 First, the initialization process is performed (step S1301 in FIG. 38). Set the variable numOrigMergeCand to the number of elements registered in the current merge candidate list, numCurrMergeCand.
　続いて、マージ候補リストの先頭から順に走査し、２つの動き情報を決定する。１つ目の動き情報を示すインデックスi=0、２つ目の動き情報を示すインデックスj=1とする。（図３８のステップＳ１３０２～Ｓ１３０３）。現在のマージ候補リストに登録されている要素の数numCurrMergeCandが(最大マージ候補数MaxNumMergeCand-1)以下でなければ、マージ候補リストのすべての要素にマージ候補が追加されたので、本履歴マージ候補導出処理を終了する（図３８のステップＳ１３０４）。現在のマージ候補リストに登録されている要素の数numCurrMergeCandが(最大マージ候補数MaxNumMergeCand-1)以下の場合は、ステップＳ１３０５以降の処理を行う。 Next, scan in order from the top of the merge candidate list and determine two movement information. It is assumed that the index i = 0 indicating the first motion information and the index j = 1 indicating the second motion information. (Steps S1302 to S1303 in FIG. 38). If the number of elements registered in the current merge candidate list numCurrMergeCand is not less than or equal to (maximum number of merge candidates MaxNumMergeCand-1), merge candidates have been added to all elements in the merge candidate list, so this history merge candidate derivation The process ends (step S1304 in FIG. 38). If the number of elements registered in the current merge candidate list numCurrMergeCand is (maximum number of merge candidates MaxNumMergeCand-1) or less, the processing of step S1305 and subsequent steps is performed.
　マージ候補リストのi番目の動き情報mergeCandList[i]とマージ候補リストのj番目の動き情報mergeCandList[j]がともに無効であるか否かを判定し（図３８のステップＳ１３０５）、ともに無効である場合は、mergeCandList[i]とmergeCandList[j]の平均マージ候補の導出を行わず、次の要素に移る。mergeCandList[i]とmergeCandList[j]がともに無効でない場合は、Xを0と1として以下の処理を繰り返す（図３８のステップＳ１３０６からＳ１３１４）。 It is determined whether or not the i-th motion information mergeCandList [i] of the merge candidate list and the j-th motion information mergeCandList [j] of the merge candidate list are both invalid (step S1305 in FIG. 38), and both are invalid. In that case, move on to the next element without deriving the average merge candidates of mergeCandList [i] and mergeCandList [j]. If both mergeCandList [i] and mergeCandList [j] are not invalid, the following processing is repeated with X as 0 and 1 (steps S1306 to 1314 in FIG. 38).
　mergeCandList[i]のLX予測が有効であるかを判定する（図３８のステップＳ１３０７）。mergeCandList[i]のLX予測が有効である場合は、mergeCandList[j]のLX予測が有効であるかを判定する（図３８のステップＳ１３０８）。mergeCandList[j]のLX予測が有効である場合、すなわち、mergeCandList[i]のLX予測とmergeCandList[j]のLX予測がともに有効である場合は、mergeCandList[i]のLX予測の動きベクトルとmergeCandList[j]のLX予測の動きベクトルを平均したLX予測の動きベクトルとmergeCandList[i]のLX予測の参照インデックスを有するLX予測の平均マージ候補を導出してaverageCandのLX予測に設定し、averageCandのLX予測を有効とする（図３８のステップＳ１３０９）。図３８のステップＳ１３０８で、mergeCandList[j]のLX予測が有効でない場合、すなわち、mergeCandList[i]のLX予測が有効、かつmergeCandList[j]のLX予測が無効である場合は、mergeCandList[i]のLX予測の動きベクトルと参照インデックスを有するLX予測の平均マージ候補を導出してaverageCandのLX予測に設定し、averageCandのLX予測を有効とする（図３８のステップＳ１３１０）。図３８のステップＳ１３０７で、mergeCandList[i]のLX予測が有効でない場合、mergeCandList[j]のLX予測が有効であるか否かを判定する（図３８のステップＳ１３１１）。mergeCandList[j]のLX予測が有効である場合、すなわちmergeCandList[i]のLX予測が無効、かつmergeCandList[j] のLX予測が有効である場合は、mergeCandList[j]のLX予測の動きベクトルと参照インデックスを有するLX予測の平均マージ候補を導出してaverageCandのLX予測に設定し、averageCandのLX予測を有効とする（図３８のステップＳ１３１２）。図３８のステップＳ１３１１で、mergeCandList[j]のLX予測が有効でない場合、すなわちmergeCandList[i]のLX予測、mergeCandList[j]のLX予測がともに無効である場合は、averageCandのLX予測を無効とする（図３８のステップＳ１３１２）。 Determine whether the LX prediction of mergeCandList [i] is valid (step S1307 of FIG. 38). When the LX prediction of mergeCandList [i] is valid, it is determined whether the LX prediction of mergeCandList [j] is valid (step S1308 in FIG. 38). If the LX prediction of mergeCandList [j] is valid, that is, if both the LX prediction of mergeCandList [i] and the LX prediction of mergeCandList [j] are valid, then the motion vector of the LX prediction of mergeCandList [i] and the mergeCandList The average merge candidate of the LX prediction having the motion vector of the LX prediction obtained by averaging the movement vectors of the LX prediction of [j] and the reference index of the LX prediction of mergeCandList [i] is derived and set to the LX prediction of the averageCand, and the averageCand Enable LX prediction (step S1309 in FIG. 38). In step S1308 of FIG. 38, if the LX prediction of mergeCandList [j] is not valid, that is, if the LX prediction of mergeCandList [i] is valid and the LX prediction of mergeCandList [j] is invalid, then mergeCandList [i] The average merge candidate of the LX prediction having the motion vector and the reference index of the LX prediction is derived and set to the LX prediction of the averageCand, and the LX prediction of the averageCand is valid (step S1310 in FIG. 38). If the LX prediction of mergeCandList [i] is not valid in step S1307 of FIG. 38, it is determined whether or not the LX prediction of mergeCandList [j] is valid (step S1311 of FIG. 38). If the LX prediction of mergeCandList [j] is valid, that is, if the LX prediction of mergeCandList [i] is invalid and the LX prediction of mergeCandList [j] is valid, then the motion vector of the LX prediction of mergeCandList [j] The average merge candidate of the LX prediction having the reference index is derived and set to the LX prediction of the averageCand, and the LX prediction of the averageCand is enabled (step S1312 in FIG. 38). In step S1311 of FIG. 38, if the LX prediction of mergeCandList [j] is not valid, that is, if both the LX prediction of mergeCandList [i] and the LX prediction of mergeCandList [j] are invalid, the LX prediction of averageCand is invalidated. (Step S1312 in FIG. 38).
　以上のように生成されたL0予測、L1予測または双予測の平均マージ候補averageCandを、マージ候補リストのnumCurrMergeCand番目のmergeCandList[numCurrMergeCand]に追加し、numCurrMergeCandを1インクリメントする（図３８のステップＳ１３１５）。以上で、平均マージ候補の導出処理を完了する。 The average merge candidate averageCand of the L0 prediction, L1 prediction or bi-prediction generated as described above is added to the mergeCandList [numCurrMergeCand] of the numCurrMergeCand th numCurrMergeCand of the merge candidate list, and the numCurrMergeCand is incremented by 1 (step S1315 in FIG. 38). This completes the process of deriving the average merge candidate.
　なお、平均マージ候補は動きベクトルの水平成分と動きベクトルの垂直成分それぞれで平均される。 The average merge candidate is averaged for each of the horizontal component of the motion vector and the vertical component of the motion vector.
　＜動き補償予測処理＞
　動き補償予測部３０６は、符号化において現在予測処理の対象となっているブロックの位置およびサイズを取得する。また、動き補償予測部３０６は、インター予測情報をインター予測モード判定部３０５から取得する。取得したインター予測情報から参照インデックスおよび動きベクトルを導出し、復号画像メモリ１０４内の参照インデックスで特定される参照ピクチャを、動きベクトルの分だけ符号化ブロックの画像信号と同一位置より移動させた位置の画像信号を取得した後に予測信号を生成する。 <Motion compensation prediction processing>
The motion compensation prediction unit 306 acquires the position and size of the block currently subject to prediction processing in coding. Further, the motion compensation prediction unit 306 acquires the inter prediction information from the inter prediction mode determination unit 305. The reference index and motion vector are derived from the acquired inter-prediction information, and the reference picture specified by the reference index in the decoded image memory 104 is moved from the same position as the image signal of the coded block by the motion vector. A prediction signal is generated after acquiring the image signal of.
　インター予測におけるインター予測モードがL0予測やL1予測のような、単一の参照ピクチャからの予測の場合には、１つの参照ピクチャから取得した予測信号を動き補償予測信号とし、インター予測モードが双予測のような、予測モードが２つの参照ピクチャからの予測の場合には、２つの参照ピクチャから取得した予測信号を重みづけ平均したものを動き補償予測信号とし、動き補償予測信号を予測方法決定部１０５に供給する。ここでは双予測の重みづけ平均の比率を１：１とするが、他の比率を用いて重みづけ平均を行っても良い。例えば、予測対象となっているピクチャと参照ピクチャとのピクチャ間隔が近いものほど重みづけの比率が大きくなるようにしてもよい。また、重みづけ比率の算出をピクチャ間隔の組み合わせと重みづけ比率との対応表を用いて行うようにしても良い。 When the inter-prediction mode in inter-prediction is prediction from a single reference picture such as L0 prediction or L1 prediction, the prediction signal acquired from one reference picture is used as the motion compensation prediction signal, and the inter-prediction mode is dual. When the prediction mode is prediction from two reference pictures such as prediction, the weighted average of the prediction signals acquired from the two reference pictures is used as the motion compensation prediction signal, and the motion compensation prediction signal is used to determine the prediction method. Supply to unit 105. Here, the ratio of the weighted averages of the biprediction is 1: 1, but weighted averages may be performed using other ratios. For example, the weighting ratio may be increased as the distance between the picture to be predicted and the reference picture is closer. Further, the weighting ratio may be calculated by using the correspondence table between the combination of picture intervals and the weighting ratio.
　動き補償予測部４０６は、符号化側の動き補償予測部３０６と同様の機能をもつ。動き補償予測部４０６は、インター予測情報を、通常予測動きベクトルモード導出部４０１、通常マージモード導出部４０２、サブブロック予測動きベクトルモード導出部４０３、サブブロックマージモード導出部４０４から、スイッチ４０８を介して取得する。動き補償予測部４０６は、得られた動き補償予測信号を、復号画像信号重畳部２０７に供給する。 The motion compensation prediction unit 406 has the same function as the motion compensation prediction unit 306 on the coding side. The motion compensation prediction unit 406 transfers the inter-prediction information from the normal prediction motion vector mode derivation unit 401, the normal merge mode derivation unit 402, the subblock prediction motion vector mode derivation unit 403, and the subblock merge mode derivation unit 404 to switch 408. Get through. The motion compensation prediction unit 406 supplies the obtained motion compensation prediction signal to the decoded image signal superimposition unit 207.
　＜インター予測モードについて＞
　単一の参照ピクチャからの予測を行う処理を単予測と定義し、単予測の場合はＬ０予測またはＬ１予測という、参照リストＬ０、Ｌ１に登録された２つの参照ピクチャのいずれか一方を利用した予測を行う。 <About inter-prediction mode>
The process of making a prediction from a single reference picture is defined as a simple prediction, and in the case of a single prediction, either one of the two reference pictures registered in the reference lists L0 and L1, which is L0 prediction or L1 prediction, is used. Make a prediction.
　図３３は単予測であってＬ０の参照ピクチャ（ＲｅｆＬ０Ｐｉｃ）が処理対象ピクチャ（ＣｕｒＰｉｃ）より前の時刻にある場合を示している。図３４は単予測であってＬ０予測の参照ピクチャが処理対象ピクチャより後の時刻にある場合を示している。同様に、図３３および図３４のＬ０予測の参照ピクチャをＬ１予測の参照ピクチャ（ＲｅｆＬ１Ｐｉｃ）に置き換えて単予測を行うこともできる。 FIG. 33 is a simple prediction and shows a case where the reference picture (RefL0Pic) of L0 is at a time before the picture to be processed (CurPic). FIG. 34 shows a case where the reference picture of the L0 prediction is at a time after the processing target picture in the simple prediction. Similarly, the reference picture for the L0 prediction in FIGS. 33 and 34 can be replaced with the reference picture for the L1 prediction (RefL1Pic) to perform simple prediction.
　２つの参照ピクチャからの予測を行う処理を双予測と定義し、双予測の場合はＬ０予測とＬ１予測の双方を利用して双予測と表現する。図３５は双予測であってＬ０予測の参照ピクチャが処理対象ピクチャより前の時刻にあって、Ｌ１予測の参照ピクチャが処理対象ピクチャより後の時刻にある場合を示している。図３６は双予測であってＬ０予測の参照ピクチャとＬ１予測の参照ピクチャが処理対象ピクチャより前の時刻にある場合を示している。図３７は双予測であってＬ０予測の参照ピクチャとＬ１予測の参照ピクチャが処理対象ピクチャより後の時刻にある場合を示している。 The process of making a prediction from two reference pictures is defined as double prediction, and in the case of double prediction, it is expressed as double prediction using both L0 prediction and L1 prediction. FIG. 35 shows a case where the reference picture of the L0 prediction is at a time before the processing target picture and the reference picture of the L1 prediction is at a time after the processing target picture in the bi-prediction. FIG. 36 shows a case where the reference picture of the L0 prediction and the reference picture of the L1 prediction are at a time before the processing target picture in the bi-prediction. FIG. 37 shows a case where the reference picture of the L0 prediction and the reference picture of the L1 prediction are at a time after the processing target picture in the bi-prediction.
　このように、Ｌ０／Ｌ１の予測種別と時間の関係は、Ｌ０が過去方向、Ｌ１が未来方向とは限定されずに用いることが可能である。また双予測の場合に、同一の参照ピクチャを用いてＬ０予測及びＬ１予測のそれぞれを行ってもよい。なお、動き補償予測を単予測で行うか双予測で行うかの判断は、例えばＬ０予測を利用するか否か及びＬ１予測を利用するか否かを示す情報（例えば、フラグ）に基づき判断される。 As described above, the relationship between the prediction type of L0 / L1 and the time can be used without limiting L0 to the past direction and L1 to the future direction. Further, in the case of bi-prediction, L0 prediction and L1 prediction may be performed using the same reference picture. It should be noted that the determination of whether the motion compensation prediction is performed by simple prediction or double prediction is determined based on, for example, information (for example, a flag) indicating whether or not to use L0 prediction and whether or not to use L1 prediction. To.
　＜参照インデックスについて＞
　本発明の実施の形態では、動き補償予測の精度向上のために、動き補償予測において複数の参照ピクチャの中から最適な参照ピクチャを選択することを可能とする。そのため、動き補償予測で利用した参照ピクチャを参照インデックスとして利用するとともに、参照インデックスを差分ベクトルとともにビットストリーム中に符号化する。 <About reference index>
In the embodiment of the present invention, in order to improve the accuracy of motion compensation prediction, it is possible to select the optimum reference picture from a plurality of reference pictures in motion compensation prediction. Therefore, the reference picture used in the motion compensation prediction is used as the reference index, and the reference index is encoded in the bit stream together with the difference vector.
　＜通常予測動きベクトルモードに基づく動き補償処理＞
　動き補償予測部３０６は、図１６の符号化側におけるインター予測部１０２でも示されるように、インター予測モード判定部３０５において、通常予測動きベクトルモード導出部３０１によるインター予測情報が選択された場合には、このインター予測情報をインター予測モード判定部３０５から取得し、現在処理対象となっているブロックのインター予測モード、参照インデックス、動きベクトルを導出し、動き補償予測信号を生成する。生成された動き補償予測信号は、予測方法決定部１０５に供給される。 <Motion compensation processing based on normal predicted motion vector mode>
As shown in the inter prediction unit 102 on the coding side of FIG. 16, the motion compensation prediction unit 306 is used when the inter prediction information by the normal prediction motion vector mode derivation unit 301 is selected in the inter prediction mode determination unit 305. Acquires this inter-prediction information from the inter-prediction mode determination unit 305, derives the inter-prediction mode, reference index, and motion vector of the block currently being processed, and generates a motion compensation prediction signal. The generated motion compensation prediction signal is supplied to the prediction method determination unit 105.
　同様に、動き補償予測部４０６は、図２２の復号側におけるインター予測部２０３でも示されるように、復号の過程でスイッチ４０８が通常予測動きベクトルモード導出部４０１に接続された場合には、通常予測動きベクトルモード導出部４０１によるインター予測情報を取得し、現在処理対象となっているブロックのインター予測モード、参照インデックス、動きベクトルを導出し、動き補償予測信号を生成する。生成された動き補償予測信号は、復号画像信号重畳部２０７に供給される。 Similarly, the motion compensation prediction unit 406 is normally used when the switch 408 is connected to the normal prediction motion vector mode derivation unit 401 in the process of decoding, as shown by the inter prediction unit 203 on the decoding side of FIG. The inter-prediction information by the prediction motion vector mode derivation unit 401 is acquired, the inter-prediction mode, the reference index, and the motion vector of the block currently being processed are derived, and the motion compensation prediction signal is generated. The generated motion compensation prediction signal is supplied to the decoded image signal superimposing unit 207.
　＜通常マージモードに基づく動き補償処理＞
　動き補償予測部３０６は、図１６の符号化側におけるインター予測部１０２でも示されるように、インター予測モード判定部３０５において、通常マージモード導出部３０２によるインター予測情報が選択された場合には、このインター予測情報をインター予測モード判定部３０５から取得し、現在処理対象となっているブロックのインター予測モード、参照インデックス、動きベクトルを導出し、動き補償予測信号を生成する。生成された動き補償予測信号は、予測方法決定部１０５に供給される。 <Motion compensation processing based on normal merge mode>
As shown in the inter-prediction unit 102 on the coding side of FIG. 16, the motion compensation prediction unit 306 is used when the inter-prediction information by the normal merge mode derivation unit 302 is selected in the inter-prediction mode determination unit 305. This inter-prediction information is acquired from the inter-prediction mode determination unit 305, the inter-prediction mode, reference index, and motion vector of the block currently being processed are derived, and a motion compensation prediction signal is generated. The generated motion compensation prediction signal is supplied to the prediction method determination unit 105.
　同様に、動き補償予測部４０６は、図２２の復号側におけるインター予測部２０３でも示されるように、復号の過程でスイッチ４０８が通常マージモード導出部４０２に接続された場合には、通常マージモード導出部４０２によるインター予測情報を取得し、現在処理対象となっているブロックのインター予測モード、参照インデックス、動きベクトルを導出し、動き補償予測信号を生成する。生成された動き補償予測信号は、復号画像信号重畳部２０７に供給される。 Similarly, the motion compensation prediction unit 406 is in the normal merge mode when the switch 408 is connected to the normal merge mode derivation unit 402 in the decoding process, as shown by the inter prediction unit 203 on the decoding side in FIG. The inter-prediction information by the derivation unit 402 is acquired, the inter-prediction mode, the reference index, and the motion vector of the block currently being processed are derived, and the motion compensation prediction signal is generated. The generated motion compensation prediction signal is supplied to the decoded image signal superimposing unit 207.
　＜サブブロック予測動きベクトルモードに基づく動き補償処理＞
　動き補償予測部３０６は、図１６の符号化側におけるインター予測部１０２でも示されるように、インター予測モード判定部３０５において、サブブロック予測動きベクトルモード導出部３０３によるインター予測情報が選択された場合には、このインター予測情報をインター予測モード判定部３０５から取得し、現在処理対象となっているブロックのインター予測モード、参照インデックス、動きベクトルを導出し、動き補償予測信号を生成する。生成された動き補償予測信号は、予測方法決定部１０５に供給される。 <Motion compensation processing based on subblock prediction motion vector mode>
In the motion compensation prediction unit 306, as shown by the inter prediction unit 102 on the coding side of FIG. 16, when the inter prediction information by the subblock prediction motion vector mode derivation unit 303 is selected in the inter prediction mode determination unit 305. The inter-prediction information is acquired from the inter-prediction mode determination unit 305, the inter-prediction mode, the reference index, and the motion vector of the block currently being processed are derived, and the motion compensation prediction signal is generated. The generated motion compensation prediction signal is supplied to the prediction method determination unit 105.
　同様に、動き補償予測部４０６は、図２２の復号側におけるインター予測部２０３でも示されるように、復号の過程でスイッチ４０８がサブブロック予測動きベクトルモード導出部４０３に接続された場合には、サブブロック予測動きベクトルモード導出部４０３によるインター予測情報を取得し、現在処理対象となっているブロックのインター予測モード、参照インデックス、動きベクトルを導出し、動き補償予測信号を生成する。生成された動き補償予測信号は、復号画像信号重畳部２０７に供給される。 Similarly, the motion compensation prediction unit 406, as shown by the inter-prediction unit 203 on the decoding side of FIG. 22, when the switch 408 is connected to the subblock prediction motion vector mode derivation unit 403 in the decoding process, The sub-block prediction motion vector mode derivation unit 403 acquires the inter-prediction information, derives the inter-prediction mode, the reference index, and the motion vector of the block currently being processed, and generates a motion compensation prediction signal. The generated motion compensation prediction signal is supplied to the decoded image signal superimposing unit 207.
　＜サブブロックマージモードに基づく動き補償処理＞
　動き補償予測部３０６は、図１６の符号化側におけるインター予測部１０２でも示されるように、インター予測モード判定部３０５において、サブブロックマージモード導出部３０４によるインター予測情報が選択された場合には、このインター予測情報をインター予測モード判定部３０５から取得し、現在処理対象となっているブロックのインター予測モード、参照インデックス、動きベクトルを導出し、動き補償予測信号を生成する。生成された動き補償予測信号は、予測方法決定部１０５に供給される。 <Motion compensation processing based on subblock merge mode>
As shown in the inter-prediction unit 102 on the coding side of FIG. 16, the motion compensation prediction unit 306 is used when the inter-prediction information by the sub-block merge mode derivation unit 304 is selected in the inter-prediction mode determination unit 305. , This inter-prediction information is acquired from the inter-prediction mode determination unit 305, the inter-prediction mode, reference index, and motion vector of the block currently being processed are derived, and the motion compensation prediction signal is generated. The generated motion compensation prediction signal is supplied to the prediction method determination unit 105.
　同様に、動き補償予測部４０６は、図２２の復号側におけるインター予測部２０３でも示されるように、復号の過程でスイッチ４０８がサブブロックマージモード導出部４０４に接続された場合には、サブブロックマージモード導出部４０４によるインター予測情報を取得し、現在処理対象となっているブロックのインター予測モード、参照インデックス、動きベクトルを導出し、動き補償予測信号を生成する。生成された動き補償予測信号は、復号画像信号重畳部２０７に供給される。 Similarly, the motion compensation prediction unit 406 is a subblock when the switch 408 is connected to the subblock merge mode derivation unit 404 in the decoding process, as shown by the inter prediction unit 203 on the decoding side of FIG. The inter-prediction information by the merge mode derivation unit 404 is acquired, the inter-prediction mode, the reference index, and the motion vector of the block currently being processed are derived, and the motion compensation prediction signal is generated. The generated motion compensation prediction signal is supplied to the decoded image signal superimposing unit 207.
　＜アフィン変換予測に基づく動き補償処理＞
　通常予測動きベクトルモード、および通常マージモードでは、以下のフラグに基づいてアフィンモデルによる動き補償が利用できる。以下のフラグは、符号化処理においてインター予測モード判定部３０５により決定されるインター予測の条件に基づいて以下のフラグに反映され、ビットストリーム中に符号化される。復号処理においては、ビットストリーム中の以下のフラグに基づいてアフィンモデルによる動き補償を行うか否かを特定する。 <Motion compensation processing based on affine transformation prediction>
In the normal predicted motion vector mode and the normal merge mode, motion compensation by the affine model can be used based on the following flags. The following flags are reflected in the following flags based on the inter-prediction conditions determined by the inter-prediction mode determination unit 305 in the coding process, and are encoded in the bit stream. In the decoding process, it is specified whether or not motion compensation by the affine model is performed based on the following flags in the bit stream.
　sps_affine_enabled_flagは、インター予測において、アフィンモデルによる動き補償が利用できるか否かを表す。sps_affine_enabled_flagが０であれば、シーケンス単位でアフィンモデルによる動き補償ではないように抑制される。また、inter_affine_flag とcu_affine_type_flag は、符号化ビデオシーケンスのＣＵ（符号化ブロック）シンタックスにおいて伝送されない。sps_affine_enabled_flagが１であれば、符号化ビデオシーケンスにおいてアフィンモデルによる動き補償を利用できる。 Sps_affine_enabled_flag indicates whether or not motion compensation by the affine model can be used in inter-prediction. If sps_affine_enabled_flag is 0, it is suppressed so that it is not motion compensation by the affine model in sequence units. Also, inter_affine_flag and cu_affine_type_flag are not transmitted in the CU (encoded block) syntax of the encoded video sequence. If sps_affine_enabled_flag is 1, motion compensation by the affine model can be used in the coded video sequence.
　sps_affine_type_flagは、インター予測において、6パラメータアフィンモデルによる動き補償が利用できるか否かを表す。sps_affine_type_flagが０であれば、6パラメータアフィンモデルによる動き補償ではないように抑制される。また、cu_affine_type_flagは、符号化ビデオシーケンスのＣＵシンタックスにおいて伝送されない。sps_affine_type_flagが１であれば、符号化ビデオシーケンスにおいて6パラメータアフィンモデルによる動き補償を利用できる。sps_affine_type_flagが存在しない場合には、０であるものとする。 Sps_affine_type_flag indicates whether or not motion compensation by the 6-parameter affine model can be used in inter-prediction. If sps_affine_type_flag is 0, it is suppressed so that it is not motion compensation by the 6-parameter affine model. Also, cu_affine_type_flag is not transmitted in the CU syntax of the encoded video sequence. If sps_affine_type_flag is 1, motion compensation by the 6-parameter affine model can be used in the coded video sequence. If sps_affine_type_flag does not exist, it shall be 0.
　PまたはBスライスを復号している場合、現在処理対象となっているＣＵにおいて、inter_affine_flagが１であれば、現在処理対象となっているＣＵの動き補償予測信号を生成するために、アフィンモデルによる動き補償が用いられる。inter_affine_flagが０であれば、現在処理対象となっているＣＵにアフィンモデルは用いられない。inter_affine_flagが存在しない場合には、０であるものとする。 When decoding P or B slices, if inter_affine_flag is 1 in the CU currently being processed, an affine model is used to generate a motion compensation prediction signal for the CU currently being processed. Motion compensation is used. If inter_affine_flag is 0, the affine model is not used for the CU currently being processed. If inter_affine_flag does not exist, it shall be 0.
　PまたはBスライスを復号している場合、現在処理対象となっているＣＵにおいて、cu_affine_type_flagが１であれば、現在処理対象となっているＣＵの動き補償予測信号を生成するために、6パラメータアフィンモデルによる動き補償が用いられる。cu_affine_type_flagが０であれば、現在処理対象となっているＣＵの動き補償予測信号を生成するために、4パラメータアフィンモデルによる動き補償が用いられる。 When decoding P or B slices, if cu_affine_type_flag is 1 in the CU currently being processed, a 6-parameter affine is used to generate a motion compensation prediction signal for the CU currently being processed. Model motion compensation is used. If cu_affine_type_flag is 0, motion compensation by the 4-parameter affine model is used to generate the motion compensation prediction signal of the CU currently being processed.
　アフィンモデルによる動き補償では、サブブロック単位で参照インデックスや動きベクトルが導出されることから、サブブロック単位で処理対象となっている参照インデックスや動きベクトルを用いて動き補償予測信号を生成する。 In motion compensation by the affine model, since the reference index and motion vector are derived in subblock units, the motion compensation prediction signal is generated using the reference index and motion vector to be processed in subblock units.
　4パラメータアフィンモデルは２つの制御点のそれぞれの動きベクトルの水平成分及び垂直成分の４つのパラメータからサブブロックの動きベクトルを導出し、サブブロック単位で動き補償を行うモードである。 The 4-parameter affine model is a mode in which the motion vector of a subblock is derived from the four parameters of the horizontal component and the vertical component of the motion vector of each of the two control points, and the motion is compensated for each subblock.
　＜イントラブロックコピー（ＩＢＣ）＞
　図３２Ａ～Ｂを参照してイントラブロックコピーの有効参照領域を説明する。図３２Ａは符号化ツリーブロック単位をイントラブロックコピー基準ブロックとして、有効参照領域を決定する場合の例である。図３２Ａの５００、５０１、５０２、５０３、５０４は符号化ツリーブロックであり、５０４が処理対象の符号化ツリーブロックである。５０５は、処理対象符号化ブロックである。符号化ツリーブロックの処理順は、５００、５０１、５０２、５０３、５０４の順とする。この場合、処理対象符号化ブロック５０５を含む符号化ツリーブロック５０４の直前に処理された３つの符号化ツリーブロック５０１、５０２、５０３を処理対象符号化ブロック５０５の有効参照領域とする。符号化ツリーブロック５０１より前に処理された符号化ツリーブロック、及び処理対象符号化ブロック５０５より前に処理が完了しているか否かに関わらず、処理対象符号化ブロック５０５を含む符号化ツリーブロック５０４に含まれる領域はすべて無効参照領域とする。 <Intrablock copy (IBC)>
The effective reference area of the intra-block copy will be described with reference to FIGS. 32A to 32B. FIG. 32A is an example in which the effective reference area is determined by using the coded tree block unit as the intra-block copy reference block. Reference numerals 500, 501, 502, 503, and 504 in FIG. 32A are coded tree blocks, and 504 is a coded tree block to be processed. Reference numeral 505 is a coded block to be processed. The processing order of the coded tree blocks is 500, 501, 502, 503, 504. In this case, the three coding tree blocks 501, 502, and 503 processed immediately before the coding tree block 504 including the processing target coding block 505 are set as effective reference areas of the processing target coding block 505. A coded tree block processed before the coded tree block 501, and a coded tree block containing the process target coded block 505 regardless of whether or not the processing is completed before the process target coded block 505. All areas included in 504 are invalid reference areas.
　図３２Ｂは、符号化ツリーブロックを４分割した単位をイントラブロックコピー基準ブロックとして、有効参照領域を決定する場合の例である。図３２Ｂの５１５、５１６は符号化ツリーブロックであり、５１６が処理対象の符号化ツリーブロックである。符号化ツリーブロック５１５は５０６、５０７、５０８、５０９に４分割され、５１６は５１０、５１１、５１２、５１３に４分割される。５１４は処理対象符号化ブロックである。イントラブロックコピー基準ブロックの処理順は、５０６、５０７、５０８、５０９、５１０、５１１、５１２、５１３の順とする。この場合、処理対象符号化ブロック５１４を含むイントラブロックコピー基準ブロック５１１の直前に処理された３つのイントラブロックコピー基準ブロック５０８、５０９、５１０を処理対象符号化ブロック５１４の有効参照領域とする。イントラブロックコピー基準ブロック５０８より前に処理された符号化ツリーブロック、及び処理対象符号化ブロック５１４より前に処理が完了しているか否かに関わらず、処理対象符号化ブロック５１４を含むイントラブロックコピー基準ブロック５１１に含まれる領域はすべて無効参照領域とする。 FIG. 32B is an example in which the effective reference area is determined by using the unit obtained by dividing the coded tree block into four as the intra-block copy reference block. Reference numerals 515 and 516 in FIG. 32B are coded tree blocks, and 516 is a coded tree block to be processed. The coded tree block 515 is divided into 506, 507, 508, and 509, and 516 is divided into 510, 511, 512, and 513. Reference numeral 514 is a coded block to be processed. The processing order of the intra-block copy reference block is 506, 507, 508, 509, 510, 511, 512, 513. In this case, the three intra-block copy reference blocks 508, 509, and 510 processed immediately before the intra-block copy reference block 511 including the processing target coding block 514 are set as the effective reference area of the processing target coding block 514. Intrablock copy Intrablock copy including the coded tree block processed before the reference block 508 and the coded block 514 to be processed, regardless of whether the processing is completed before the coded block 514 to be processed. All the areas included in the reference block 511 are invalid reference areas.
　図４３は、符号化側におけるイントラブロックコピー予測部３５２の構成を説明するためのブロック図である。図４３のイントラブロックコピー予測部３５２は、少なくともＩＢＣ空間ブロックベクトル候補導出部３７１、ＩＢＣ履歴ブロックベクトル候補導出部３７２、ＩＢＣ予測ブロックベクトル補充部３７３、ＩＢＣマージ候補選択部３７４、ＩＢＣブロックベクトル検出部３７５、ＩＢＣ予測ブロックベクトル候補選択部３７６、ＩＢＣ予測モード判定部３７７、ブロックベクトル減算部３７８を含む。 FIG. 43 is a block diagram for explaining the configuration of the intra-block copy prediction unit 352 on the coding side. The intra block copy prediction unit 352 of FIG. 43 is at least an IBC space block vector candidate derivation unit 371, an IBC history block vector candidate derivation unit 372, an IBC prediction block vector replenishment unit 373, an IBC merge candidate selection unit 374, and an IBC block vector detection unit. 375, IBC prediction block vector candidate selection unit 376, IBC prediction mode determination unit 377, block vector subtraction unit 378 are included.
　また、図４３のイントラブロックコピー予測部３５２は、更に、参照位置補正部３８０、ブロックベクトル減算部３８１を含むと良い。 Further, the intra-block copy prediction unit 352 of FIG. 43 may further include a reference position correction unit 380 and a block vector subtraction unit 381.
　図４４は、復号側におけるイントラブロックコピー予測部３６２の構成を説明するためのブロック図である。図４４のイントラブロックコピー予測部３６２は、少なくともＩＢＣ空間ブロックベクトル候補導出部４７１、ＩＢＣ履歴ブロックベクトル候補導出部４７２、ＩＢＣ予測ブロックベクトル補充部４７３、ＩＢＣマージ候補選択部４７４、スイッチ４７５、ＩＢＣ予測ブロックベクトル候補選択部４７６、ブロックコピー部４７７、ブロックベクトル加算部４７８を含む。 FIG. 44 is a block diagram for explaining the configuration of the intra-block copy prediction unit 362 on the decoding side. The intra-block copy prediction unit 362 of FIG. 44 has at least an IBC space block vector candidate derivation unit 471, an IBC history block vector candidate derivation unit 472, an IBC prediction block vector replenishment unit 473, an IBC merge candidate selection unit 474, a switch 475, and an IBC prediction. It includes a block vector candidate selection unit 476, a block copy unit 477, and a block vector addition unit 478.
　また、図４４のイントラブロックコピー予測部３６２は、更に、参照位置補正部４８０を含むと良い。 Further, the intra-block copy prediction unit 362 of FIG. 44 may further include a reference position correction unit 480.
　ＩＢＣ空間ブロックベクトル候補導出部３７１および４７１は、イントラブロックコピーにおいて復号済みで参照可能な空間方向の予測ブロックベクトルの候補を導出して、予測ブロックベクトル候補リストを構築する。 The IBC spatial block vector candidate derivation units 371 and 471 derive the candidates for the predicted block vector in the spatial direction that have been decoded and can be referred to in the intra block copy, and construct the predicted block vector candidate list.
　ＩＢＣ履歴ブロックベクトル候補導出部３７２および４７２は、履歴ブロックベクトル候補リストに登録されている履歴ブロックベクトル候補から、予測ブロックベクトル候補を導出して、予測ブロックベクトル候補リストを構築する。 The IBC history block vector candidate derivation units 372 and 472 derive the prediction block vector candidates from the history block vector candidates registered in the history block vector candidate list, and construct the prediction block vector candidate list.
　ＩＢＣ予測ブロックベクトル補充部３７３および４７３は、予測ブロックベクトル候補リストを満たすまで（０，０）等、所定の値のブロックベクトルを追加して、予測ブロックベクトル候補リストを構築する。 The IBC prediction block vector replenishment units 373 and 473 build a prediction block vector candidate list by adding block vectors having predetermined values until the prediction block vector candidate list is satisfied (0,0).
　ＩＢＣマージ候補選択部３７４および４７４は、イントラブロックマージ候補リスト内に登録されているイントラブロックマージ候補から１つを選択する。 The IBC merge candidate selection units 374 and 474 select one from the intra-block merge candidates registered in the intra-block merge candidate list.
　ＩＢＣブロックベクトル検出部３７５は、イントラブロックコピーにおいて復号済みで参照可能な領域からブロックベクトルを検出する。 The IBC block vector detection unit 375 detects the block vector from the decoded and referenceable area in the intra block copy.
　ＩＢＣ予測ブロックベクトル候補選択部３７６および４７６は、予測ブロックベクトル候補リストから予測ブロックベクトルを選択する。 The IBC prediction block vector candidate selection units 376 and 476 select the prediction block vector from the prediction block vector candidate list.
　ＩＢＣ予測モード判定部３７７は、符号量とひずみ量を算出することにより、予測モードを選択する。ここで、予測モードは予測イントラブロックコピーモードと、マージイントラブロックコピーモードが選択可能である。更に、予測マージイントラブロックコピーモードを選択できるようにしても良い。 The IBC prediction mode determination unit 377 selects the prediction mode by calculating the code amount and the strain amount. Here, the prediction mode can be selected from the prediction intra-block copy mode and the merge intra-block copy mode. In addition, the predictive merge intra-block copy mode may be selectable.
　ブロックベクトル減算部３７８および３８１は、ブロックベクトルと予測ブロックベクトルを取得し、差分ブロックベクトルを算出する。 The block vector subtraction units 378 and 381 acquire the block vector and the predicted block vector, and calculate the difference block vector.
　参照位置補正部３８０および４８０は、処理対象となる予測ブロックベクトルが、参照可能な領域の外側を参照しようとしている場合に、参照位置を補正する処理を行う。 The reference position correction units 380 and 480 perform processing for correcting the reference position when the prediction block vector to be processed is trying to refer to the outside of the referenceable area.
　スイッチ４７５は、イントラブロックコピー処理における予測モードに応じて、供給される各種情報の供給先を選択する。 Switch 475 selects the supply destination of various information to be supplied according to the prediction mode in the intra-block copy processing.
　ブロックベクトル加算部４７８は、予測ブロックベクトルと差分ブロックベクトルを取得し、ブロックベクトルを算出する。 The block vector addition unit 478 acquires the predicted block vector and the difference block vector, and calculates the block vector.
　ブロックコピー部４７７は、ブロックベクトルに基づいて、参照位置の復号画像を復号画像メモリから取得し、供給する。 The block copy unit 477 acquires the decoded image at the reference position from the decoded image memory based on the block vector and supplies it.
　以上の各部により構成することで、予測イントラブロックコピー処理を実現する。イントラブロックコピー予測部３５２および３６２の、より詳細な説明は、後述する。 Predictive intra-block copy processing is realized by configuring with each of the above parts. A more detailed description of the intra-block copy prediction units 352 and 362 will be described later.
　＜予測イントラブロックコピー：符号化側の説明＞
　図４３、及び図４５を参照して符号化側の予測イントラブロックコピー処理手順を説明する。 <Predictive intra-block copy: Explanation on the coding side>
The prediction intra-block copy processing procedure on the coding side will be described with reference to FIGS. 43 and 45.
　まず、ブロックベクトル検出部３７５で輝度ブロックの動きベクトルであるブロックベクトルmvLを検出する（図４５のステップＳ４５００）。 First, the block vector detection unit 375 detects the block vector mvL, which is the motion vector of the luminance block (step S4500 in FIG. 45).
　続いて、図４３のＩＢＣ空間ブロックベクトル候補導出部３７１、ＩＢＣ履歴予測ブロックベクトル候補導出部３７２、ＩＢＣ予測ブロックベクトル候補補充部３７３、ＩＢＣ予測ブロックベクトル候補選択部３７６、ブロックベクトル減算部３７８で、予測ブロックベクトルモードで用いるブロックベクトルの差分ブロックベクトルを算出する（図４５のステップＳ４５０１～Ｓ４５０３）。 Subsequently, the IBC space block vector candidate derivation unit 371, the IBC history prediction block vector candidate derivation unit 372, the IBC prediction block vector candidate supplementation unit 373, the IBC prediction block vector candidate selection unit 376, and the block vector subtraction unit 378 in FIG. 43. The difference block vector of the block vector used in the predicted block vector mode is calculated (steps S4501 to S4503 in FIG. 45).
　予測ブロックベクトルの候補を算出してブロックベクトル候補リストmvpListを構築する（図４５のステップＳ４５０１）。図４３のＩＢＣ空間ブロックベクトル候補導出部３７１、ＩＢＣ履歴ブロックベクトル候補導出部３７２、ＩＢＣ予測ブロックベクトル候補補充部３７３で複数の予測ブロックベクトルの候補を導出して予測ブロックベクトル候補リストmvpListを構築する。図４５のステップＳ４５０１の詳細な処理手順については図４８のフローチャートを用いて後述する。 Calculate the candidates for the predicted block vector and construct the block vector candidate list mvpList (step S4501 in FIG. 45). A plurality of prediction block vector candidates are derived by the IBC space block vector candidate derivation unit 371, the IBC history block vector candidate derivation unit 372, and the IBC prediction block vector candidate supplementation unit 373 in FIG. 43 to construct a prediction block vector candidate list mvpList. .. The detailed processing procedure of step S4501 of FIG. 45 will be described later using the flowchart of FIG. 48.
　続いて、図４３のＩＢＣ予測ブロックベクトル候補選択部３７６により、予測ブロックベクトル候補リストmvpListLから予測ブロックベクトルmvpLを選択する（図４５のステップＳ４５０２）。ブロックベクトルmvLと予測ブロックベクトル候補リストmvpListLの中に格納された各予測ブロックベクトルの候補mvpListL[i]との差分であるそれぞれの差分ブロックベクトルを算出する。それら差分ブロックベクトルを符号化したときの符号量を予測ブロックベクトル候補リストmvpListLの要素ごとに算出する。そして、予測ブロックベクトル候補リストmvpListLに登録された各要素の中で、予測ブロックベクトルの候補毎の符号量が最小となる予測ブロックベクトルの候補mvpListL[i]を予測ブロックベクトルmvpLとして選択し、そのインデックスiを取得する。予測ブロックベクトル候補リストmvpListLの中で最小の発生符号量となる予測ブロックベクトルの候補が複数存在する場合には、予測ブロックベクトル候補リストmvpListLの中のインデックスiが小さい番号で表される予測ブロックベクトルの候補mvpListL[i]を最適予測ブロックベクトルmvpLとして選択し、そのインデックスiを取得する。 Subsequently, the IBC prediction block vector candidate selection unit 376 of FIG. 43 selects the prediction block vector mvpL from the prediction block vector candidate list mvpListL (step S4502 of FIG. 45). Calculate each difference block vector which is the difference between the block vector mvL and the candidate mvpListL [i] of each prediction block vector stored in the prediction block vector candidate list mvpListL. The amount of code when these difference block vectors are encoded is calculated for each element of the predicted block vector candidate list mvpListL. Then, among the elements registered in the prediction block vector candidate list mvpListL, the prediction block vector candidate mvpListL [i] having the minimum sign amount for each candidate of the prediction block vector is selected as the prediction block vector mvpL, and the candidate mvpListL [i] is selected. Get index i. When there are multiple candidates for the predicted block vector that is the smallest generated code amount in the predicted block vector candidate list mvpListL, the predicted block vector whose index i in the predicted block vector candidate list mvpListL is represented by a small number. The candidate mvpListL [i] of is selected as the optimal prediction block vector mvpL, and its index i is acquired.
　続いて、図４３のブロックベクトル減算部３７８で、ブロックベクトルmvLから選択された予測ブロックベクトルmvpLを減算し、
　　mvdL = mvL - mvpL
として差分ブロックベクトルmvdLを算出する（図４５のステップＳ４５０３）。 Subsequently, the block vector subtraction unit 378 of FIG. 43 subtracts the predicted block vector mvpL selected from the block vector mvL.
mvdL = mvL --mvpL
The difference block vector mvdL is calculated as (step S4503 in FIG. 45).
　＜イントラブロックコピー(予測)：復号側の説明＞
　次に、図４４、及び図４６を参照して復号側の予測ブロックベクトルモード処理手順を説明する。復号側では、図４４のＩＢＣ空間予測ブロックベクトル候補導出部４７１、ＩＢＣ履歴ブロックベクトル候補導出部４７２、ＩＢＣ予測ブロックベクトル補充部４７３で、予測ブロックベクトルモードで用いるブロックベクトルを算出する（図４６のステップＳ４６００～Ｓ４６０２）。具体的には予測ブロックベクトル候補リストmvpListLを算出して、予測ブロックベクトルmvpLを選択し、ブロックベクトルmvLを算出する。 <Intrablock copy (prediction): Explanation on the decoding side>
Next, the prediction block vector mode processing procedure on the decoding side will be described with reference to FIGS. 44 and 46. On the decoding side, the IBC space prediction block vector candidate derivation unit 471, the IBC history block vector candidate derivation unit 472, and the IBC prediction block vector replenishment unit 473 of FIG. 44 calculate the block vector used in the prediction block vector mode (FIG. 46). Steps S4600 to S4602). Specifically, the prediction block vector candidate list mvpListL is calculated, the prediction block vector mvpL is selected, and the block vector mvL is calculated.
　予測ブロックベクトルの候補を算出して予測ブロックベクトル候補リストmvpListLを構築する（図４６のステップＳ４６０１）。イントラブロックコピー予測部３６２の中のＩＢＣ空間ブロックベクトル候補導出部４７１、ＩＢＣ履歴ブロックベクトル候補導出部４７２、ＩＢＣブロックベクトル補充部４７３で複数の予測ブロックベクトルの候補を算出し、予測ブロックベクトル候補リストmvpListLを構築する。 Prediction block vector candidates are calculated and a prediction block vector candidate list mvpListL is constructed (step S4601 in FIG. 46). IBC space block vector candidate derivation unit 471, IBC history block vector candidate derivation unit 472, and IBC block vector replenishment unit 473 in the intra block copy prediction unit 362 calculate multiple prediction block vector candidates, and the prediction block vector candidate list. Build mvpListL.
　続いて、ＩＢＣ予測ブロックベクトル候補選択部４７６で予測ブロックベクトル候補リストmvpListLからビット列復号部２０１にて復号されて供給される予測ブロックベクトルのインデックスmvpIdxLに対応する予測ブロックベクトルの候補mvpListL[mvpIdxL]を選択された予測ブロックベクトルmvpLとして取り出す（図４６のステップＳ４６０１）。 Subsequently, the IBC prediction block vector candidate selection unit 476 obtains the prediction block vector candidate mvpListL [mvpIdxL] corresponding to the prediction block vector index mvpIdxL decoded and supplied by the bit string decoding unit 201 from the prediction block vector candidate list mvpListL. Extracted as the selected predicted block vector mvpL (step S4601 in FIG. 46).
　続いて、ブロックベクトル加算部４７８でビット列復号部２０１にて復号されて供給される差分ブロックベクトルmvdLと予測ブロックベクトルmvpLを加算し、
　　mvL = mvpL + mvdL
としてブロックベクトルmvLを算出する（図４６のステップＳ４６０２）。 Subsequently, the difference block vector mvdL decoded and supplied by the bit string decoding unit 201 by the block vector addition unit 478 and the prediction block vector mvpL are added.
mvL = mvpL + mvdL
The block vector mvL is calculated as (step S4602 in FIG. 46).
　＜予測ブロックベクトルモード：ブロックベクトルの予測方法＞
　図４８は本発明の実施の形態に係る画像符号化装置のイントラブロックコピー予測部３５２及び画像復号装置のイントラブロックコピー予測部３６２とで共通する機能を有する予測イントラブロックコピーモード導出処理の処理手順を表すフローチャートである。 <Prediction block vector mode: Block vector prediction method>
FIG. 48 shows a processing procedure of the prediction intra-block copy mode derivation process having a function common to the intra-block copy prediction unit 352 of the image coding device and the intra-block copy prediction unit 362 of the image decoding device according to the embodiment of the present invention. It is a flowchart showing.
　イントラブロックコピー予測部３５２及びイントラブロックコピー予測部３６２では、予測ブロックベクトル候補リストmvpListLを備えている。予測ブロックベクトル候補リストmvpListLはリスト構造を成し、予測ブロックベクトル候補リスト内部の所在を示す予測ブロックベクトルインデックスと、インデックスに対応する予測ブロックベクトル候補を要素として格納する記憶領域が設けられている。予測ブロックベクトルインデックスの数字は０から開始され、予測ブロックベクトル候補リストmvpListLの記憶領域に、予測ブロックベクトル候補が格納される。本実施の形態においては、予測ブロックベクトル候補リストmvpListLは３個の予測ブロックベクトル候補を登録することができるものとする。さらに、予測ブロックベクトル候補リストmvpListLに登録されている予測ブロックベクトル候補数を示す変数numCurrMvpIbcCandに０を設定する。 The intra-block copy prediction unit 352 and the intra-block copy prediction unit 362 include a prediction block vector candidate list mvpListL. The predicted block vector candidate list mvpListL has a list structure, and is provided with a predicted block vector index indicating the location inside the predicted block vector candidate list and a storage area for storing the predicted block vector candidates corresponding to the index as elements. The number of the prediction block vector index starts from 0, and the prediction block vector candidate is stored in the storage area of the prediction block vector candidate list mvpListL. In the present embodiment, the prediction block vector candidate list mvpListL can register three prediction block vector candidates. Further, 0 is set in the variable numCurrMvpIbcCand indicating the number of predicted block vector candidates registered in the predicted block vector candidate list mvpListL.
　ＩＢＣ空間ブロックベクトル候補導出部３７１及び４７１は、左側に隣接するブロックからの予測ブロックベクトルの候補を導出する（図４８のステップＳ４８０１）。この処理では、左側に隣接するブロック（Ａ０またはＡ１）の予測ブロックベクトル候補が利用できるか否かを示すフラグavailableFlagLA、及びブロックベクトルmvLAを導出し、mvLAを予測ブロックベクトル候補リストmvpListLに追加する。続いて、ＩＢＣ空間ブロックベクトル候補導出部３７１及び４７１は、上側に隣接するブロック（Ｂ０，Ｂ１またはＢ２）からの予測ブロックベクトルの候補を導出する（図４８のステップＳ４８０２）。この処理では、上側に隣接するブロックの予測動きベクトル候補が利用できるか否かを示すフラグavailableFlagLB、及びブロックベクトルmvLBを導出し、mvLAとmvLBが等しくなければ、mvLBを予測ブロックベクトル候補リストmvpListLに追加する。図４８のステップＳ４８０１とＳ４８０２の処理は参照する隣接ブロックの位置と数が異なる点以外は共通であり、符号化ブロックの予測ブロックベクトル候補が利用できるか否かを示すフラグavailableFlagLN、及び動きベクトルmvLN（ＮはＡまたはＢ、以下同様）を導出する。 The IBC spatial block vector candidate derivation units 371 and 471 derive candidates for the predicted block vector from the blocks adjacent to the left side (step S4801 in FIG. 48). In this process, the flag availableFlagLA indicating whether or not the predicted block vector candidate of the block (A0 or A1) adjacent to the left side is available and the block vector mvLA are derived, and mvLA is added to the predicted block vector candidate list mvpListL. Subsequently, the IBC spatial block vector candidate derivation units 371 and 471 derive candidates for the predicted block vector from the blocks (B0, B1 or B2) adjacent to the upper side (step S4802 in FIG. 48). In this process, the flag availableFlagLB indicating whether the predicted motion vector candidates of the adjacent blocks on the upper side are available and the block vector mvLB are derived, and if mvLA and mvLB are not equal, mvLB is added to the predicted block vector candidate list mvpListL. to add. The processing of steps S4801 and S4802 of FIG. 48 is common except that the position and number of adjacent blocks to be referred to are different, and the flag availableFlagLN indicating whether or not the predicted block vector candidate of the coded block can be used, and the motion vector mvLN (N is A or B, and so on) is derived.
　続いて、ＩＢＣ履歴ブロックベクトル候補導出部３７２及び４７２は履歴ブロックベクトル候補リストHmvpIbcCandListに登録されている履歴ブロックベクトル候補を予測ブロックベクトル候補リストmvpListLに追加する。（図４８のステップＳ４８０３）。このステップＳ４８０３の登録処理手順の詳細については図２９のフローチャートで示された動作の説明において、動きベクトルをブロックベクトル、参照インデックスのリストをＬ０、履歴予測動きベクトル候補リストHmvpCandListを履歴ブロックベクトル候補リストHmvpIbcCandListとした場合の動作と同様であれば良いため、説明を省略する。 Subsequently, the IBC history block vector candidate derivation units 372 and 472 add the history block vector candidates registered in the history block vector candidate list HmvpIbcCandList to the prediction block vector candidate list mvpListL. (Step S4803 in FIG. 48). For details of the registration processing procedure in step S4803, in the description of the operation shown in the flowchart of FIG. 29, the motion vector is the block vector, the reference index list is L0, and the history prediction motion vector candidate list HmvpCandList is the history block vector candidate list. Since it is sufficient if the operation is the same as that of HmvpIbcCandList, the description is omitted.
　続いてＩＢＣ予測ブロックベクトル補充部３７３及び４７３は予測ブロックベクトル候補リストmvpListLを満たすまで（０，０）等、所定の値のブロックベクトルを追加する（図４８のステップＳ４８０４）。 Subsequently, the IBC prediction block vector replenishment units 373 and 473 add block vectors having predetermined values, such as until the prediction block vector candidate list mvpListL is satisfied (0,0) (step S4804 in FIG. 48).
　＜マージイントラブロックコピーモード導出部＞
　図４３のイントラブロックコピー予測部３５２は、ＩＢＣ空間ブロックベクトル候補導出部３７１、ＩＢＣ履歴ブロックベクトル候補導出部３７２、ＩＢＣブロックベクトル補充部３７３、参照位置補正部３８０、ＩＢＣマージ候補選択部３７４、ＩＢＣ予測モード判定部３７７を含む。 <Merge Intrablock Copy Mode Derivation Unit>
The intra-block copy prediction unit 352 of FIG. 43 includes an IBC space block vector candidate derivation unit 371, an IBC history block vector candidate derivation unit 372, an IBC block vector replenishment unit 373, a reference position correction unit 380, an IBC merge candidate selection unit 374, and an IBC. Prediction mode determination unit 377 is included.
　図４４のイントラブロックコピー予測部３６２は、ＩＢＣ空間ブロックベクトル候補導出部４７１、ＩＢＣ履歴ブロックベクトル候補導出部４７２、ＩＢＣブロックベクトル補充部４７３、ＩＢＣマージ候補選択部４７４、参照位置補正部４８０、ブロックコピー部４７７を含む。 The intra-block copy prediction unit 362 of FIG. 44 includes an IBC space block vector candidate derivation unit 471, an IBC history block vector candidate derivation unit 472, an IBC block vector replenishment unit 473, an IBC merge candidate selection unit 474, a reference position correction unit 480, and a block. Includes copy section 477.
　図４７は本発明の実施の形態に係る画像符号化装置のイントラブロックコピー予測部３５２及び画像復号装置のイントラブロックコピー予測部３６２とで共通する機能を有するマージイントラブロックコピーモード導出処理の手順を説明するフローチャートである。 FIG. 47 shows a procedure for merging intra-block copy mode derivation processing having a function common to the intra-block copy prediction unit 352 of the image coding device and the intra-block copy prediction unit 362 of the image decoding device according to the embodiment of the present invention. It is a flowchart to explain.
　イントラブロックコピー予測部３５２及びイントラブロックコピー予測部３６２では、マージイントラブロックコピー候補リストmergeIbcCandListを備えている。マージイントラブロックコピー候補リストmergeIbcCandListはリスト構造を成し、マージイントラブロックコピー候補内部の所在を示すマージインデックスと、インデックスに対応するマージイントラブロックコピー候補を要素として格納する記憶領域が設けられている。マージインデックスの数字は０から開始され、マージイントラブロックコピー候補リストmergeIbcCandListの記憶領域に、マージイントラブロックコピー候補が格納される。以降の処理では、マージイントラブロックコピー候補リストmergeIbcCandListに登録されたマージインデックスｉのマージ候補は、mergeIbcCandList[i]で表すこととする。本実施の形態においては、マージ候補リストmergeCandListは少なくとも３個のマージイントラブロックコピー候補を登録することができるものとする。さらに、マージイントラブロックコピー候補リストmergeIbcCandListに登録されているマージイントラブロックコピー候補数を示す変数numCurrMergeIbcCandに０を設定する。 The intra-block copy prediction unit 352 and the intra-block copy prediction unit 362 include a merge intra-block copy candidate list mergeIbcCandList. Merge intra-block copy candidate list mergeIbcCandList has a list structure, and has a merge index indicating the location inside the merge intra-block copy candidate and a storage area for storing the merge intra-block copy candidate corresponding to the index as an element. The numbers in the merge index start from 0, and the merge intrablock copy candidates are stored in the storage area of the mergeIbcCandList merge intrablock copy candidate list. In the subsequent processing, the merge candidate of the merge index i registered in the merge intra-block copy candidate list mergeIbcCandList is represented by mergeIbcCandList [i]. In the present embodiment, the merge candidate list mergeCandList can register at least three merge intra-block copy candidates. Further, 0 is set in the variable numCurrMergeIbcCand indicating the number of merge intrablock copy candidates registered in the mergeIbcCandList merge intrablock copy candidate list.
　ＩＢＣ空間ブロックベクトル候補導出部３７１及びＩＢＣ空間ブロックベクトル候補導出部４７１では、画像符号化装置の符号化情報格納メモリ１１１または画像復号装置の符号化情報格納メモリ２０５に格納されている符号化情報から、処理対象ブロックの左側と上側に隣接するブロックからの空間マージ候補Ａ，Ｂを導出して、導出された空間マージ候補をマージイントラブロックコピー候補リストmergeIbcCandListに登録する（図４７のステップＳ４７０１）。ここで、空間マージ候補Ａ，Ｂのいずれかを示すＮを定義する。ブロックＮのイントラブロックコピー予測情報が空間ブロックベクトルマージ候補Ｎとして利用できるか否かを示すフラグavailableFlagN、ブロックベクトルmvLを導出する。ただし、本実施の形態においては処理対象となる符号化ブロックを含むブロックに含まれる他の符号化ブロックを参照せずに、ブロックベクトルマージ候補を導出するので、処理対象の符号化ブロックを含むブロックに含まれる空間ブロックベクトルマージ候補は導出しない。 In the IBC space block vector candidate derivation unit 371 and the IBC space block vector candidate derivation unit 471, from the coding information stored in the coding information storage memory 111 of the image coding device or the coding information storage memory 205 of the image decoding device, , Spatial merge candidates A and B from blocks adjacent to the left and upper sides of the block to be processed are derived, and the derived spatial merge candidates are registered in the merge intra-block copy candidate list mergeIbcCandList (step S4701 in FIG. 47). Here, N indicating either one of the spatial merge candidates A and B is defined. The flag availableFlagN and the block vector mvL indicating whether or not the intra-block copy prediction information of the block N can be used as the spatial block vector merge candidate N are derived. However, in the present embodiment, since the block vector merge candidate is derived without referring to other coded blocks included in the block including the coded block to be processed, the block including the coded block to be processed is derived. Spatial block vector merge candidates included in are not derived.
　続いて、ＩＢＣ履歴ブロックベクトル候補導出部３７２及びＩＢＣ履歴ブロックベクトル候補導出部４７２では、履歴予測ブロックベクトル候補リストHmvpIbcCandListに登録されている履歴予測ブロックベクトル候補をマージイントラブロックコピー候補リストmergeIbcCandListに追加する（図４７のステップＳ４７０２）。本実施例においては、mergeIbcCandListに追加済みのブロックベクトルと履歴予測ブロックベクトル候補のブロックベクトルが同一の値を持つ場合には、mergeIbcCandListへの追加を行わないものとする。 Subsequently, the IBC history block vector candidate derivation unit 372 and the IBC history block vector candidate derivation unit 472 add the history prediction block vector candidates registered in the history prediction block vector candidate list HmvpIbcCandList to the merge intrablock copy candidate list mergeIbcCandList. (Step S4702 in FIG. 47). In this embodiment, if the block vector already added to the mergeIbcCandList and the block vector of the history prediction block vector candidate have the same value, the block vector is not added to the mergeIbcCandList.
　続いて、ＩＢＣ予測ブロックベクトル補充部３７３及びＩＢＣ予測ブロックベクトル補充部４７３は、マージイントラブロックコピー候補リストmergeIbcCandList内に登録されているマージ候補数numCurrMergeIbcCandが、最大イントラブロックマージ候補数MaxNumMergeIbcCandより小さい場合、マージイントラブロックコピー候補リストmergeIbcCandList内に登録されているマージ候補数numCurrMergeIbcCandが最大マージ候補数MaxNumMergeIbcCandを上限として追加イントラブロックマージ候補を導出して、マージイントラブロックコピー候補リストmergeIbcCandListに登録する（図４７のステップＳ４７０３）。最大マージ候補数MaxNumMergeIbcCandを上限として、（０，０）の値を持つブロックベクトルをマージイントラブロックコピー候補リストmergeIbcCandListに追加する。 Next, when the number of merge candidates numCurrMergeIbcCand registered in the merge intrablock copy candidate list mergeIbcCandList is smaller than the maximum number of intrablock merge candidates MaxNumMergeIbcCand, the IBC prediction block vector replenishment unit 373 and the IBC prediction block vector replenishment unit 473 The number of merge candidates registered in the mergeIbcCandList merge intra-block copy candidate list numCurrMergeIbcCand adds up to the maximum number of merge candidates MaxNumMergeIbcCand Derives the intra-block merge candidates and registers them in the merge-intra-block copy candidate list mergeIbcCandList (Fig. 47). Step S4703). Up to the maximum number of merge candidates MaxNumMergeIbcCand, a block vector with a value of (0,0) is added to the mergeintra block copy candidate list mergeIbcCandList.
　続いて、ＩＢＣマージ候補選択部３７４及びＩＢＣマージ候補選択部４７４では、イントラブロックマージ候補リストmergeIbcCandList内に登録されているマージイントラブロックコピー候補から１つを選択する（図４７のステップＳ４７０４）。ＩＢＣマージ候補選択部３７４では、参照位置の復号画像を復号画像メモリ１０４から取得して符号量とひずみ量を算出することによりマージ候補を選択し、選択されたイントラブロックマージ候補を示すマージインデックスをＩＢＣ予測モード判定部３７７に供給する。ＩＢＣ予測モード判定部３７７は、符号量とひずみ量を算出することによりマージモードか否かを選択し、その結果を予測方法決定部１０５に供給する。一方、復号側のＩＢＣマージ候補選択部４７４では、復号されたマージインデックスに基づいて、イントラブロックマージ候補を選択し、選択したイントラブロックマージ候補を参照位置補正部４８０に供給する。ここで、ブロックコピー部４７７では、輝度成分と色差成分がコピーされる。 Subsequently, the IBC merge candidate selection unit 374 and the IBC merge candidate selection unit 474 select one from the merge intrablock copy candidates registered in the intrablock merge candidate list mergeIbcCandList (step S4704 in FIG. 47). The IBC merge candidate selection unit 374 selects a merge candidate by acquiring the decoded image at the reference position from the decoded image memory 104 and calculating the code amount and the strain amount, and sets a merge index indicating the selected intra-block merge candidate. It is supplied to the IBC prediction mode determination unit 377. The IBC prediction mode determination unit 377 selects whether or not it is in the merge mode by calculating the code amount and the strain amount, and supplies the result to the prediction method determination unit 105. On the other hand, the IBC merge candidate selection unit 474 on the decoding side selects an intra-block merge candidate based on the decoded merge index, and supplies the selected intra-block merge candidate to the reference position correction unit 480. Here, the block copy unit 477 copies the luminance component and the color difference component.
　続いて、参照位置補正部３８０及び参照位置補正部４８０では、イントラブロックマージ候補に対し参照位置を補正する処理を行う（図４７のステップＳ４７０５）。参照位置補正部３８０及び参照位置補正部４８０の処理の詳細は後述する。 Subsequently, the reference position correction unit 380 and the reference position correction unit 480 perform a process of correcting the reference position for the intra-block merge candidate (step S4705 in FIG. 47). Details of the processing of the reference position correction unit 380 and the reference position correction unit 480 will be described later.
　ブロックコピー部４７７は、参照位置の復号画像を復号画像メモリ２０８から取得し、復号画像信号重畳部２０７に供給する。 The block copy unit 477 acquires the decoded image at the reference position from the decoded image memory 208 and supplies it to the decoded image signal superimposing unit 207.
　＜色差ブロックベクトル＞
　ブロックベクトルmvLは輝度のブロックベクトルを示す。色差のブロックベクトルmvCは、色差フォーマットが４：２：０の場合、
　　mvC = ( ( mvL >> ( 3 + 2 ) ) * 32
となる。上式により、mvCのx,y成分それぞれが処理される。 <Color difference block vector>
The block vector mvL indicates the brightness block vector. The color difference block vector mvC is when the color difference format is 4: 2: 0.
mvC = ((mvL >> (3 + 2))) * 32
Will be. According to the above equation, each of the x and y components of mvC is processed.
　ここで、本実施の形態においては、処理対象の符号化ブロックの親ブロックにおいて、イントラ予測、またはIBC予測において、分割モードに基づいて分割対象の色差ブロックを分割せずに、色差符号化ブロックとすると判断した場合、すなわち色差ブロック非分割フラグchroma_non_split_flagが１（真）に設定された場合は、色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックのブロックベクトルmvLに基づいて、前述の式により輝度信号の符号化ブロックのブロックベクトルmvCを算出する。 Here, in the present embodiment, in the parent block of the coded block to be processed, in the intra prediction or the IBC prediction, the color difference block to be divided is not divided based on the division mode, and the color difference coded block is used. When it is determined that, that is, when the color difference block undivided flag chroma_non_split_flag is set to 1 (true), it is described above based on the block vector mvL of the luminance signal coding block at the same position as the luminance signal coding block. The block vector mvC of the coded block of the luminance signal is calculated by the formula.
　なお、本実施の形態においては、色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックを特定する際に、色差信号の画像空間における色差信号の符号化ブロックの中央の右下の画素に対応する輝度信号の画像空間で同じ位置の画素を含む輝度信号の符号化ブロックを色差信号の符号化ブロックと同じ位置の輝度信号の符号化ブロックとする。 In the present embodiment, when specifying the luminance signal coding block at the same position as the color difference signal coding block, the lower right pixel in the center of the color difference signal coding block in the image space of the color difference signal. A luminance signal coding block containing pixels at the same position in the image space of the luminance signal corresponding to is defined as a luminance signal coding block at the same position as the color difference signal coding block.
　＜参照位置補正部＞
　図４９は、参照位置補正部３８０及び参照位置補正部４８０の処理を説明するフローチャートである。いま、イントラブロックコピー基準ブロックの単位は符号化ツリーブロック（CTU）であり、その大きさは128x128画素でないものとする。 <Reference position correction unit>
FIG. 49 is a flowchart illustrating the processing of the reference position correction unit 380 and the reference position correction unit 480. Now, it is assumed that the unit of the intra-block copy reference block is the coded tree block (CTU), and its size is not 128x128 pixels.
　まず、参照ブロックの左上および右下の位置を算出する（ステップＳ６００１）。参照ブロックとは、処理対象符号化ブロックがブロックベクトルを用いて参照するブロックを示す。参照ブロックの左上を( xRefTL, yRefTL )、右下を( xRefBR, yRefBR )とすると、
　　( xRefTL, yRefTL ) = ( xCb + ( mvL[ 0 ] >> 4 ), yCb + ( mvL[ 1 ] >> 4 ) )
　　( xRefBR, yRefBR ) = ( xRefTL + cbWidth - 1, yRefTL + cbHeight - 1 ) 
となる。ここで、処理対象符号化ブロックの位置を(xCb,yCb)、ブロックベクトルを(mvL[0],mvL[1])とし、処理対象符号化ブロックの幅はcbWidth、高さはcbHeightとする。 First, the upper left and lower right positions of the reference block are calculated (step S6001). The reference block refers to a block that the coded block to be processed refers to using a block vector. If the upper left of the reference block is (xRefTL, yRefTL) and the lower right is (xRefBR, yRefBR),
(xRefTL, yRefTL) = (xCb + (mvL [0] >> 4), yCb + (mvL [1] >> 4))
(xRefBR, yRefBR) = (xRefTL + cbWidth --1, yRefTL + cbHeight --1)
Will be. Here, the position of the coded block to be processed is (xCb, yCb), the block vector is (mvL [0], mvL [1]), the width of the coded block to be processed is cbWidth, and the height is cbHeight.
　次に、CTUの大きさが128x128画素か否かを判定する（ステップＳ６００２）。いま、その大きさは128x128画素でないので（ステップＳ６００２：ＮＯ）、参照可能領域の左上および右下の位置を算出する（ステップＳ６００３）。参照可能領域の左上を( xAvlTL, yAvlTL )、右下を( xAvlBR, yAvlBR )とすると、
　　NL = Min( 1, 7 - CtbLog2SizeY ) - ( 1 << ((7 - CtbLog2SizeY) << 1) )
　　( xAvlTL, yAvlTL ) = ( ((xCb >> CtbLog2SizeY) + NL) << CtbLog2SizeY,
　　　　 (yCb >> CtbLog2SizeY) << CtbLog2SizeY )
　　( xAvlBR, yAvlBR ) = ( ((xCb >> CtbLog2SizeY) << CtbLog2SizeY) - 1,
　　　　 (((yCb >> CtbLog2SizeY) + 1) << CtbLog2SizeY) - 1 )
となる。ここで、CTUのサイズはCtbLog2SizeYとする。 Next, it is determined whether or not the size of the CTU is 128x128 pixels (step S6002). Since the size is not 128x128 pixels (step S6002: NO), the upper left and lower right positions of the referenceable area are calculated (step S6003). If the upper left of the referenceable area is (xAvlTL, yAvlTL) and the lower right is (xAvlBR, yAvlBR),
NL = Min (1, 7 --CtbLog2SizeY)-(1 << ((7 --CtbLog2SizeY) << 1))
(xAvlTL, yAvlTL) = (((xCb >> CtbLog2SizeY) + NL) << CtbLog2SizeY,
(yCb >> CtbLog2SizeY) << CtbLog2SizeY)
(xAvlBR, yAvlBR) = (((xCb >> CtbLog2SizeY) << CtbLog2SizeY)-1,
(((yCb >> CtbLog2SizeY) + 1) << CtbLog2SizeY) ―― 1)
Will be. Here, the size of CTU is CtbLog2SizeY.
　次に、参照ブロックのx方向の参照位置が、参照可能領域の左上より小さいか否かを判定する（ステップＳ６００４）。判定が偽ならば（ステップＳ６００４：ＮＯ）、次の処理（ステップＳ６００６）に進む。一方、判定が真ならば（ステップＳ６００４：ＹＥＳ）、参照可能領域の左上に合わせてx方向の参照位置を補正する（ステップＳ６００５）。 Next, it is determined whether or not the reference position of the reference block in the x direction is smaller than the upper left of the referenceable area (step S6004). If the determination is false (step S6004: NO), the process proceeds to the next process (step S6006). On the other hand, if the determination is true (step S6004: YES), the reference position in the x direction is corrected according to the upper left of the referenceable area (step S6005).
　図５０は、参照位置を補正する様子を示す図である。６００１は処理対象符号化ツリーブロックを、６００２は処理対象符号化ブロックを、６００３は参照可能領域を示す。いま、参照ブロックr2が６０１１に位置していたとすると、x方向の参照位置が、参照可能領域の左上より小さい（ステップＳ６００４：ＹＥＳ）。よって、xRefTL=xAvlTLとして６０１２の位置に参照位置を補正する（ステップＳ６００５）。ここで、Ｓ６００１にあるようにxRefBR=xRefTL+cbWidth-1であるから、xRefTLを補正したことに伴ってxRefBRも補正されることになる。この参照位置の補正において、ブロックベクトルmvL[0]を補正しても良い。つまり、
　　mvL[0] = (xAvlTL - xCb) << 4
と補正する。これにより、xRefTL=xAvlTLとなるので、参照位置を補正できる。 FIG. 50 is a diagram showing how the reference position is corrected. 6001 indicates a processing target coding tree block, 6002 indicates a processing target coding block, and 6003 indicates a referenceable area. Assuming that the reference block r2 is located at 6011, the reference position in the x direction is smaller than the upper left of the referenceable area (step S6004: YES). Therefore, the reference position is corrected to the position of 6012 with xRefTL = xAvlTL (step S6005). Here, since xRefBR = xRefTL + cbWidth-1 as in S6001, xRefBR is also corrected as xRefTL is corrected. In the correction of this reference position, the block vector mvL [0] may be corrected. In other words
mvL [0] = (xAvlTL-xCb) << 4
To correct. As a result, xRefTL = xAvlTL, so the reference position can be corrected.
　このように、参照ブロックが参照可能領域の外部に位置していた場合に、その参照位置を補正することによって、参照可能となる。 In this way, when the reference block is located outside the referenceable area, it can be referenced by correcting the reference position.
　いま、イントラブロックコピー予測部３５２において構築したブロックベクトル候補リストのうち、いくつかのブロックベクトルが参照可能領域の外側であったとする。参照位置を補正しない場合には、それらのブロックベクトルによる参照が不可能なので、それらのブロックベクトルをＩＢＣマージモードの候補とすることが出来ない。一方、本発明において参照位置を補正する場合には、構築したブロックベクトル候補リストの全てのブロックベクトルは、参照可能領域の内側となる。よって、全てのブロックベクトルによる参照が可能であり、全てのブロックベクトルをＩＢＣマージモードの候補とすることが出来る。従って、ＩＢＣマージモード選択部３７４において、全てのブロックベクトルに対応するそれぞれのＩＢＣマージモードの候補から最適な予測モードを選択できるので、符号化効率が向上する。 It is assumed that some block vectors in the block vector candidate list constructed by the intra-block copy prediction unit 352 are outside the referenceable area. If the reference position is not corrected, those block vectors cannot be used as candidates for the IBC merge mode because they cannot be referenced by the block vectors. On the other hand, when the reference position is corrected in the present invention, all the block vectors of the constructed block vector candidate list are inside the referenceable area. Therefore, it is possible to refer to all the block vectors, and all the block vectors can be candidates for the IBC merge mode. Therefore, in the IBC merge mode selection unit 374, the optimum prediction mode can be selected from the candidates of each IBC merge mode corresponding to all the block vectors, so that the coding efficiency is improved.
　いま、イントラブロックコピー予測部３６２において構築したブロックベクトル候補リストのうち、いくつかのブロックベクトルが参照可能領域の外側であったとする。参照位置を補正しない場合には、それらのブロックベクトルによる参照が不可能なので、それらのブロックベクトルを用いたＩＢＣマージモードは、復号することが出来ない。本発明ではない符号化装置では、それらのブロックベクトルを用いたＩＢＣマージモードを示すマージインデックスは、符号化しないものとして動作する。しかし、動作不良などのため、そのようなマージインデックスが符号化されて、ビットストリームが生成される可能性がある。あるいはパケットロスなどによりビットストリームの一部が欠けるなどして、復号結果がそのようなマージインデックスとなる可能性がある。このような不完全なビットストリームを復号しようとすると、参照可能領域の外側を参照しようとして正しくない位置の復号画像メモリにアクセスする可能性がある。その結果、復号装置によって復号結果が異なったり、復号処理が停止したりする。一方、本発明において参照位置を補正する場合には、構築したブロックベクトル候補リストの全てのブロックベクトルは、参照可能領域の内側となる。従って、このような不完全なビットストリームを復号しても、参照可能領域の内側に参照位置が補正されて参照が可能となる。このように、参照位置を補正することにより、メモリアクセス範囲を保証する。その結果、復号装置によって復号結果が同じになり、復号処理を継続できるので、復号装置のロバスト性を向上させることができる。 It is assumed that some block vectors in the block vector candidate list constructed by the intra-block copy prediction unit 362 are outside the referenceable area. If the reference position is not corrected, reference by those block vectors is impossible, so the IBC merge mode using those block vectors cannot be decoded. In a coding device other than the present invention, the merge index indicating the IBC merge mode using those block vectors operates as unencoded. However, due to malfunction or the like, such a merge index may be encoded to generate a bitstream. Alternatively, a part of the bitstream may be missing due to packet loss or the like, and the decryption result may become such a merge index. Attempting to decode such an incomplete bitstream may access the decoded image memory at the wrong location in an attempt to reference outside the referable area. As a result, the decoding result may differ depending on the decoding device, or the decoding process may stop. On the other hand, when the reference position is corrected in the present invention, all the block vectors of the constructed block vector candidate list are inside the referenceable area. Therefore, even if such an incomplete bit stream is decoded, the reference position is corrected inside the referenceable area and reference is possible. By correcting the reference position in this way, the memory access range is guaranteed. As a result, the decoding result becomes the same depending on the decoding device, and the decoding process can be continued, so that the robustness of the decoding device can be improved.
　また、参照位置の補正においてブロックベクトルを補正する場合、その対象は輝度のブロックベクトルである。ここで、色差のブロックベクトルは、輝度のブロックベクトルから算出される。つまり、輝度のブロックベクトルを補正すれば、色差のブロックベクトルも補正されることになる。よって、色差において、再び参照位置を補正する必要はない。ブロックベクトルを補正しない場合に輝度と色差の両方で参照可能か否かを判定する必要があるのに比べて、処理量を削減することができる。 Also, when the block vector is corrected in the correction of the reference position, the target is the brightness block vector. Here, the color difference block vector is calculated from the luminance block vector. That is, if the luminance block vector is corrected, the color difference block vector is also corrected. Therefore, it is not necessary to correct the reference position again in the color difference. Compared with the need to determine whether or not reference is possible based on both the luminance and the color difference when the block vector is not corrected, the amount of processing can be reduced.
　加えて、参照位置の補正においてブロックベクトルを補正する場合、補正したブロックベクトルは処理対象符号化ブロックのブロックベクトルとして、符号化情報格納メモリ１１１または符号化情報格納メモリ２０５に格納される。つまり、補正した参照位置とブロックベクトルが指す位置が同じである。ここで、復号結果を復号画像メモリに保存する際にデブロックフィルタ処理をすることがある。このフィルタ処理において、ブロック境界に面した２つのブロックが持つブロックベクトルの差分によって、フィルタの強度を制御する。ブロックベクトルを補正しない場合には補正した参照位置とブロックベクトルが指す位置が異なるのに比べて、より適切なフィルタの強度となるため、符号化効率を向上させることができる。 In addition, when the block vector is corrected in the correction of the reference position, the corrected block vector is stored in the coding information storage memory 111 or the coding information storage memory 205 as the block vector of the coded block to be processed. That is, the corrected reference position and the position pointed to by the block vector are the same. Here, a deblocking filter process may be performed when the decoding result is saved in the decoded image memory. In this filtering process, the strength of the filter is controlled by the difference between the block vectors of the two blocks facing the block boundary. When the block vector is not corrected, the corrected reference position and the position pointed to by the block vector are different, and the filter strength is more appropriate, so that the coding efficiency can be improved.
　続いて、参照ブロックのy方向の参照位置が、参照可能領域の左上より小さいか否かを判定する（ステップＳ６００６）。判定が偽ならば（ステップＳ６００６：ＮＯ）、次の処理（ステップＳ６００８）に進む。一方、判定が真ならば（ステップＳ６００６：ＹＥＳ）、参照可能領域の左上に合わせてy方向の参照位置を補正する（ステップＳ６００７）。 Subsequently, it is determined whether or not the reference position of the reference block in the y direction is smaller than the upper left of the referenceable area (step S6006). If the determination is false (step S6006: NO), the process proceeds to the next process (step S6008). On the other hand, if the determination is true (step S6006: YES), the reference position in the y direction is corrected according to the upper left of the referenceable area (step S6007).
　いま、参照ブロックr4が６０２１に位置していたとすると、y方向の参照位置が、参照可能領域の左上より小さい（ステップＳ６００６：ＹＥＳ）。よって、yRefTL=yAvlTLとして６０２２の位置に参照位置を補正する（ステップＳ６００７）。ここで、ステップＳ６００１にあるようにyRefBR=yRefTL+cbHeight-1であるから、yRefTLを補正したことに伴ってyRefBRも補正されることになる。この参照位置の補正において、ブロックベクトルmvL[1]を補正しても良い。つまり、
　　mvL[1] = (yAvlTL - yCb) << 4
と補正する。これにより、yRefTL=yAvlTLとなるので、参照位置を補正できる。 Assuming that the reference block r4 is located at 6021, the reference position in the y direction is smaller than the upper left of the referenceable area (step S6006: YES). Therefore, the reference position is corrected to the position of 6022 with yRefTL = yAvlTL (step S6007). Here, since yRefBR = yRefTL + cbHeight-1 as in step S6001, yRefBR is also corrected as yRefTL is corrected. In the correction of this reference position, the block vector mvL [1] may be corrected. In other words
mvL [1] = (yAvlTL --yCb) << 4
To correct. As a result, yRefTL = yAvlTL, so the reference position can be corrected.
　続いて、参照ブロックのx方向の参照位置が、参照可能領域の右下より大きいか否かを判定する（ステップＳ６００８）。判定が偽ならば（ステップＳ６００８：ＮＯ）、次の処理（ステップＳ６０１０）に進む。一方、判定が真ならば（ステップＳ６００８：ＹＥＳ）、参照可能領域の右下に合わせてx方向の参照位置を補正する（ステップＳ６００９）。 Subsequently, it is determined whether or not the reference position of the reference block in the x direction is larger than the lower right of the referenceable area (step S6008). If the determination is false (step S6008: NO), the process proceeds to the next process (step S6010). On the other hand, if the determination is true (step S6008: YES), the reference position in the x direction is corrected according to the lower right of the referenceable area (step S6009).
　いま、参照ブロックr7が６０３１に位置していたとすると、x方向の参照位置が、参照可能領域の右下より大きい（ステップＳ６００８：ＹＥＳ）。よって、xRefBR=xAvlBRとして６０３２の位置に参照位置を補正する（ステップＳ６００９）。ここで、ステップＳ６００１にあるようにxRefBR=xRefTL+cbWidth-1、つまりxRefTL=xRefBR-(cbWidth-1)であるから、xRefBRを補正したことに伴ってxRefTLも補正されることになる。この参照位置の補正において、ブロックベクトルmvL[0]を補正しても良い。つまり、
　　mvL[0] = (xAvlBR - (xCb + cbWidth - 1)) << 4
と補正する。これにより、xRefBR=xAvlBRとなるので、参照位置を補正できる。 Assuming that the reference block r7 is located at 6031, the reference position in the x direction is larger than the lower right of the referenceable area (step S6008: YES). Therefore, the reference position is corrected to the position of 6032 by setting xRefBR = xAvlBR (step S6009). Here, since xRefBR = xRefTL + cbWidth-1 as in step S6001, that is, xRefTL = xRefBR- (cbWidth-1), xRefTL is also corrected as xRefBR is corrected. In the correction of this reference position, the block vector mvL [0] may be corrected. In other words
mvL [0] = (xAvlBR-(xCb + cbWidth --1)) << 4
To correct. As a result, xRefBR = xAvlBR, so the reference position can be corrected.
　続いて、参照ブロックのy方向の参照位置が、参照可能領域の右下より大きいか否かを判定する（ステップＳ６０１０）。判定が偽ならば（ステップＳ６０１０：ＮＯ）、処理を終了する。一方、判定が真ならば（ステップＳ６０１０：ＹＥＳ）、参照可能領域の右下に合わせてy方向の参照位置を補正する（ステップＳ６０１１）。 Subsequently, it is determined whether or not the reference position of the reference block in the y direction is larger than the lower right of the referenceable area (step S6010). If the determination is false (step S6010: NO), the process ends. On the other hand, if the determination is true (step S6010: YES), the reference position in the y direction is corrected according to the lower right of the referenceable area (step S6011).
　いま、参照ブロックr5が６０４１に位置していたとすると、y方向の参照位置が、参照可能領域の右下より大きい（ステップＳ６０１０：ＹＥＳ）。よって、yRefBR=yAvlBRとして６０４２の位置に参照位置を補正する（ステップＳ６０１１）。ここで、ステップＳ６００１にあるようにyRefBR=yRefTL+cbHeight-1、つまりyRefTL=yRefBR-(cbHeight-1)であるから、yRefBRを補正したことに伴ってyRefTLも補正されることになる。この参照位置の補正において、ブロックベクトルmvL[1]を補正しても良い。つまり、
　　mvL[1] = (yAvlBR - (yCb + cbHeitght - 1)) << 4
と補正する。これにより、yRefBR=yAvlBRとなるので、参照位置を補正できる。 Assuming that the reference block r5 is located at 6041, the reference position in the y direction is larger than the lower right of the referenceable area (step S6010: YES). Therefore, the reference position is corrected to the position of 6042 by setting yRefBR = yAvlBR (step S6011). Here, since yRefBR = yRefTL + cbHeight-1 as in step S6001, that is, yRefTL = yRefBR- (cbHeight-1), yRefTL is also corrected as yRefBR is corrected. In the correction of this reference position, the block vector mvL [1] may be corrected. In other words
mvL [1] = (yAvlBR-(yCb + cbHeitght --1)) << 4
To correct. As a result, yRefBR = yAvlBR, so the reference position can be corrected.
　ここで、参照ブロックr1が６０５１に位置している場合について説明する。この場合は、参照ブロックがr2の場合と同様に、x方向の参照位置を補正する。さらに、参照ブロックがr4の場合と同様に、y方向の参照位置を補正する。その結果、参照ブロックr1は、参照可能領域の内部である６０５２に位置する。 Here, the case where the reference block r1 is located at 6051 will be described. In this case, the reference position in the x direction is corrected as in the case where the reference block is r2. Further, the reference position in the y direction is corrected as in the case where the reference block is r4. As a result, the reference block r1 is located at 6052, which is inside the referenceable area.
　参照ブロックr3が６０６１に位置している場合、参照ブロックr6が６０６２に位置している場合、参照ブロックr8が６０６３に位置している場合は、上記と同様にx,y各方向の参照位置を補正する。その結果、それぞれの参照ブロックは、参照可能領域の内部に位置する。 If the reference block r3 is located at 6061, the reference block r6 is located at 6062, and the reference block r8 is located at 6063, the reference positions in the x and y directions are set in the same manner as above. to correct. As a result, each reference block is located inside the referenceable area.
　以上により、CTUの大きさが128x128画素でない場合の処理は終了する。一方、CTUの大きさが128x128画素の場合（ステップＳ６００２：YES）、参照可能領域を矩形状とした場合の左上および右下の位置を算出する（ステップＳ６０１２）。 From the above, the processing when the size of CTU is not 128x128 pixels is completed. On the other hand, when the size of the CTU is 128x128 pixels (step S6002: YES), the upper left and lower right positions when the referenceable area is rectangular are calculated (step S6012).
　図５１Ａ～Ｄは、参照可能領域を矩形状とした場合の左上および右下の位置を説明する図である。図５１Ａの場合、処理対象の符号化ツリーブロック６１０１は４分割されており、その分割の左上に処理対象の符号化ブロック６１０２が位置している。このとき、参照可能領域は６１０３内の斜線部のように逆Ｌ字形となる。参照可能領域を矩形状とした場合、その範囲は６１０３の矩形状の範囲とする。参照可能領域を矩形状とした場合、参照ブロックの左上を( xRefTL, yRefTL )、右下を( xRefBR, yRefBR )とすると、
　　offset[4] = {0, 64, 128, 128}
　　NL = -offset[3 - blk_idx], NR = offset[blk_idx]
　　( xAvlTL, yAvlTL ) = ( (xCb >> CtbLog2SizeY) << CtbLog2SizeY + NL,
　　　　 (yCb >> CtbLog2SizeY) << CtbLog2SizeY )
　　( xAvlBR, yAvlBR ) = ( ((xCb >> CtbLog2SizeY) << CtbLog2SizeY) - 1 + NR,
　　　　 (((yCb >> CtbLog2SizeY) + 1) << CtbLog2SizeY) - 1 )
となる。ここで、blk_idxは、処理対象の符号化ブロックの位置を示すインデックスである。処理対象の符号化ツリーブロックを４分割したうち、処理対象の符号化ブロックが左上に位置している場合は、blk_idx=0とする。同様に、処理対象の符号化ブロックがそれぞれ右上、左下、右下に位置している場合は、blk_idxは1,2,3とする。図５１Ａはblk_idx=0の場合を示す図である。同様に、図５１Ｂ、Ｃ、Ｄは、それぞれblk_idx=1,2,3の場合を示す図である。 51A to 51D are diagrams for explaining the upper left and lower right positions when the referenceable area is rectangular. In the case of FIG. 51A, the coded tree block 6101 to be processed is divided into four, and the coded block 6102 to be processed is located at the upper left of the division. At this time, the referenceable area has an inverted L shape like the shaded area in 6103. When the referenceable area is rectangular, the range is 6103. When the referenceable area is rectangular, if the upper left of the reference block is (xRefTL, yRefTL) and the lower right is (xRefBR, yRefBR),
offset [4] = {0, 64, 128, 128}
NL = -offset [3 --blk_idx], NR = offset [blk_idx]
(xAvlTL, yAvlTL) = ((xCb >> CtbLog2SizeY) << CtbLog2SizeY + NL,
(yCb >> CtbLog2SizeY) << CtbLog2SizeY)
(xAvlBR, yAvlBR) = (((xCb >> CtbLog2SizeY) << CtbLog2SizeY) -1 + NR,
(((yCb >> CtbLog2SizeY) + 1) << CtbLog2SizeY) ―― 1)
Will be. Here, blk_idx is an index indicating the position of the coded block to be processed. If the coded block to be processed is divided into four and the coded block to be processed is located in the upper left, blk_idx = 0 is set. Similarly, if the coded blocks to be processed are located at the upper right, lower left, and lower right, respectively, blk_idx is set to 1, 2, and 3. FIG. 51A is a diagram showing the case of blk_idx = 0. Similarly, FIGS. 51B, C, and D are diagrams showing the cases of blk_idx = 1, 2, and 3, respectively.
　次に、参照可能領域が矩形でない部分の参照位置を補正する（ステップＳ６０１３）。図５２は、参照可能領域が矩形でない部分の参照位置を補正する処理を説明するフローチャートである。まず、参照可能領域の左上の位置を算出する（ステップＳ６０２１）。参照可能領域は図５１Ａ～Ｄの斜線部なので、blk_idx=3の場合を除いて、左上の位置は６１１１と６１１２の2点ある。それぞれ(X1, Y1),(X2, Y2)とすると、
　　offset[4] = {64, 128, 64, 0}, NL = offset[blk_idx]
　　(X1, Y1) = (xAvlTL, yAvlTL + 64)
　　(X2, Y2) = (xAvlTL + NL, yAvlTL)
となる。 Next, the reference position of the portion where the referenceable area is not rectangular is corrected (step S6013). FIG. 52 is a flowchart illustrating a process of correcting a reference position in a portion where the referenceable area is not rectangular. First, the upper left position of the referenceable area is calculated (step S6021). Since the referenceable area is the shaded area in FIGS. 51A to 51D, there are two upper left positions, 6111 and 6112, except for the case of blk_idx = 3. If they are (X1, Y1) and (X2, Y2), respectively,
offset [4] = {64, 128, 64, 0}, NL = offset [blk_idx]
(X1, Y1) = (xAvlTL, yAvlTL + 64)
(X2, Y2) = (xAvlTL + NL, yAvlTL)
Will be.
　次に、参照可能領域の左上に合わせて参照位置を補正するか否かを判定する（ステップＳ６０２２）。この判定では、blk_idx=3でなく、かつ参照ブロックがX2とY1より小さい領域に位置している場合に真と判定する（ステップＳ６０２２：ＹＥＳ）。偽の場合（ステップＳ６０２２：ＮＯ）、次の処理（ステップＳ６０２６）に進む。 Next, it is determined whether or not to correct the reference position according to the upper left of the referenceable area (step S6022). In this determination, if blk_idx = 3 is not satisfied and the reference block is located in a region smaller than X2 and Y1, it is determined to be true (step S6022: YES). If false (step S6022: NO), the process proceeds to the next process (step S6026).
　次に、参照ブロックと参照可能領域のx方向との差分が、参照ブロックと参照可能領域のy方向との差分より小さいか否かを判定する（ステップＳ６０２３）。判定が真の場合（ステップＳ６０２３：ＹＥＳ）、x方向の参照位置を補正する（ステップＳ６０２４）。一方、判定が偽の場合（ステップＳ６０２３：ＮＯ）、y方向の参照位置を補正する（ステップＳ６０２５）。 Next, it is determined whether or not the difference between the reference block and the referenceable area in the x direction is smaller than the difference between the reference block and the referenceable area in the y direction (step S6023). If the determination is true (step S6023: YES), the reference position in the x direction is corrected (step S6024). On the other hand, when the determination is false (step S6023: NO), the reference position in the y direction is corrected (step S6025).
　図５３Ａは、ステップＳ６０２４とステップＳ６０２５において、参照位置を補正する様子を示す図である。いま、blk_idx=0である。参照ブロックr1が６２０１に位置していたとすると、blk_idx=3でなく、かつ参照ブロックの左上がX2（６１１２のx方向）とY1（６１１１のy方向）より小さい領域に位置している（ステップＳ６０２２：ＹＥＳ）。また、参照ブロックと参照可能領域のx方向との差分が、参照ブロックと参照可能領域のy方向との差分より小さい（ステップＳ６０２３：ＹＥＳ）。よって、xRefTL=xAvlTL+NLとして６２０２の位置にx方向の参照位置を補正する（ステップＳ６０２４）。ここで、ステップＳ６００１にあるようにxRefBR=xRefTL+cbWidth-1であるから、xRefTLを補正したことに伴ってxRefBRも補正されることになる。この参照位置の補正において、ブロックベクトルmvL[0]を補正しても良い。つまり、
　　mvL[0] = (xAvlTL + NL - xCb) << 4
と補正する。これにより、xRefTL=xAvlTL+NLとなるので、参照位置を補正できる。 FIG. 53A is a diagram showing how the reference position is corrected in step S6024 and step S6025. Now, blk_idx = 0. Assuming that the reference block r1 is located at 6201, the upper left corner of the reference block is located in a region smaller than X2 (x direction of 6112) and Y1 (y direction of 6111) without blk_idx = 3 (step S6022). : YES). Further, the difference between the reference block and the referenceable area in the x direction is smaller than the difference between the reference block and the referenceable area in the y direction (step S6023: YES). Therefore, xRefTL = xAvlTL + NL is set to correct the reference position in the x direction to the position of 6202 (step S6024). Here, since xRefBR = xRefTL + cbWidth-1 as in step S6001, xRefBR is also corrected as xRefTL is corrected. In the correction of this reference position, the block vector mvL [0] may be corrected. In other words
mvL [0] = (xAvlTL + NL-xCb) << 4
To correct. As a result, xRefTL = xAvlTL + NL, so the reference position can be corrected.
　一方、参照ブロックr2が６２０３に位置していたとすると、blk_idx=3でなく、かつ参照ブロックの左上がX2（６１１２のx方向）とY1（６１１１のy方向）より小さい領域に位置している（ステップＳ６０２２：ＹＥＳ）。また、参照ブロックと参照可能領域のx方向との差分が、参照ブロックと参照可能領域のy方向との差分より小さくない（ステップＳ６０２３：ＮＯ）。よって、yRefTL=yAvlTL+64として６２０４の位置にy方向の参照位置を補正する（ステップＳ６０２５）。ここで、ステップＳ６００１にあるようにyRefBR=yRefTL+cbHeight-1であるから、yRefTLを補正したことに伴ってyRefBRも補正されることになる。この参照位置の補正において、ブロックベクトルmvL[0]を補正しても良い。つまり、
　　mvL[1] = (yAvlTL + 64 - yCb) << 4
と補正する。これにより、yRefTL=yAvlTL+64となるので、参照位置を補正できる。 On the other hand, if the reference block r2 is located at 6203, blk_idx = 3 is not satisfied, and the upper left of the reference block is located in a region smaller than X2 (x direction of 6112) and Y1 (y direction of 6111) ( Step S6022: YES). Further, the difference between the reference block and the referenceable area in the x direction is not smaller than the difference between the reference block and the referenceable area in the y direction (step S6023: NO). Therefore, the reference position in the y direction is corrected to the position of 6204 by setting yRefTL = yAvlTL + 64 (step S6025). Here, since yRefBR = yRefTL + cbHeight-1 as in step S6001, yRefBR is also corrected as yRefTL is corrected. In the correction of this reference position, the block vector mvL [0] may be corrected. In other words
mvL [1] = (yAvlTL + 64 --yCb) << 4
To correct. As a result, yRefTL = yAvlTL + 64, so the reference position can be corrected.
　ここで、参照ブロックr3が６２０５に位置していたとする。この場合、参照ブロックと参照可能領域のx方向との差分が、参照ブロックと参照可能領域のy方向との差分より小さい（ステップＳ６０２３：ＹＥＳ）。よって、参照ブロックr1と同様にx方向の参照位置を補正することで、６２０６に位置する（ステップＳ６０２４）。この時点において、参照ブロックは参照可能領域の外側である。しかし、後述のステップＳ６００６とＳ６００７の処理により、y方向の参照位置を補正する。結局、参照ブロックは、参照可能領域の内側となる。 Here, it is assumed that the reference block r3 is located at 6205. In this case, the difference between the reference block and the referenceable area in the x direction is smaller than the difference between the reference block and the referenceable area in the y direction (step S6023: YES). Therefore, it is located at 6206 by correcting the reference position in the x direction in the same manner as the reference block r1 (step S6024). At this point, the reference block is outside the referenceable area. However, the reference position in the y direction is corrected by the processing of steps S6006 and S6007 described later. After all, the reference block is inside the referenceable area.
　続いて、参照可能領域の右下の位置を算出する（ステップＳ６０２６）。参照可能領域は図５１の斜線部なので、blk_idx=0の場合を除いて、右下の位置は６１１３と６１１４の2点ある。それぞれ(X3, Y3),(X4, Y4)とすると、
　　offset[4] = {0, 64, 128, 64}, NR = offset[blk_idx]
　　(X3, Y3) = (xAvlBR, yAvlBR - 64)
　　(X4, Y4) = (xAvlBR - NR, yAvlBR)
となる。 Subsequently, the lower right position of the referenceable area is calculated (step S6026). Since the referenceable area is the shaded area in FIG. 51, there are two lower right positions, 6113 and 6114, except when blk_idx = 0. If each is (X3, Y3), (X4, Y4),
offset [4] = {0, 64, 128, 64}, NR = offset [blk_idx]
(X3, Y3) = (xAvlBR, yAvlBR --64)
(X4, Y4) = (xAvlBR --NR, yAvlBR)
Will be.
　次に、参照可能領域の右下に合わせて参照位置を補正するか否かを判定する（ステップＳ６０２７）。この判定では、blk_idx=0でなく、かつ参照ブロックがX4とY3より大きい領域に位置している場合に真と判定する（ステップＳ６０２７：ＹＥＳ）。偽の場合（ステップＳ６０２７：ＮＯ）、処理を終了する。 Next, it is determined whether or not to correct the reference position according to the lower right of the referenceable area (step S6027). In this determination, if blk_idx = 0 is not satisfied and the reference block is located in a region larger than X4 and Y3, the determination is true (step S6027: YES). If false (step S6027: NO), the process ends.
　次に、参照ブロックと参照可能領域のx方向との差分が、参照ブロックと参照可能領域のy方向との差分より小さいか否かを判定する（ステップＳ６０２８）。判定が真の場合（ステップＳ６０２８：ＹＥＳ）、x方向の参照位置を補正する（ステップＳ６０２９）。一方、判定が偽の場合（ステップＳ６０２８：ＮＯ）、y方向の参照位置を補正する（ステップＳ６０３０）。 Next, it is determined whether or not the difference between the reference block and the referenceable area in the x direction is smaller than the difference between the reference block and the referenceable area in the y direction (step S6028). If the determination is true (step S6028: YES), the reference position in the x direction is corrected (step S6029). On the other hand, when the determination is false (step S6028: NO), the reference position in the y direction is corrected (step S6030).
　図５３Ｂは、ステップＳ６０２９とステップＳ６０３０において、参照位置を補正する様子を示す図である。いま、blk_idx=3である。参照ブロックr1が６２１１に位置していたとすると、blk_idx=0でなく、かつ参照ブロックの右下がX4（６１１４のx方向）とY3（６１１３のy方向）より大きい領域に位置している（ステップＳ６０２７：ＹＥＳ）。また、参照ブロックと参照可能領域のx方向との差分が、参照ブロックと参照可能領域のy方向との差分より小さい（ステップＳ６０２８：ＹＥＳ）。よって、xRefBR=xAvlBRとして６２１２の位置にx方向の参照位置を補正する（ステップＳ６０２９）。ここで、ステップＳ６００１にあるようにxRefBR=xRefTL+cbWidth-1、つまりxRefTL=xRefBR-(cbWidth-1)であるから、xRefBRを補正したことに伴ってxRefTLも補正されることになる。この参照位置の補正において、ブロックベクトルmvL[0]を補正しても良い。つまり、
　　mvL[0] = (xAvlBR - NR - (xCb + cbWitdh - 1)) << 4
と補正する。これにより、xRefBR=xAvlBRとなるので、参照位置を補正できる。 FIG. 53B is a diagram showing how the reference position is corrected in step S6029 and step S6030. Now, blk_idx = 3. Assuming that the reference block r1 is located at 6211, blk_idx = 0 is not present, and the lower right corner of the reference block is located in a region larger than X4 (x direction of 6114) and Y3 (y direction of 6113) (step). S6027: YES). Further, the difference between the reference block and the referenceable area in the x direction is smaller than the difference between the reference block and the referenceable area in the y direction (step S6028: YES). Therefore, the reference position in the x direction is corrected to the position of 6212 by setting xRefBR = xAvlBR (step S6029). Here, since xRefBR = xRefTL + cbWidth-1 as in step S6001, that is, xRefTL = xRefBR- (cbWidth-1), xRefTL is also corrected as xRefBR is corrected. In the correction of this reference position, the block vector mvL [0] may be corrected. In other words
mvL [0] = (xAvlBR --NR-(xCb + cbWitdh --1)) << 4
To correct. As a result, xRefBR = xAvlBR, so the reference position can be corrected.
　一方、参照ブロックr2が６２１３に位置していたとすると、blk_idx=0でなく、かつ参照ブロックの右下がX4（６１１４のx方向）とY3（６１１３のy方向）より大きい領域に位置している（ステップＳ６０２７：ＹＥＳ）。また、参照ブロックと参照可能領域のx方向との差分が、参照ブロックと参照可能領域のy方向との差分より小さくない（ステップＳ６０２８：ＮＯ）。よって、yRefBR=yAvlBRとして６２１４の位置にy方向の参照位置を補正する（ステップＳ６０３０）。ここで、ステップＳ６００１にあるようにyRefBR=yRefTL+cbHeight-1、つまりyRefTL=yRefBR-(cbHeight-1)であるから、yRefBRを補正したことに伴ってyRefTLも補正されることになる。この参照位置の補正において、ブロックベクトルmvL[1]を補正しても良い。つまり、
　　mvL[1] = (yAvlBR - 64 - (yCb + cbHeight - 1)) << 4
と補正する。これにより、yRefBR=yAvlBRとなるので、参照位置を補正できる。 On the other hand, if the reference block r2 is located at 6213, blk_idx = 0 is not satisfied, and the lower right of the reference block is located in a region larger than X4 (x direction of 6114) and Y3 (y direction of 6113). (Step S6027: YES). Further, the difference between the reference block and the referenceable area in the x direction is not smaller than the difference between the reference block and the referenceable area in the y direction (step S6028: NO). Therefore, the reference position in the y direction is corrected to the position of 6214 with yRefBR = yAvlBR (step S6030). Here, since yRefBR = yRefTL + cbHeight-1 as in step S6001, that is, yRefTL = yRefBR- (cbHeight-1), yRefTL is also corrected as yRefBR is corrected. In the correction of this reference position, the block vector mvL [1] may be corrected. In other words
mvL [1] = (yAvlBR --64-(yCb + cbHeight --1)) << 4
To correct. As a result, yRefBR = yAvlBR, so the reference position can be corrected.
　ここで、参照ブロックr3が６２１５に位置していたとする。この場合、参照ブロックと参照可能領域のx方向との差分が、参照ブロックと参照可能領域のy方向との差分より小さくない（ステップＳ６０２８：ＮＯ）。よって、参照ブロックr2と同様にy方向の参照位置を補正することで、６２１６に位置する（ステップＳ６０３０）。この時点において、参照ブロックは参照可能領域の外側である。しかし、後述のステップＳ６００８とステップＳ６００９の処理により、x方向の参照位置を補正する。結局、参照ブロックは、参照可能領域の内側となる。 Here, it is assumed that the reference block r3 is located at 6215. In this case, the difference between the reference block and the referenceable area in the x direction is not smaller than the difference between the reference block and the referenceable area in the y direction (step S6028: NO). Therefore, it is located at 6216 by correcting the reference position in the y direction in the same manner as the reference block r2 (step S6030). At this point, the reference block is outside the referenceable area. However, the reference position in the x direction is corrected by the processing of step S6008 and step S6009 described later. After all, the reference block is inside the referenceable area.
　図５３Ａ～Ｂでは、blk_idx=0と3の場合を例に参照位置を補正する処理を説明した。blk_idx=1や2の場合、blk_idx=0と3の場合と同様に参照位置を補正する処理をする。 In FIGS. 53A to 53B, the process of correcting the reference position was described by taking the cases of blk_idx = 0 and 3 as an example. When blk_idx = 1 or 2, the reference position is corrected in the same way as when blk_idx = 0 and 3.
　参照可能領域が矩形でない部分の参照位置を補正する処理（ステップＳ６０１３）の後、ステップＳ６００４からステップＳ６０１１の処理をする。以上により、CTUの大きさが128x128画素の場合の処理は終了する。 After the process of correcting the reference position of the portion where the referenceable area is not rectangular (step S6013), the processes of steps S6004 to S6011 are performed. With the above, the processing when the size of CTU is 128x128 pixels is completed.
　いま、参照可能領域が矩形でない部分の参照位置を補正する処理（ステップＳ６０１３）において、参照可能領域の左上に合わせてx方向の参照位置を補正する処理（ステップＳ６０２４）をしたとする。すると、参照ブロックのx方向の参照位置が、参照可能領域の左上より小さくなることはないので、ステップＳ６００４の判定は常に偽（ステップＳ６００４：ＮＯ）となる。従って、ステップＳ６０２４の処理をした場合は、ステップＳ６００４とステップＳ６００５の処理をしないようにしても良い。同様に、ステップＳ６０２５の処理をした場合はステップＳ６００６とステップＳ６００７の処理をしないようにしても良いし、ステップＳ６０２９の処理をした場合はステップＳ６００８とステップＳ６００９の処理をしないようにしても良いし、ステップＳ６０３０の処理をした場合はステップＳ６０１０とステップＳ６０１１の処理をしないようにしても良い。 It is assumed that in the process of correcting the reference position of the portion where the referenceable area is not rectangular (step S6013), the process of correcting the reference position in the x direction according to the upper left of the referenceable area (step S6024) is performed. Then, since the reference position of the reference block in the x direction is not smaller than the upper left of the referenceable area, the determination in step S6004 is always false (step S6004: NO). Therefore, when the process of step S6024 is performed, the processes of step S6004 and step S6005 may not be performed. Similarly, when the processing of step S6025 is performed, the processing of steps S6006 and S6007 may be omitted, and when the processing of step S6029 is performed, the processing of steps S6008 and S6009 may not be performed. When the process of step S6030 is performed, the processes of step S6010 and step S6011 may not be performed.
　また、図５２のフローチャートにおいて、ステップＳ６０２３の比較処理を省略し、常にステップＳ６０２４を実行するような構成を取っても良いし、常にステップＳ６０２５を実行するような構成を取っても良い。同様に、ステップＳ６０２８の比較処理を省略し、常にステップＳ６０２９を実行するような構成を取っても良いし、常にステップＳ６０３０を実行するような構成を取っても良い。そのような構成においては、簡便な処理で参照位置を補正することが可能となる。 Further, in the flowchart of FIG. 52, the comparison process of step S6023 may be omitted and the configuration may be such that step S6024 is always executed, or the configuration may be such that step S6025 is always executed. Similarly, the comparison process of step S6028 may be omitted, and the configuration may be such that step S6029 is always executed, or the configuration may be such that step S6030 is always executed. In such a configuration, the reference position can be corrected by a simple process.
　図４９では、CTUの大きさが128x128画素の場合において、Ｓ６０１２、Ｓ６０１３およびＳ６００４からＳ６０１１の処理を用いて参照位置を補正している。これに代わり、図５４のように、参照可能領域を２つに分解し、それぞれの参照位置を補正する処理（図５４のＳ６１０１）によっても実現出来る。 In FIG. 49, when the size of the CTU is 128x128 pixels, the reference position is corrected by using the processes of S6012, S6013 and S6004 to S6011. Instead of this, as shown in FIG. 54, it can also be realized by a process of decomposing the referenceable area into two and correcting each reference position (S6101 in FIG. 54).
　図５５Ａ～Ｄは、参照可能領域を２つに分解する様子を説明する図である。図５１において参照可能領域を矩形状としているのとは異なり、図５５Ａ～Ｄでは参照可能領域を２つに分解している。処理対象の符号化ツリーブロック（６１０１）を４分割したうち、処理対象の符号化ブロック（６１０２）が左上に位置している場合は、blk_idx=0とする。同様に、処理対象の符号化ブロックがそれぞれ右上、左下、右下に位置している場合は、blk_idxは1,2,3とする。図５５Ａはblk_idx=0の場合を示す図である。同様に、図５５Ｂ～Ｄは、それぞれblk_idx=1から3の場合を示す図である。また、一方の参照可能領域（６３０１）を参照可能領域Ａとし、他方の参照可能領域（６３０２）を参照可能領域Ｂとする。 FIGS. 55A to 55D are diagrams for explaining how the referenceable region is decomposed into two. Unlike the rectangular shape of the referenceable area in FIG. 51, the referenceable area is decomposed into two in FIGS. 55A to 55D. If the coded block (6102) to be processed is located in the upper left of the coded tree block (6101) to be processed, blk_idx = 0 is set. Similarly, if the coded blocks to be processed are located at the upper right, lower left, and lower right, respectively, blk_idx is set to 1, 2, and 3. FIG. 55A is a diagram showing the case of blk_idx = 0. Similarly, FIGS. 55B to 55D are diagrams showing the cases of blk_idx = 1 to 3, respectively. Further, one referenceable area (6301) is designated as a referenceable area A, and the other referenceable area (6302) is designated as a referenceable area B.
　図５６は、参照可能領域を２つに分解し、それぞれの参照位置を補正する処理（Ｓ６１０１）を説明するフローチャートである。図５６において、図４９と同じ処理には同じステップ番号を付し、説明を省略する。まず、参照可能領域Ａの左上および右下の位置を算出する（Ｓ６１１１）。参照可能領域Ａの左上を( xAvlTL, yAvlTL )、右下を( xAvlBR, yAvlBR )とすると、
　　xOffsetTL[4] = {-128, -128, -64, 0}, yOffsetTL[4] = {64, 64, 64, 0}
　　xOffsetBR[4] = {0, 0, 0, 128}, yOffsetBR[4] = {128, 128, 128, 64}
　　( xAvlTL, yAvlTL ) = ( (xCb >> CtbLog2SizeY) << CtbLog2SizeY
　　　　+ xOffsetTL[blk_idx],
　　　　(yCb >> CtbLog2SizeY) << CtbLog2SizeY + yOffsetTL[blk_idx])
　　( xAvlBR, yAvlBR ) = ( ((xCb >> CtbLog2SizeY) << CtbLog2SizeY) - 1
　　　　+ xOffsetBR[blk_idx],
　　　　(((yCb >> CtbLog2SizeY) + 1) << CtbLog2SizeY) - 1 + yOffsetBR[blk_idx] )となる。 FIG. 56 is a flowchart illustrating a process (S6101) of decomposing the referenceable area into two and correcting each reference position. In FIG. 56, the same process as in FIG. 49 is assigned the same step number, and the description thereof will be omitted. First, the upper left and lower right positions of the referenceable area A are calculated (S6111). If the upper left of the referenceable area A is (xAvlTL, yAvlTL) and the lower right is (xAvlBR, yAvlBR),
xOffsetTL [4] = {-128, -128, -64, 0}, yOffsetTL [4] = {64, 64, 64, 0}
xOffsetBR [4] = {0, 0, 0, 128}, yOffsetBR [4] = {128, 128, 128, 64}
(xAvlTL, yAvlTL) = ((xCb >> CtbLog2SizeY) << CtbLog2SizeY
+ xOffsetTL [blk_idx],
(yCb >> CtbLog2SizeY) << CtbLog2SizeY + yOffsetTL [blk_idx])
(xAvlBR, yAvlBR) = (((xCb >> CtbLog2SizeY) << CtbLog2SizeY) -1
+ xOffsetBR [blk_idx],
(((yCb >> CtbLog2SizeY) + 1) << CtbLog2SizeY) -1 + yOffsetBR [blk_idx]).
　次に、参照ブロックが参照可能領域Ａの外部か否かについて、
　　out_xRefTL = xRefTL < xAvlTL
　　out_yRefTL = yRefTL < yAvlTL
　　out_xRefBR = xRefBR > xAvlBR
　　out_yRefBR = yRefBR > yAvlBR
として算出する（Ｓ６１１２）。 Next, regarding whether or not the reference block is outside the referenceable area A,
out_xRefTL = xRefTL <xAvlTL
out_yRefTL = yRefTL <yAvlTL
out_xRefBR = xRefBR> xAvlBR
out_yRefBR = yRefBR> yAvlBR
Is calculated as (S6112).
　次に、参照可能領域Ｂの左上および右下の位置を算出する（Ｓ６１１３）。参照可能領域Ｂの左上を( xAvlTL, yAvlTL )、右下を( xAvlBR, yAvlBR )とすると、
　　xOffsetTL[4] = {-64, 0, 0, 0}, yOffsetTL[4] = {0, 0, 0, 0}
　　xOffsetBR[4] = {0, 64, 128, 64}, yOffsetBR[4] = {128, 64, 64, 128}
　　( xAvlTL, yAvlTL ) = ( (xCb >> CtbLog2SizeY) << CtbLog2SizeY
　　　　+ xOffsetTL[blk_idx],
　　　　(yCb >> CtbLog2SizeY) << CtbLog2SizeY + yOffsetTL[blk_idx])
　　( xAvlBR, yAvlBR ) = ( ((xCb >> CtbLog2SizeY) << CtbLog2SizeY) - 1
　　　　+ xOffsetBR[blk_idx],
　　　　(((yCb >> CtbLog2SizeY) + 1) << CtbLog2SizeY) - 1 + yOffsetBR[blk_idx] )
となる。 Next, the upper left and lower right positions of the referenceable area B are calculated (S6113). If the upper left of the referenceable area B is (xAvlTL, yAvlTL) and the lower right is (xAvlBR, yAvlBR),
xOffsetTL [4] = {-64, 0, 0, 0}, yOffsetTL [4] = {0, 0, 0, 0}
xOffsetBR [4] = {0, 64, 128, 64}, yOffsetBR [4] = {128, 64, 64, 128}
(xAvlTL, yAvlTL) = ((xCb >> CtbLog2SizeY) << CtbLog2SizeY
+ xOffsetTL [blk_idx],
(yCb >> CtbLog2SizeY) << CtbLog2SizeY + yOffsetTL [blk_idx])
(xAvlBR, yAvlBR) = (((xCb >> CtbLog2SizeY) << CtbLog2SizeY) -1
+ xOffsetBR [blk_idx],
(((yCb >> CtbLog2SizeY) + 1) << CtbLog2SizeY) -1 + yOffsetBR [blk_idx])
Will be.
　次に、参照ブロックのx方向の参照位置が参照可能領域Ａの左上より小さく、かつ参照ブロックのx方向の参照位置が参照可能領域Ｂの左上より小さいか否かを判定する（Ｓ６１１４）。判定が偽ならば（Ｓ６１１４：ＮＯ）、次の処理（Ｓ６１１６）に進む。一方、判定が真ならば（Ｓ６１１４：ＹＥＳ）、参照可能領域Ｂの左上に合わせてx方向の参照位置を補正する（Ｓ６００５）。Ｓ６００５の処理はすでに説明しているため、説明を省略する。 Next, it is determined whether or not the reference position of the reference block in the x direction is smaller than the upper left of the referenceable area A and the reference position of the reference block in the x direction is smaller than the upper left of the referenceable area B (S6114). If the determination is false (S6114: NO), the process proceeds to the next process (S6116). On the other hand, if the determination is true (S6114: YES), the reference position in the x direction is corrected according to the upper left of the referenceable area B (S6005). Since the process of S6005 has already been described, the description thereof will be omitted.
　続いて、参照ブロックのy方向の参照位置が参照可能領域Ａの左上より小さく、かつ参照ブロックのy方向の参照位置が参照可能領域Ｂの左上より小さいか否かを判定する（Ｓ６１１６）。判定が偽ならば（Ｓ６１１６：ＮＯ）、次の処理（Ｓ６１１８）に進む。一方、判定が真ならば（Ｓ６１１６：ＹＥＳ）、参照可能領域Ｂの左上に合わせてy方向の参照位置を補正する（Ｓ６００７）。Ｓ６００７の処理はすでに説明しているため、説明を省略する。 Subsequently, it is determined whether or not the reference position of the reference block in the y direction is smaller than the upper left of the referenceable area A and the reference position of the reference block in the y direction is smaller than the upper left of the referenceable area B (S6116). If the determination is false (S6116: NO), the process proceeds to the next process (S6118). On the other hand, if the determination is true (S6116: YES), the reference position in the y direction is corrected according to the upper left of the referenceable area B (S6007). Since the process of S6007 has already been described, the description thereof will be omitted.
　次に、参照ブロックのx方向の参照位置が参照可能領域Ａの右下より大きく、かつ参照ブロックのx方向の参照位置が参照可能領域Ｂの右下より大きいか否かを判定する（Ｓ６１１８）。判定が偽ならば（Ｓ６１１８：ＮＯ）、次の処理（Ｓ６１２０）に進む。一方、判定が真ならば（Ｓ６１１８：ＹＥＳ）、参照可能領域Ｂの右下に合わせてx方向の参照位置を補正する（Ｓ６００９）。Ｓ６００９の処理はすでに説明しているため、説明を省略する。 Next, it is determined whether or not the reference position of the reference block in the x direction is larger than the lower right of the referenceable area A and the reference position of the reference block in the x direction is larger than the lower right of the referenceable area B (S6118). .. If the determination is false (S6118: NO), the process proceeds to the next process (S6120). On the other hand, if the determination is true (S6118: YES), the reference position in the x direction is corrected according to the lower right of the referenceable area B (S6009). Since the process of S6009 has already been described, the description thereof will be omitted.
　次に、参照ブロックのy方向の参照位置が参照可能領域Ａの右下より大きく、かつ参照ブロックのy方向の参照位置が参照可能領域Ｂの右下より大きいか否かを判定する（Ｓ６１２０）。判定が偽ならば（Ｓ６１２０：ＮＯ）、処理を終了する。一方、判定が真ならば（Ｓ６１２０：ＹＥＳ）、参照可能領域Ｂの右下に合わせてy方向の参照位置を補正する（Ｓ６０１１）。Ｓ６０１１の処理はすでに説明しているため、説明を省略する。 Next, it is determined whether or not the reference position of the reference block in the y direction is larger than the lower right of the referenceable area A and the reference position of the reference block in the y direction is larger than the lower right of the referenceable area B (S6120). .. If the determination is false (S6120: NO), the process ends. On the other hand, if the determination is true (S6120: YES), the reference position in the y direction is corrected according to the lower right of the referenceable area B (S6011). Since the process of S6011 has already been described, the description thereof will be omitted.
　以上により、CTUの大きさが128x128画素の場合において、参照ブロックが参照可能領域の外部に位置していたとしても、参照位置を補正して参照可能となる。また、参照可能領域を２つに分解してそれぞれの参照位置を補正することで、処理を簡易化して演算量を削減することが出来る。ここでは、一方の参照可能領域（６３０１）を参照可能領域Ａとし、他方の参照可能領域（６３０２）を参照可能領域Ｂとしている。代わりに、参照可能領域Ａと参照可能領域Ｂを入れ替えて、一方の参照可能領域（６３０１）を参照可能領域Ｂとし、他方の参照可能領域（６３０２）を参照可能領域Ａとして処理しても良い。 From the above, when the size of the CTU is 128x128 pixels, even if the reference block is located outside the referenceable area, the reference position can be corrected and the reference can be made. Further, by decomposing the referenceable area into two and correcting each reference position, the processing can be simplified and the amount of calculation can be reduced. Here, one referenceable area (6301) is designated as a referenceable area A, and the other referenceable area (6302) is designated as a referenceable area B. Alternatively, the referenceable area A and the referenceable area B may be exchanged so that one referenceable area (6301) becomes the referenceable area B and the other referenceable area (6302) is treated as the referenceable area A. ..
　本実施例では、CTUの大きさが128x128画素か否かを判定し（Ｓ６００２）、処理を切り替えている。これは、イントラブロックコピー基準ブロックが、符号化ツリーブロックを４分割した単位か否か判定するようにしても良いし、CTUの大きさが符号化ブロックの最大サイズより大きいか否かを判定するようにしても良い。 In this embodiment, it is determined whether or not the size of the CTU is 128x128 pixels (S6002), and the processing is switched. This may determine whether the intra-block copy reference block is a unit obtained by dividing the coded tree block into four, or whether the size of the CTU is larger than the maximum size of the coded block. You may do so.
　以上に述べた全ての実施の形態は、複数を組み合わせても良い。 A plurality of the above-described embodiments may be combined.
　以上に述べた全ての実施の形態において、画像符号化装置が出力するビットストリームは、実施の形態で用いられた符号化方法に応じて復号することができるように特定のデータフォーマットを有している。ビットストリームは、ＨＤＤ、ＳＳＤ、フラッシュメモリ、光ディスク等のコンピュータ等で読み解き可能な記録媒体に記録して提供しても良いし、有線あるいは無線のネットワークを通してサーバから提供しても良い。従って、この画像符号化装置に対応する画像復号装置は、提供手段によらず、この特定のデータフォーマットのビットストリームを復号することができる。 In all of the embodiments described above, the bitstream output by the image coding apparatus has a specific data format so that it can be decoded according to the coding method used in the embodiment. There is. The bit stream may be recorded and provided on a recording medium that can be read by a computer such as an HDD, SSD, flash memory, or optical disk, or may be provided from a server via a wired or wireless network. Therefore, the image decoding device corresponding to this image coding device can decode the bit stream of this specific data format regardless of the providing means.
　画像符号化装置と画像復号装置の間でビットストリームをやりとりするために、有線または無線のネットワークが用いられる場合、通信路の伝送形態に適したデータ形式にビットストリームを変換して伝送してもよい。その場合、画像符号化装置が出力するビットストリームを通信路の伝送形態に適したデータ形式の符号化データに変換してネットワークに送信する送信装置と、ネットワークから符号化データを受信してビットストリームに復元して画像復号装置に供給する受信装置とが設けられる。送信装置は、画像符号化装置が出力するビットストリームをバッファするメモリと、ビットストリームをパケット化するパケット処理部と、ネットワークを介してパケット化された符号化データを送信する送信部とを含む。受信装置は、ネットワークを介してパケット化された符号化データを受信する受信部と、受信された符号化データをバッファするメモリと、符号化データをパケット処理してビットストリームを生成し、画像復号装置に提供するパケット処理部とを含む。 When a wired or wireless network is used to exchange the bitstream between the image encoding device and the image decoding device, the bitstream may be converted and transmitted in a data format suitable for the transmission form of the communication path. Good. In that case, a transmission device that converts the bitstream output by the image encoding device into encoded data in a data format suitable for the transmission form of the communication path and transmits it to the network, and a transmission device that receives the encoded data from the network and sends the bitstream. A receiving device that restores the data and supplies it to the image decoding device is provided. The transmitting device includes a memory for buffering a bit stream output by the image coding device, a packet processing unit for packetizing the bit stream, and a transmitting unit for transmitting the encoded data packetized via the network. The receiving device receives the encoded data packetized via the network, a memory for buffering the received encoded data, and packet-processes the encoded data to generate a bit stream for image decoding. Includes a packet processing unit provided to the device.
　画像符号化装置と画像復号装置の間でビットストリームをやりとりするために、有線または無線のネットワークが用いられる場合、送信装置、受信装置に加え、さらに、送信装置が送信する符号化データを受信し、受信装置に供給する中継装置が設けられても良い。中継装置は、送信装置が送信するパケット化された符号化データを受信する受信部と、受信された符号化データをバッファするメモリと、パケットされた符号化データとネットワークに送信する送信部とを含む。さらに、中継装置は、パケット化された符号化データをパケット処理してビットストリームを生成する受信パケット処理部と、ビットストリームを蓄積する記録媒体と、ビットストリームをパケット化する送信パケット処理部を含んでも良い。 When a wired or wireless network is used to exchange bitstreams between the image encoder and the image decoder, it receives the coded data transmitted by the transmitter in addition to the transmitter and receiver. , A relay device for supplying to the receiving device may be provided. The relay device includes a receiving unit that receives the packetized encoded data transmitted by the transmitting device, a memory that buffers the received encoded data, and a transmitting unit that transmits the packetized encoded data to the network. Including. Further, the relay device includes a received packet processing unit that packet-processes the packetized encoded data to generate a bit stream, a recording medium that stores the bit stream, and a transmission packet processing unit that packets the bit stream. But it's okay.
　また、画像復号装置で復号された画像を表示する表示部を構成に追加することで、表示装置としても良い。その場合、表示部は、復号画像信号重畳部２０７により生成され、復号画像メモリ２０８に格納された復号画像信号を読み出して画面に表示する。 Further, by adding a display unit for displaying the image decoded by the image decoding device to the configuration, the display device may be used. In that case, the display unit reads the decoded image signal generated by the decoded image signal superimposing unit 207 and stored in the decoded image memory 208 and displays it on the screen.
　また、撮像部を構成に追加し、撮像した画像を画像符号化装置に入力することで、撮像装置としても良い。その場合、撮像部は、撮像した画像信号をブロック分割部１０１に入力する。 Further, by adding an image pickup unit to the configuration and inputting the captured image into the image coding device, the image pickup device may be used. In that case, the image pickup unit inputs the captured image signal to the block division unit 101.
　図６０に、本実施の形態の符号化復号装置のハードウェア構成の一例を示す。符号化復号装置は、本発明の実施の形態に係る画像符号化装置、および画像復号装置の構成を包含する。係る符号化復号装置９０００は、ＣＰＵ９００１、コーデックＩＣ９００２、Ｉ／Ｏインターフェース９００３、メモリ９００４、光学ディスクドライブ９００５、ネットワークインターフェース９００６、ビデオインターフェース９００９を有し、各部はバス９０１０により接続される。 FIG. 60 shows an example of the hardware configuration of the coding / decoding device of this embodiment. The coding / decoding device includes the configuration of the image coding device and the image decoding device according to the embodiment of the present invention. The coding / decoding device 9000 includes a CPU 9001, a codec IC 9002, an I / O interface 9003, a memory 9004, an optical disk drive 9005, a network interface 9006, and a video interface 9009, and each part is connected by a bus 9010.
　画像符号化部９００７と画像復号部９００８は、典型的にはコーデックＩＣ９００２として実装される。本発明の実施の形態に係る画像符号化装置の画像符号化処理は、画像符号化部９００７により実行され、本発明の実施の形態に係る画像復号装置における画像復号処理は、画像復号部９００８により実行される。Ｉ／Ｏインターフェース９００３は、例えばＵＳＢインターフェースにより実現され、外部のキーボード９１０４、マウス９１０５等と接続する。ＣＰＵ９００１は、Ｉ／Ｏインターフェース９００３を介して入力したユーザー操作に基づき、ユーザーの所望する動作を実行するように符号化復号装置９０００を制御する。キーボード９１０４、マウス９１０５等によるユーザーの操作としては、符号化、復号のどちらの機能を実行するかの選択、符号化品質の設定、ビットストリームの入出力先、画像の入出力先等がある。 The image coding unit 9007 and the image decoding unit 9008 are typically implemented as a codec IC9002. The image coding process of the image coding device according to the embodiment of the present invention is executed by the image coding unit 9007, and the image decoding process in the image decoding device according to the embodiment of the present invention is performed by the image decoding unit 9008. Will be executed. The I / O interface 9003 is realized by, for example, a USB interface, and is connected to an external keyboard 9104, mouse 9105, or the like. The CPU 9001 controls the coding / decoding device 9000 so as to execute the operation desired by the user based on the user operation input via the I / O interface 9003. User operations using the keyboard 9104, mouse 9105, and the like include selection of which function to execute, coding or decoding, setting of coding quality, bitstream input / output destination, image input / output destination, and the like.
　ユーザーがディスク記録媒体９１００に記録された画像を再生する操作を所望する場合、光学ディスクドライブ９００５は、挿入されたディスク記録媒体９１００からビットストリームを読出し、読み出したビットストリームを、バス９０１０を介してコーデックＩＣ９００２の画像復号部９００８に送る。画像復号部９００８は入力したビットストリームに対して本発明の実施の形態に係る画像復号装置における画像復号処理を実行し、復号画像を、ビデオインターフェース９００９を介して外部のモニタ９１０３へ送る。また、符号化復号装置９０００は、ネットワークインターフェース９００６を有し、ネットワーク９１０１を介して、外部の配信サーバ９１０６や、携帯端末９１０７と接続可能である。ユーザーがディスク記録媒体９１００に記録された画像に変えて、配信サーバ９１０６や携帯端末９１０７に記録された画像を再生することを所望する場合は、ネットワークインターフェース９００６は、入力されたディスク記録媒体９１００からビットストリームを読出すことに変えて、ネットワーク９１０１よりビットストリームを取得する。また、ユーザーがメモリ９００４に記録された画像を再生することを所望する場合は、メモリ９００４に記録されたビットストリームに対して、本発明の実施の形態に係る画像復号装置における画像復号処理を実行する。 When the user desires an operation of reproducing an image recorded on the disc recording medium 9100, the optical disc drive 9005 reads a bit stream from the inserted disc recording medium 9100 and reads the read bit stream via the bus 9010. It is sent to the image decoding unit 9008 of the codec IC9002. The image decoding unit 9008 executes the image decoding process in the image decoding device according to the embodiment of the present invention on the input bit stream, and sends the decoded image to the external monitor 9103 via the video interface 9009. Further, the coding / decoding device 9000 has a network interface 9006 and can be connected to an external distribution server 9106 or a mobile terminal 9107 via the network 9101. When the user desires to play back the image recorded on the distribution server 9106 or the mobile terminal 9107 instead of the image recorded on the disc recording medium 9100, the network interface 9006 is used from the input disc recording medium 9100. Instead of reading the bitstream, it gets the bitstream from network 9101. Further, when the user desires to reproduce the image recorded in the memory 9004, the image decoding process in the image decoding device according to the embodiment of the present invention is executed on the bit stream recorded in the memory 9004. To do.
　ユーザーが外部のカメラ９１０２で撮像した画像を符号化しメモリ９００４に記録する操作を所望する場合、ビデオインターフェース９００９は、カメラ９１０２から画像を入力し、バス９０１０を介し、コーデックＩＣ９００２の画像符号化部９００７に送る。画像符号化部９００７は、ビデオインターフェース９００９を介して入力した画像に対して本発明の実施の形態に係る画像符号化装置における画像符号化処理を実行し、ビットストリームを作成する。そしてビットストリームを、バス９０１０を介し、メモリ９００４へ送る。ユーザーがメモリ９００４に変えて、ディスク記録媒体９１００にビットストリームを記録することを所望する場合は、光学ディスクドライブ９００５は、挿入されたディスク記録媒体９１００に対しビットストリームの書き出しを行う。 When the user desires an operation of encoding an image captured by an external camera 9102 and recording it in the memory 9004, the video interface 9009 inputs an image from the camera 9102, and the image coding unit 9007 of the codec IC 9002 via the bus 9010. Send to. The image coding unit 9007 executes the image coding process in the image coding device according to the embodiment of the present invention on the image input via the video interface 9009 to create a bit stream. Then, the bit stream is sent to the memory 9004 via the bus 9010. If the user desires to record the bitstream on the disc recording medium 9100 instead of the memory 9004, the optical disc drive 9005 writes the bitstream to the inserted disc recording medium 9100.
　画像符号化装置を有し画像復号装置を有さないハードウェア構成や、画像復号装置を有し画像符号化装置を有さないハードウェア構成を実現することも可能である。そのようなハードウェア構成は、例えばコーデックＩＣ９００２が、画像符号化部９００７、または画像復号部９００８にそれぞれ置き換わることにより実現される。 It is also possible to realize a hardware configuration having an image coding device and no image decoding device, or a hardware configuration having an image decoding device and no image decoding device. Such a hardware configuration is realized, for example, by replacing the codec IC9002 with an image coding unit 9007 or an image decoding unit 9008, respectively.
　以上の符号化及び復号に関する処理は、ハードウェアを用いた伝送、蓄積、受信装置として実現しても良いのは勿論のこと、ＲＯＭ（リード・オンリー・メモリ）やフラッシュメモリ等に記憶されているファームウェアや、コンピュータ等のソフトウェアによって実現しても良い。そのファームウェアプログラム、ソフトウェアプログラムをコンピュータ等で読み取り可能な記録媒体に記録して提供しても良いし、有線あるいは無線のネットワークを通してサーバから提供しても良いし、地上波あるいは衛星ディジタル放送のデータ放送として提供しても良い。 The above processing related to coding and decoding may be realized as a transmission, storage, and reception device using hardware, and is stored in a ROM (read-only memory), a flash memory, or the like. It may be realized by firmware or software such as a computer. The firmware program and software program may be recorded on a recording medium readable by a computer or the like and provided, or may be provided from a server via a wired or wireless network, or terrestrial or satellite digital broadcasting data broadcasting. May be provided as.
　以上、本発明を実施の形態をもとに説明した。実施の形態は例示であり、それらの各構成要素や各処理プロセスの組み合わせにいろいろな変形例が可能なこと、またそうした変形例も本発明の範囲にあることは当業者に理解されるところである。 The present invention has been described above based on the embodiments. Embodiments are examples, and it is understood by those skilled in the art that various modifications are possible for each of these components and combinations of each processing process, and that such modifications are also within the scope of the present invention. ..
　本発明は、画像をブロックに分割して予測を行う画像符号化及び復号技術に利用できる。 The present invention can be used in an image coding and decoding technique for dividing an image into blocks and performing prediction.
　１００　画像符号化装置、　１０１　ブロック分割部、　１０２　インター予測部、　１０３　イントラ予測部、１０４　復号画像メモリ、　１０５　予測方法決定部、　１０６　残差信号生成部、　１０７　直交変換・量子化部、　１０８　ビット列符号化部、　１０９　逆量子化・逆直交変換部、　１１０　復号画像信号重畳部、　１１１　符号化情報格納メモリ、　２００　画像復号装置、　２０１　ビット列復号部、　２０２　ブロック分割部、　２０３　インター予測部　２０４　イントラ予測部、　２０５　符号化情報格納メモリ　２０６　逆量子化・逆直交変換部、　２０７　復号画像信号重畳部、　２０８　復号画像メモリ。 100 image encoding device, 101 block division unit, 102 inter-prediction unit, 103 intra-prediction unit, 104 decoded image memory, 105 prediction method determination unit, 106 residual signal generation unit, 107 orthogonal conversion / quantization unit, 108 bit string code Chemical unit, 109 inverse quantization / inverse orthogonal conversion unit, 110 decoded image signal superimposition unit, 111 coded information storage memory, 200 image decoding device, 201 bit string decoding unit, 202 block division unit, 203 inter prediction unit 204 intra prediction unit. , 205 Coding information storage memory 206 Inverse quantization / inverse orthogonal conversion section, 207 Decoded image signal superimposition section, 208 Decoded image memory.

Claims (6)

  1. 　画像の各ピクチャを分割したブロック単位で前記画像を符号化する画像符号化装置であって、
    　画像の各ピクチャを分割したブロック単位に分割するブロック分割部と、
    　イントラ予測モードに応じて画面内の復号済の画素を予測値として参照してブロックを予測するイントラ予測部とを備え、
    　前記ブロック分割部は、
    　輝度ブロックと色差ブロックが互いに同期して共通の分割モードにしたがって再帰的に分割し、
    　イントラ予測において、所定の色差符号化ブロック最小サイズ以下の色差の符号化ブロックを禁止し、
    　色差フォーマットが４：２：０で、輝度ブロックを再帰的に分割し、それに対応する色差ブロックが分割する際に所定の色差符号化ブロック最小サイズよりも小さい色差の符号化ブロックとなる場合は、色差ブロックを分割しないものとした場合に、
    　分割対象ブロックを３分割する３分割モードにおいて、輝度信号の分割対象ブロックを第１の輝度信号の符号化ブロック、第２の輝度信号の符号化ブロック、第３の輝度信号の符号化ブロックに分割されるとともに、色差信号の分割対象ブロックを分割せずに１つの色差信号の符号化ブロックとし、
    　前記イントラ予測部は、色差信号の符号化ブロックの中心の右下の画素の位置に対応する色差信号の画素を含む符号化ブロックのイントラ輝度予測モードの値を色差信号の符号化ブロックのイントラ色差予測モードの値としてイントラ予測を行う、
    　ことを特徴とする画像符号化装置。     An image coding device that encodes the image in block units that divide each picture of the image.
    A block division part that divides each picture of the image into divided block units,
    It is equipped with an intra prediction unit that predicts blocks by referring to decoded pixels in the screen as prediction values according to the intra prediction mode.
    The block division portion
    The luminance block and the color difference block are synchronized with each other and recursively divided according to a common division mode.
    In the intra prediction, the coded block of the color difference less than the predetermined minimum size of the color difference coded block is prohibited.
    When the color difference format is 4: 2: 0, the brightness block is recursively divided, and the corresponding color difference block becomes a color difference coded block smaller than a predetermined color difference coded block minimum size when divided. If the color difference block is not divided,
    In the three-division mode in which the division target block is divided into three, the division target block of the luminance signal is divided into a first luminance signal coding block, a second luminance signal coding block, and a third luminance signal coding block. At the same time, the division target block of the color difference signal is not divided into one coded block of the color difference signal.
    The intra prediction unit sets the value of the intra-luminance prediction mode of the coded block including the pixel of the color difference signal corresponding to the position of the lower right pixel in the center of the coded block of the color difference signal to the intra color difference of the coded block of the color difference signal. Intra-prediction as the value of the prediction mode,
    An image coding device characterized in that.
  2. 　画像の各ピクチャを分割したブロック単位で前記画像を符号化する画像符号化方法であって、
    　画像の各ピクチャを分割したブロック単位に分割するブロック分割ステップと、
    　イントラ予測モードに応じて画面内の復号済の画素を予測値として参照してブロックを予測するイントラ予測ステップとを備え、
    　前記ブロック分割ステップは、
    　輝度ブロックと色差ブロックが互いに同期して共通の分割モードにしたがって再帰的に分割し、
    　イントラ予測において、所定の色差符号化ブロック最小サイズ以下の色差の符号化ブロックを禁止し、
    　色差フォーマットが４：２：０で、輝度ブロックを再帰的に分割し、それに対応する色差ブロックが分割する際に所定の色差符号化ブロック最小サイズよりも小さい色差の符号化ブロックとなる場合は、色差ブロックを分割しないものとした場合に、
    　分割対象ブロックを３分割する３分割モードにおいて、輝度信号の分割対象ブロックを第１の輝度信号の符号化ブロック、第２の輝度信号の符号化ブロック、第３の輝度信号の符号化ブロックに分割されるとともに、色差信号の分割対象ブロックを分割せずに１つの色差信号の符号化ブロックとし、
    　前記イントラ予測ステップは、色差信号の符号化ブロックの中心の右下の画素の位置に対応する色差信号の画素を含む符号化ブロックのイントラ輝度予測モードの値を色差信号の符号化ブロックのイントラ色差予測モードの値としてイントラ予測を行う、
    　ことを特徴とする画像符号化方法。     An image coding method for encoding the image in block units in which each picture of the image is divided.
    A block division step that divides each picture of an image into divided blocks,
    It is equipped with an intra prediction step that predicts a block by referring to the decoded pixels in the screen as a prediction value according to the intra prediction mode.
    The block division step
    The luminance block and the color difference block are synchronized with each other and recursively divided according to a common division mode.
    In the intra prediction, the coded block of the color difference less than the predetermined minimum size of the color difference coded block is prohibited.
    When the color difference format is 4: 2: 0, the brightness block is recursively divided, and the corresponding color difference block becomes a color difference coded block smaller than a predetermined color difference coded block minimum size when divided. If the color difference block is not divided,
    In the three-division mode in which the division target block is divided into three, the division target block of the luminance signal is divided into a first luminance signal coding block, a second luminance signal coding block, and a third luminance signal coding block. At the same time, the division target block of the color difference signal is not divided into one coded block of the color difference signal.
    In the intra prediction step, the value of the intra-luminance prediction mode of the coded block including the pixel of the color difference signal corresponding to the position of the lower right pixel in the center of the coded block of the color difference signal is set to the value of the intra color difference of the coded block of the color difference signal. Intra-prediction as the value of the prediction mode,
    An image coding method characterized by that.
  3. 　画像の各ピクチャを分割したブロック単位で前記画像を符号化する画像符号化プログラムであって、
    　画像の各ピクチャを分割したブロック単位に分割するブロック分割ステップと、
    　イントラ予測モードに応じて画面内の復号済の画素を予測値として参照してブロックを予測するイントラ予測ステップとをコンピュータに実行させ、
    　前記ブロック分割ステップは、
    　輝度ブロックと色差ブロックが互いに同期して共通の分割モードにしたがって再帰的に分割し、
    　イントラ予測において、所定の色差符号化ブロック最小サイズ以下の色差の符号化ブロックを禁止し、
    　色差フォーマットが４：２：０で、輝度ブロックを再帰的に分割し、それに対応する色差ブロックが分割する際に所定の色差符号化ブロック最小サイズよりも小さい色差の符号化ブロックとなる場合は、色差ブロックを分割しないものとした場合に、
    　分割対象ブロックを３分割する３分割モードにおいて、輝度信号の分割対象ブロックを第１の輝度信号の符号化ブロック、第２の輝度信号の符号化ブロック、第３の輝度信号の符号化ブロックに分割されるとともに、色差信号の分割対象ブロックを分割せずに１つの色差信号の符号化ブロックとし、
    　前記イントラ予測ステップは、色差信号の符号化ブロックの中心の右下の画素の位置に対応する色差信号の画素を含む符号化ブロックのイントラ輝度予測モードの値を色差信号の符号化ブロックのイントラ色差予測モードの値としてイントラ予測を行う、
    　ことを特徴とする画像符号化プログラム。     An image coding program that encodes the image in block units that divide each picture of the image.
    A block division step that divides each picture of an image into divided blocks,
    The computer is made to execute an intra prediction step of predicting a block by referring to the decoded pixel in the screen as a predicted value according to the intra prediction mode.
    The block division step
    The luminance block and the color difference block are synchronized with each other and recursively divided according to a common division mode.
    In the intra prediction, the coded block of the color difference less than the predetermined minimum size of the color difference coded block is prohibited.
    When the color difference format is 4: 2: 0, the brightness block is recursively divided, and the corresponding color difference block becomes a color difference coded block smaller than a predetermined color difference coded block minimum size when divided. If the color difference block is not divided,
    In the three-division mode in which the division target block is divided into three, the division target block of the luminance signal is divided into a first luminance signal coding block, a second luminance signal coding block, and a third luminance signal coding block. At the same time, the division target block of the color difference signal is not divided into one coded block of the color difference signal.
    In the intra prediction step, the value of the intra-luminance prediction mode of the coded block including the pixel of the color difference signal corresponding to the position of the lower right pixel in the center of the coded block of the color difference signal is set to the value of the intra color difference of the coded block of the color difference signal. Intra-prediction as the value of the prediction mode,
    An image coding program characterized by this.
  4. 　画像の各ピクチャを分割したブロック単位で前記画像が符号化された符号化ビット列を復号する画像復号装置であって、
    　画像の各ピクチャを分割したブロック単位に分割するブロック分割部と、
    　イントラ予測モードに応じて画面内の復号済の画素を予測値として参照してブロックを予測するイントラ予測部とを備え、
    　前記ブロック分割部は、
    　輝度ブロックと色差ブロックが互いに同期して共通の分割モードにしたがって再帰的に分割され、
    　イントラ予測において、所定の色差符号化ブロック最小サイズ以下の色差の符号化ブロックを禁止し、
    　色差フォーマットが４：２：０で、輝度ブロックを再帰的に分割し、それに対応する色差ブロックが分割する際に所定の色差符号化ブロック最小サイズよりも小さい色差の符号化ブロックとなる場合は、色差ブロックを分割しないものとした場合に、
    　分割対象ブロックを３分割する３分割モードにおいて、輝度信号の分割対象ブロックを第１の輝度信号の符号化ブロック、第２の輝度信号の符号化ブロック、第３の輝度信号の符号化ブロックに分割されるとともに、色差信号の分割対象ブロックを分割せずに１つの色差信号の符号化ブロックとし、
    　前記イントラ予測部は、色差信号の符号化ブロックの中心の右下の画素の位置に対応する色差信号の画素を含む符号化ブロックのイントラ輝度予測モードの値を色差信号の符号化ブロックのイントラ色差予測モードの値としてイントラ予測を行う、
    　ことを特徴とする画像復号装置。     An image decoding device that decodes a coded bit string in which the image is encoded in block units obtained by dividing each picture of the image.
    A block division part that divides each picture of the image into divided block units,
    It is equipped with an intra prediction unit that predicts blocks by referring to decoded pixels in the screen as prediction values according to the intra prediction mode.
    The block division portion
    Luminance blocks and color difference blocks are synchronized with each other and recursively divided according to a common division mode.
    In the intra prediction, the coded block of the color difference less than the predetermined minimum size of the color difference coded block is prohibited.
    When the color difference format is 4: 2: 0, the brightness block is recursively divided, and the corresponding color difference block becomes a color difference coded block smaller than a predetermined color difference coded block minimum size when divided. If the color difference block is not divided,
    In the three-division mode in which the division target block is divided into three, the division target block of the luminance signal is divided into a first luminance signal coding block, a second luminance signal coding block, and a third luminance signal coding block. At the same time, the division target block of the color difference signal is not divided into one coded block of the color difference signal.
    The intra prediction unit sets the value of the intra-luminance prediction mode of the coded block including the pixel of the color difference signal corresponding to the position of the lower right pixel in the center of the coded block of the color difference signal to the intra color difference of the coded block of the color difference signal. Intra-prediction as the value of the prediction mode,
    An image decoding device characterized in that.
  5. 　画像の各ピクチャを分割したブロック単位で前記画像が符号化された符号化ビット列を復号する画像復号方法であって、
    　画像の各ピクチャを分割したブロック単位に分割するブロック分割ステップと、
    　イントラ予測モードに応じて画面内の復号済の画素を予測値として参照してブロックを予測するイントラ予測ステップとを備え、
    　前記ブロック分割ステップは、
    　輝度ブロックと色差ブロックが互いに同期して共通の分割モードにしたがって再帰的に分割され、
    　イントラ予測において、所定の色差符号化ブロック最小サイズ以下の色差の符号化ブロックを禁止し、
    　色差フォーマットが４：２：０で、輝度ブロックを再帰的に分割し、それに対応する色差ブロックが分割する際に所定の色差符号化ブロック最小サイズよりも小さい色差の符号化ブロックとなる場合は、色差ブロックを分割しないものとした場合に、
    　分割対象ブロックを３分割する３分割モードにおいて、輝度信号の分割対象ブロックを第１の輝度信号の符号化ブロック、第２の輝度信号の符号化ブロック、第３の輝度信号の符号化ブロックに分割されるとともに、色差信号の分割対象ブロックを分割せずに１つの色差信号の符号化ブロックとし、
    　前記イントラ予測ステップは、色差信号の符号化ブロックの中心の右下の画素の位置に対応する色差信号の画素を含む符号化ブロックのイントラ輝度予測モードの値を色差信号の符号化ブロックのイントラ色差予測モードの値としてイントラ予測を行う、
    　ことを特徴とする画像復号方法。     An image decoding method for decoding a coded bit string in which the image is encoded in block units obtained by dividing each picture of the image.
    A block division step that divides each picture of an image into divided blocks,
    It is equipped with an intra prediction step that predicts a block by referring to the decoded pixels in the screen as a prediction value according to the intra prediction mode.
    The block division step
    Luminance blocks and color difference blocks are synchronized with each other and recursively divided according to a common division mode.
    In the intra prediction, the coded block of the color difference less than the predetermined minimum size of the color difference coded block is prohibited.
    When the color difference format is 4: 2: 0, the brightness block is recursively divided, and the corresponding color difference block becomes a color difference coded block smaller than a predetermined color difference coded block minimum size when divided. If the color difference block is not divided,
    In the three-division mode in which the division target block is divided into three, the division target block of the luminance signal is divided into a first luminance signal coding block, a second luminance signal coding block, and a third luminance signal coding block. At the same time, the division target block of the color difference signal is not divided into one coded block of the color difference signal.
    In the intra prediction step, the value of the intra-luminance prediction mode of the coded block including the pixel of the color difference signal corresponding to the position of the lower right pixel in the center of the coded block of the color difference signal is set to the value of the intra color difference of the coded block of the color difference signal. Intra-prediction as the value of the prediction mode,
    An image decoding method characterized by that.
  6. 　画像の各ピクチャを分割したブロック単位で前記画像が符号化された符号化ビット列を復号する画像復号プログラムであって、
    　画像の各ピクチャを分割したブロック単位に分割するブロック分割ステップと、
    　イントラ予測モードに応じて画面内の復号済の画素を予測値として参照してブロックを予測するイントラ予測ステップとをコンピュータに実行させ、
    　前記ブロック分割ステップは、
    　輝度ブロックと色差ブロックが互いに同期して共通の分割モードにしたがって再帰的に分割され、
    　イントラ予測において、所定の色差符号化ブロック最小サイズ以下の色差の符号化ブロックを禁止し、
    　色差フォーマットが４：２：０で、輝度ブロックを再帰的に分割し、それに対応する色差ブロックが分割する際に所定の色差符号化ブロック最小サイズよりも小さい色差の符号化ブロックとなる場合は、色差ブロックを分割しないものとした場合に、
    　分割対象ブロックを３分割する３分割モードにおいて、輝度信号の分割対象ブロックを第１の輝度信号の符号化ブロック、第２の輝度信号の符号化ブロック、第３の輝度信号の符号化ブロックに分割されるとともに、色差信号の分割対象ブロックを分割せずに１つの色差信号の符号化ブロックとし、
    　前記イントラ予測ステップは、色差信号の符号化ブロックの中心の右下の画素の位置に対応する色差信号の画素を含む符号化ブロックのイントラ輝度予測モードの値を色差信号の符号化ブロックのイントラ色差予測モードの値としてイントラ予測を行う、
    　ことを特徴とする画像復号プログラム。     An image decoding program that decodes a coded bit string in which the image is encoded in block units obtained by dividing each picture of the image.
    A block division step that divides each picture of an image into divided blocks,
    The computer is made to execute an intra prediction step of predicting a block by referring to the decoded pixel in the screen as a predicted value according to the intra prediction mode.
    The block division step
    Luminance blocks and color difference blocks are synchronized with each other and recursively divided according to a common division mode.
    In the intra prediction, the coded block of the color difference less than the predetermined minimum size of the color difference coded block is prohibited.
    When the color difference format is 4: 2: 0, the brightness block is recursively divided, and the corresponding color difference block becomes a color difference coded block smaller than a predetermined color difference coded block minimum size when divided. If the color difference block is not divided,
    In the three-division mode in which the division target block is divided into three, the division target block of the luminance signal is divided into a first luminance signal coding block, a second luminance signal coding block, and a third luminance signal coding block. At the same time, the division target block of the color difference signal is not divided into one coded block of the color difference signal.
    In the intra prediction step, the value of the intra-luminance prediction mode of the coded block including the pixel of the color difference signal corresponding to the position of the lower right pixel in the center of the coded block of the color difference signal is set to the value of the intra color difference of the coded block of the color difference signal. Intra-prediction as the value of the prediction mode,
    An image decoding program characterized by this.
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BROSS, BENJAMIN ET AL.: "Versatile Video Coding (Draft 5)", JOINT VIDEO EXPERTS TEAM (JVET), no. JVET-J0042v3, 11 June 2019 (2019-06-11), pages 134 - 135 *
LIN, ZHIYI ET AL.: "CE3-related: Constrained partitioning of chroma intra CBs", JOINT VIDEO EXPERTS TEAM (JVET), no. JVET-N0082v3, 23 March 2019 (2019-03-23), XP030204596 *

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