WO2016185651A1 - Video encoding device, video decoding device, video encoding method, video decoding method, and program - Google Patents
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- WO2016185651A1 WO2016185651A1 PCT/JP2016/001600 JP2016001600W WO2016185651A1 WO 2016185651 A1 WO2016185651 A1 WO 2016185651A1 JP 2016001600 W JP2016001600 W JP 2016001600W WO 2016185651 A1 WO2016185651 A1 WO 2016185651A1
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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
- H04N19/124—Quantisation
- H04N19/126—Details of normalisation or weighting functions, e.g. normalisation matrices or variable uniform quantisers
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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
- H04N19/169—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
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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
- H04N19/169—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
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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
- H04N19/70—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals characterised by syntax aspects related to video coding, e.g. related to compression standards
Definitions
- the present invention relates to a video encoding device and a video decoding device that use residual area adaptive color conversion and color difference quantization offset.
- each frame of the digitized image is divided into Coding Tree Units (CTU: Coding Tree Unit), and each CTU in the raster scan order. Encoded.
- CTU is divided into coding units (CU: Coding Unit) in a quad tree structure and encoded.
- CU Coding Unit
- Each CU is predicted by being divided into prediction units (PU: Prediction Unit).
- PU Prediction Unit
- the prediction error of each CU is divided into transform units (TU: Transform Unit) in a quadtree structure, and is subjected to frequency conversion.
- CU is a coding unit for intra prediction / interframe prediction.
- Intra prediction is prediction in which a prediction signal is generated from a reconstructed image of an encoding target frame.
- HEVC / H.265 defines 33 types of angle intra prediction.
- an intra prediction signal is generated by extrapolating the reconstructed pixels around the encoding target block in any of 33 types of directions.
- DC prediction and Planar prediction are specified as intra prediction.
- DC prediction the average value of the reference image is used as the prediction value for all pixels of the prediction target TU.
- Planar prediction a predicted image is generated by linear interpolation from pixels in a reference image.
- Inter-frame prediction is prediction based on an image of a reconstructed frame (reference picture) having a display time different from that of the encoding target frame. Inter-frame prediction is also called inter prediction. In inter prediction, an inter prediction signal is generated based on a reconstructed image block of a reference picture (using pixel interpolation if necessary).
- a digital color image is composed of R, G, and B digital images.
- the RGB space is used to increase compression efficiency (to reduce the amount of data).
- the image signal is converted into a signal in a color space (YCoCr space) that is a combination of a luminance signal (Y) and a color difference signal (Cb, Cr).
- the quantization parameter (QP) for the color difference signal is generated by converting the QP for the luminance signal using an offset value called chroma_qp_index_offset.
- QP quantization parameter
- cb_qp_index_offset first color difference quantization offset
- cr_qp_index_offset second color difference quantization offset
- Non-Patent Document 2 proposes a technique called residual area adaptive color transformation (Adaptive color transform in residual domain).
- the residual area adaptive color conversion is a technique for adaptively switching the prediction error signal of the image signal in the RGB color space to the signal in the YCoCr color space in units of blocks.
- FIG. 20 shows an example in which data compression is performed in the YCoCr space for the hatched blocks and data compression is performed in the RGB space for the other blocks.
- cu_residual_csc_flag 0 indicates that the signal in the RGB space is compressed
- cu_residual_csc_flag 1 indicates that the signal is compressed after being converted into the YCoCr space.
- the receiver performs a decoding process after returning the YCoCr space signal to the RGB space signal using the Backward color space conversion matrix described below.
- Patent Document 1 describes a video encoding device and a video decoding device that perform different signal processing depending on whether the input image signal is a signal in the RGB color space or the YCoCr space. Specifically, when performing weighted prediction based on the H.264 / AVC method, the video encoding device relates to the offset added to the prediction signal, the R, G, B signal, and the luminance signal (Y signal). ) And the same offset are applied to the color difference signal. However, Patent Document 1 does not teach new knowledge regarding color difference quantization offset.
- 21 includes a switch 101 ⁇ , a color space converter 102, a switch 103, a frequency converter / quantizer 104, an inverse quantization / inverse frequency converter 105, a switch 106, an inverse color space converter 107, A switch 108, a buffer 109, a predictor 110, a prediction parameter determiner 111 ⁇ , an entropy encoder 112, a subtractor 115, and an adder 116 are provided.
- the predictor 110 generates a prediction signal for the input image signal of the CU. Specifically, the predictor 110 generates a prediction signal (intra prediction signal) based on the intra prediction, and generates a prediction signal (inter prediction signal) based on the inter prediction.
- the image input to the video encoding device is input to the switch 101 ⁇ ⁇ ⁇ as a prediction error image after the prediction image supplied from the predictor 110 ⁇ is subtracted by the subtractor 115.
- the input image signal is a signal in the RGB color space.
- the video encoding device has a residual area adaptive color conversion function.
- the video encoding apparatus can adaptively switch the prediction error signal of the image signal in the RGB Y space to the signal in the YCoCr space in units of blocks.
- the switch 101 When the prediction error signal is handled in the RGB space, the switch 101 is set so that the prediction error image is input to the switch 103. When the prediction error signal is handled in the YCoCr space, the switch 101 is set so that the prediction error image is input to the color space converter 102. Note that the switch 101 sets the output destination of the prediction error image, for example, according to the control of the prediction parameter determiner 111.
- the color space converter 102 ⁇ ⁇ converts the RGB ⁇ space prediction error signal into a YCoCr space signal using the above equation (1) (Forward color space conversion matrix), and then outputs the signal to the switch 103.
- the switch 103 ⁇ ⁇ When the prediction error signal is handled in the RGB color space, the switch 103 ⁇ ⁇ outputs the prediction error signal from the switch 101 ⁇ ⁇ to the frequency converter / quantizer 104. When the prediction error signal is handled in the YCoCr space, the switch 103 outputs the prediction error signal from the color space converter 102 to the frequency converter / quantizer 104. Note that the switch 103 ⁇ ⁇ selects the input source of the prediction error image, for example, according to the control of the prediction parameter determiner 111.
- the frequency converter / quantizer 104 performs frequency conversion on the prediction error image and quantizes the frequency converted prediction error image (coefficient image).
- the entropy encoder 112 performs entropy encoding on the prediction parameter and the quantized coefficient image, and outputs a bit stream.
- the inverse quantization / inverse frequency converter 105 inversely quantizes the quantized coefficient image. Further, the inverse quantization / inverse frequency converter 105 performs inverse frequency conversion on the inversely quantized coefficient image.
- the reconstructed prediction error image subjected to the inverse frequency conversion is input to the switch 106 ⁇ ⁇ ⁇ ⁇ .
- the switch 106 When the prediction error signal is handled in the RGB space, the switch 106 is set so that the reconstructed prediction error image is input to the switch 108. When the prediction error signal is handled in the YCoCr space, the switch 106 is set so that the reconstructed prediction error image is input to the inverse color space converter 107. Note that the switch 106 selects the output destination of the reconstructed prediction error image according to the control of the prediction parameter determiner 111, for example.
- the inverse color space converter 107 converts the reconstruction prediction error signal of the YCoCr space into a signal in the RGB space using the above equation (1) (Backward color space conversion matrix), and then outputs it to the switch 108.
- Switch 108 selects the reconstructed prediction error signal from switch 106 when handling the prediction error signal in the RGB space.
- the switch 108 selects the reconstructed prediction error signal from the inverse color space converter 107. Note that the switch 108 ⁇ ⁇ selects any one of the reconstructed prediction error images according to the control of the prediction parameter determiner 111 ⁇ ⁇ ⁇ , for example.
- the reconstructed prediction error image from the switch 108 is supplied to the buffer 109 ⁇ as a reconstructed image after the prediction signal is added by the adder 116.
- the buffer 109 stores the reconstructed image.
- the prediction parameter determiner 111 instructs the predictor 110 to compare the input image signal and the prediction signal and determine, for example, a prediction parameter that minimizes the coding cost.
- the prediction parameter determiner 111 ⁇ ⁇ ⁇ supplies the determined prediction parameter to the entropy encoder 112.
- the prediction parameter is information related to block prediction, such as a prediction mode (intra prediction, inter prediction), an intra prediction block size, an intra prediction direction, an inter prediction block size, and a motion vector.
- the prediction parameter determiner 111 further determines, for each block, whether to handle the prediction error signal in RGB space or YCoCr space.
- FIG. 22 is a block diagram illustrating an example of a configuration of a general video decoding apparatus that decodes a bitstream output from a general video encoding apparatus and obtains a decoded image. The configuration and operation of a general video decoding device will be described with reference to FIG.
- the video decoding apparatus shown in FIG. 22 includes an entropy decoder 212, an inverse quantization / inverse frequency converter 205, a switch 206, an inverse color space converter 207, a switch 208, a buffer 209, a predictor 210, and an adder 216. .
- the entropy decoder 212 performs entropy decoding on the input bit stream.
- the entropy decoder 212 supplies the quantized coefficient image to the inverse quantization / inverse frequency converter 205, and supplies the prediction parameters to the predictor 210.
- the inverse quantization / inverse frequency converter 205 inversely quantizes the input quantized coefficient image and outputs it as a coefficient image. Further, the inverse quantization / inverse frequency converter 205 converts the frequency domain coefficient image into a spatial domain image and outputs it as a prediction error image. The prediction error image is input to the switch 206.
- the switch 206 When the prediction error signal is handled in the RGB color space, the switch 206 is set so that the prediction error image is input to the switch 208. When the prediction error signal is handled in the YCoCr space, the switch 206 is set so that the prediction error image is input to the inverse color space converter 207.
- the switch 206 ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ can specify whether the prediction error signal should be handled in the RGB space or the prediction error signal in the YCoCr ⁇ ⁇ ⁇ ⁇ space by signaling from the video encoding device.
- the inverse color space converter 207 converts the YCoCr ⁇ space prediction error signal into the RGB space signal using the above equation (1) (Backward color space conversion matrix), and then outputs the prediction error signal to the switch 208. .
- the switch 208 ⁇ ⁇ selects the prediction error signal from the switch 206 ⁇ ⁇ when handling the prediction error signal in the RGB space.
- the switch 208 selects the prediction error signal from the inverse color space converter 207.
- the switch 208 ⁇ can specify whether the prediction error signal should be handled in the RGB space or the prediction error signal in the YCoCr space by signaling from the video encoding device.
- the prediction error image from the switch 208 ⁇ ⁇ is supplied to the buffer 209 ⁇ as a reconstructed image after the prediction signal from the predictor 210 ⁇ ⁇ is added by the adder 216.
- the buffer 209 stores the reconstructed image.
- the reconstructed image stored in the buffer 209 is output as a decoded image (decoded video).
- the buffer 209 accumulates previously decoded images as reference images.
- the predictor 210 predicts a decoding target image from adjacent reconstructed images decoded in the past in the image currently being decoded, and generates a predicted image.
- the predictor 210 ⁇ ⁇ generates a prediction image based on the reference image supplied from the buffer 209 when performing inter prediction.
- the color difference quantization offset technique is a technique for adjusting a quantization parameter for each color component by signaling a color difference quantization offset value for the second color component and the third color component. That is, the quantization intensity can be changed.
- -Picture unit pps_cb_qp_offset / pps_cr_qp_offset / slice_qp_delta_cb / slice_qp_delta_cr ⁇
- Slice unit slice_qp_delta_cb / slice_qp_delta_cr -Block unit: cu_chroma_qp_offset_idx
- Subjective image quality can be improved by adjusting the quantization intensity for each color component using the above syntax.
- the video encoding apparatus shown in FIG. 21 and the video decoding apparatus shown in FIG. 22 also apply a chrominance quantization offset. As shown in FIG. 21, a predetermined color difference quantization offset is input to the video encoding device.
- the quantization parameter of the B component is set as shown in FIG. Increase / decrease according to one color difference quantization offset, and increase / decrease the quantization parameter of R component according to the second color difference quantization offset.
- the inverse quantization / inverse frequency converter 105 increases / decreases the inverse quantization parameter of the B component according to the first color difference quantization offset, and increases / decreases the inverse quantization parameter of the R component according to the second color difference quantization offset.
- the quantization parameter of the Co component is set according to the first color difference quantization offset as shown in FIG. Increase / decrease, and increase / decrease the Cr component quantization parameter according to the second color difference quantization offset.
- the inverse quantization / inverse frequency converter 105 increases or decreases the inverse quantization parameter of the Co component according to the first color difference quantization offset, and increases or decreases the inverse quantization parameter of the Cr component according to the second color difference quantization offset.
- the inverse quantization / inverse frequency converter 205 operates in the same manner as the inverse quantization / inverse frequency converter 105 in the video encoding device.
- the color difference quantization offset technique is a technique of signaling the color difference quantization offset value for the second color component (second color component) and the third color component (third color component).
- the residual area adaptation is performed.
- the block compressed in the RGB space and the block compressed in the YCoCr space share the quantization intensity.
- the quantization intensity cannot be set appropriately according to the color space.
- the subjective image quality improvement effect by the color difference quantization offset technique cannot be obtained.
- the present invention relates to a video encoding device, a video decoding device, a video encoding method, and a video decoding method that do not impair the subjective image quality improvement effect when residual region adaptive color conversion and color difference quantization offset are used in combination. And to provide a program.
- the video encoding device can select a color space of a prediction error signal from a plurality of color spaces in units of encoding blocks, and derive an adaptive color difference quantization offset for deriving a color difference quantization offset for each color space.
- Means, and inverse quantization means for inversely quantizing the quantization coefficient image using a color difference quantization offset for each color space that can be expressed in a different dynamic range.
- the video decoding apparatus is capable of selecting a color space of a prediction error signal in units of encoding blocks from a plurality of color spaces, and deriving an adaptive color difference quantization offset deriving unit that derives a color difference quantization offset for each color space And inverse quantization means for inversely quantizing the quantization coefficient image using a color difference quantization offset for each color space that can be expressed in different dynamic ranges.
- the video encoding method can select a color space of a prediction error signal from a plurality of color spaces in units of encoding blocks, derive a color difference quantization offset for each color space, and express it in different dynamic ranges.
- the quantization coefficient image is inversely quantized using a color difference quantization offset for each color space that can be performed.
- the video decoding method can select a color space of a prediction error signal from a plurality of color spaces in units of coding blocks, derive a color difference quantization offset for each color space, and can be expressed in different dynamic ranges.
- the quantization coefficient image is inversely quantized using a color difference quantization offset for each possible color space.
- a video encoding program is a video encoding program that implements a video encoding method capable of selecting a color space of a prediction error signal from a plurality of color spaces in units of encoding blocks.
- a video decoding program is a video decoding program for executing a video decoding method capable of selecting a color space of a prediction error signal from a plurality of color spaces in units of encoding blocks.
- a process for deriving a color difference quantization offset and a process for dequantizing a quantization coefficient image using a color difference quantization offset for each color space that can be expressed in different dynamic ranges are performed.
- the subjective image quality improvement effect can be prevented from being impaired.
- FIG. 10 is an explanatory diagram illustrating an example of syntax for transmitting cb_qp_offset_list [i] and cr_qp_offset_list [i]. It is explanatory drawing which shows an example of the syntax for transmitting alt_cb_qp_offset_list
- FIG. FIG. 1 is a block diagram showing a first embodiment of a video encoding device. With reference to FIG. 1, the configuration of a video encoding apparatus that outputs a bit stream using each frame of a digitized video as an input image will be described.
- the video encoding apparatus of the first embodiment is similar to the general video encoding apparatus shown in FIG. 21 in that a switch 101, a color space converter 102, a switch 103, a frequency conversion / Quantizer 104, Inverse quantization / inverse frequency converter 105, Switch 106, Inverse color space converter 107, Switch 108 ⁇ ⁇ , Buffer 109, Predictor 110, Prediction parameter determiner 111, Entropy encoder 112 ⁇ , Subtractor 115 and adder 116 are provided.
- the video encoding apparatus further includes an adaptive color difference quantization offset deriving unit 121 and a switch 122.
- FIG. 2 (b) is a flowchart showing processing related to signaling of the color difference quantization offset.
- the video encoding apparatus signals information indicating whether or not to perform residual area adaptive color conversion using adaptive_color_trans_flag. Further, when performing the residual area adaptive color conversion, the video encoding apparatus signals information indicating the color space of the block with cu_residual_csc_flag.
- the RGB offset space color difference quantization offset) input to the quantization offset deriving unit 121 ⁇ ⁇ is transmitted with the following syntax (steps S 101 and S 102).
- the entropy encoder 112 ⁇ ⁇ transmits the color difference quantization offset for the RGB color space derived by the adaptive color difference quantization offset deriving unit 121 ⁇ with the following syntax (steps S103 and S104). .
- -Picture unit pps_cb_qp_offset / pps_cr_qp_offset / slice_qp_delta_cb / slice_qp_delta_cr ⁇ Slice unit: slice_qp_delta_cb / slice_qp_delta_cr
- the entropy encoder 112 transmits the color difference quantization offset for the YCoCr space derived by the adaptive color difference quantization offset derivation 121 ⁇ with the following syntax (steps S103 and S105).
- the adaptive color difference quantization offset deriving unit 121 outputs the derived color difference quantization offsets for the YCoCr space (first color difference quantization offset and second color difference quantization offset) to the switch 122.
- the adaptive color difference quantization offset deriving unit 121 outputs the derived RGB color space color difference quantization offsets (first color difference quantization offset and second color difference quantization offset) to the switch 122.
- the adaptive color difference quantization offset derivation unit 121 recognizes whether compression is performed in the RGB color space or the YCoCr color space according to the cu_residual_csc_flag.
- the frequency transformer / quantizer 104 adjusts the quantization parameter using the color difference quantization offset determined by the prediction parameter determiner 111 ⁇ .
- the prediction parameter determiner 111 stores, for example, a color difference quantization offset value for RGB space and a color difference quantization offset value for YCoCr ⁇ ⁇ space in advance, and an appropriate value for the RGB space quantization offset or YCoCr space.
- the value of the color difference quantization offset for use is supplied to the frequency converter / quantizer 104.
- the color difference quantization offset value for the RGB color space and the color difference quantization offset value for the YCoCr space are included in the prediction parameters supplied to the entropy encoder 112.
- the entropy encoder 112 signals the value of the color difference quantization offset for the RGB color space and the value of the color difference quantization offset for the YCoCr space.
- the video encoding apparatus explicitly signals the color difference quantization offset.
- the value of the color difference quantization offset is signaled.
- the operation of the video encoding device other than the above operation is the same as the operation of the video encoding device shown in FIG.
- FIG. FIG. 3 is a block diagram illustrating a configuration of a video decoding apparatus that decodes a bitstream output from a video encoding apparatus that signals a color difference quantization offset and obtains a decoded image.
- the configuration of the video decoding apparatus according to the second embodiment will be described.
- the video decoding device of the present embodiment is similar to the general video decoding device shown in FIG. 22, with an entropy decoder 212, an inverse quantization / inverse frequency converter 205, a switch 206, An inverse color space converter 207, a switch 208, a buffer 209, a predictor 210, and an adder 216 ⁇ ⁇ are provided.
- the video decoding apparatus further includes an adaptive color difference quantization offset deriving unit 221 and a switch 222.
- Fig. 4 is a flowchart showing processing related to derivation of the color difference quantization offset.
- the adaptive color difference quantization offset derivation unit 221 derives a color difference quantization offset for the YCoCr space (step S204).
- the adaptive color difference quantization offset derivation 221 derives the color difference quantization offset for RGB space. (Step S203).
- the adaptive color difference quantization offset deriving unit 221 derives the color difference quantization offset for the RGB space (first color difference quantization offset qPi Cb and second color difference quantization offset qPi Cr ) as follows.
- qPi Cb Clip3 (-QpBdOffset C , 57, Qp Y + pps_cb_qp_offset + slice_cb_qp_offset + CuQpOffset Cb )
- qPi Cr Clip3 (-QpBdOffset C , 57, Qp Y + pps_cr_qp_offset + slice_cr_qp_offset + CuQpOffset Cr ) (2)
- Clip3 (x, y, z) is a function for clipping the input z into the range [x, y].
- Qp Y is a quantization parameter for the first color component
- CuQpOffset Cb is a color difference quantization offset for each block of the second color component
- CuQpOffset Cr is a color difference quantization offset for each block of the third color component.
- QPI Cb has been described as QPI Cr
- the first color component is a G component
- a second color component B component when the third color component of the RGB space of the R component
- QPI Cb, for the B component corresponds to the color difference quantization offset
- QPI Cr corresponds to the color difference quantization offset for R component.
- the adaptive chrominance quantization offset derivation unit 221 derives a chrominance quantization offset (first chrominance quantization offset qPi Cb and second chrominance quantization offset qPi Cr ) for YCoCr space as shown in the following equation (3). .
- qPi Cb Clip3 (-QpBdOffset C , 57, Qp Y + alt_pps_cb_qp_offset + alt_slice_cb_qp_offset + CuQpOffset Cb )
- qPi Cr Clip3 (-QpBdOffset C , 57, Qp Y + alt_pps_cr_qp_offset + alt_slice_cr_qp_offset + CuQpOffset Cr ) (3)
- the quantization parameters (Qp ′ Cb , Qp ′ Cr ) are calculated as in the following equation (4).
- qP Cb Clip3 (-QpBdOffset C , 57, Qp Y + pps_cb_qp_offset + slice_cb_qp_offset + CuQpOffset Cb )
- qPi Cr Clip3 (-QpBdOffset C , 57, Qp Y + pps_cr_qp_offset + slice_cr_qp_offset + CuQpOffset Cr ) -"Otherwise (cu_residual_csc_flag is equal to 1)
- the variables qP Cb and qP Cr are set equal to Min (qPi, 51), based on the index qPi equal to qPi Cb and qPi Cr , respectively.
- the inverse quantization / inverse frequency converter 205 dequantizes the input quantized coefficient image and outputs the coefficient image as a coefficient image by converting the quantization parameter into the color difference quantization offset from the adaptive color difference quantization offset deriving device 221. Increase or decrease according to
- the color difference quantization offset for RGB space (first color difference quantization offset qPi Cb and second color difference quantization offset qPi Cr ) calculated by the adaptive color difference quantization offset deriving unit 221 according to the above equation (2). Is used.
- the inverse quantization / inverse frequency converter 205 converts the inverse quantization parameter of the Co component to the first color difference quantum in the YCoCr space.
- the inverse quantization parameter of the Cr component is increased or decreased according to the second color difference quantization offset in the YCoCr space.
- the color difference quantization offset for the YCoCr space first color difference quantization offset qPi Cb and second color difference quantization offset qPi Cr ) calculated by the adaptive color difference quantization offset derivation unit 221 according to the above equation (3). Is used.
- the first color difference quantization offset for RGB color space is represented by cb_qp_offset
- the second color difference quantization offset for RGB color space is represented by cr_qp_offset
- the first color difference quantization offset for YCoCrCospace is represented by alt_cb_qp_offset
- the second color difference quantization offset for YCoCr space is represented by alt_cr_qp_offset.
- the range of the first color difference quantization offset for the RGB color space and the range of the first color difference quantization offset for the YCoCr color space -12% to 12 is exemplified, and the second color difference quantization offset for the RGB color space and the value for the YCoCr color space As a range of the second color difference quantization offset, -12 to 12 is illustrated.
- the adaptive color difference quantization offset derivation unit 221 derives the color difference quantization offset for each color space, and the inverse quantization / inverse frequency converter 205 uses the color difference quantization offset for each color space as shown in FIG. Since the quantization coefficient image is inversely quantized, when the residual area adaptive color conversion and the color difference quantization offset are used in combination, the subjective image quality improvement effect can be prevented from being impaired.
- the inverse quantization / inverse frequency converter 105 in the video encoding device operates in the same manner as the inverse quantization / inverse frequency converter 205.
- FIG. 6 is an explanatory diagram showing an example of syntax for transmitting alt_pps_cb_qp_offset and alt_pps_cr_qp_offset (improvement of 7.3.2.3.2 Picture parameter set range extensions syntax described in Non-Patent Document 1).
- italicized display locations indicate the characteristic locations of this embodiment.
- FIGS. 7 and 8 are explanatory diagrams showing an example of syntax for transmitting alt_slice_qp_delta_cb and alt_slice_qp_delta_cr (improvement of 7.3.1.1 General slice segment header syntax described in Non-Patent Document 1). 7B and 8B, the italicized display locations indicate the characteristic locations of the present embodiment.
- the configuration of the video encoding apparatus of the present embodiment is the same as that shown in FIG.
- the entropy encoder 112 specifies information that can specify the color difference quantization offset for the RGB space (for example, specifies a data table in which the color difference quantization offset held in the video decoding device is set) Index or color difference quantization offset value) is transmitted to the video decoding device.
- the entropy encoder 112 uses the syntax illustrated in FIGS. 6, 7, and 8 ⁇ as information that can specify the color difference quantization offset for the YCoCr space (for example, the color difference quantum). Signaling offset value itself).
- Embodiment 4 FIG. Next, a video decoding apparatus according to the fourth embodiment will be described.
- the video decoding apparatus according to the present embodiment corresponds to the video encoding apparatus according to the third embodiment. Note that the configuration of the video decoding apparatus of the present embodiment is the same as the configuration shown in FIG.
- the adaptive color difference quantization offset derivation 221 Similar to the case of the second embodiment, a chrominance quantization offset is derived.
- the adaptive color difference quantization offset derivation unit 121 operates in the same manner as the adaptive color difference quantization offset derivation unit 221.
- FIG. 9 shows an example of syntax for additionally transmitting cb_qp_offset_list [i] and cr_qp_offset_list [i] for the YCoCr space (7.3.2.3.2 Picture parameter set range extensions syntax described in Non-Patent Document 1)
- FIG. 9 the italicized display location indicates the feature location of the present embodiment (that is, the size of the cb_qp_offset_list / cr_qp_offset_list (the range of chroma_qp_offset_list_len_minus1) is expanded according to the value of adaptive_color_trans_flag).
- the quantization offset for RGB space and YCoCr space is switched in units of blocks by adjusting the value of cu_chroma_qp_offset_idx syntax transmitted in units of blocks according to the value of cu_residual_csc_flag syntax. Can do.
- the entropy encoder 112 specifies information that can specify the color difference quantization offset for the RGB space (for example, specifies a data table in which the color difference quantization offset held in the video decoding device is set) Cu_chroma_qp_offset_idx syntax) that is an index to be transmitted to the video decoding device.
- the entropy encoder 112 has information that can specify the color difference quantization offset for the YCoCr space (for example, the color difference quantization offset held in the video decoding device is set).
- Cu_chroma_qp_offset_idx syntax that is an index for designating the data table is transmitted to the video decoding device.
- italicized display locations correspond to the color difference quantization offset for the YCoCr space described above.
- the video decoding apparatus according to the present embodiment corresponds to the video encoding apparatus according to the fifth embodiment. Note that the configuration of the video decoding apparatus of the present embodiment is the same as the configuration shown in FIG.
- the entropy decoder 212 decodes that the data is compressed in the YCoCr ⁇ ⁇ ⁇ space by the syntax illustrated in Fig. 9 ⁇ ⁇ ⁇ , for example, reads the color difference quantization offset from the data table specified by the index, and adapts The color difference quantization offset derivation unit 221 calculates the color difference quantization parameter as in the case of the second embodiment.
- the adaptive color difference quantization offset derivation unit 121 operates in the same manner as the adaptive color difference quantization offset derivation unit 221.
- FIG. 10 shows an example of syntax for transmitting alt_cb_qp_offset_list [i] and alt_cr_qp_offset_list [i] for YCoCr space (7.3.2.3.2 Picture parameter set range extensions syntax described in Non-Patent Document 1). It is explanatory drawing shown. In FIG. 10, italicized display locations indicate characteristic locations of the present embodiment.
- cu_chroma_qp_offset_idx 0 derives cb_qp_offset_list [0] and cr_qp_offset_list [0] for RGB. Therefore, in the fifth embodiment, when the size of the list is 4 (when chroma_qp_offset_list_len_minus1 is 3), in order to derive cb_qp_offset_list [4] and alt_cr_qp_offset_list [4] for YCoCr, cu_chroma_qp_offset_ Must be transmitted.
- the configuration of the video encoding apparatus of the present embodiment is the same as that shown in FIG.
- the entropy encoder 112 specifies information that can specify the color difference quantization offset for the RGB space (for example, specifies a data table in which the color difference quantization offset held in the video decoding device is set) Is transmitted to the video decoding device.
- the entropy encoder 112 has information that can specify the color difference quantization offset for the YCoCr space (for example, the color difference quantization offset held in the video decoding device is set).
- the index for designating the data table is transmitted to the video decoding device.
- Embodiment 8 FIG. Next, a video decoding apparatus according to the eighth embodiment will be described.
- the video decoding apparatus according to the present embodiment corresponds to the video encoding apparatus according to the seventh embodiment. Note that the configuration of the video decoding apparatus of the present embodiment is the same as the configuration shown in FIG.
- the color difference quantization offset is read from the data table specified by the index, and adaptively
- the color difference quantization offset derivation unit 221 calculates the color difference quantization parameter as in the case of the second embodiment.
- the adaptive color difference quantization offset derivation unit 121 operates in the same manner as the adaptive color difference quantization offset derivation unit 221.
- cu_chroma_qp_offset_idx when present, specifies the index into the cb_qp_offset_list [] and cr_qp_offset_list [] or the alt_cb_qp_offset_list [] and alt_cr_qp_offset_list [] that is used to determine the value of CuQpOffsetCb_ Cu_p_offsetCb_ Cu_p of 0 to chroma_qp_offset_list_len_minus1, inclusive.When not present, the value of cu_chroma_qp_offset_idx is inferred to be equal to 0.
- CuQpOffsetCb cb_qp_offset_list [cu_chroma_qp_offset_idx]
- Embodiment 9 FIG.
- the video encoding apparatus explicitly signals the color difference quantization offset, but signals that the color space of the prediction error signal is selected in units of blocks, but does not signal the color difference quantization offset. It may be. In this specification, this is referred to as implicit color difference quantization offset signaling.
- the adaptive color difference quantization offset derivation unit 221 Reads out the color difference quantization offset value for the RGB color space stored in advance in the video decoding device.
- the adaptive color difference quantization offset derivation unit 221 ⁇ ⁇ calculates the YCoCr from the color difference quantization offset value for the RGB color space stored in advance. The value of the color difference quantization offset for space is calculated.
- the color difference quantization offset for RGB color space and the color difference quantization offset for YCoCr color space are correlated to some extent, that is, to calculate the color difference quantization offset for YCoCr color space from the color difference quantization offset for RGB color space. Therefore, the adaptive color difference quantization offset deriving unit 221 can derive the color difference quantization offset for YCoCr space by such a calculation equation.
- the video decoding device implicitly derives the color difference quantization offset.
- the adaptive color difference quantization offset derivation unit 121 operates in the same manner as the adaptive color difference quantization offset derivation unit 221.
- the video encoding device implicitly signals the color difference quantization offset, the amount of data to be transmitted can be reduced.
- the color difference quantization offset for one color space may be 0.
- the entropy decoder 212 ⁇ ⁇ decodes cu_residual_csc_flag 0 (indicating that data compression is performed in RGB space)
- the adaptive color difference quantization offset derivation unit 221 is pps_cb_qp_offset / pps_cr_qp_offset / slice_qp_delta_cb
- the value of the color difference quantization offset for YCoCr space is calculated from slice_qp_delta_cb / slice_qp_delta_cr transmitted in units of slices.
- qP Cb Clip3 (-QpBdOffset C , 57, Qp Y + pps_cb_qp_offset + slice_cb_qp_offset + CuQpOffset Cb )
- the variables qP Cb and qP Cr are set equal to Min (qPi, 51), based on the index qPi equal to qPi Cb and qPi Cr , respectively.
- Embodiment 10 It is conceivable to use an additive specification when deriving the color difference quantization offset of the other color space (eg, YCoCr space).
- the other color space eg, YCoCr space.
- the color difference quantization offset for one color space may be set to 0. .
- FIG. 11 is an explanatory diagram for explaining additive specifications.
- the derivation process of the color difference quantization offset for one color space (in this case, the RGB color space) can be made the same as the general derivation process in HEVC.
- the derivation process of qPCb and qPCr does not depend on the color space.
- the dynamic range of alt_pps_cb_qp_offset and alt_pps_cr_qp_offset, and alt_slice_qp_delta_cb and alt_slice_qp_delta_cr is the dynamic range of the color difference quantization offset in one color space (in this case, RGB space). If it is constrained to be the same as ⁇ 12 to 12, the quantization offset for the YCoCr space may not be set to a desired value depending on the value of the color difference quantization offset of one set color space. When the color difference quantization offset of one color space and the additional color difference quantization offset (in this case, the color difference quantization offset for YCoCr space) are constrained to the same dynamic range, favorable color reproduction cannot be achieved for each color space There is.
- the second color component (B component) of one color space in this case, RGB space
- the second color component (Co component) of the other color space in this case, YCoCr space
- the maximum value that can be added to the B component -12 is 12, and the result of addition is only 0.
- the adaptive color difference quantization offset derivation unit 121 performs the following processing, for example. Execute.
- the dynamic range after executing the process of adding the color difference quantization offset in one color space is made to be the same as the dynamic range in the one color space from -12% to 12.
- the dynamic range of the color difference quantization offset in the other color space in this case, YCoCr space
- the dynamic range of the color difference quantization offset in one color space in this case, RGB space (-12 to 12). It can also be said that it is not to be the same.
- the configuration of the video decoding apparatus of the present embodiment is the same as the configuration shown in FIG.
- the adaptive color difference quantization offset derivation unit 221 performs the following processing in the same manner as the adaptive color difference quantization offset derivation unit 121.
- alt_pps_y_qp_offset, alt_pps_cb_qp_offset and alt_pps_cr_qp_offset specify offsets to the luma, cb and cr quantization parameter qP derived in the above equations (7) to (9), respectively.
- alt_pps_y_qp_offset, alt_pps_cb_qp_offset + pps_cb_qp_offset, and alt_pps_cr_qp_offset + pps_cr_qp_offset and shall be in the range of -12 to +12, inclusive.
- alt_pps_cb_qp_offset and alt_pps_cr_qp_offset are not used in the decoding process and decoders shall ignore their value.
- alt_slice_y_qp_offset, alt_slice_cb_qp_offset and alt_slice_cr_qp_offset specify offsets to the luma, cb and cr quantization parameter qP derived in the above equations (7) to (9), respectively.
- alt_slice_y_qp_offset The values of alt_slice_y_qp_offset, alt_slice_cb_qp_offset and alt_slice_cr_qp_offset shall be in the range of -12 to +12, inclusive.
- ChromaArrayType is equal to 0
- alt_slice_cb_qp_offset and alt_slice_cr_qp_offset are not used in the decoding process and decoders shall ignore their value.
- the value of alt_pps_y_qp_offset + alt_slice_y_qp_offset shall be in the range of -12 to +12, inclusive.
- alt_pps_cb_qp_offset + alt_slice_cb_qp_offset + pps_cb_qp_offset + slice_cb_qp_offset shall be in the range of -12 to +12, inclusive.
- the value of alt_pps_cr_qp_offset + alt_slice_cr_qp_offset + pps_cr_qp_offset + slice_cr_qp_offset shall be in the range of -12 to +12, inclusive.
- FIG. 12 is an explanatory diagram for explaining processing in the present embodiment when an additive specification is used.
- the color difference quantization offset for YCoCr color space is simply added to the color difference quantization offset of RGB color space, but in this embodiment, adaptive color difference quantization is performed.
- the offset derivation unit 121 has a dynamic range (range) after the color difference quantization offset for the YCoCr space is added to the color difference quantization offset of the RGB color space, and the dynamic range (for example, ⁇ 12 to 12) in one color space. ) To be the same.
- the adaptive color difference quantization offset deriving unit 121 uses a conversion table prepared in advance to limit the dynamic range of the color difference quantization offset after addition processing to, for example, ⁇ 12 to 12. To convert.
- the adaptive chrominance quantization offset derivation unit uses a color quantization offset having a different dynamic range for each color space, so that the video encoding device can reproduce color more preferable for each space. Can be achieved.
- the video decoding apparatus can reproduce a decoded video with a more preferable color reproduction for each space.
- the RGB color space and the YCoCr color space are exemplified as the two color spaces.
- the method of each of the above embodiments Can be applied.
- the first color component is G
- the second color component is B
- the third color component is R (see Fig. 5)
- the color signal allocation method for each color component is as follows.
- the present invention is not limited to this, and an arbitrary color signal can be assigned to each color component.
- the video encoding device and the video decoding device handle two color spaces, but it is also possible to handle three or more color spaces.
- each of the above embodiments can be configured by hardware, it can also be realized by a computer program.
- the information processing system shown in FIG. 13 includes a processor 1001, a program memory 1002, a storage medium 1003 for storing video data, and a storage medium 1004 for storing a bitstream.
- the storage medium 1003 and the storage medium 1004 may be separate storage media, or may be storage areas composed of the same storage medium.
- a magnetic storage medium such as a hard disk can be used as the storage medium.
- the program memory 1002 stores a program for realizing the function of each block (excluding the buffer block) shown in FIGS.
- the processor 1001 implements the functions of the video encoding device or the video decoding device shown in FIGS. 1B and 3B by executing processing according to the program stored in the program memory 1002.
- FIG. 14 is a block diagram showing the main part of the video encoding device.
- the video encoding device 301 includes an adaptive color difference quantization offset deriving unit 311 that derives a color difference quantization offset for each color space (for example, the adaptive color difference quantization offset deriving device shown in FIG.
- Inverse quantization unit 312 that dequantizes the quantized coefficient image using the color difference quantization offset for each color space (as an example, the inverse quantization / inverse frequency converter shown in Fig. 1) Equivalent to 105).
- the adaptive color difference quantization offset deriving unit 311 adds an offset for the other color space (for example, an offset of YCoCr space) to a color difference quantization offset of one color space (for example, color difference quantization offset of RGB space). And an adjustment unit that stores the addition result of the addition unit within the dynamic range for the other color space.
- FIG. 15 is a block diagram showing a main part of another example of the video encoding device.
- the video encoding device 302 signals the color space selection notification unit 313 that signals that the color space of the prediction error signal is selected in units of blocks (for example, the entropy encoder shown in FIG. 112 equivalent).
- the video encoding device 302 ⁇ does not include means for signaling information that can specify the value of the quantization offset for each color space, in the video encoding device 302,
- the color difference quantization offset is derived implicitly.
- FIG. 16 is a block diagram showing a main part of a further example of the video encoding device.
- the video encoding device 303 is a quantization offset information transmission unit 314 that signals information that can specify the value of the color difference quantization offset for each color space (for example, the entropy shown in FIG. And an encoder 112).
- the information that can specify the color difference quantization offset value is, for example, the color difference quantization offset value itself, or an index that designates a data table in which the color difference quantization offset held in the video decoding device is set. .
- FIG. 17 is a block diagram showing the main part of the video decoding apparatus.
- the video decoding apparatus 401 includes an adaptive color difference quantization offset deriving unit 411 that derives a color difference quantization offset for each color space (for example, the adaptive color difference quantization offset deriving device 221 shown in FIG. And an inverse quantization unit 412 that inversely quantizes the quantized coefficient image using the color difference quantization offset for each color space (for example, the inverse quantization / inverse frequency converter 205 shown in FIG. 3 205) Equivalent).
- the adaptive color difference quantization offset deriving unit 411 adds the offset for the other color space (for example, the offset of the YCoCr space) to the color difference quantization offset of one color space (for example, the color difference quantization offset of the RGB color space). And an adjustment unit that stores the addition result of the addition unit within the dynamic range for the other color space.
- FIG. 18 is a block diagram showing the main part of another example of the video decoding apparatus. As shown in FIG. 18, the video decoding device 402 decodes the fact that the color space of the prediction error signal is selected in units of blocks from the received bitstream (see FIG. 3 ⁇ as an example). An entropy decoder 212).
- the video decoding device 402 ⁇ ⁇ does not include means for decoding information that can specify the value of the color difference quantization offset for each color space, the video decoding device 402 Thus, a color difference quantization offset is derived.
- FIG. 19 is a block diagram showing a main part of still another example of the video decoding apparatus.
- the video decoding device 403 specifies a color difference quantization offset decoding unit 414 (for example, FIG. 19) that specifies the value of the color difference quantization offset for each color space based on the information decoded from the received bitstream.
- a color difference quantization offset decoding unit 414 for example, FIG. 19
- an entropy decoder 212 shown in 3 an entropy decoder 212 shown in 3).
- the above encoding and decoding techniques can be applied to broadcasting equipment.
- it can be installed as a broadcast transmission codec or a broadcast receiving terminal, and a broadcast device equipped with the above-described technology can improve the user experience of the broadcast service by providing a preferable image quality.
- the video encoding device of each embodiment can be incorporated in, for example, a transmission facility or a transmission device in a digital television broadcast or a multimedia (content) distribution system.
- the video decoding device of each of the above embodiments can be incorporated into, for example, a receiving device (receiving terminal) that receives a digital television broadcast or a receiving device (receiving terminal) that receives multimedia distribution.
- a broadcasting device that includes a video encoding device capable of selecting a color space of a prediction error signal from a plurality of color spaces in units of encoding blocks, and provides broadcast content using the video encoding device.
- the video encoding apparatus performs quantization using an adaptive color difference quantization offset deriving unit that derives a color difference quantization offset for each color space, and a color difference quantization offset for each color space that can be expressed in a different dynamic range.
- dequantizing means for dequantizing the coefficient image.
- a receiving terminal for viewing broadcast content including a video decoding device capable of selecting a color space of a prediction error signal in units of encoding blocks from a plurality of color spaces,
- the video decoding device uses an adaptive color difference quantization offset deriving unit that derives a color difference quantization offset for each color space, and a color difference quantization offset for each color space that can be expressed in a different dynamic range to generate a quantization coefficient image.
- an inverse quantization means for performing inverse quantization.
- a video encoding method implemented in a broadcast device that provides broadcast content and capable of selecting a color space of a prediction error signal in units of blocks from a plurality of color spaces, A quantization offset is derived, and a quantization coefficient image is inversely quantized using a color difference quantization offset for each color space that can be expressed in different dynamic ranges.
- a video decoding method that is implemented in a receiving terminal for viewing broadcast content and that can select a color space of a prediction error signal in units of blocks from a plurality of color spaces, for each color space A color difference quantization offset is derived, and a quantization coefficient image is inversely quantized using a color difference quantization offset for each color space that can be expressed in different dynamic ranges.
- a video encoding program installed in a broadcasting device that provides broadcast content, and a video encoding method capable of selecting a color space of a prediction error signal in units of encoding blocks from a plurality of color spaces is implemented.
- a video decoding program installed in a receiving terminal for viewing broadcast content, and implementing a video decoding method capable of selecting a color space of a prediction error signal in units of encoding blocks from a plurality of color spaces
- An image decoding program that performs a process of deriving a color difference quantization offset for each color space on a computer and reverses the quantization coefficient image using the color difference quantization offset for each color space that can be expressed in a different dynamic range. And a process of performing quantization.
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Abstract
A video encoding device that is capable of selecting, from a plurality of color spaces, the color space for a prediction error signal using coding blocks, said video encoding device comprising an adaptive chrominance quantization offset derivation means that derives a quantization offset for each color space, and an inverse-quantization means that inverse-quantizes a quantized coefficient video using the chrominance quantization offset for each of the color spaces that can be expressed in different dynamic ranges.
Description
本発明は、残差領域適応色変換と色差量子化オフセットとを用いる映像符号化装置及び映像復号装置に関する。
The present invention relates to a video encoding device and a video decoding device that use residual area adaptive color conversion and color difference quantization offset.
HEVC(High Efficiency Video Coding)/H.265 に基づく映像符号化方式において、ディジタル化された画像の各フレームは符号化ツリーユニット(CTU :Coding Tree Unit)に分割され、ラスタスキャン順で各CTU が符号化される。CTU は、クアッドツリー構造で符号化ユニット(CU:Coding Unit )に分割されて符号化される。各CUは、予測ユニット(PU:Prediction Unit )に分割されて予測される。また、各CUの予測誤差は、クアッドツリー構造で、変換ユニット(TU:Transform Unit)に分割されて周波数変換される。
In the video coding system based on HEVC (High Efficiency Video Coding) /H.265, each frame of the digitized image is divided into Coding Tree Units (CTU: Coding Tree Unit), and each CTU in the raster scan order. Encoded. CTU is divided into coding units (CU: Coding Unit) in a quad tree structure and encoded. Each CU is predicted by being divided into prediction units (PU: Prediction Unit). In addition, the prediction error of each CU is divided into transform units (TU: Transform Unit) in a quadtree structure, and is subjected to frequency conversion.
CUは、イントラ予測/フレーム間予測の符号化単位である。
CU is a coding unit for intra prediction / interframe prediction.
イントラ予測(画面内予測)は、予測信号を符号化対象フレームの再構築画像から生成する予測である。HEVC/H.265では、33種類の角度イントラ予測などが定義されている。角度イントラ予測では、符号化対象ブロック周辺の再構築画素を33種類の方向のいずれかに外挿して、イントラ予測信号が生成される。
Intra prediction (intra-screen prediction) is prediction in which a prediction signal is generated from a reconstructed image of an encoding target frame. HEVC / H.265 defines 33 types of angle intra prediction. In the angle intra prediction, an intra prediction signal is generated by extrapolating the reconstructed pixels around the encoding target block in any of 33 types of directions.
イントラ予測として、角度イントラ予測に加えて、DC予測及びPlanar予測が規定されている。DC予測では、参照画像の平均値が予測対象TUの全画素の予測値とされる。Planar予測では、予測画像は、参照画像における画素から線形補間によって生成される。
DC In addition to angle intra prediction, DC prediction and Planar prediction are specified as intra prediction. In DC prediction, the average value of the reference image is used as the prediction value for all pixels of the prediction target TU. In Planar prediction, a predicted image is generated by linear interpolation from pixels in a reference image.
フレーム間予測は、符号化対象フレームと表示時刻が異なる再構築フレーム(参照ピクチャ)の画像に基づく予測である。フレーム間予測をインター予測とも呼ぶ。インター予測では、参照ピクチャの再構築画像ブロックに基づいて(必要であれば画素補間を用いて)、インター予測信号が生成される。
Inter-frame prediction is prediction based on an image of a reconstructed frame (reference picture) having a display time different from that of the encoding target frame. Inter-frame prediction is also called inter prediction. In inter prediction, an inter prediction signal is generated based on a reconstructed image block of a reference picture (using pixel interpolation if necessary).
ディジタルカラー画像は、R,G,B のディジタル画像で構成されるが、伝送路を介してカラー画像を伝送する場合、圧縮効率を高めるために(データ量を減らすために)、一般に、RGB 空間以外の色空間の信号に変換される。例えば、画像信号は、輝度信号(Y) と色差信号(Cb,Cr) との組み合わせの色空間(YCoCr 空間)の信号に変換される。
A digital color image is composed of R, G, and B digital images. When a color image is transmitted via a transmission line, generally, the RGB space is used to increase compression efficiency (to reduce the amount of data). Is converted to a signal in a color space other than. For example, the image signal is converted into a signal in a color space (YCoCr space) that is a combination of a luminance signal (Y) and a color difference signal (Cb, Cr).
色差信号に対する量子化パラメータ(QP)は、chroma_qp_index_offsetというオフセット値を用いて、輝度信号に対するQPを変換することにより生成される。HEVCでは、Cbに対してcb_qp_index_offset(第1色差量子化オフセット)が適用され、Crに対してcr_qp_index_offset(第2色差量子化オフセット)が適用される。
The quantization parameter (QP) for the color difference signal is generated by converting the QP for the luminance signal using an offset value called chroma_qp_index_offset. In HEVC, cb_qp_index_offset (first color difference quantization offset) is applied to Cb, and cr_qp_index_offset (second color difference quantization offset) is applied to Cr.
HEVCのRExt(Range Extension )において、拡張機能の標準化作業が進められた(非特許文献1参照)。
In HEVC's RExt (Range Extension), standardization work for extended functions was advanced (see Non-Patent Document 1).
RExtによる拡張機能の圧縮効率をより高めるための方式として、非特許文献2で、残差領域適応色変換(Adaptive color transform in residual domain )と呼ばれる技術が提案されている。図20に示すように、残差領域適応色変換は、RGB 空間の画像信号の予測誤差信号を、ブロック単位で適応的にYCoCr 空間の信号に切り替える技術である。
As a method for further improving the compression efficiency of the extended function by RExt, Non-Patent Document 2 proposes a technique called residual area adaptive color transformation (Adaptive color transform in residual domain). As shown in FIG. 20, the residual area adaptive color conversion is a technique for adaptively switching the prediction error signal of the image signal in the RGB color space to the signal in the YCoCr color space in units of blocks.
つまり、RGB の予測誤差信号をそのまま圧縮するか、下記のForward 色空間変換行列((1)式参照)を用いてYCoCr 空間の信号に変換して圧縮するかをブロック単位で選択できる。なお、図20には、斜線が施されたブロックについてYCoCr 空間でデータ圧縮が行われ、他のブロックについてRGB 空間でデータ圧縮が行われた例が示されている。
That is, it is possible to select in block units whether the RGB error prediction signal is compressed as it is or converted into a YCoCr space signal using the following Forward color space conversion matrix (see equation (1)). FIG. 20 shows an example in which data compression is performed in the YCoCr space for the hatched blocks and data compression is performed in the RGB space for the other blocks.
ブロックのデータ圧縮に利用された色空間の情報はcu_residual_csc_flagシンタクスでシグナリングされる。cu_residual_csc_flag=0は、RGB 空間の信号が圧縮されたことを示し、cu_residual_csc_flag=1は、YCoCr 空間に変換された後に信号が圧縮されたことを示す。
Information on the color space used for block data compression is signaled with the cu_residual_csc_flag syntax. cu_residual_csc_flag = 0 indicates that the signal in the RGB space is compressed, and cu_residual_csc_flag = 1 indicates that the signal is compressed after being converted into the YCoCr space.
受信機(映像復号装置)は、cu_residual_csc_flag=1の場合には、下記のBackward色空間変換行列を用いてYCoCr 空間の信号をRGB 空間の信号に戻した後、復号処理を行う。
In the case of cu_residual_csc_flag = 1, the receiver (video decoding device) performs a decoding process after returning the YCoCr space signal to the RGB space signal using the Backward color space conversion matrix described below.
なお、上記の色変換行列においてノルムが一定ではないため、cu_residual_csc_flag=1の場合、ブロックの予測誤差信号の量子化処理と逆量子化処理において、YCoCr 成分毎に、異なる色差量子化オフセットが量子化パラメータに加算される。
Note that since the norm is not constant in the above color conversion matrix, when cu_residual_csc_flag = 1, different color difference quantization offsets are quantized for each YCoCr component in the block prediction error signal quantization process and inverse quantization process. It is added to the parameter.
また、特許文献1には、入力画像信号がRGB 空間の信号である場合と、YCoCr 空間である場合とで、異なる信号処理を行う映像符号化装置及び映像復号装置が記載されている。具体的には、映像符号化装置は、H.264/AVC 方式に基づく重み付き予測を実行するときに、予測信号に加算されるオフセットに関して、R,G,B の信号と輝度信号(Y 信号)とに対して同じオフセットを適用し、色差信号に対して別のオフセットを適用する。しかし、特許文献1は、色差量子化オフセットに関して、新たな知見を教示していない。
Also, Patent Document 1 describes a video encoding device and a video decoding device that perform different signal processing depending on whether the input image signal is a signal in the RGB color space or the YCoCr space. Specifically, when performing weighted prediction based on the H.264 / AVC method, the video encoding device relates to the offset added to the prediction signal, the R, G, B signal, and the luminance signal (Y signal). ) And the same offset are applied to the color difference signal. However, Patent Document 1 does not teach new knowledge regarding color difference quantization offset.
次に、図21を参照して、ディジタル化された画像の各フレームの各CUを入力画像としてビットストリームを出力する一般的な映像符号化装置の構成と動作を説明する。
Next, the configuration and operation of a general video encoding apparatus that outputs a bit stream using each CU of each frame of a digitized image as an input image will be described with reference to FIG.
図21に示す映像符号化装置は、スイッチ101 、色空間変換器102 、スイッチ103 、周波数変換/量子化器104 、逆量子化/逆周波数変換器105 、スイッチ106 、逆色空間変換器107 、スイッチ108 、バッファ109 、予測器110 、予測パラメータ決定器111 、エントロピー符号化器112 、減算器115 及び加算器116 を備える。
21 includes a switch 101 図, a color space converter 102, a switch 103, a frequency converter / quantizer 104, an inverse quantization / inverse frequency converter 105, a switch 106, an inverse color space converter 107, A switch 108, a buffer 109, a predictor 110, a prediction parameter determiner 111 決定, an entropy encoder 112, a subtractor 115, and an adder 116 are provided.
予測器110 は、CUの入力画像信号に対する予測信号を生成する。具体的には、予測器110 は、イントラ予測に基づいて予測信号(イントラ予測信号)を生成し、インター予測に基づいて予測信号(インター予測信号)を生成する。
The predictor 110 generates a prediction signal for the input image signal of the CU. Specifically, the predictor 110 generates a prediction signal (intra prediction signal) based on the intra prediction, and generates a prediction signal (inter prediction signal) based on the inter prediction.
映像符号化装置に入力された画像は、予測器110 から供給される予測画像が減算器115 で減じられた後、予測誤差画像としてスイッチ101 に入力される。図21に示す例では、入力画像信号は、RGB 空間の信号である。また、映像符号化装置は、残差領域適応色変換機能を有している。例えば、映像符号化装置は、ブロック単位で、RGB 空間の画像信号の予測誤差信号を適応的にYCoCr 空間の信号に切り替えることができる。
The image input to the video encoding device is input to the switch 101 と し て as a prediction error image after the prediction image supplied from the predictor 110 減 is subtracted by the subtractor 115. In the example shown in FIG. 21, the input image signal is a signal in the RGB color space. Further, the video encoding device has a residual area adaptive color conversion function. For example, the video encoding apparatus can adaptively switch the prediction error signal of the image signal in the RGB Y space to the signal in the YCoCr space in units of blocks.
RGB 空間で予測誤差信号を扱うときには、スイッチ101 は、予測誤差画像がスイッチ103 に入力されるように設定される。YCoCr 空間で予測誤差信号を扱うときには、スイッチ101 は、予測誤差画像が色空間変換器102 に入力されるように設定される。なお、スイッチ101 は、例えば、予測パラメータ決定器111 の制御に従って、予測誤差画像の出力先を設定する。
When the prediction error signal is handled in the RGB space, the switch 101 is set so that the prediction error image is input to the switch 103. When the prediction error signal is handled in the YCoCr space, the switch 101 is set so that the prediction error image is input to the color space converter 102. Note that the switch 101 sets the output destination of the prediction error image, for example, according to the control of the prediction parameter determiner 111.
色空間変換器102 は、上記の(1)式(Forward 色空間変換行列)を用いて、RGB 空間の予測誤差信号をYCoCr 空間の信号に変換した後、スイッチ103 に出力する。
The color space converter 102 変 換 converts the RGB の space prediction error signal into a YCoCr space signal using the above equation (1) (Forward color space conversion matrix), and then outputs the signal to the switch 103.
スイッチ103 は、RGB 空間で予測誤差信号を扱うときには、スイッチ101 からの予測誤差信号を周波数変換/量子化器104 に出力する。YCoCr 空間で予測誤差信号を扱うときには、スイッチ103 は、色空間変換器102 からの予測誤差信号を周波数変換/量子化器104 に出力する。なお、スイッチ103 は、例えば、予測パラメータ決定器111 の制御に従って、予測誤差画像の入力元を選択する。
When the prediction error signal is handled in the RGB color space, the switch 103 周波 数 outputs the prediction error signal from the switch 101 予 測 to the frequency converter / quantizer 104. When the prediction error signal is handled in the YCoCr space, the switch 103 outputs the prediction error signal from the color space converter 102 to the frequency converter / quantizer 104. Note that the switch 103 選 択 selects the input source of the prediction error image, for example, according to the control of the prediction parameter determiner 111.
周波数変換/量子化器104 は、予測誤差画像を周波数変換し、周波数変換された予測誤差画像(係数画像)を量子化する。エントロピー符号化器112 は、予測パラメータ及び量子化係数画像をエントロピー符号化して、ビットストリームを出力する。
The frequency converter / quantizer 104 performs frequency conversion on the prediction error image and quantizes the frequency converted prediction error image (coefficient image). The entropy encoder 112 performs entropy encoding on the prediction parameter and the quantized coefficient image, and outputs a bit stream.
逆量子化/逆周波数変換器105 は、量子化係数画像を逆量子化する。さらに、逆量子化/逆周波数変換器105 は、逆量子化された係数画像を逆周波数変換する。逆周波数変換された再構築予測誤差画像は、スイッチ106 に入力される。
The inverse quantization / inverse frequency converter 105 inversely quantizes the quantized coefficient image. Further, the inverse quantization / inverse frequency converter 105 performs inverse frequency conversion on the inversely quantized coefficient image. The reconstructed prediction error image subjected to the inverse frequency conversion is input to the switch 106 ス イ ッ チ.
RGB 空間で予測誤差信号を扱うときには、スイッチ106 は、再構築予測誤差画像がスイッチ108 に入力されるように設定される。YCoCr 空間で予測誤差信号を扱うときには、スイッチ106 は、再構築予測誤差画像が逆色空間変換器107 に入力されるように設定される。なお、スイッチ106 は、例えば、予測パラメータ決定器111 の制御に従って、再構築予測誤差画像の出力先を選択する。
When the prediction error signal is handled in the RGB space, the switch 106 is set so that the reconstructed prediction error image is input to the switch 108. When the prediction error signal is handled in the YCoCr space, the switch 106 is set so that the reconstructed prediction error image is input to the inverse color space converter 107. Note that the switch 106 selects the output destination of the reconstructed prediction error image according to the control of the prediction parameter determiner 111, for example.
逆色空間変換器107 は、上記の(1)式(Backward色空間変換行列)を用いて、YCoCr 空間の再構築予測誤差信号をRGB 空間の信号に変換した後、スイッチ108 に出力する。
The inverse color space converter 107 converts the reconstruction prediction error signal of the YCoCr space into a signal in the RGB space using the above equation (1) (Backward color space conversion matrix), and then outputs it to the switch 108.
スイッチ108 は、RGB 空間で予測誤差信号を扱うときには、スイッチ106 からの再構築予測誤差信号を選択する。YCoCr 空間で予測誤差信号を扱うときには、スイッチ108 は、逆色空間変換器107 からの再構築予測誤差信号を選択する。なお、スイッチ108 は、例えば、予測パラメータ決定器111 の制御に従って、いずれかの再構築予測誤差画像を選択する。
Switch 108 selects the reconstructed prediction error signal from switch 106 when handling the prediction error signal in the RGB space. When the prediction error signal is handled in the YCoCr space, the switch 108 selects the reconstructed prediction error signal from the inverse color space converter 107. Note that the switch 108 選 択 selects any one of the reconstructed prediction error images according to the control of the prediction parameter determiner 111 例 え ば, for example.
スイッチ108 からの再構築予測誤差画像は、加算器116 で予測信号が加えられた後、再構築画像としてバッファ109 に供給される。バッファ109 は、再構築画像を格納する。
The reconstructed prediction error image from the switch 108 is supplied to the buffer 109 画像 as a reconstructed image after the prediction signal is added by the adder 116. The buffer 109 stores the reconstructed image.
予測パラメータ決定器111 は、入力画像信号と予測信号とを比較して、例えば符号化コストが最小になる予測パラメータを決定するように、予測器110 に指示する。予測パラメータ決定器111 は、決定された予測パラメータをエントロピー符号化器112 に供給する。予測パラメータは、予測モード(イントラ予測、インター予測)、イントラ予測ブロックサイズ、イントラ予測方向、インター予測ブロックサイズ、及び動きベクトルなど、ブロックの予測に関連した情報である。
The prediction parameter determiner 111 instructs the predictor 110 to compare the input image signal and the prediction signal and determine, for example, a prediction parameter that minimizes the coding cost. The prediction parameter determiner 111 供給 す る supplies the determined prediction parameter to the entropy encoder 112. The prediction parameter is information related to block prediction, such as a prediction mode (intra prediction, inter prediction), an intra prediction block size, an intra prediction direction, an inter prediction block size, and a motion vector.
予測パラメータ決定器111 は、さらに、各ブロックについて、RGB 空間で予測誤差信号を扱うかYCoCr 空間で予測誤差信号を扱うかを決定させる。
The prediction parameter determiner 111 further determines, for each block, whether to handle the prediction error signal in RGB space or YCoCr space.
映像符号化装置から出力されたビットストリームは、映像復号装置に伝達される。映像復号装置は、復号処理を行って、動画像を復元する。図22は、一般的な映像符号化装置が出力したビットストリームを復号し復号画像を得る一般的な映像復号装置の構成の一例を示すブロック図である。図22を参照して、一般的な映像復号装置の構成と動作を説明する。
The bit stream output from the video encoding device is transmitted to the video decoding device. The video decoding device performs a decoding process to restore a moving image. FIG. 22 is a block diagram illustrating an example of a configuration of a general video decoding apparatus that decodes a bitstream output from a general video encoding apparatus and obtains a decoded image. The configuration and operation of a general video decoding device will be described with reference to FIG.
図22に示す映像復号装置は、エントロピー復号器212 、逆量子化/逆周波数変換器205 、スイッチ206 、逆色空間変換器207 、スイッチ208 、バッファ209 、予測器210 、及び加算器216 を備える。
The video decoding apparatus shown in FIG. 22 includes an entropy decoder 212, an inverse quantization / inverse frequency converter 205, a switch 206, an inverse color space converter 207, a switch 208, a buffer 209, a predictor 210, and an adder 216. .
エントロピー復号器212 は、入力されたビットストリームをエントロピー復号する。エントロピー復号器212 は、量子化係数画像を逆量子化/逆周波数変換器205 に供給し、予測パラメータを予測器210 に供給する。
The entropy decoder 212 performs entropy decoding on the input bit stream. The entropy decoder 212 supplies the quantized coefficient image to the inverse quantization / inverse frequency converter 205, and supplies the prediction parameters to the predictor 210.
逆量子化/逆周波数変換器205 は、入力された量子化係数画像を逆量子化して、係数画像として出力する。さらに、逆量子化/逆周波数変換器205 は、周波数領域の係数画像を空間領域の画像に変換し、予測誤差画像として出力する。予測誤差画像は、スイッチ206 に入力される。
The inverse quantization / inverse frequency converter 205 inversely quantizes the input quantized coefficient image and outputs it as a coefficient image. Further, the inverse quantization / inverse frequency converter 205 converts the frequency domain coefficient image into a spatial domain image and outputs it as a prediction error image. The prediction error image is input to the switch 206.
RGB 空間で予測誤差信号を扱うときには、スイッチ206 は、予測誤差画像がスイッチ208 に入力されるように設定される。YCoCr 空間で予測誤差信号を扱うときには、スイッチ206 は、予測誤差画像が逆色空間変換器207 に入力されるように設定される。なお、スイッチ206 は、映像符号化装置からのシグナリングによって、RGB 空間で予測誤差信号を扱うべきかYCoCr 空間で予測誤差信号を扱うべきかを特定できる。
When the prediction error signal is handled in the RGB color space, the switch 206 is set so that the prediction error image is input to the switch 208. When the prediction error signal is handled in the YCoCr space, the switch 206 is set so that the prediction error image is input to the inverse color space converter 207. The switch 206 シ グ ナ リ ン グ can specify whether the prediction error signal should be handled in the RGB space or the prediction error signal in the YCoCr に よ っ て space by signaling from the video encoding device.
逆色空間変換器207 は、上記の(1)式(Backward色空間変換行列)を用いて、YCoCr 空間の予測誤差信号をRGB 空間の信号に変換した後、予測誤差信号をスイッチ208 に出力する。
The inverse color space converter 207 converts the YCoCr の space prediction error signal into the RGB space signal using the above equation (1) (Backward color space conversion matrix), and then outputs the prediction error signal to the switch 208. .
スイッチ208 は、RGB 空間で予測誤差信号を扱うときには、スイッチ206 からの予測誤差信号を選択する。YCoCr 空間で予測誤差信号を扱うときには、スイッチ208 は、逆色空間変換器207 からの予測誤差信号を選択する。スイッチ208 は、映像符号化装置からのシグナリングによって、RGB 空間で予測誤差信号を扱うべきかYCoCr 空間で予測誤差信号を扱うべきかを特定できる。
The switch 208 選 択 selects the prediction error signal from the switch 206 扱 う when handling the prediction error signal in the RGB space. When the prediction error signal is handled in the YCoCr space, the switch 208 selects the prediction error signal from the inverse color space converter 207. The switch 208 特定 can specify whether the prediction error signal should be handled in the RGB space or the prediction error signal in the YCoCr space by signaling from the video encoding device.
スイッチ208 からの予測誤差画像は、加算器216 で予測器210 からの予測信号が加えられた後、再構築画像としてバッファ209 に供給される。バッファ209 は、再構築画像を格納する。
The prediction error image from the switch 208 ら れ is supplied to the buffer 209 再 as a reconstructed image after the prediction signal from the predictor 210 加 え is added by the adder 216. The buffer 209 stores the reconstructed image.
また、バッファ209 に格納された再構築画像が復号画像(復号映像)として出力される。
Also, the reconstructed image stored in the buffer 209 is output as a decoded image (decoded video).
バッファ209 は、過去に復号された画像を参照画像として蓄積する。予測器210 は、イントラ予測を行うときには、現在復号中の画像内において過去に復号された、隣接する再構築画像から復号処理対象の画像を予測して予測画像を生成する。予測器210 は、インター予測を行うときには、バッファ209 から供給される参照画像に基づいて予測画像を生成する。
The buffer 209 accumulates previously decoded images as reference images. When performing the intra prediction, the predictor 210 predicts a decoding target image from adjacent reconstructed images decoded in the past in the image currently being decoded, and generates a predicted image. The predictor 210 予 測 generates a prediction image based on the reference image supplied from the buffer 209 when performing inter prediction.
RExtにおいて、主観的な画質改善を目的とする色差量子化オフセット(色差QPオフセット)技術が提案されている。色差量子化オフセット技術は、2番目の色成分と3番目の色成分に対する色差量子化オフセット値をシグナリングすることによって、色成分毎の量子化パラメータを調整する技術である。すなわち、量子化強度を変更できる。
In RExt, a color difference quantization offset (color difference QP offset) technology for the purpose of subjective image quality improvement has been proposed. The color difference quantization offset technique is a technique for adjusting a quantization parameter for each color component by signaling a color difference quantization offset value for the second color component and the third color component. That is, the quantization intensity can be changed.
色差量子化オフセット値をシグナリングするシンタクスとして以下がある。
・ピクチャ単位: pps_cb_qp_offset/pps_cr_qp_offset/slice_qp_delta_cb/slice_qp_delta_cr
・スライス単位: slice_qp_delta_cb/slice_qp_delta_cr
・ブロック単位: cu_chroma_qp_offset_idx The syntax for signaling the color difference quantization offset value is as follows.
-Picture unit: pps_cb_qp_offset / pps_cr_qp_offset / slice_qp_delta_cb / slice_qp_delta_cr
・ Slice unit: slice_qp_delta_cb / slice_qp_delta_cr
-Block unit: cu_chroma_qp_offset_idx
・ピクチャ単位: pps_cb_qp_offset/pps_cr_qp_offset/slice_qp_delta_cb/slice_qp_delta_cr
・スライス単位: slice_qp_delta_cb/slice_qp_delta_cr
・ブロック単位: cu_chroma_qp_offset_idx The syntax for signaling the color difference quantization offset value is as follows.
-Picture unit: pps_cb_qp_offset / pps_cr_qp_offset / slice_qp_delta_cb / slice_qp_delta_cr
・ Slice unit: slice_qp_delta_cb / slice_qp_delta_cr
-Block unit: cu_chroma_qp_offset_idx
上記のシンタクスを用いて色成分毎の量子化強度を調整することによって、主観画質を高めることができる。
Subjective image quality can be improved by adjusting the quantization intensity for each color component using the above syntax.
図21に示された映像符号化装置及び図22に示された映像復号装置は、色差量子化オフセットも適用する。図21に示されているように、映像符号化装置には、予め定められた色差量子化オフセットが入力されている。
21. The video encoding apparatus shown in FIG. 21 and the video decoding apparatus shown in FIG. 22 also apply a chrominance quantization offset. As shown in FIG. 21, a predetermined color difference quantization offset is input to the video encoding device.
映像符号化装置において、周波数変換/量子化器104 は、RGB 空間で予測誤差信号を扱う場合に、係数画像を量子化するときに、図23に示すように、B 成分の量子化パラメータを第1色差量子化オフセットに従って増減し、R 成分の量子化パラメータを第2色差量子化オフセットに従って増減する。逆量子化/逆周波数変換器105 は、B 成分の逆量子化パラメータを第1色差量子化オフセットに従って増減し、R 成分の逆量子化パラメータを第2色差量子化オフセットに従って増減する。
In the video encoding apparatus, when the frequency converter / quantizer 104 扱 う quantizes the coefficient image when handling the prediction error signal in the RGB space, the quantization parameter of the B component is set as shown in FIG. Increase / decrease according to one color difference quantization offset, and increase / decrease the quantization parameter of R component according to the second color difference quantization offset. The inverse quantization / inverse frequency converter 105 increases / decreases the inverse quantization parameter of the B component according to the first color difference quantization offset, and increases / decreases the inverse quantization parameter of the R component according to the second color difference quantization offset.
周波数変換/量子化器104 は、YCoCr 空間で予測誤差信号を扱う場合に、係数画像を量子化するときに、図23に示すように、Co成分の量子化パラメータを第1色差量子化オフセットに従って増減し、Cr成分の量子化パラメータを第2色差量子化オフセットに従って増減する。逆量子化/逆周波数変換器105 は、Co成分の逆量子化パラメータを第1色差量子化オフセットに従って増減し、Cr成分の逆量子化パラメータを第2色差量子化オフセットに従って増減する。
When the frequency transformer / quantizer 104 係数 quantizes the coefficient image when handling the prediction error signal in the YCoCr space, the quantization parameter of the Co component is set according to the first color difference quantization offset as shown in FIG. Increase / decrease, and increase / decrease the Cr component quantization parameter according to the second color difference quantization offset. The inverse quantization / inverse frequency converter 105 increases or decreases the inverse quantization parameter of the Co component according to the first color difference quantization offset, and increases or decreases the inverse quantization parameter of the Cr component according to the second color difference quantization offset.
映像復号装置において、逆量子化/逆周波数変換器205 は、映像符号化装置における逆量子化/逆周波数変換器105 と同様に動作する。
In the video decoding device, the inverse quantization / inverse frequency converter 205 operates in the same manner as the inverse quantization / inverse frequency converter 105 in the video encoding device.
しかし、色差量子化オフセット技術は2番目の色成分(第2色成分)と3番目の色成分(第3色成分)に対する色差量子化オフセット値をシグナリングするという技術であるから、残差領域適応色変換と色差量子化オフセットを組み合わせると、図23に示すように、RGB 空間で圧縮されたブロックとYCoCr 空間で圧縮されたブロックとが量子化強度を共有する。その結果、色空間に応じて適切に量子化強度を設定できなくなる。この結果、色差量子化オフセット技術による主観画質改善効果が得らなくなる。
However, since the color difference quantization offset technique is a technique of signaling the color difference quantization offset value for the second color component (second color component) and the third color component (third color component), the residual area adaptation is performed. When color conversion and color difference quantization offset are combined, as shown in FIG. 23, the block compressed in the RGB space and the block compressed in the YCoCr space share the quantization intensity. As a result, the quantization intensity cannot be set appropriately according to the color space. As a result, the subjective image quality improvement effect by the color difference quantization offset technique cannot be obtained.
本発明は、残差領域適応色変換と色差量子化オフセットとが併用される場合に、主観画質改善効果を損なわないようにする映像符号化装置、映像復号装置、映像符号化方法、映像復号方法及びプログラムを提供することを目的とする。
The present invention relates to a video encoding device, a video decoding device, a video encoding method, and a video decoding method that do not impair the subjective image quality improvement effect when residual region adaptive color conversion and color difference quantization offset are used in combination. And to provide a program.
本発明による映像符号化装置は、複数の色空間から、符号化のブロック単位で予測誤差信号の色空間を選択可能であり、色空間毎の色差量子化オフセットを導出する適応色差量子化オフセット導出手段と、異なるダイナミックレンジで表現されうる色空間毎の色差量子化オフセットを使用して量子化係数画像を逆量子化する逆量子化手段とを含むことを特徴とする。
The video encoding device according to the present invention can select a color space of a prediction error signal from a plurality of color spaces in units of encoding blocks, and derive an adaptive color difference quantization offset for deriving a color difference quantization offset for each color space. Means, and inverse quantization means for inversely quantizing the quantization coefficient image using a color difference quantization offset for each color space that can be expressed in a different dynamic range.
本発明による映像復号装置は、複数の色空間から、符号化のブロック単位で予測誤差信号の色空間を選択可能であり、色空間毎の色差量子化オフセットを導出する適応色差量子化オフセット導出手段と、異なるダイナミックレンジで表現されうる色空間毎の色差量子化オフセットを使用して量子化係数画像を逆量子化する逆量子化手段とを含むことを特徴とする。
The video decoding apparatus according to the present invention is capable of selecting a color space of a prediction error signal in units of encoding blocks from a plurality of color spaces, and deriving an adaptive color difference quantization offset deriving unit that derives a color difference quantization offset for each color space And inverse quantization means for inversely quantizing the quantization coefficient image using a color difference quantization offset for each color space that can be expressed in different dynamic ranges.
本発明による映像符号化方法は、複数の色空間から、符号化のブロック単位で予測誤差信号の色空間を選択可能であり、色空間毎の色差量子化オフセットを導出し、異なるダイナミックレンジで表現されうる色空間毎の色差量子化オフセットを使用して量子化係数画像を逆量子化することを特徴とする。
The video encoding method according to the present invention can select a color space of a prediction error signal from a plurality of color spaces in units of encoding blocks, derive a color difference quantization offset for each color space, and express it in different dynamic ranges. The quantization coefficient image is inversely quantized using a color difference quantization offset for each color space that can be performed.
本発明による映像復号方法は、複数の色空間から、符号化のブロック単位で予測誤差信号の色空間を選択可能であり、色空間毎の色差量子化オフセットを導出し、異なるダイナミックレンジで表現されうる色空間毎の色差量子化オフセットを使用して量子化係数画像を逆量子化することを特徴とする。
The video decoding method according to the present invention can select a color space of a prediction error signal from a plurality of color spaces in units of coding blocks, derive a color difference quantization offset for each color space, and can be expressed in different dynamic ranges. The quantization coefficient image is inversely quantized using a color difference quantization offset for each possible color space.
本発明による映像符号化プログラムは、複数の色空間から、符号化のブロック単位で予測誤差信号の色空間を選択可能な映像符号化方法を実施する映像符号化プログラムであって、コンピュータに、色空間毎の色差量子化オフセットを導出する処理と、異なるダイナミックレンジで表現されうる色空間毎の色差量子化オフセットを使用して量子化係数画像を逆量子化する処理とを実行させることを特徴とする。
A video encoding program according to the present invention is a video encoding program that implements a video encoding method capable of selecting a color space of a prediction error signal from a plurality of color spaces in units of encoding blocks. A process for deriving a color difference quantization offset for each space and a process for dequantizing a quantization coefficient image using a color difference quantization offset for each color space that can be expressed in different dynamic ranges. To do.
本発明による映像復号プログラムは、複数の色空間から、符号化のブロック単位で予測誤差信号の色空間を選択可能な映像復号方法を実施する映像復号プログラムであって、コンピュータに、色空間毎の色差量子化オフセットを導出する処理と、異なるダイナミックレンジで表現されうる色空間毎の色差量子化オフセットを使用して量子化係数画像を逆量子化する処理とを実行させることを特徴とする。
A video decoding program according to the present invention is a video decoding program for executing a video decoding method capable of selecting a color space of a prediction error signal from a plurality of color spaces in units of encoding blocks. A process for deriving a color difference quantization offset and a process for dequantizing a quantization coefficient image using a color difference quantization offset for each color space that can be expressed in different dynamic ranges are performed.
本発明によれば、主観画質改善効果を損なわないようにすることができる。
According to the present invention, the subjective image quality improvement effect can be prevented from being impaired.
実施形態1.
図1 は、映像符号化装置の第1の実施形態を示すブロック図である。図1 を参照して、ディジタル化された映像の各フレームを入力画像としてビットストリームを出力する映像符号化装置の構成を説明する。Embodiment 1. FIG.
FIG. 1 is a block diagram showing a first embodiment of a video encoding device. With reference to FIG. 1, the configuration of a video encoding apparatus that outputs a bit stream using each frame of a digitized video as an input image will be described.
図1 は、映像符号化装置の第1の実施形態を示すブロック図である。図1 を参照して、ディジタル化された映像の各フレームを入力画像としてビットストリームを出力する映像符号化装置の構成を説明する。
FIG. 1 is a block diagram showing a first embodiment of a video encoding device. With reference to FIG. 1, the configuration of a video encoding apparatus that outputs a bit stream using each frame of a digitized video as an input image will be described.
図1に示すように、第1の実施形態の映像符号化装置は、図21に示された一般的な映像符号化装置と同様に、スイッチ101 、色空間変換器102 、スイッチ103 、周波数変換/量子化器104 、逆量子化/逆周波数変換器105 、スイッチ106 、逆色空間変換器107 、スイッチ108 、バッファ109 、予測器110 、予測パラメータ決定器111 、エントロピー符号化器112 、減算器115 及び加算器116 を備える。
As shown in FIG. 1, the video encoding apparatus of the first embodiment is similar to the general video encoding apparatus shown in FIG. 21 in that a switch 101, a color space converter 102, a switch 103, a frequency conversion / Quantizer 104, Inverse quantization / inverse frequency converter 105, Switch 106, Inverse color space converter 107, Switch 108 変 換, Buffer 109, Predictor 110, Prediction parameter determiner 111, Entropy encoder 112 決定, Subtractor 115 and adder 116 are provided.
図1 に示すように、映像符号化装置は、さらに、適応色差量子化オフセット導出器121 とスイッチ122 とを備える。
As shown in FIG. 1B, the video encoding apparatus further includes an adaptive color difference quantization offset deriving unit 121 and a switch 122.
スイッチ101 、色空間変換器102 、スイッチ103 、周波数変換/量子化器104 、逆量子化/逆周波数変換器105 、スイッチ106 、逆色空間変換器107 、スイッチ108 、バッファ109 、予測器110 、減算器115 及び加算器116 は、図21に示されたそれらと同様に動作するので、以下、主として、適応色差量子化オフセット導出器121 とスイッチ122 の動作と、色差量子化オフセットのシグナリングに関連する予測パラメータ決定器111 及びエントロピー符号化器112 の動作とを説明する。なお、適応色差量子化オフセット導出器121 には、RGB 空間用の色差量子化オフセットとYCoCr 空間用の色差量子化オフセットとが入力されている。
Switch 101, color space converter 102, switch 103, frequency converter / quantizer 104, inverse quantization / inverse frequency converter 105, switch 106, inverse color space converter 107, switch 108, buffer 109, predictor 110, Since the subtractor 115 and the adder 116 operate in the same manner as those shown in FIG. 21, the following mainly relates to the operation of the adaptive color difference quantization offset deriving unit 121 and the switch 122 and the color difference quantization offset signaling. The operation of the prediction parameter determiner 111 and the entropy encoder 112 to be performed will be described. Note that the color difference quantization offset for RGB color space and the color difference quantization offset for YCoCr color space are input to the adaptive color difference quantization offset deriving unit 121.
図2 は、色差量子化オフセットのシグナリングに関連する処理を示すフローチャートである。
FIG. 2 (b) is a flowchart showing processing related to signaling of the color difference quantization offset.
映像符号化装置は、adaptive_color_trans_flag で残差領域適応色変換を実施するか否かを示す情報をシグナリングする。また、映像符号化装置は、残差領域適応色変換を実施する場合、cu_residual_csc_flagでブロックの色空間を示す情報をシグナリングする。
The video encoding apparatus signals information indicating whether or not to perform residual area adaptive color conversion using adaptive_color_trans_flag. Further, when performing the residual area adaptive color conversion, the video encoding apparatus signals information indicating the color space of the block with cu_residual_csc_flag.
残差領域適応色変換が実施されない場合には、エントロピー符号化器112 は、adaptive_color_trans_flag=0 をシグナリングするが、適応色差量子化オフセット導出器121 が導出したRGB 空間用の色差量子化オフセット(適応色差量子化オフセット導出器121 に入力されたRGB 空間用の色差量子化オフセット)を下記のようなシンタクスで伝送する(ステップS101,S102)。残差領域適応色変換が実施される場合には、エントロピー符号化器112 は、adaptive_color_trans_flag=1 にする。そして、RGB 空間で圧縮が行われるときには、エントロピー符号化器112 は、適応色差量子化オフセット導出器121 が導出したRGB 空間用の色差量子化オフセットを以下のシンタクスで伝送する(ステップS103,S104)。
When the residual area adaptive color conversion is not performed, the entropy encoder 112 シ グ ナ リ ン グ signals adaptive_color_trans_flag = 0 、, but the color difference quantization offset for RGB space (adaptive color difference) derived by the adaptive color difference quantization offset derivation unit 121 導出. The RGB offset space color difference quantization offset) input to the quantization offset deriving unit 121 伝 送 is transmitted with the following syntax (steps S 101 and S 102). When the residual area adaptive color conversion is performed, the entropy encoder 112 sets adaptive_color_trans_flag = 1. When compression is performed in the RGB color space, the entropy encoder 112 伝 送 transmits the color difference quantization offset for the RGB color space derived by the adaptive color difference quantization offset deriving unit 121 で with the following syntax (steps S103 and S104). .
・ピクチャ単位: pps_cb_qp_offset/pps_cr_qp_offset/slice_qp_delta_cb/slice_qp_delta_cr
・スライス単位: slice_qp_delta_cb/slice_qp_delta_cr -Picture unit: pps_cb_qp_offset / pps_cr_qp_offset / slice_qp_delta_cb / slice_qp_delta_cr
・ Slice unit: slice_qp_delta_cb / slice_qp_delta_cr
・スライス単位: slice_qp_delta_cb/slice_qp_delta_cr -Picture unit: pps_cb_qp_offset / pps_cr_qp_offset / slice_qp_delta_cb / slice_qp_delta_cr
・ Slice unit: slice_qp_delta_cb / slice_qp_delta_cr
YCoCr 空間で圧縮が行われるときには、エントロピー符号化器112 は、適応色差量子化オフセット導出器121 が導出したYCoCr 空間用の色差量子化オフセットを以下のシンタクスで伝送する(ステップS103,S105)。
When compression is performed in the YCoCr space, the entropy encoder 112 transmits the color difference quantization offset for the YCoCr space derived by the adaptive color difference quantization offset derivation 121 で with the following syntax (steps S103 and S105).
・ピクチャ単位: alt_pps_cb_qp_offset/alt_pps_cr_qp_offset/alt_slice_qp_delta_cb/alt_slice_qp_delta_cr
・スライス単位: alt_slice_qp_delta_cb/alt_slice_qp_delta_cr -Picture unit: alt_pps_cb_qp_offset / alt_pps_cr_qp_offset / alt_slice_qp_delta_cb / alt_slice_qp_delta_cr
・ Slice unit: alt_slice_qp_delta_cb / alt_slice_qp_delta_cr
・スライス単位: alt_slice_qp_delta_cb/alt_slice_qp_delta_cr -Picture unit: alt_pps_cb_qp_offset / alt_pps_cr_qp_offset / alt_slice_qp_delta_cb / alt_slice_qp_delta_cr
・ Slice unit: alt_slice_qp_delta_cb / alt_slice_qp_delta_cr
また、残差領域適応色変換が実施される場合、YCoCr 空間で圧縮が行われるとき(RGB 空間で圧縮が行われないとき)には、エントロピー符号化器112 は、cu_residual_csc_flag=1をシグナリングする。適応色差量子化オフセット導出器121 は、導出したYCoCr 空間用の色差量子化オフセット(第1色差量子化オフセット及び第2色差量子化オフセット)をスイッチ122 に出力する。
In addition, when residual area adaptive color conversion is performed, when compression is performed in the YCoCr space (when compression is not performed in the RGB space), the entropy encoder 112 シ グ ナ リ ン グ signals cu_residual_csc_flag = 1. The adaptive color difference quantization offset deriving unit 121 outputs the derived color difference quantization offsets for the YCoCr space (first color difference quantization offset and second color difference quantization offset) to the switch 122.
RGB 空間で圧縮が行われるときには、エントロピー符号化器112 は、cu_residual_csc_flag=0をシグナリングする。適応色差量子化オフセット導出器121 は、導出したRGB 空間用の色差量子化オフセット(第1色差量子化オフセット及び第2色差量子化オフセット)をスイッチ122 に出力する。
When compression is performed in the RGB space, the entropy encoder 112 シ グ ナ リ ン グ signals cu_residual_csc_flag = 0. The adaptive color difference quantization offset deriving unit 121 outputs the derived RGB color space color difference quantization offsets (first color difference quantization offset and second color difference quantization offset) to the switch 122.
なお、適応色差量子化オフセット導出器121 は、cu_residual_csc_flagに従って、RGB 空間で圧縮が行われるのかYCoCr 空間で圧縮が行われるのかを認識する。
Note that the adaptive color difference quantization offset derivation unit 121 recognizes whether compression is performed in the RGB color space or the YCoCr color space according to the cu_residual_csc_flag.
また、周波数変換/量子化器104 は、予測パラメータ決定器111 が決定する色差量子化オフセットを使用して量子化パラメータを調整する。
Also, the frequency transformer / quantizer 104 adjusts the quantization parameter using the color difference quantization offset determined by the prediction parameter determiner 111 決定.
予測パラメータ決定器111 は、例えば、予めRGB 空間用の色差量子化オフセットの値とYCoCr 空間用の色差量子化オフセットの値とを記憶し、適宜、RGB 空間用の量子化オフセットの値又はYCoCr 空間用の色差量子化オフセットの値を周波数変換/量子化器104 に供給する。その場合、RGB 空間用の色差量子化オフセットの値及びYCoCr 空間用の色差量子化オフセットの値が、エントロピー符号化器112 に供給される予測パラメータに含められる。エントロピー符号化器112 は、RGB 空間用の色差量子化オフセットの値及びYCoCr 空間用の色差量子化オフセットの値をシグナリングする
The prediction parameter determiner 111 stores, for example, a color difference quantization offset value for RGB space and a color difference quantization offset value for YCoCr 予 め space in advance, and an appropriate value for the RGB space quantization offset or YCoCr space. The value of the color difference quantization offset for use is supplied to the frequency converter / quantizer 104. In this case, the color difference quantization offset value for the RGB color space and the color difference quantization offset value for the YCoCr space are included in the prediction parameters supplied to the entropy encoder 112. The entropy encoder 112 signals the value of the color difference quantization offset for the RGB color space and the value of the color difference quantization offset for the YCoCr space.
この場合、映像符号化装置は、明示的に(explicit)色差量子化オフセットをシグナリングする。しかも、色差量子化オフセットの値をシグナリングする。
In this case, the video encoding apparatus explicitly signals the color difference quantization offset. In addition, the value of the color difference quantization offset is signaled.
なお、適応色差量子化オフセット導出器121 のより詳細な動作については第2の実施形態で詳述される。
Note that the more detailed operation of the adaptive color difference quantization offset deriving unit 121 will be described in detail in the second embodiment.
上記の動作以外の映像符号化装置の動作は、図21に示された映像符号化装置の動作と同じである。
The operation of the video encoding device other than the above operation is the same as the operation of the video encoding device shown in FIG.
実施形態2.
図3 は、色差量子化オフセットをシグナリングする映像符号化装置が出力したビットストリームを復号し復号画像を得る映像復号装置の構成を示すブロック図である。図3 を参照して、第2の実施形態の映像復号装置の構成を説明する。Embodiment 2. FIG.
FIG. 3 is a block diagram illustrating a configuration of a video decoding apparatus that decodes a bitstream output from a video encoding apparatus that signals a color difference quantization offset and obtains a decoded image. With reference to FIG. 3, the configuration of the video decoding apparatus according to the second embodiment will be described.
図3 は、色差量子化オフセットをシグナリングする映像符号化装置が出力したビットストリームを復号し復号画像を得る映像復号装置の構成を示すブロック図である。図3 を参照して、第2の実施形態の映像復号装置の構成を説明する。
FIG. 3 is a block diagram illustrating a configuration of a video decoding apparatus that decodes a bitstream output from a video encoding apparatus that signals a color difference quantization offset and obtains a decoded image. With reference to FIG. 3, the configuration of the video decoding apparatus according to the second embodiment will be described.
図3に示すように、本実施形態の映像復号装置は、図22に示された一般的な映像復号装置と同様に、エントロピー復号器212 、逆量子化/逆周波数変換器205 、スイッチ206 、逆色空間変換器207 、スイッチ208 、バッファ209 、予測器210 、及び加算器216 を備える。
As shown in FIG. 3, the video decoding device of the present embodiment is similar to the general video decoding device shown in FIG. 22, with an entropy decoder 212, an inverse quantization / inverse frequency converter 205, a switch 206, An inverse color space converter 207, a switch 208, a buffer 209, a predictor 210, and an adder 216 加 算 are provided.
図3 に示すように、映像復号装置は、さらに、適応色差量子化オフセット導出器221 とスイッチ222 とを備える。
As shown in FIG. 3B, the video decoding apparatus further includes an adaptive color difference quantization offset deriving unit 221 and a switch 222.
逆量子化/逆周波数変換器205 、スイッチ206 、逆色空間変換器207 、スイッチ208 、バッファ209 、予測器210 、及び加算器216 は、図22に示されたそれらと同様に動作するので、以下、主として、適応色差量子化オフセット導出器221 とスイッチ222 の動作と、色差量子化オフセットの導出に関連するエントロピー復号器212 の動作とを説明する。
Since the inverse quantization / inverse frequency converter 205, switch 206, inverse color space converter 207, switch 208, buffer 209, predictor 210, and adder 216 動作 operate in the same manner as those shown in FIG. Hereinafter, the operations of the adaptive color difference quantization offset derivation unit 221 and the switch 222 and the operation of the entropy decoder 212 復 号 related to the derivation of the color difference quantization offset will be mainly described.
図4 は、色差量子化オフセットの導出に関連する処理を示すフローチャートである。
Fig. 4 is a flowchart showing processing related to derivation of the color difference quantization offset.
エントロピー復号器212 がビットストリームからadaptive_color_trans_flag=1 (残差領域適応色変換が実施されることを示す。)を解読した場合(ステップS201)、cu_residual_csc_flag=1(YCoCr 空間でデータ圧縮されたことを示す。)を解読したときには(ステップS202)、適応色差量子化オフセット導出器221 は、YCoCr 空間用の色差量子化オフセットを導出する(ステップS204)。エントロピー復号器212 がcu_residual_csc_flag=0(RGB 空間でデータ圧縮されたことを示す。)を解読したときには(ステップS202)、適応色差量子化オフセット導出器221 は、RGB 空間用の色差量子化オフセットを導出する(ステップS203)。
When the entropy decoder 212 decodes adaptive_color_trans_flag = 1 (indicating that residual area adaptive color conversion is performed) from the bitstream (step S201), cu_residual_csc_flag = 1 (indicates that data compression is performed in the YCoCr space .) Is decoded (step S202), the adaptive color difference quantization offset derivation unit 221 derives a color difference quantization offset for the YCoCr space (step S204). When the entropy decoder 212 decodes cu_residual_csc_flag = 0 (indicating that data compression is performed in RGB space) (step S202), the adaptive color difference quantization offset derivation 221 derives the color difference quantization offset for RGB space. (Step S203).
適応色差量子化オフセット導出器221 は、以下のように、RGB 空間用の色差量子化オフセット(第1色差量子化オフセットqPiCb 及び第2色差量子化オフセットqPiCr )を導出する。
The adaptive color difference quantization offset deriving unit 221 derives the color difference quantization offset for the RGB space (first color difference quantization offset qPi Cb and second color difference quantization offset qPi Cr ) as follows.
qPiCb = Clip3 ( -QpBdOffsetC, 57, QpY + pps_cb_qp_offset + slice_cb_qp_offset + CuQpOffsetCb )
qPiCr = Clip3 ( -QpBdOffsetC, 57, QpY + pps_cr_qp_offset + slice_cr_qp_offset + CuQpOffsetCr ) (2) qPi Cb = Clip3 (-QpBdOffset C , 57, Qp Y + pps_cb_qp_offset + slice_cb_qp_offset + CuQpOffset Cb )
qPi Cr = Clip3 (-QpBdOffset C , 57, Qp Y + pps_cr_qp_offset + slice_cr_qp_offset + CuQpOffset Cr ) (2)
qPiCr = Clip3 ( -QpBdOffsetC, 57, QpY + pps_cr_qp_offset + slice_cr_qp_offset + CuQpOffsetCr ) (2) qPi Cb = Clip3 (-QpBdOffset C , 57, Qp Y + pps_cb_qp_offset + slice_cb_qp_offset + CuQpOffset Cb )
qPi Cr = Clip3 (-QpBdOffset C , 57, Qp Y + pps_cr_qp_offset + slice_cr_qp_offset + CuQpOffset Cr ) (2)
(2)式において、 Clip3 (x , y ,z)は、入力z を、[x ,y ]の値域にクリッピングする関数である。QpY は、第1色成分の量子化パラメータ、CuQpOffsetCbは、第2色成分のブロック毎の色差量子化オフセット、CuQpOffsetCrは、第3色成分のブロック毎の色差量子化オフセットである。なお、qPiCb ,qPiCr と表現されているが、第1色成分がG 成分、第2色成分がB 成分、第3色成分がR 成分のRGB 空間の場合、qPiCb は、B 成分についての色差量子化オフセットに相当し、qPiCr は、R 成分についての色差量子化オフセットに相当する。
In Expression (2), Clip3 (x, y, z) is a function for clipping the input z into the range [x, y]. Qp Y is a quantization parameter for the first color component, CuQpOffset Cb is a color difference quantization offset for each block of the second color component, and CuQpOffset Cr is a color difference quantization offset for each block of the third color component. Incidentally, QPI Cb, has been described as QPI Cr, the first color component is a G component, a second color component B component, when the third color component of the RGB space of the R component, QPI Cb, for the B component corresponds to the color difference quantization offset, QPI Cr corresponds to the color difference quantization offset for R component.
適応色差量子化オフセット導出器221 は、以下の(3)式のように、YCoCr 空間用の色差量子化オフセット(第1色差量子化オフセットqPiCb 及び第2色差量子化オフセットqPiCr )を導出する。
The adaptive chrominance quantization offset derivation unit 221 derives a chrominance quantization offset (first chrominance quantization offset qPi Cb and second chrominance quantization offset qPi Cr ) for YCoCr space as shown in the following equation (3). .
qPiCb = Clip3( -QpBdOffsetC, 57, QpY + alt_pps_cb_qp_offset + alt_slice_cb_qp_offset + CuQpOffsetCb )
qPiCr = Clip3( -QpBdOffsetC, 57, QpY + alt_pps_cr_qp_offset + alt_slice_cr_qp_offset + CuQpOffsetCr ) (3) qPi Cb = Clip3 (-QpBdOffset C , 57, Qp Y + alt_pps_cb_qp_offset + alt_slice_cb_qp_offset + CuQpOffset Cb )
qPi Cr = Clip3 (-QpBdOffset C , 57, Qp Y + alt_pps_cr_qp_offset + alt_slice_cr_qp_offset + CuQpOffset Cr ) (3)
qPiCr = Clip3( -QpBdOffsetC, 57, QpY + alt_pps_cr_qp_offset + alt_slice_cr_qp_offset + CuQpOffsetCr ) (3) qPi Cb = Clip3 (-QpBdOffset C , 57, Qp Y + alt_pps_cb_qp_offset + alt_slice_cb_qp_offset + CuQpOffset Cb )
qPi Cr = Clip3 (-QpBdOffset C , 57, Qp Y + alt_pps_cr_qp_offset + alt_slice_cr_qp_offset + CuQpOffset Cr ) (3)
なお、量子化パラメータ(Qp'Cb ,Qp'Cr )は、以下の(4)式のよう算出される。
The quantization parameters (Qp ′ Cb , Qp ′ Cr ) are calculated as in the following equation (4).
Qp'Cb = qPCb + QpBdOffsetC
Qp'Cr = qPCr + QpBdOffsetC (4) Qp ' Cb = qP Cb + QpBdOffset C
Qp ' Cr = qP Cr + QpBdOffset C (4)
Qp'Cr = qPCr + QpBdOffsetC (4) Qp ' Cb = qP Cb + QpBdOffset C
Qp ' Cr = qP Cr + QpBdOffset C (4)
以下に、色差量子化オフセットの導出の手続の具体例を示す。下記の記述において、クォーテーションマークで囲まれた部分は、本実施形態における特徴的な部分である。
The following is a specific example of the procedure for deriving the color difference quantization offset. In the following description, a part surrounded by quotation marks is a characteristic part in the present embodiment.
- "If cu_residual_csc_flag is equal to 0", the variables qPCb and qPCr are derived as follows:
qPiCb = Clip3( -QpBdOffsetC, 57, QpY + pps_cb_qp_offset + slice_cb_qp_offset + CuQpOffsetCb )
qPiCr = Clip3( -QpBdOffsetC, 57, QpY + pps_cr_qp_offset + slice_cr_qp_offset + CuQpOffsetCr )
- "Otherwise (cu_residual_csc_flag is equal to 1), the variables qPCb and
qPCr are derived as follows:"
"qPiCb = Clip3( -QpBdOffsetC, 57, QpY + alt_pps_cb_qp_offset + alt_slice_cb_qp_offset + CuQpOffsetCb )"
"qPiCr = Clip3( -QpBdOffsetC, 57, QpY + alt_pps_cr_qp_offset + alt_slice_cr_qp_offset + CuQpOffsetCr )"
- If ChromaArrayType is equal to 1, the variables qPCb and qPCr are set equal to the value of QpC as specified in Predetermined Table based on the index qPi equal to qPiCb and qPiCr, respectively.
- Otherwise, the variables qPCb and qPCr are set equal to Min( qPi, 51 ), based on the index qPi equal to qPiCb and qPiCr, respectively.
- The chroma quantization parameters for the Cb and Cr components, Qp'Cb and Qp'Cr, are derived as follows:
Qp'Cb = qPCb + QpBdOffsetC
Qp'Cr = qPCr + QpBdOffsetC -"If cu_residual_csc_flag is equal to 0", the variables qP Cb and qP Cr are derived as follows:
qPi Cb = Clip3 (-QpBdOffset C , 57, Qp Y + pps_cb_qp_offset + slice_cb_qp_offset + CuQpOffset Cb )
qPi Cr = Clip3 (-QpBdOffset C , 57, Qp Y + pps_cr_qp_offset + slice_cr_qp_offset + CuQpOffset Cr )
-"Otherwise (cu_residual_csc_flag is equal to 1), the variables qP Cb and
qP Cr are derived as follows: "
"qPi Cb = Clip3 (-QpBdOffset C , 57, Qp Y + alt_pps_cb_qp_offset + alt_slice_cb_qp_offset + CuQpOffset Cb )"
"qPi Cr = Clip3 (-QpBdOffset C , 57, Qp Y + alt_pps_cr_qp_offset + alt_slice_cr_qp_offset + CuQpOffset Cr )"
-If ChromaArrayType is equal to 1, the variables qP Cb and qP Cr are set equal to the value of Qp C as specified in Predetermined Table based on the index qPi equal to qPi Cb and qPi Cr , respectively.
-Otherwise, the variables qP Cb and qP Cr are set equal to Min (qPi, 51), based on the index qPi equal to qPi Cb and qPi Cr , respectively.
-The chroma quantization parameters for the Cb and Cr components, Qp ' Cb and Qp' Cr, are derived as follows:
Qp ' Cb = qP Cb + QpBdOffset C
Qp ' Cr = qP Cr + QpBdOffset C
qPiCb = Clip3( -QpBdOffsetC, 57, QpY + pps_cb_qp_offset + slice_cb_qp_offset + CuQpOffsetCb )
qPiCr = Clip3( -QpBdOffsetC, 57, QpY + pps_cr_qp_offset + slice_cr_qp_offset + CuQpOffsetCr )
- "Otherwise (cu_residual_csc_flag is equal to 1), the variables qPCb and
qPCr are derived as follows:"
"qPiCb = Clip3( -QpBdOffsetC, 57, QpY + alt_pps_cb_qp_offset + alt_slice_cb_qp_offset + CuQpOffsetCb )"
"qPiCr = Clip3( -QpBdOffsetC, 57, QpY + alt_pps_cr_qp_offset + alt_slice_cr_qp_offset + CuQpOffsetCr )"
- If ChromaArrayType is equal to 1, the variables qPCb and qPCr are set equal to the value of QpC as specified in Predetermined Table based on the index qPi equal to qPiCb and qPiCr, respectively.
- Otherwise, the variables qPCb and qPCr are set equal to Min( qPi, 51 ), based on the index qPi equal to qPiCb and qPiCr, respectively.
- The chroma quantization parameters for the Cb and Cr components, Qp'Cb and Qp'Cr, are derived as follows:
Qp'Cb = qPCb + QpBdOffsetC
Qp'Cr = qPCr + QpBdOffsetC -"If cu_residual_csc_flag is equal to 0", the variables qP Cb and qP Cr are derived as follows:
qPi Cb = Clip3 (-QpBdOffset C , 57, Qp Y + pps_cb_qp_offset + slice_cb_qp_offset + CuQpOffset Cb )
qPi Cr = Clip3 (-QpBdOffset C , 57, Qp Y + pps_cr_qp_offset + slice_cr_qp_offset + CuQpOffset Cr )
-"Otherwise (cu_residual_csc_flag is equal to 1), the variables qP Cb and
qP Cr are derived as follows: "
"qPi Cb = Clip3 (-QpBdOffset C , 57, Qp Y + alt_pps_cb_qp_offset + alt_slice_cb_qp_offset + CuQpOffset Cb )"
"qPi Cr = Clip3 (-QpBdOffset C , 57, Qp Y + alt_pps_cr_qp_offset + alt_slice_cr_qp_offset + CuQpOffset Cr )"
-If ChromaArrayType is equal to 1, the variables qP Cb and qP Cr are set equal to the value of Qp C as specified in Predetermined Table based on the index qPi equal to qPi Cb and qPi Cr , respectively.
-Otherwise, the variables qP Cb and qP Cr are set equal to Min (qPi, 51), based on the index qPi equal to qPi Cb and qPi Cr , respectively.
-The chroma quantization parameters for the Cb and Cr components, Qp ' Cb and Qp' Cr, are derived as follows:
Qp ' Cb = qP Cb + QpBdOffset C
Qp ' Cr = qP Cr + QpBdOffset C
逆量子化/逆周波数変換器205 は、入力された量子化係数画像を逆量子化して、係数画像として出力する際に、量子化パラメータを適応色差量子化オフセット導出器221 からの色差量子化オフセットに従って増減する。
The inverse quantization / inverse frequency converter 205 dequantizes the input quantized coefficient image and outputs the coefficient image as a coefficient image by converting the quantization parameter into the color difference quantization offset from the adaptive color difference quantization offset deriving device 221. Increase or decrease according to
図5 に示すように、第2の実施形態の映像復号装置において、逆量子化/逆周波数変換器205 は、adaptive_color_trans_flag=1 (残差領域適応色変換が実施されることを示す。)がシグナリングされ、かつ、cu_residual_csc_flag=0(RGB 空間でデータ圧縮されたことを示す。)がシグナリングされた場合、B 成分の逆量子化パラメータをRGB 空間用の第1色差量子化オフセットに従って増減し、R 成分の逆量子化パラメータをRGB 空間用の第2色差量子化オフセットに従って増減する。具体的には、適応色差量子化オフセット導出器221 が上記の(2)式で計算したRGB 空間用の色差量子化オフセット(第1色差量子化オフセットqPiCb 及び第2色差量子化オフセットqPiCr )を使用する。
As shown in FIG. 5, in the video decoding apparatus of the second embodiment, the inverse quantization / inverse frequency converter 205 performs signaling with adaptive_color_trans_flag = 1 (indicating that residual area adaptive color conversion is performed). And cu_residual_csc_flag = 0 (indicating that data compression is performed in RGB space) is signaled, the inverse quantization parameter of B component is increased or decreased according to the first color difference quantization offset for RGB space, and R component Are increased or decreased according to the second color difference quantization offset for RGB space. Specifically, the color difference quantization offset for RGB space (first color difference quantization offset qPi Cb and second color difference quantization offset qPi Cr ) calculated by the adaptive color difference quantization offset deriving unit 221 according to the above equation (2). Is used.
また、逆量子化/逆周波数変換器205 は、cu_residual_csc_flag=1(YCoCr 空間でデータ圧縮されたことを示す。)がシグナリングされた場合、Co成分の逆量子化パラメータをYCoCr 空間の第1色差量子化オフセットに従って増減し、Cr成分の逆量子化パラメータをYCoCr 空間の第2色差量子化オフセットに従って増減する。具体的には、適応色差量子化オフセット導出器221 が上記の(3)式で計算したYCoCr 空間用の色差量子化オフセット(第1色差量子化オフセットqPiCb 及び第2色差量子化オフセットqPiCr )を使用する。
Further, when cu_residual_csc_flag = 1 (indicating that data compression is performed in the YCoCr space) is signaled, the inverse quantization / inverse frequency converter 205 converts the inverse quantization parameter of the Co component to the first color difference quantum in the YCoCr space. The inverse quantization parameter of the Cr component is increased or decreased according to the second color difference quantization offset in the YCoCr space. Specifically, the color difference quantization offset for the YCoCr space (first color difference quantization offset qPi Cb and second color difference quantization offset qPi Cr ) calculated by the adaptive color difference quantization offset derivation unit 221 according to the above equation (3). Is used.
なお、図5 において、RGB 空間用の第1色差量子化オフセットは、cb_qp_offsetで表され、RGB 空間用の第2色差量子化オフセットは、cr_qp_offsetで表されている。YCoCr 空間用の第1色差量子化オフセットは、alt_cb_qp_offsetで表され、YCoCr 空間用の第2色差量子化オフセットは、alt_cr_qp_offsetで表されている。
In FIG. 5B, the first color difference quantization offset for RGB color space is represented by cb_qp_offset, and the second color difference quantization offset for RGB color space is represented by cr_qp_offset. The first color difference quantization offset for YCoCrCospace is represented by alt_cb_qp_offset, and the second color difference quantization offset for YCoCr space is represented by alt_cr_qp_offset.
また、RGB 空間用の第1色差量子化オフセット及びYCoCr 空間用の第1色差量子化オフセットの値域として、-12 ~12が例示され、RGB 空間用の第2色差量子化オフセット及びYCoCr 空間用の第2色差量子化オフセットの値域として、-12 ~12が例示されている。
Also, as the range of the first color difference quantization offset for the RGB color space and the range of the first color difference quantization offset for the YCoCr color space, -12% to 12 is exemplified, and the second color difference quantization offset for the RGB color space and the value for the YCoCr color space As a range of the second color difference quantization offset, -12 to 12 is illustrated.
適応色差量子化オフセット導出器221 が色空間毎の色差量子化オフセットを導出し、逆量子化/逆周波数変換器205 が、図5 に示すように、色空間毎の色差量子化オフセットを使用して量子化係数画像を逆量子化するので、残差領域適応色変換と色差量子化オフセットとが併用される場合に、主観画質改善効果が損なわれないようにすることができる。
The adaptive color difference quantization offset derivation unit 221 derives the color difference quantization offset for each color space, and the inverse quantization / inverse frequency converter 205 uses the color difference quantization offset for each color space as shown in FIG. Since the quantization coefficient image is inversely quantized, when the residual area adaptive color conversion and the color difference quantization offset are used in combination, the subjective image quality improvement effect can be prevented from being impaired.
なお、図1 に示された映像符号化装置において、映像符号化装置における逆量子化/逆周波数変換器105 は、逆量子化/逆周波数変換器205 と同様に動作する。
In the video encoding device shown in FIG. 1B, the inverse quantization / inverse frequency converter 105 in the video encoding device operates in the same manner as the inverse quantization / inverse frequency converter 205.
実施形態3.
次に、第3の実施形態の映像符号化装置を説明する。図6 は、alt_pps_cb_qp_offset及びalt_pps_cr_qp_offsetを伝送するためのシンタクスの一例(非特許文献1に記載されている7.3.2.3.2 Picture parameter set range extensions syntax の改良)を示す説明図である。図6 において、斜体字の表示箇所は、本実施形態の特徴箇所を示す。 Embodiment 3. FIG.
Next, a video encoding apparatus according to the third embodiment will be described. FIG. 6 is an explanatory diagram showing an example of syntax for transmitting alt_pps_cb_qp_offset and alt_pps_cr_qp_offset (improvement of 7.3.2.3.2 Picture parameter set range extensions syntax described in Non-Patent Document 1). In FIG. 6, italicized display locations indicate the characteristic locations of this embodiment.
次に、第3の実施形態の映像符号化装置を説明する。図6 は、alt_pps_cb_qp_offset及びalt_pps_cr_qp_offsetを伝送するためのシンタクスの一例(非特許文献1に記載されている7.3.2.3.2 Picture parameter set range extensions syntax の改良)を示す説明図である。図6 において、斜体字の表示箇所は、本実施形態の特徴箇所を示す。 Embodiment 3. FIG.
Next, a video encoding apparatus according to the third embodiment will be described. FIG. 6 is an explanatory diagram showing an example of syntax for transmitting alt_pps_cb_qp_offset and alt_pps_cr_qp_offset (improvement of 7.3.2.3.2 Picture parameter set range extensions syntax described in Non-Patent Document 1). In FIG. 6, italicized display locations indicate the characteristic locations of this embodiment.
図7 ,図8 は、alt_slice_qp_delta_cb及びalt_slice_qp_delta_cr伝送するためのシンタクスの一例(非特許文献1に記載されている7.3.6.1 General slice segment header syntax の改良)を示す説明図である。図7 ,図8 において、斜体字の表示箇所は、本実施形態の特徴箇所を示す。
FIGS. 7 and 8 are explanatory diagrams showing an example of syntax for transmitting alt_slice_qp_delta_cb and alt_slice_qp_delta_cr (improvement of 7.3.1.1 General slice segment header syntax described in Non-Patent Document 1). 7B and 8B, the italicized display locations indicate the characteristic locations of the present embodiment.
なお、本実施形態の映像符号化装置の構成は、図1 に示された構成と同じである。映像符号化装置において、エントロピー符号化器112 は、RGB 空間用の色差量子化オフセットを特定可能な情報(例えば、映像復号装置に保持されている色差量子化オフセットが設定されているデータテーブルを指定するインデックス、又は色差量子化オフセットの値)を映像復号装置に伝送している。
Note that the configuration of the video encoding apparatus of the present embodiment is the same as that shown in FIG. In the video encoding device, the entropy encoder 112 specifies information that can specify the color difference quantization offset for the RGB space (for example, specifies a data table in which the color difference quantization offset held in the video decoding device is set) Index or color difference quantization offset value) is transmitted to the video decoding device.
エントロピー符号化器112 は、YCoCr 空間でデータ圧縮する場合には、図6 及び図7 ,図8 に例示されたシンタクスで、YCoCr 空間用の色差量子化オフセットを特定可能な情報(例えば、色差量子化オフセットの値そのもの)をシグナリングする。
When data compression is performed in the YCoCr space, the entropy encoder 112 uses the syntax illustrated in FIGS. 6, 7, and 8 情報 as information that can specify the color difference quantization offset for the YCoCr space (for example, the color difference quantum). Signaling offset value itself).
実施形態4.
次に、第4の実施形態の映像復号装置を説明する。本実施形態の映像復号装置は、第3の実施形態の映像符号化装置に対応する。なお、本実施形態の映像復号装置の構成は、図3 に示された構成と同じである。 Embodiment 4 FIG.
Next, a video decoding apparatus according to the fourth embodiment will be described. The video decoding apparatus according to the present embodiment corresponds to the video encoding apparatus according to the third embodiment. Note that the configuration of the video decoding apparatus of the present embodiment is the same as the configuration shown in FIG.
次に、第4の実施形態の映像復号装置を説明する。本実施形態の映像復号装置は、第3の実施形態の映像符号化装置に対応する。なお、本実施形態の映像復号装置の構成は、図3 に示された構成と同じである。 Embodiment 4 FIG.
Next, a video decoding apparatus according to the fourth embodiment will be described. The video decoding apparatus according to the present embodiment corresponds to the video encoding apparatus according to the third embodiment. Note that the configuration of the video decoding apparatus of the present embodiment is the same as the configuration shown in FIG.
映像復号装置において、エントロピー復号器212 が、図6 及び図7 ,図8 に例示されたシンタクスによりYCoCr 空間でデータ圧縮されたことを解読した場合には、適応色差量子化オフセット導出器221 は、第2の実施形態の場合と同様に、色差量子化オフセットを導出する。
In the video decoding apparatus, when the entropy decoder 212 decodes that the data is compressed in the YCoCr space by the syntax illustrated in FIGS. 6, 7, and 8, the adaptive color difference quantization offset derivation 221 Similar to the case of the second embodiment, a chrominance quantization offset is derived.
また、映像符号化装置において、適応色差量子化オフセット導出器121 は、適応色差量子化オフセット導出器221 と同様に動作する。
Also, in the video encoding apparatus, the adaptive color difference quantization offset derivation unit 121 operates in the same manner as the adaptive color difference quantization offset derivation unit 221.
実施形態5.
次に、第5の実施形態の映像符号化装置を説明する。図9 は、YCoCr 空間用に追加でcb_qp_offset_list [i] 及びcr_qp_offset_list [i] を伝送するためのシンタクスの一例(非特許文献1に記載されている7.3.2.3.2 Picture parameter set range extensions syntax の改良)を示す説明図である。図9 において、斜体字の表示箇所は、本実施形態の特徴箇所を示す(つまり、adaptive_color_trans_flagの値に応じてcb_qp_offset_list/cr_qp_offset_list のサイズ(chroma_qp_offset_list_len_minus1のレンジ)を拡張することを示す)。本実施形態の映像符号化装置においては、cu_residual_csc_flagシンタクスの値に応じてブロック単位で伝送するcu_chroma_qp_offset_idx シンタクスの値を調整することによって、ブロック単位でRGB 空間用とYCoCr 空間用の量子化オフセットを切り替えることができる。 Embodiment 5. FIG.
Next, a video encoding device according to a fifth embodiment will be described. Fig. 9 shows an example of syntax for additionally transmitting cb_qp_offset_list [i] and cr_qp_offset_list [i] for the YCoCr space (7.3.2.3.2 Picture parameter set range extensions syntax described in Non-Patent Document 1) FIG. In FIG. 9, the italicized display location indicates the feature location of the present embodiment (that is, the size of the cb_qp_offset_list / cr_qp_offset_list (the range of chroma_qp_offset_list_len_minus1) is expanded according to the value of adaptive_color_trans_flag). In the video encoding apparatus according to the present embodiment, the quantization offset for RGB space and YCoCr space is switched in units of blocks by adjusting the value of cu_chroma_qp_offset_idx syntax transmitted in units of blocks according to the value of cu_residual_csc_flag syntax. Can do.
次に、第5の実施形態の映像符号化装置を説明する。図9 は、YCoCr 空間用に追加でcb_qp_offset_list [i] 及びcr_qp_offset_list [i] を伝送するためのシンタクスの一例(非特許文献1に記載されている7.3.2.3.2 Picture parameter set range extensions syntax の改良)を示す説明図である。図9 において、斜体字の表示箇所は、本実施形態の特徴箇所を示す(つまり、adaptive_color_trans_flagの値に応じてcb_qp_offset_list/cr_qp_offset_list のサイズ(chroma_qp_offset_list_len_minus1のレンジ)を拡張することを示す)。本実施形態の映像符号化装置においては、cu_residual_csc_flagシンタクスの値に応じてブロック単位で伝送するcu_chroma_qp_offset_idx シンタクスの値を調整することによって、ブロック単位でRGB 空間用とYCoCr 空間用の量子化オフセットを切り替えることができる。 Embodiment 5. FIG.
Next, a video encoding device according to a fifth embodiment will be described. Fig. 9 shows an example of syntax for additionally transmitting cb_qp_offset_list [i] and cr_qp_offset_list [i] for the YCoCr space (7.3.2.3.2 Picture parameter set range extensions syntax described in Non-Patent Document 1) FIG. In FIG. 9, the italicized display location indicates the feature location of the present embodiment (that is, the size of the cb_qp_offset_list / cr_qp_offset_list (the range of chroma_qp_offset_list_len_minus1) is expanded according to the value of adaptive_color_trans_flag). In the video encoding apparatus according to the present embodiment, the quantization offset for RGB space and YCoCr space is switched in units of blocks by adjusting the value of cu_chroma_qp_offset_idx syntax transmitted in units of blocks according to the value of cu_residual_csc_flag syntax. Can do.
なお、本実施形態の映像符号化装置の構成は、図1 に示された構成と同じである。映像符号化装置において、エントロピー符号化器112 は、RGB 空間用の色差量子化オフセットを特定可能な情報(例えば、映像復号装置に保持されている色差量子化オフセットが設定されているデータテーブルを指定するインデックスであるcu_chroma_qp_offset_idx シンタクス)を映像復号装置に伝送している。
Note that the configuration of the video encoding apparatus of the present embodiment is the same as that shown in FIG. In the video encoding device, the entropy encoder 112 specifies information that can specify the color difference quantization offset for the RGB space (for example, specifies a data table in which the color difference quantization offset held in the video decoding device is set) Cu_chroma_qp_offset_idx syntax) that is an index to be transmitted to the video decoding device.
本実施形態では、映像符号化装置において、エントロピー符号化器112 は、YCoCr 空間用の色差量子化オフセットを特定可能な情報(例えば、映像復号装置に保持されている色差量子化オフセットが設定されているデータテーブルを指定するインデックスであるcu_chroma_qp_offset_idx シンタクス)を映像復号装置に伝送する。本実施形態の映像復号装置では、cu_residual_csc_flagシンタクスの値に応じてブロック単位で伝送されたcu_chroma_qp_offset_idx シンタクスの値に基づいて、ブロック単位でRGB 空間用とYCoCr 空間用の色差量子化オフセットを切り替えることができる。
In the present embodiment, in the video encoding device, the entropy encoder 112 has information that can specify the color difference quantization offset for the YCoCr space (for example, the color difference quantization offset held in the video decoding device is set). Cu_chroma_qp_offset_idx syntax) that is an index for designating the data table is transmitted to the video decoding device. In the video decoding apparatus according to the present embodiment, it is possible to switch the color difference quantization offset for RGB space and YCoCr で space for each block based on the value of cu_chroma_qp_offset_idx syntax transmitted for each block according to the value of cu_residual_csc_flag syntax .
なお、図9 において、斜体字の表示箇所(cb_qp_offset_list [i] 及びcr_qp_offset_list [i] は、上記のYCoCr 空間用の色差量子化オフセットに対応する。
In FIG. 9 (b), italicized display locations (cb_qp_offset_list [i] and cr_qp_offset_list [i]) correspond to the color difference quantization offset for the YCoCr space described above.
実施形態6.
次に、第6の実施形態の映像復号装置を説明する。本実施形態の映像復号装置は、第5の実施形態の映像符号化装置に対応する。なお、本実施形態の映像復号装置の構成は、図3 に示された構成と同じである。 Embodiment 6. FIG.
Next, a video decoding apparatus according to the sixth embodiment will be described. The video decoding apparatus according to the present embodiment corresponds to the video encoding apparatus according to the fifth embodiment. Note that the configuration of the video decoding apparatus of the present embodiment is the same as the configuration shown in FIG.
次に、第6の実施形態の映像復号装置を説明する。本実施形態の映像復号装置は、第5の実施形態の映像符号化装置に対応する。なお、本実施形態の映像復号装置の構成は、図3 に示された構成と同じである。 Embodiment 6. FIG.
Next, a video decoding apparatus according to the sixth embodiment will be described. The video decoding apparatus according to the present embodiment corresponds to the video encoding apparatus according to the fifth embodiment. Note that the configuration of the video decoding apparatus of the present embodiment is the same as the configuration shown in FIG.
映像復号装置において、エントロピー復号器212 が、図9 に例示されたシンタクスによりYCoCr 空間でデータ圧縮されたことを解読した場合に、例えばインデックスで指定されるデータテーブルから色差量子化オフセットを読み出し、適応色差量子化オフセット導出器221 は、第2の実施形態の場合と同様に、色差量子化パラメータを算出する。
In the video decoding device, when the entropy decoder 212 decodes that the data is compressed in the YCoCr に よ り space by the syntax illustrated in Fig. 9 例 え ば, for example, reads the color difference quantization offset from the data table specified by the index, and adapts The color difference quantization offset derivation unit 221 calculates the color difference quantization parameter as in the case of the second embodiment.
また、映像符号化装置において、適応色差量子化オフセット導出器121 は、適応色差量子化オフセット導出器221 と同様に動作する。
Also, in the video encoding apparatus, the adaptive color difference quantization offset derivation unit 121 operates in the same manner as the adaptive color difference quantization offset derivation unit 221.
実施形態7.
次に、第7の実施形態の映像符号化装置を説明する。図10は、YCoCr 空間用にalt_cb_qp_offset_list [i] 及びalt_cr_qp_offset_list [i] を伝送するためのシンタクスの一例(非特許文献1に記載されている7.3.2.3.2 Picture parameter set range extensions syntax の改良)を示す説明図である。図10において、斜体字の表示箇所は、本実施形態の特徴箇所を示す。 Embodiment 7. FIG.
Next, a video encoding device according to a seventh embodiment will be described. Fig. 10 shows an example of syntax for transmitting alt_cb_qp_offset_list [i] and alt_cr_qp_offset_list [i] for YCoCr space (7.3.2.3.2 Picture parameter set range extensions syntax described in Non-Patent Document 1). It is explanatory drawing shown. In FIG. 10, italicized display locations indicate characteristic locations of the present embodiment.
次に、第7の実施形態の映像符号化装置を説明する。図10は、YCoCr 空間用にalt_cb_qp_offset_list [i] 及びalt_cr_qp_offset_list [i] を伝送するためのシンタクスの一例(非特許文献1に記載されている7.3.2.3.2 Picture parameter set range extensions syntax の改良)を示す説明図である。図10において、斜体字の表示箇所は、本実施形態の特徴箇所を示す。 Embodiment 7. FIG.
Next, a video encoding device according to a seventh embodiment will be described. Fig. 10 shows an example of syntax for transmitting alt_cb_qp_offset_list [i] and alt_cr_qp_offset_list [i] for YCoCr space (7.3.2.3.2 Picture parameter set range extensions syntax described in Non-Patent Document 1). It is explanatory drawing shown. In FIG. 10, italicized display locations indicate characteristic locations of the present embodiment.
第7の実施形態では、後述するように、第5の実施形態と比較して、cu_residual_csc_flagシンタクスの値に応じてcu_chroma_qp_offset_idx シンタクスの値の解釈が変わるため、ブロックごとに伝送するcu_chroma_qp_offset_idx シンタクスのビット数を節約できる。例えば、第7の実施形態では、cu_chroma_qp_offset_idx=0 でも、cu_residual_csc_flag=0の場合RGB 用のcb_qp_offset_list [0] 及びcr_qp_offset_list [0] を導出し、cu_residual_csc_flag=1の場合YCoCr 用のalt_cb_qp_offset_list [0] 及びalt_cr_qp_offset_list [0] を導出する。一方、第5の実施形態では、cu_chroma_qp_offset_idx=0 は、RGB 用のcb_qp_offset_list [0] 及びcr_qp_offset_list [0] を導出することになる。このため、第5の実施形態においては、同listの大きさが4の場合(chroma_qp_offset_list_len_minus1が3の場合)、YCoCr 用のcb_qp_offset_list [4] 及びalt_cr_qp_offset_list [4] を導出するためには、cu_chroma_qp_offset_idx=4 を伝送しなくてはならない。
In the seventh embodiment, as will be described later, since the interpretation of the value of the cu_chroma_qp_offset_idx syntax changes according to the value of the cu_residual_csc_flag syntax as compared to the fifth embodiment, the number of bits of the cu_chroma_qp_offset_idx syntax transmitted for each block Can save. For example, in the seventh embodiment, even when cu_chroma_qp_offset_idx = 0, when cu_residual_csc_flag = 0, cb_qp_offset_list [0] and cr_qp_offset_list [0] for RGB are derived, and when _c_list_ 0] Derive. On the other hand, in the fifth embodiment, cu_chroma_qp_offset_idx = 0 derives cb_qp_offset_list [0] and cr_qp_offset_list [0] for RGB. Therefore, in the fifth embodiment, when the size of the list is 4 (when chroma_qp_offset_list_len_minus1 is 3), in order to derive cb_qp_offset_list [4] and alt_cr_qp_offset_list [4] for YCoCr, cu_chroma_qp_offset_ Must be transmitted.
なお、本実施形態の映像符号化装置の構成は、図1 に示された構成と同じである。映像符号化装置において、エントロピー符号化器112 は、RGB 空間用の色差量子化オフセットを特定可能な情報(例えば、映像復号装置に保持されている色差量子化オフセットが設定されているデータテーブルを指定するインデックス)を映像復号装置に伝送している。
Note that the configuration of the video encoding apparatus of the present embodiment is the same as that shown in FIG. In the video encoding device, the entropy encoder 112 specifies information that can specify the color difference quantization offset for the RGB space (for example, specifies a data table in which the color difference quantization offset held in the video decoding device is set) Is transmitted to the video decoding device.
本実施形態では、映像符号化装置において、エントロピー符号化器112 は、YCoCr 空間用の色差量子化オフセットを特定可能な情報(例えば、映像復号装置に保持されている色差量子化オフセットが設定されているデータテーブルを指定するインデックス)を映像復号装置に伝送する。
In the present embodiment, in the video encoding device, the entropy encoder 112 has information that can specify the color difference quantization offset for the YCoCr space (for example, the color difference quantization offset held in the video decoding device is set). The index for designating the data table is transmitted to the video decoding device.
実施形態8.
次に、第8の実施形態の映像復号装置を説明する。本実施形態の映像復号装置は、第7の実施形態の映像符号化装置に対応する。なお、本実施形態の映像復号装置の構成は、図3 に示された構成と同じである。 Embodiment 8. FIG.
Next, a video decoding apparatus according to the eighth embodiment will be described. The video decoding apparatus according to the present embodiment corresponds to the video encoding apparatus according to the seventh embodiment. Note that the configuration of the video decoding apparatus of the present embodiment is the same as the configuration shown in FIG.
次に、第8の実施形態の映像復号装置を説明する。本実施形態の映像復号装置は、第7の実施形態の映像符号化装置に対応する。なお、本実施形態の映像復号装置の構成は、図3 に示された構成と同じである。 Embodiment 8. FIG.
Next, a video decoding apparatus according to the eighth embodiment will be described. The video decoding apparatus according to the present embodiment corresponds to the video encoding apparatus according to the seventh embodiment. Note that the configuration of the video decoding apparatus of the present embodiment is the same as the configuration shown in FIG.
映像復号装置において、エントロピー復号器212 が、図10に例示されたシンタクスによりYCoCr 空間でデータ圧縮されたことを解読した場合に、例えばインデックスで指定されるデータテーブルから色差量子化オフセットを読み出し、適応色差量子化オフセット導出器221 は、第2の実施形態の場合と同様に、色差量子化パラメータを算出する。
In the video decoding device, when the entropy decoder 212 decodes the data compression in the YCoCr space by the syntax illustrated in FIG. 10, for example, the color difference quantization offset is read from the data table specified by the index, and adaptively The color difference quantization offset derivation unit 221 calculates the color difference quantization parameter as in the case of the second embodiment.
また、映像符号化装置において、適応色差量子化オフセット導出器121 は、適応色差量子化オフセット導出器221 と同様に動作する。
Also, in the video encoding apparatus, the adaptive color difference quantization offset derivation unit 121 operates in the same manner as the adaptive color difference quantization offset derivation unit 221.
以下に、色差量子化オフセットの導出の手続の具体例を示す。下記の記述において、クォーテーションマークで囲まれた部分は、本実施形態における特徴的な部分である。
The following is a specific example of the procedure for deriving the color difference quantization offset. In the following description, a part surrounded by quotation marks is a characteristic part in the present embodiment.
cu_chroma_qp_offset_idx, when present, specifies the index into the cb_qp_offset_list [ ] and cr_qp_offset_list [ ] or the alt_cb_qp_offset_list [ ] and alt_cr_qp_offset_list [ ] that is used to determine the value of CuQpOffsetCb and CuQpOffsetCr. When present, the value of cu_chroma_qp_offset_idx shall be in the range of 0 to chroma_qp_offset_list_len_minus1, inclusive. When not present, the value of cu_chroma_qp_offset_idx is inferred to be equal to 0.
When cu_chroma_qp_offset_flag is present, the following applies:
- The variable IsCuChromaQpOffsetCoded is set equal to 1.
- The variables CuQpOffsetCb and CuQpOffsetCr are derived as follows:
- If cu_chroma_qp_offset_flag is equal to 1 and "cu_residual_csc_flag is equal to 0", the following applies:
CuQpOffsetCb = cb_qp_offset_list [cu_chroma_qp_offset_idx]
CuQpOffsetCr = cr_qp_offset_list [cu_chroma_qp_offset_idx]
- "Otherwise if cu_chroma_qp_offset_flag is equal to 1 and cu_residual_csc_flag is equal to 1, the following applies:"
"CuQpOffsetCb = alt_cb_qp_offset_list [cu_chroma_qp_offset_idx]"
"CuQpOffsetCr = alt_cr_qp_offset_list [cu_chroma_qp_offset_idx]"
- Otherwise (cu_chroma_qp_offset_flag is equal to 0), CuQpOffsetCb and CuQpOffsetCr are both set equal to 0. cu_chroma_qp_offset_idx, when present, specifies the index into the cb_qp_offset_list [] and cr_qp_offset_list [] or the alt_cb_qp_offset_list [] and alt_cr_qp_offset_list [] that is used to determine the value of CuQpOffsetCb_ Cu_p_offsetCb_ Cu_p of 0 to chroma_qp_offset_list_len_minus1, inclusive.When not present, the value of cu_chroma_qp_offset_idx is inferred to be equal to 0.
When cu_chroma_qp_offset_flag is present, the following applies:
-The variable IsCuChromaQpOffsetCoded is set equal to 1.
-The variables CuQpOffsetCb and CuQpOffsetCr are derived as follows:
-If cu_chroma_qp_offset_flag is equal to 1 and "cu_residual_csc_flag is equal to 0", the following applies:
CuQpOffsetCb = cb_qp_offset_list [cu_chroma_qp_offset_idx]
CuQpOffsetCr = cr_qp_offset_list [cu_chroma_qp_offset_idx]
-"Otherwise if cu_chroma_qp_offset_flag is equal to 1 and cu_residual_csc_flag is equal to 1, the following applies:"
"CuQpOffsetCb = alt_cb_qp_offset_list [cu_chroma_qp_offset_idx]"
"CuQpOffsetCr = alt_cr_qp_offset_list [cu_chroma_qp_offset_idx]"
-Otherwise (cu_chroma_qp_offset_flag is equal to 0), CuQpOffsetCb and CuQpOffsetCr are both set equal to 0.
When cu_chroma_qp_offset_flag is present, the following applies:
- The variable IsCuChromaQpOffsetCoded is set equal to 1.
- The variables CuQpOffsetCb and CuQpOffsetCr are derived as follows:
- If cu_chroma_qp_offset_flag is equal to 1 and "cu_residual_csc_flag is equal to 0", the following applies:
CuQpOffsetCb = cb_qp_offset_list [cu_chroma_qp_offset_idx]
CuQpOffsetCr = cr_qp_offset_list [cu_chroma_qp_offset_idx]
- "Otherwise if cu_chroma_qp_offset_flag is equal to 1 and cu_residual_csc_flag is equal to 1, the following applies:"
"CuQpOffsetCb = alt_cb_qp_offset_list [cu_chroma_qp_offset_idx]"
"CuQpOffsetCr = alt_cr_qp_offset_list [cu_chroma_qp_offset_idx]"
- Otherwise (cu_chroma_qp_offset_flag is equal to 0), CuQpOffsetCb and CuQpOffsetCr are both set equal to 0. cu_chroma_qp_offset_idx, when present, specifies the index into the cb_qp_offset_list [] and cr_qp_offset_list [] or the alt_cb_qp_offset_list [] and alt_cr_qp_offset_list [] that is used to determine the value of CuQpOffsetCb_ Cu_p_offsetCb_ Cu_p of 0 to chroma_qp_offset_list_len_minus1, inclusive.When not present, the value of cu_chroma_qp_offset_idx is inferred to be equal to 0.
When cu_chroma_qp_offset_flag is present, the following applies:
-The variable IsCuChromaQpOffsetCoded is set equal to 1.
-The variables CuQpOffsetCb and CuQpOffsetCr are derived as follows:
-If cu_chroma_qp_offset_flag is equal to 1 and "cu_residual_csc_flag is equal to 0", the following applies:
CuQpOffsetCb = cb_qp_offset_list [cu_chroma_qp_offset_idx]
CuQpOffsetCr = cr_qp_offset_list [cu_chroma_qp_offset_idx]
-"Otherwise if cu_chroma_qp_offset_flag is equal to 1 and cu_residual_csc_flag is equal to 1, the following applies:"
"CuQpOffsetCb = alt_cb_qp_offset_list [cu_chroma_qp_offset_idx]"
"CuQpOffsetCr = alt_cr_qp_offset_list [cu_chroma_qp_offset_idx]"
-Otherwise (cu_chroma_qp_offset_flag is equal to 0), CuQpOffsetCb and CuQpOffsetCr are both set equal to 0.
実施形態9.
上記の各実施形態では、映像符号化装置は、明示的に色差量子化オフセットをシグナリングしたが、ブロック単位で予測誤差信号の色空間を選択する旨をシグナリングするが色差量子化オフセットをシグナリングしないようにしてもよい。本明細書では、そのことを、暗黙的に(implicit)色差量子化オフセットをシグナリングするという。 Embodiment 9. FIG.
In each of the above embodiments, the video encoding apparatus explicitly signals the color difference quantization offset, but signals that the color space of the prediction error signal is selected in units of blocks, but does not signal the color difference quantization offset. It may be. In this specification, this is referred to as implicit color difference quantization offset signaling.
上記の各実施形態では、映像符号化装置は、明示的に色差量子化オフセットをシグナリングしたが、ブロック単位で予測誤差信号の色空間を選択する旨をシグナリングするが色差量子化オフセットをシグナリングしないようにしてもよい。本明細書では、そのことを、暗黙的に(implicit)色差量子化オフセットをシグナリングするという。 Embodiment 9. FIG.
In each of the above embodiments, the video encoding apparatus explicitly signals the color difference quantization offset, but signals that the color space of the prediction error signal is selected in units of blocks, but does not signal the color difference quantization offset. It may be. In this specification, this is referred to as implicit color difference quantization offset signaling.
映像符号化装置が暗黙的に色差量子化オフセットをシグナリングする場合、エントロピー符号化器は、adaptive_color_trans_flag=1 をシグナリングし、例えばブロック単位でcu_residual_csc_flagをシグナリングするが、色差量子化オフセットの値を特定可能な情報をシグナリングしない。
When the video encoding device implicitly signals the color difference quantization offset, the entropy encoder signals adaptive_color_trans_flag = 1, for example, signals cu_residual_csc_flag in units of blocks, but the value of the color difference quantization offset can be specified. Does not signal information.
映像復号装置において、エントロピー復号器が、ビットストリームからadaptive_color_trans_flag=1 を解読した場合、cu_residual_csc_flag=0(RGB 空間でデータ圧縮されたことを示す。)を解読したときには、適応色差量子化オフセット導出器221 は、映像復号装置において予め記憶されているRGB 空間用の色差量子化オフセットの値を読み出す。また、cu_residual_csc_flag=1(YCoCr 空間でデータ圧縮されたことを示す。)を解読したときには、適応色差量子化オフセット導出器221 は、予め記憶されているRGB 空間用の色差量子化オフセットの値からYCoCr 空間用の色差量子化オフセットの値を算出する。
In the video decoding apparatus, when the entropy decoder decodes adaptive_color_trans_flag = 1 from the bitstream, when decoding cu_residual_csc_flag = 0 (indicating that data compression is performed in RGB space), the adaptive color difference quantization offset derivation unit 221 Reads out the color difference quantization offset value for the RGB color space stored in advance in the video decoding device. In addition, when cu_residual_csc_flag = 1 (indicating that data compression is performed in the YCoCr space), the adaptive color difference quantization offset derivation unit 221 か ら calculates the YCoCr from the color difference quantization offset value for the RGB color space stored in advance. The value of the color difference quantization offset for space is calculated.
RGB 空間用の色差量子化オフセットとYCoCr 空間用の色差量子化オフセットとはある程度相関関係があることから、すなわち、YCoCr 空間用の色差量子化オフセットをRGB 空間用の色差量子化オフセットから算出するための計算式を定めることが可能であることから、適応色差量子化オフセット導出器221 は、そのような計算式によってYCoCr 空間用の色差量子化オフセットを導出できる。
The color difference quantization offset for RGB color space and the color difference quantization offset for YCoCr color space are correlated to some extent, that is, to calculate the color difference quantization offset for YCoCr color space from the color difference quantization offset for RGB color space. Therefore, the adaptive color difference quantization offset deriving unit 221 can derive the color difference quantization offset for YCoCr space by such a calculation equation.
すなわち、映像復号装置は、暗黙的に色差量子化オフセットを導出する。
That is, the video decoding device implicitly derives the color difference quantization offset.
また、映像符号化装置において、適応色差量子化オフセット導出器121 は、適応色差量子化オフセット導出器221 と同様に動作する。
Also, in the video encoding apparatus, the adaptive color difference quantization offset derivation unit 121 operates in the same manner as the adaptive color difference quantization offset derivation unit 221.
なお、映像符号化装置が暗黙的に色差量子化オフセットをシグナリングする場合には、伝送されるデータ量を削減できる。
Note that, when the video encoding device implicitly signals the color difference quantization offset, the amount of data to be transmitted can be reduced.
映像符号化装置及び映像復号装置が暗黙的に色差量子化オフセットを導出する場合、一方の色空間用の色差量子化オフセットを0 にしてもよい。例えば、エントロピー復号器212 がcu_residual_csc_flag=0(RGB 空間でデータ圧縮されたことを示す。)を解読したときには、適応色差量子化オフセット導出器221 は、映像復号装置において予め記憶されているRGB 空間用の値0 の色差量子化オフセットの値を読み出す。また、エントロピー復号器212 がcu_residual_csc_flag=1(YCoCr 空間でデータ圧縮されたことを示す。)を解読したときには、適応色差量子化オフセット導出器221 は、ピクチャ単位で伝送されるpps_cb_qp_offset/pps_cr_qp_offset/slice_qp_delta_cb とスライス単位で伝送されるslice_qp_delta_cb/slice_qp_delta_cr からYCoCr 空間用の色差量子化オフセットの値を算出する。
When the video encoding device and the video decoding device implicitly derive the color difference quantization offset, the color difference quantization offset for one color space may be 0. For example, when the entropy decoder 212 解 読 decodes cu_residual_csc_flag = 0 (indicating that data compression is performed in RGB space), the adaptive color difference quantization offset derivation 221 用The value of the color difference quantization offset with the value of 0 is read. When the entropy decoder 212 解 読 decodes cu_residual_csc_flag = 1 (indicating that data compression is performed in the YCoCr space), the adaptive color difference quantization offset derivation unit 221 is pps_cb_qp_offset / pps_cr_qp_offset / slice_qp_delta_cb The value of the color difference quantization offset for YCoCr space is calculated from slice_qp_delta_cb / slice_qp_delta_cr transmitted in units of slices.
以下に、色差量子化オフセットの導出の手続の具体例を示す。下記の記述において、クォーテーションマークで囲まれた部分は、本実施形態における特徴的な部分である。
The following is a specific example of the procedure for deriving the color difference quantization offset. In the following description, a part surrounded by quotation marks is a characteristic part in the present embodiment.
- "If adaptive_color_trans_flag is equal to 0", the variables qPCb and qPCr are derived as follows:
qPiCb = Clip3( -QpBdOffsetC, 57, QpY + pps_cb_qp_offset + slice_cb_qp_offset + CuQpOffsetCb )
qPiCr = Clip3( -QpBdOffsetC, 57, QpY + pps_cr_qp_offset + slice_cr_qp_offset + CuQpOffsetCr )
- "Otherwise if adaptive_color_trans_flag is equal to 1 and cu_residual_csc_flag is equal to 0", the variables qPCb and qPCr are derived as follows:
qPiCb = Clip3( -QpBdOffsetC, 57, QpY + CuQpOffsetCb )
qPiCr = Clip3( -QpBdOffsetC, 57, QpY + CuQpOffsetCr )
- "Otherwise (aptive_color_trans_flag is equal to 1 and cu_residual_csc_flag is equal to 1), the variables qPCb and qPCr are derived as follows:"
"qPiCb = Clip3( -QpBdOffsetC, 57, QpY + alt_pps_cb_qp_offset + alt_slice_cb_qp_offset + CuQpOffsetCb )"
"qPiCr = Clip3( -QpBdOffsetC, 57, QpY + alt_pps_cr_qp_offset + alt_slice_cr_qp_offset + CuQpOffsetCr )"
- If ChromaArrayType is equal to 1, the variables qPCb and qPCr are set equal to the value of QpC as specified in Predetermined Table based on the index qPi equal to qPiCb and qPiCr, respectively.
- Otherwise, the variables qPCb and qPCr are set equal to Min( qPi, 51 ), based on the index qPi equal to qPiCb and qPiCr, respectively.
- The chroma quantization parameters for the Cb and Cr components, Qp'Cb and Qp'Cr, are derived as follows:
Qp'Cb = qPCb + QpBdOffsetC
Qp'Cr = qPCr + QpBdOffsetC -"If adaptive_color_trans_flag is equal to 0", the variables qP Cb and qP Cr are derived as follows:
qPi Cb = Clip3 (-QpBdOffset C , 57, Qp Y + pps_cb_qp_offset + slice_cb_qp_offset + CuQpOffset Cb )
qPi Cr = Clip3 (-QpBdOffset C , 57, Qp Y + pps_cr_qp_offset + slice_cr_qp_offset + CuQpOffset Cr )
-"Otherwise if adaptive_color_trans_flag is equal to 1 and cu_residual_csc_flag is equal to 0", the variables qP Cb and qP Cr are derived as follows:
qPi Cb = Clip3 (-QpBdOffset C , 57, Qp Y + CuQpOffset Cb )
qPi Cr = Clip3 (-QpBdOffset C , 57, Qp Y + CuQpOffset Cr )
-"Otherwise (aptive_color_trans_flag is equal to 1 and cu_residual_csc_flag is equal to 1), the variables qP Cb and qP Cr are derived as follows:"
"qPi Cb = Clip3 (-QpBdOffset C , 57, Qp Y + alt_pps_cb_qp_offset + alt_slice_cb_qp_offset + CuQpOffset Cb )"
"qPi Cr = Clip3 (-QpBdOffset C , 57, Qp Y + alt_pps_cr_qp_offset + alt_slice_cr_qp_offset + CuQpOffset Cr )"
-If ChromaArrayType is equal to 1, the variables qP Cb and qP Cr are set equal to the value of Qp C as specified in Predetermined Table based on the index qPi equal to qPi Cb and qPi Cr , respectively.
-Otherwise, the variables qP Cb and qP Cr are set equal to Min (qPi, 51), based on the index qPi equal to qPi Cb and qPi Cr , respectively.
-The chroma quantization parameters for the Cb and Cr components, Qp ' Cb and Qp' Cr, are derived as follows:
Qp ' Cb = qP Cb + QpBdOffset C
Qp ' Cr = qP Cr + QpBdOffset C
qPiCb = Clip3( -QpBdOffsetC, 57, QpY + pps_cb_qp_offset + slice_cb_qp_offset + CuQpOffsetCb )
qPiCr = Clip3( -QpBdOffsetC, 57, QpY + pps_cr_qp_offset + slice_cr_qp_offset + CuQpOffsetCr )
- "Otherwise if adaptive_color_trans_flag is equal to 1 and cu_residual_csc_flag is equal to 0", the variables qPCb and qPCr are derived as follows:
qPiCb = Clip3( -QpBdOffsetC, 57, QpY + CuQpOffsetCb )
qPiCr = Clip3( -QpBdOffsetC, 57, QpY + CuQpOffsetCr )
- "Otherwise (aptive_color_trans_flag is equal to 1 and cu_residual_csc_flag is equal to 1), the variables qPCb and qPCr are derived as follows:"
"qPiCb = Clip3( -QpBdOffsetC, 57, QpY + alt_pps_cb_qp_offset + alt_slice_cb_qp_offset + CuQpOffsetCb )"
"qPiCr = Clip3( -QpBdOffsetC, 57, QpY + alt_pps_cr_qp_offset + alt_slice_cr_qp_offset + CuQpOffsetCr )"
- If ChromaArrayType is equal to 1, the variables qPCb and qPCr are set equal to the value of QpC as specified in Predetermined Table based on the index qPi equal to qPiCb and qPiCr, respectively.
- Otherwise, the variables qPCb and qPCr are set equal to Min( qPi, 51 ), based on the index qPi equal to qPiCb and qPiCr, respectively.
- The chroma quantization parameters for the Cb and Cr components, Qp'Cb and Qp'Cr, are derived as follows:
Qp'Cb = qPCb + QpBdOffsetC
Qp'Cr = qPCr + QpBdOffsetC -"If adaptive_color_trans_flag is equal to 0", the variables qP Cb and qP Cr are derived as follows:
qPi Cb = Clip3 (-QpBdOffset C , 57, Qp Y + pps_cb_qp_offset + slice_cb_qp_offset + CuQpOffset Cb )
qPi Cr = Clip3 (-QpBdOffset C , 57, Qp Y + pps_cr_qp_offset + slice_cr_qp_offset + CuQpOffset Cr )
-"Otherwise if adaptive_color_trans_flag is equal to 1 and cu_residual_csc_flag is equal to 0", the variables qP Cb and qP Cr are derived as follows:
qPi Cb = Clip3 (-QpBdOffset C , 57, Qp Y + CuQpOffset Cb )
qPi Cr = Clip3 (-QpBdOffset C , 57, Qp Y + CuQpOffset Cr )
-"Otherwise (aptive_color_trans_flag is equal to 1 and cu_residual_csc_flag is equal to 1), the variables qP Cb and qP Cr are derived as follows:"
"qPi Cb = Clip3 (-QpBdOffset C , 57, Qp Y + alt_pps_cb_qp_offset + alt_slice_cb_qp_offset + CuQpOffset Cb )"
"qPi Cr = Clip3 (-QpBdOffset C , 57, Qp Y + alt_pps_cr_qp_offset + alt_slice_cr_qp_offset + CuQpOffset Cr )"
-If ChromaArrayType is equal to 1, the variables qP Cb and qP Cr are set equal to the value of Qp C as specified in Predetermined Table based on the index qPi equal to qPi Cb and qPi Cr , respectively.
-Otherwise, the variables qP Cb and qP Cr are set equal to Min (qPi, 51), based on the index qPi equal to qPi Cb and qPi Cr , respectively.
-The chroma quantization parameters for the Cb and Cr components, Qp ' Cb and Qp' Cr, are derived as follows:
Qp ' Cb = qP Cb + QpBdOffset C
Qp ' Cr = qP Cr + QpBdOffset C
実施形態10.
他方の色空間(例えば、YCoCr 空間)の色差量子化オフセットを導出する際に、加法的仕様を使用することが考えられる。 Embodiment 10 FIG.
It is conceivable to use an additive specification when deriving the color difference quantization offset of the other color space (eg, YCoCr space).
他方の色空間(例えば、YCoCr 空間)の色差量子化オフセットを導出する際に、加法的仕様を使用することが考えられる。 Embodiment 10 FIG.
It is conceivable to use an additive specification when deriving the color difference quantization offset of the other color space (eg, YCoCr space).
上述したように、第9の実施形態において、映像符号化装置及び映像復号装置が暗黙的に色差量子化オフセットを導出する場合に、一方の色空間用の色差量子化オフセットを0 にしてもよい。これは、以下のようにも定義できる。なお、下記の例では、一方の色空間は、RGB 空間である。
As described above, in the ninth embodiment, when the video encoding device and the video decoding device implicitly derive the color difference quantization offset, the color difference quantization offset for one color space may be set to 0. . This can also be defined as follows: In the following example, one color space is an RGB color space.
"The variables qPCb and qPCr are derived as follows:
qPiCb = Clip3( -QpBdOffsetC, 57, QpY + pps_cb_qp_offset + slice_cb_qp_offset + CuQpOffsetCb ) (5)
qPiCr = Clip3( -QpBdOffsetC, 57, QpY + pps_cr_qp_offset + slice_cr_qp_offset + CuQpOffsetCr ) (6)
If cIdx is equal to 0,
qP = Clip3( 0, 51 + QpBdOffsetY, Qp'Y + (cu_residual_csc_flag [ xTbY ][ yTbY ] ?
alt_pps_y_qp_offset + alt_slice_y_qp_offset : 0 ) ) (7)
Otherwise, if cIdx is equal to 1,
qP = Clip3( 0, 51 + QpBdOffsetC, Qp'Cb + (cu_residual_csc_flag [ xTbY ][ yTbY ] ?
alt_pps_cb_qp_offset + alt_slice_cb_qp_offset : 0 ) ) (8)
Otherwise (cIdx is equal to 2),
qP = Clip3( 0, 51 + QpBdOffsetC, Qp'Cr + (cu_residual_csc_flag [ xTbY ][ yTbY ] ?
alt_pps_cb_qp_offset + alt_slice_cb_qp_offset : 0 ) ) (9) "The variables qPCb and qPCr are derived as follows:
qPiCb = Clip3 (-QpBdOffsetC, 57, QpY + pps_cb_qp_offset + slice_cb_qp_offset + CuQpOffsetCb) (5)
qPiCr = Clip3 (-QpBdOffsetC, 57, QpY + pps_cr_qp_offset + slice_cr_qp_offset + CuQpOffsetCr) (6)
If cIdx is equal to 0,
qP = Clip3 (0, 51 + QpBdOffsetY, Qp'Y + (cu_residual_csc_flag [xTbY] [yTbY]?
alt_pps_y_qp_offset + alt_slice_y_qp_offset: 0)) (7)
Otherwise, if cIdx is equal to 1,
qP = Clip3 (0, 51 + QpBdOffsetC, Qp'Cb + (cu_residual_csc_flag [xTbY] [yTbY]?
alt_pps_cb_qp_offset + alt_slice_cb_qp_offset: 0)) (8)
Otherwise (cIdx is equal to 2),
qP = Clip3 (0, 51 + QpBdOffsetC, Qp'Cr + (cu_residual_csc_flag [xTbY] [yTbY]?
alt_pps_cb_qp_offset + alt_slice_cb_qp_offset: 0)) (9)
qPiCb = Clip3( -QpBdOffsetC, 57, QpY + pps_cb_qp_offset + slice_cb_qp_offset + CuQpOffsetCb ) (5)
qPiCr = Clip3( -QpBdOffsetC, 57, QpY + pps_cr_qp_offset + slice_cr_qp_offset + CuQpOffsetCr ) (6)
If cIdx is equal to 0,
qP = Clip3( 0, 51 + QpBdOffsetY, Qp'Y + (cu_residual_csc_flag [ xTbY ][ yTbY ] ?
alt_pps_y_qp_offset + alt_slice_y_qp_offset : 0 ) ) (7)
Otherwise, if cIdx is equal to 1,
qP = Clip3( 0, 51 + QpBdOffsetC, Qp'Cb + (cu_residual_csc_flag [ xTbY ][ yTbY ] ?
alt_pps_cb_qp_offset + alt_slice_cb_qp_offset : 0 ) ) (8)
Otherwise (cIdx is equal to 2),
qP = Clip3( 0, 51 + QpBdOffsetC, Qp'Cr + (cu_residual_csc_flag [ xTbY ][ yTbY ] ?
alt_pps_cb_qp_offset + alt_slice_cb_qp_offset : 0 ) ) (9) "The variables qPCb and qPCr are derived as follows:
qPiCb = Clip3 (-QpBdOffsetC, 57, QpY + pps_cb_qp_offset + slice_cb_qp_offset + CuQpOffsetCb) (5)
qPiCr = Clip3 (-QpBdOffsetC, 57, QpY + pps_cr_qp_offset + slice_cr_qp_offset + CuQpOffsetCr) (6)
If cIdx is equal to 0,
qP = Clip3 (0, 51 + QpBdOffsetY, Qp'Y + (cu_residual_csc_flag [xTbY] [yTbY]?
alt_pps_y_qp_offset + alt_slice_y_qp_offset: 0)) (7)
Otherwise, if cIdx is equal to 1,
qP = Clip3 (0, 51 + QpBdOffsetC, Qp'Cb + (cu_residual_csc_flag [xTbY] [yTbY]?
alt_pps_cb_qp_offset + alt_slice_cb_qp_offset: 0)) (8)
Otherwise (cIdx is equal to 2),
qP = Clip3 (0, 51 + QpBdOffsetC, Qp'Cr + (cu_residual_csc_flag [xTbY] [yTbY]?
alt_pps_cb_qp_offset + alt_slice_cb_qp_offset: 0)) (9)
なお、(5)式及び(6)式は、上記の(2)式と同じである。
In addition, (5) Formula and (6) Formula are the same as said (2) Formula.
また、cIdx = 0 は、第1色成分(この例では、Y )に対応し、cIdx = 1 は、第2色成分(この例では、Co)に対応し、cIdx = 2 は、第3色成分(この例では、Cr)に対応する。
CIdx = 0 corresponds to the first color component (Y in this example), cIdx = 1 corresponds to the second color component (Co in this example), and cIdx = 2 corresponds to the third color. Corresponds to the component (Cr in this example).
(7)~(9)式から明らかなように、YCoCr 空間について、cu_residual_csc_flagが0 の場合、つまり、RGB 色空間の場合の0 の色差量子化オフセットを利用可能である。
As is clear from the equations (7) to (9), for the YCoCr space, when the cu_residual_csc_flag is 0, that is, the color difference quantization offset of 0 in the case of the RGB color space can be used.
図11は、加法的仕様を説明するための説明図である。加法的仕様は、色差量子化オフセットを導出する際に実行される演算が加法的であるという仕様である。図11に示すように、加法的仕様では、cu_residual_csc_flag=1である場合、RGB 色空間の色差量子化オフセットに、YCoCr 空間用の色差量子化オフセット(又は、0 )が加算される。
FIG. 11 is an explanatory diagram for explaining additive specifications. The additive specification is a specification that the operation executed when deriving the color difference quantization offset is additive. As shown in FIG. 11, in the additive specification, when cu_residual_csc_flag = 1, the color difference quantization offset for YCoCr space (or 0) is added to the color difference quantization offset of RGB color space.
加法的仕様が使用される場合、一方の色空間(この場合、RGB 空間)に対する色差量子化オフセットの導出処理を、HEVCにおける一般的な導出処理と同じにできる利点がある。換言すると、qPCbとqPCrの導出処理が色空間に依存しなくなる利点がある。
When the additive specification is used, there is an advantage that the derivation process of the color difference quantization offset for one color space (in this case, the RGB color space) can be made the same as the general derivation process in HEVC. In other words, there is an advantage that the derivation process of qPCb and qPCr does not depend on the color space.
しかし、図6 及び図8 に記載されているように、alt_pps_cb_qp_offset及びalt_pps_cr_qp_offset、ならびに、alt_slice_qp_delta_cb 及びalt_slice_qp_delta_cr のダイナミックレンジが、一方の色空間(この場合、RGB 空間)の色差量子化オフセットのダイナミックレンジである-12 ~12と同一になるように制約すると、設定された一方の色空間の色差量子化オフセットの値によってYCoCr 空間用の量子化オフセットを所望する値に設定できないことがある。一方の色空間の色差量子化オフセットと追加色差量子化オフセット(この場合には、YCoCr 空間用の色差量子化オフセット)を同じダイナミックレンジに制約すると、色空間毎に好ましい色再現を達成できなくなる場合がある。
However, as described in FIGS. 6 and 8, the dynamic range of alt_pps_cb_qp_offset and alt_pps_cr_qp_offset, and alt_slice_qp_delta_cb and alt_slice_qp_delta_cr is the dynamic range of the color difference quantization offset in one color space (in this case, RGB space). If it is constrained to be the same as −12 to 12, the quantization offset for the YCoCr space may not be set to a desired value depending on the value of the color difference quantization offset of one set color space. When the color difference quantization offset of one color space and the additional color difference quantization offset (in this case, the color difference quantization offset for YCoCr space) are constrained to the same dynamic range, favorable color reproduction cannot be achieved for each color space There is.
例えば、一方の色空間(この場合、RGB 空間)の第2色成分(B 成分)が-12 であるときに、他方の色空間(この場合、YCoCr 空間)の第2色成分(Co成分)を12にすることはできない。本来の加法的仕様では、B 成分である-12 に加算できる値は最大12であって、加算結果は0 にしかならないからである。
For example, when the second color component (B component) of one color space (in this case, RGB space) is -12, the second color component (Co component) of the other color space (in this case, YCoCr space) Cannot be 12. This is because in the original additive specification, the maximum value that can be added to the B component -12 is 12, and the result of addition is only 0.
そこで、本実施形態では、加法的仕様を使用する場合、色空間毎に異なるダイナミックレンジの色量子化オフセットが用いられる。すなわち、本実施形態の映像符号化装置の構成は、図1 に示された構成と同じであるが、本実施形態では、適応色差量子化オフセット導出器121 は、例えば、以下のような処理を実行する。
Therefore, in this embodiment, when an additive specification is used, a color quantization offset having a different dynamic range for each color space is used. That is, the configuration of the video encoding apparatus of the present embodiment is the same as the configuration shown in FIG. 1B. However, in this embodiment, the adaptive color difference quantization offset derivation unit 121 performs the following processing, for example. Execute.
一方の色空間(この場合、RGB 空間)の色差量子化オフセットを加算する処理を実行後のダイナミックレンジが、一方の色空間におけるダイナミックレンジである-12 ~12と同じになるようにする。そのことは、他方の色空間(この場合、YCoCr 空間)における色差量子化オフセットのダイナミックレンジが、一方の色空間(この場合、RGB 空間)における色差量子化オフセットのダイナミックレンジ(-12 ~12)と同じになるようにはしないということであるということもできる。
The dynamic range after executing the process of adding the color difference quantization offset in one color space (in this case, the RGB color space) is made to be the same as the dynamic range in the one color space from -12% to 12. This means that the dynamic range of the color difference quantization offset in the other color space (in this case, YCoCr space) is the dynamic range of the color difference quantization offset in one color space (in this case, RGB space) (-12 to 12). It can also be said that it is not to be the same.
なお、本実施形態の映像復号装置の構成は、図3 に示された構成と同じである。ただし、本実施形態では、適応色差量子化オフセット導出器221 は、適応色差量子化オフセット導出器121 と同様、以下のような処理を実行する。
Note that the configuration of the video decoding apparatus of the present embodiment is the same as the configuration shown in FIG. However, in the present embodiment, the adaptive color difference quantization offset derivation unit 221 performs the following processing in the same manner as the adaptive color difference quantization offset derivation unit 121.
"alt_pps_y_qp_offset, alt_pps_cb_qp_offset and alt_pps_cr_qp_offset specify offsets to the luma, cb and cr quantization parameter qP derived in the above equations (7) to (9), respectively.
alt_pps_y_qp_offset, alt_pps_cb_qp_offset + pps_cb_qp_offset, and alt_pps_cr_qp_offset + pps_cr_qp_offset and shall be in the range of -12 to +12, inclusive.
When ChromaArrayType is equal to 0, alt_pps_cb_qp_offset and alt_pps_cr_qp_offset are not used in the decoding process and decoders shall ignore their value. When not present, the values of alt_pps_y_qp_offset, alt_pps_cb_qp_offset and alt_pps_cr_qp_offset are inferred to be equal to 0."
"alt_slice_y_qp_offset, alt_slice_cb_qp_offset and alt_slice_cr_qp_offset specify offsets to the luma, cb and cr quantization parameter qP derived in the above equations (7) to (9), respectively.
The values of alt_slice_y_qp_offset, alt_slice_cb_qp_offset and alt_slice_cr_qp_offset shall be in the range of -12 to +12, inclusive.
When ChromaArrayType is equal to 0, alt_slice_cb_qp_offset and alt_slice_cr_qp_offset are not used in the decoding process and decoders shall ignore their value. When not present, the values of alt_slice_y_qp_offset, alt_slice_cb_qp_offset and alt_slice_cr_qp_offset are inferred to be equal to 0.
The value of alt_pps_y_qp_offset + alt_slice_y_qp_offset shall be in the range of -12 to +12, inclusive.
The value of alt_pps_cb_qp_offset + alt_slice_cb_qp_offset + pps_cb_qp_offset + slice_cb_qp_offset shall be in the range of -12 to +12, inclusive.
The value of alt_pps_cr_qp_offset + alt_slice_cr_qp_offset + pps_cr_qp_offset + slice_cr_qp_offset shall be in the range of -12 to +12, inclusive." "alt_pps_y_qp_offset, alt_pps_cb_qp_offset and alt_pps_cr_qp_offset specify offsets to the luma, cb and cr quantization parameter qP derived in the above equations (7) to (9), respectively.
alt_pps_y_qp_offset, alt_pps_cb_qp_offset + pps_cb_qp_offset, and alt_pps_cr_qp_offset + pps_cr_qp_offset and shall be in the range of -12 to +12, inclusive.
When ChromaArrayType is equal to 0, alt_pps_cb_qp_offset and alt_pps_cr_qp_offset are not used in the decoding process and decoders shall ignore their value.
"alt_slice_y_qp_offset, alt_slice_cb_qp_offset and alt_slice_cr_qp_offset specify offsets to the luma, cb and cr quantization parameter qP derived in the above equations (7) to (9), respectively.
The values of alt_slice_y_qp_offset, alt_slice_cb_qp_offset and alt_slice_cr_qp_offset shall be in the range of -12 to +12, inclusive.
When ChromaArrayType is equal to 0, alt_slice_cb_qp_offset and alt_slice_cr_qp_offset are not used in the decoding process and decoders shall ignore their value.
The value of alt_pps_y_qp_offset + alt_slice_y_qp_offset shall be in the range of -12 to +12, inclusive.
The value of alt_pps_cb_qp_offset + alt_slice_cb_qp_offset + pps_cb_qp_offset + slice_cb_qp_offset shall be in the range of -12 to +12, inclusive.
The value of alt_pps_cr_qp_offset + alt_slice_cr_qp_offset + pps_cr_qp_offset + slice_cr_qp_offset shall be in the range of -12 to +12, inclusive. "
alt_pps_y_qp_offset, alt_pps_cb_qp_offset + pps_cb_qp_offset, and alt_pps_cr_qp_offset + pps_cr_qp_offset and shall be in the range of -12 to +12, inclusive.
When ChromaArrayType is equal to 0, alt_pps_cb_qp_offset and alt_pps_cr_qp_offset are not used in the decoding process and decoders shall ignore their value. When not present, the values of alt_pps_y_qp_offset, alt_pps_cb_qp_offset and alt_pps_cr_qp_offset are inferred to be equal to 0."
"alt_slice_y_qp_offset, alt_slice_cb_qp_offset and alt_slice_cr_qp_offset specify offsets to the luma, cb and cr quantization parameter qP derived in the above equations (7) to (9), respectively.
The values of alt_slice_y_qp_offset, alt_slice_cb_qp_offset and alt_slice_cr_qp_offset shall be in the range of -12 to +12, inclusive.
When ChromaArrayType is equal to 0, alt_slice_cb_qp_offset and alt_slice_cr_qp_offset are not used in the decoding process and decoders shall ignore their value. When not present, the values of alt_slice_y_qp_offset, alt_slice_cb_qp_offset and alt_slice_cr_qp_offset are inferred to be equal to 0.
The value of alt_pps_y_qp_offset + alt_slice_y_qp_offset shall be in the range of -12 to +12, inclusive.
The value of alt_pps_cb_qp_offset + alt_slice_cb_qp_offset + pps_cb_qp_offset + slice_cb_qp_offset shall be in the range of -12 to +12, inclusive.
The value of alt_pps_cr_qp_offset + alt_slice_cr_qp_offset + pps_cr_qp_offset + slice_cr_qp_offset shall be in the range of -12 to +12, inclusive." "alt_pps_y_qp_offset, alt_pps_cb_qp_offset and alt_pps_cr_qp_offset specify offsets to the luma, cb and cr quantization parameter qP derived in the above equations (7) to (9), respectively.
alt_pps_y_qp_offset, alt_pps_cb_qp_offset + pps_cb_qp_offset, and alt_pps_cr_qp_offset + pps_cr_qp_offset and shall be in the range of -12 to +12, inclusive.
When ChromaArrayType is equal to 0, alt_pps_cb_qp_offset and alt_pps_cr_qp_offset are not used in the decoding process and decoders shall ignore their value.
"alt_slice_y_qp_offset, alt_slice_cb_qp_offset and alt_slice_cr_qp_offset specify offsets to the luma, cb and cr quantization parameter qP derived in the above equations (7) to (9), respectively.
The values of alt_slice_y_qp_offset, alt_slice_cb_qp_offset and alt_slice_cr_qp_offset shall be in the range of -12 to +12, inclusive.
When ChromaArrayType is equal to 0, alt_slice_cb_qp_offset and alt_slice_cr_qp_offset are not used in the decoding process and decoders shall ignore their value.
The value of alt_pps_y_qp_offset + alt_slice_y_qp_offset shall be in the range of -12 to +12, inclusive.
The value of alt_pps_cb_qp_offset + alt_slice_cb_qp_offset + pps_cb_qp_offset + slice_cb_qp_offset shall be in the range of -12 to +12, inclusive.
The value of alt_pps_cr_qp_offset + alt_slice_cr_qp_offset + pps_cr_qp_offset + slice_cr_qp_offset shall be in the range of -12 to +12, inclusive. "
図12は、加法的仕様を使用した場合の本実施形態での処理を説明するための説明図である。図11に示された例では、cu_residual_csc_flag=1である場合、単に、RGB 色空間の色差量子化オフセットにYCoCr 空間用の色差量子化オフセットが加算されたが、本実施形態では、適応色差量子化オフセット導出器121 は、RGB 色空間の色差量子化オフセットにYCoCr 空間用の色差量子化オフセットが加算された後のダイナミックレンジ(値域)が、一方の色空間におけるダイナミックレンジ(例えば、-12 ~12)と同じになるようにする。
FIG. 12 is an explanatory diagram for explaining processing in the present embodiment when an additive specification is used. In the example shown in FIG. 11, when cu_residual_csc_flag = 1, the color difference quantization offset for YCoCr color space is simply added to the color difference quantization offset of RGB color space, but in this embodiment, adaptive color difference quantization is performed. The offset derivation unit 121 has a dynamic range (range) after the color difference quantization offset for the YCoCr space is added to the color difference quantization offset of the RGB color space, and the dynamic range (for example, −12 to 12) in one color space. ) To be the same.
適応色差量子化オフセット導出器121 は、一例として、加算処理後の色差量子化オフセットのダイナミックレンジを例えば-12 ~12に制約するために、加算結果を、あらかじめ用意されている変換テーブルを使用して変換する。
As an example, the adaptive color difference quantization offset deriving unit 121 uses a conversion table prepared in advance to limit the dynamic range of the color difference quantization offset after addition processing to, for example, −12 to 12. To convert.
本実施形態では、加法的仕様を使用する場合に、適応色差量子化オフセット導出器が色空間毎に異なるダイナミックレンジの色量子化オフセットを用いることにより、映像符号化装置は空間毎により好ましい色再現を達成できる。また、映像復号装置は、空間毎により好ましい色再現がされたデコード映像を再生できる。
In this embodiment, when the additive specification is used, the adaptive chrominance quantization offset derivation unit uses a color quantization offset having a different dynamic range for each color space, so that the video encoding device can reproduce color more preferable for each space. Can be achieved. In addition, the video decoding apparatus can reproduce a decoded video with a more preferable color reproduction for each space.
なお、上記の各実施形態では、2つの色空間としてRGB 空間とYCoCr 空間とが例示されたが、2つの色空間の一方又は双方が他の色空間であっても上記の各実施形態の方式を適用することができる。また、上記の実施形態では、RGB 空間では、第1色成分をG 、第2色成分をB 、第3色成分をR としたが(図5 参照)、各色成分に対する色信号の割り当て方はそれに限られず、各色成分に対して任意の色信号を割り当てることができる。
In each of the above embodiments, the RGB color space and the YCoCr color space are exemplified as the two color spaces. However, even if one or both of the two color spaces are other color spaces, the method of each of the above embodiments Can be applied. In the above embodiment, in the RGB 成分 space, the first color component is G, the second color component is B, and the third color component is R (see Fig. 5), but the color signal allocation method for each color component is as follows. However, the present invention is not limited to this, and an arbitrary color signal can be assigned to each color component.
また、上記の各実施形態では、映像符号化装置及び映像復号装置が2つの色空間を扱ったが、3つ以上の色空間を扱うことも可能である。
In each of the above embodiments, the video encoding device and the video decoding device handle two color spaces, but it is also possible to handle three or more color spaces.
また、上記の各実施形態を、ハードウェアで構成することも可能であるが、コンピュータプログラムにより実現することも可能である。
Further, although each of the above embodiments can be configured by hardware, it can also be realized by a computer program.
図13に示す情報処理システムは、プロセッサ1001、プログラムメモリ1002、映像データを格納するための記憶媒体1003及びビットストリームを格納するための記憶媒体1004を備える。記憶媒体1003と記憶媒体1004とは、別個の記憶媒体であってもよいし、同一の記憶媒体からなる記憶領域であってもよい。記憶媒体として、ハードディスク等の磁気記憶媒体を用いることができる。
The information processing system shown in FIG. 13 includes a processor 1001, a program memory 1002, a storage medium 1003 for storing video data, and a storage medium 1004 for storing a bitstream. The storage medium 1003 and the storage medium 1004 may be separate storage media, or may be storage areas composed of the same storage medium. A magnetic storage medium such as a hard disk can be used as the storage medium.
図13に示された情報処理システムにおいて、プログラムメモリ1002には、図1 ,図3 のそれぞれに示された各ブロック(バッファのブロックを除く)の機能を実現するためのプログラムが格納される。そして、プロセッサ1001は、プログラムメモリ1002に格納されているプログラムに従って処理を実行することによって、図1 ,図3 のそれぞれに示された映像符号化装置又は映像復号装置の機能を実現する。
In the information processing system shown in FIG. 13, the program memory 1002 stores a program for realizing the function of each block (excluding the buffer block) shown in FIGS. The processor 1001 implements the functions of the video encoding device or the video decoding device shown in FIGS. 1B and 3B by executing processing according to the program stored in the program memory 1002.
図14は、映像符号化装置の主要部を示すブロック図である。図14に示すように、映像符号化装置301 は、色空間毎の色差量子化オフセットを導出する適応色差量子化オフセット導出部311 (一例として、図1 に示された適応色差量子化オフセット導出器121 に相当)と、色空間毎の色差量子化オフセットを使用して量子化係数画像を逆量子化する逆量子化部312 (一例として、図1 に示された逆量子化/逆周波数変換器105 に相当)とを備える。
FIG. 14 is a block diagram showing the main part of the video encoding device. As shown in FIG. 14, the video encoding device 301 includes an adaptive color difference quantization offset deriving unit 311 that derives a color difference quantization offset for each color space (for example, the adaptive color difference quantization offset deriving device shown in FIG. Inverse quantization unit 312 that dequantizes the quantized coefficient image using the color difference quantization offset for each color space (as an example, the inverse quantization / inverse frequency converter shown in Fig. 1) Equivalent to 105).
適応色差量子化オフセット導出部311 は、一方の色空間の色差量子化オフセット(例えば、RGB 空間の色差量子化オフセット)に他方の色空間用のオフセット(例えば、YCoCr 空間のオフセット)を加算する加算部と、加算部による加算結果を他方の色空間用のダイナミックレンジ内に収める調整部とを含んでいてもよい。
The adaptive color difference quantization offset deriving unit 311 adds an offset for the other color space (for example, an offset of YCoCr space) to a color difference quantization offset of one color space (for example, color difference quantization offset of RGB space). And an adjustment unit that stores the addition result of the addition unit within the dynamic range for the other color space.
図15は、映像符号化装置の他の例の主要部を示すブロック図である。図15に示すように、映像符号化装置302 は、ブロック単位で予測誤差信号の色空間を選択する旨をシグナリングする色空間選択通知部313 (一例として、図1 に示されたエントロピー符号化器112 に相当)をさらに備える。
FIG. 15 is a block diagram showing a main part of another example of the video encoding device. As shown in FIG. 15, the video encoding device 302 signals the color space selection notification unit 313 that signals that the color space of the prediction error signal is selected in units of blocks (for example, the entropy encoder shown in FIG. 112 equivalent).
なお、図15に示された構成において、映像符号化装置302 が色空間毎の量子化オフセットの値を特定可能な情報をシグナリングする手段を含んでいない場合には、映像符号化装置302 において、色差量子化オフセットは暗黙的に導出される。
In the configuration shown in FIG. 15, in the case where the video encoding device 302 を does not include means for signaling information that can specify the value of the quantization offset for each color space, in the video encoding device 302, The color difference quantization offset is derived implicitly.
図16は、映像符号化装置のさらに例の主要部を示すブロック図である。図16に示すように、映像符号化装置303 は、色空間毎の色差量子化オフセットの値を特定可能な情報をシグナリングする量子化オフセット情報伝送部314 (一例として、図1 に示されたエントロピー符号化器112 に相当)をさらに備える。色差量子化オフセットの値を特定可能な情報は、例えば、色差量子化オフセットの値そのもの、又は、映像復号装置に保持されている色差量子化オフセットが設定されているデータテーブルを指定するインデックスである。
FIG. 16 is a block diagram showing a main part of a further example of the video encoding device. As shown in FIG. 16, the video encoding device 303 is a quantization offset information transmission unit 314 that signals information that can specify the value of the color difference quantization offset for each color space (for example, the entropy shown in FIG. And an encoder 112). The information that can specify the color difference quantization offset value is, for example, the color difference quantization offset value itself, or an index that designates a data table in which the color difference quantization offset held in the video decoding device is set. .
図17は、映像復号装置の主要部を示すブロック図である。図17に示すように、映像復号装置401 は、色空間毎の色差量子化オフセットを導出する適応色差量子化オフセット導出部411 (一例として、図3 に示された適応色差量子化オフセット導出器221 に相当)と、色空間毎の色差量子化オフセットを使用して量子化係数画像を逆量子化する逆量子化部412 (一例として、図3 に示された逆量子化/逆周波数変換器205 に相当)とを備える。
FIG. 17 is a block diagram showing the main part of the video decoding apparatus. As shown in FIG. 17, the video decoding apparatus 401 includes an adaptive color difference quantization offset deriving unit 411 that derives a color difference quantization offset for each color space (for example, the adaptive color difference quantization offset deriving device 221 shown in FIG. And an inverse quantization unit 412 that inversely quantizes the quantized coefficient image using the color difference quantization offset for each color space (for example, the inverse quantization / inverse frequency converter 205 shown in FIG. 3 205) Equivalent).
適応色差量子化オフセット導出部411 は、一方の色空間の色差量子化オフセット(例えば、RGB 空間の色差量子化オフセット)に他方の色空間用のオフセット(例えば、YCoCr 空間のオフセット)を加算する加算部と、加算部による加算結果を他方の色空間用のダイナミックレンジ内に収める調整部とを含んでいてもよい。
The adaptive color difference quantization offset deriving unit 411 adds the offset for the other color space (for example, the offset of the YCoCr space) to the color difference quantization offset of one color space (for example, the color difference quantization offset of the RGB color space). And an adjustment unit that stores the addition result of the addition unit within the dynamic range for the other color space.
図18は、映像復号装置の他の例の主要部を示すブロック図である。図18に示すように、映像復号装置402 は、受信したビットストリームからブロック単位で予測誤差信号の色空間を選択する旨を解読する色空間選択解読部413 (一例として、図3 に示されたエントロピー復号器212 に相当)をさらに備える。
FIG. 18 is a block diagram showing the main part of another example of the video decoding apparatus. As shown in FIG. 18, the video decoding device 402 decodes the fact that the color space of the prediction error signal is selected in units of blocks from the received bitstream (see FIG. 3 た as an example). An entropy decoder 212).
なお、図18に示された構成において、映像復号装置402 が色空間毎の色差量子化オフセットの値を特定可能な情報を解読する手段を含んでいない場合には、映像復号装置402 は、暗黙的に色差量子化オフセットを導出する。
In the configuration shown in FIG. 18, when the video decoding device 402 復 号 does not include means for decoding information that can specify the value of the color difference quantization offset for each color space, the video decoding device 402 Thus, a color difference quantization offset is derived.
図19は、映像復号装置のさらに他の例の主要部を示すブロック図である。図19に示すように、映像復号装置403 は、受信したビットストリームから解読される情報に基づいて色空間毎の色差量子化オフセットの値を特定する色差量子化オフセット解読部414 (一例として、図3 に示されたエントロピー復号器212 に相当)をさらに備える。
FIG. 19 is a block diagram showing a main part of still another example of the video decoding apparatus. As shown in FIG. 19, the video decoding device 403 specifies a color difference quantization offset decoding unit 414 (for example, FIG. 19) that specifies the value of the color difference quantization offset for each color space based on the information decoded from the received bitstream. And an entropy decoder 212 shown in 3).
上記の符号化及び復号技術については、放送機器に応用が可能である。例えば、放送送出コーデック、放送受信端末として搭載が可能であり、上述の技術を搭載した放送機器においては好ましい画質の提供により放送サービスのユーザエキスぺリエンス向上効果が得られる。
The above encoding and decoding techniques can be applied to broadcasting equipment. For example, it can be installed as a broadcast transmission codec or a broadcast receiving terminal, and a broadcast device equipped with the above-described technology can improve the user experience of the broadcast service by providing a preferable image quality.
また、一例として、各実施形態の映像符号化装置は、例えばディジタルテレビジョン放送やマルチメディア(コンテンツ)配信システムにおける送信設備や送信装置に組み込まれうる。また、上記の各実施形態の映像復号装置は、例えばディジタルテレビジョン放送を受信する受信装置(受信端末)やマルチメディア配信を受ける受信装置(受信端末)に組み込まれうる。
Also, as an example, the video encoding device of each embodiment can be incorporated in, for example, a transmission facility or a transmission device in a digital television broadcast or a multimedia (content) distribution system. In addition, the video decoding device of each of the above embodiments can be incorporated into, for example, a receiving device (receiving terminal) that receives a digital television broadcast or a receiving device (receiving terminal) that receives multimedia distribution.
上記の実施形態の一部または全部は以下の付記のようにも記載されうるが、本発明の構成は以下の構成に限定されない。
Some or all of the above embodiments can be described as in the following supplementary notes, but the configuration of the present invention is not limited to the following configuration.
(付記1)複数の色空間から、符号化のブロック単位で予測誤差信号の色空間を選択可能な映像符号化装置を含み、該映像符号化装置を用いて放送コンテンツを提供する放送機器であって、前記映像符号化装置は、色空間毎の色差量子化オフセットを導出する適応色差量子化オフセット導出手段と、異なるダイナミックレンジで表現されうる色空間毎の色差量子化オフセットを使用して量子化係数画像を逆量子化する逆量子化手段とを含むことを特徴とする。
(Supplementary note 1) A broadcasting device that includes a video encoding device capable of selecting a color space of a prediction error signal from a plurality of color spaces in units of encoding blocks, and provides broadcast content using the video encoding device. The video encoding apparatus performs quantization using an adaptive color difference quantization offset deriving unit that derives a color difference quantization offset for each color space, and a color difference quantization offset for each color space that can be expressed in a different dynamic range. And dequantizing means for dequantizing the coefficient image.
(付記2)放送コンテンツを視聴するための受信端末であって、該受信端末は、複数の色空間から、符号化のブロック単位で予測誤差信号の色空間を選択可能な映像復号装置を含み、前記映像復号装置は、色空間毎の色差量子化オフセットを導出する適応色差量子化オフセット導出手段と、異なるダイナミックレンジで表現されうる色空間毎の色差量子化オフセットを使用して量子化係数画像を逆量子化する逆量子化手段とを含むことを特徴とする。
(Supplementary Note 2) A receiving terminal for viewing broadcast content, the receiving terminal including a video decoding device capable of selecting a color space of a prediction error signal in units of encoding blocks from a plurality of color spaces, The video decoding device uses an adaptive color difference quantization offset deriving unit that derives a color difference quantization offset for each color space, and a color difference quantization offset for each color space that can be expressed in a different dynamic range to generate a quantization coefficient image. And an inverse quantization means for performing inverse quantization.
(付記3)放送コンテンツを提供する放送機器において実施され、複数の色空間から、符号化のブロック単位で予測誤差信号の色空間を選択可能な映像符号化方法であって、色空間毎の量子化オフセットを導出し、異なるダイナミックレンジで表現されうる色空間毎の色差量子化オフセットを使用して量子化係数画像を逆量子化することを特徴とする。
(Supplementary Note 3) A video encoding method implemented in a broadcast device that provides broadcast content and capable of selecting a color space of a prediction error signal in units of blocks from a plurality of color spaces, A quantization offset is derived, and a quantization coefficient image is inversely quantized using a color difference quantization offset for each color space that can be expressed in different dynamic ranges.
(付記4)放送コンテンツを視聴するための受信端末において実施され、複数の色空間から、符号化のブロック単位で予測誤差信号の色空間を選択可能な映像復号方法であって、色空間毎の色差量子化オフセットを導出し、異なるダイナミックレンジで表現されうる色空間毎の色差量子化オフセットを使用して量子化係数画像を逆量子化することを特徴とする。
(Supplementary Note 4) A video decoding method that is implemented in a receiving terminal for viewing broadcast content and that can select a color space of a prediction error signal in units of blocks from a plurality of color spaces, for each color space A color difference quantization offset is derived, and a quantization coefficient image is inversely quantized using a color difference quantization offset for each color space that can be expressed in different dynamic ranges.
(付記5)放送コンテンツを提供する放送機器に搭載される映像符号化プログラムであり、複数の色空間から、符号化のブロック単位で予測誤差信号の色空間を選択可能な映像符号化方法を実施する映像符号化プログラムであって、コンピュータに、色空間毎の色差量子化オフセットを導出する処理と、異なるダイナミックレンジで表現されうる色空間毎の色差量子化オフセットを使用して量子化係数画像を逆量子化する処理とを実行させることを特徴とする。
(Supplementary Note 5) A video encoding program installed in a broadcasting device that provides broadcast content, and a video encoding method capable of selecting a color space of a prediction error signal in units of encoding blocks from a plurality of color spaces is implemented. An image encoding program for processing a quantization coefficient image using a process for deriving a color difference quantization offset for each color space and a color difference quantization offset for each color space that can be expressed in different dynamic ranges. And performing a process of inverse quantization.
(付記6)放送コンテンツを視聴するための受信端末に搭載される映像復号プログラムであり、複数の色空間から、符号化のブロック単位で予測誤差信号の色空間を選択可能な映像復号方法を実施する映像復号プログラムであって、コンピュータに、色空間毎の色差量子化オフセットを導出する処理と、異なるダイナミックレンジで表現されうる色空間毎の色差量子化オフセットを使用して量子化係数画像を逆量子化する処理とを実行させることを特徴とする。
(Appendix 6) A video decoding program installed in a receiving terminal for viewing broadcast content, and implementing a video decoding method capable of selecting a color space of a prediction error signal in units of encoding blocks from a plurality of color spaces An image decoding program that performs a process of deriving a color difference quantization offset for each color space on a computer and reverses the quantization coefficient image using the color difference quantization offset for each color space that can be expressed in a different dynamic range. And a process of performing quantization.
以上、実施形態および実施例を参照して本願発明を説明したが、本願発明は上記実施形態および実施例に限定されるものではない。本願発明の構成や詳細には、本願発明のスコープ内で当業者が理解し得る様々な変更をすることができる。
Although the present invention has been described with reference to the embodiments and examples, the present invention is not limited to the above embodiments and examples. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.
この出願は、2015年5月20日に出願された日本特許出願2015-102980を基礎とする優先権を主張し、その開示の全てをここに取り込む。
This application claims priority based on Japanese Patent Application No. 2015-102980 filed on May 20, 2015, the entire disclosure of which is incorporated herein.
101 スイッチ
102 色空間変換器
103 スイッチ
104 周波数変換/量子化器
105 逆量子化/逆周波数変換器
106 スイッチ
107 逆色空間変換器
108 スイッチ
109 バッファ
110 予測器
111 予測パラメータ決定器
112 エントロピー符号化器
115 減算器
116 加算器
121 適応色差量子化オフセット導出器
122 スイッチ
205 逆量子化/逆周波数変換器
206 スイッチ
207 逆色空間変換器
208 スイッチ
209 バッファ
210 予測器
212 エントロピー復号器
216 加算器
221 適応色差量子化オフセット導出器
222 スイッチ
301,302,303 映像符号化装置
311 適応色差量子化オフセット導出部
312 逆量子化部
313 色空間選択通知部
314 量子化オフセット情報伝送部
401,402,403 映像復号装置
411 適応色差量子化オフセット導出部
412 逆量子化部
413 色空間選択解読部
414 色差量子化オフセット解読部
1001 プロセッサ
1002 プログラムメモリ
1003 記憶媒体
1004 記憶媒体 101switch 102 color space converter 103 switch 104 frequency converter / quantizer 105 inverse quantization / inverse frequency converter 106 switch 107 inverse color space converter 108 switch 109 buffer 110 predictor 111 prediction parameter determiner 112 entropy encoder 115 Subtractor 116 Adder 121 Adaptive color difference quantization offset derivation 122 Switch 205 Inverse quantization / inverse frequency converter 206 Switch 207 Inverse color space converter 208 Switch 209 Buffer 210 Predictor 212 Entropy decoder 216 Adder 221 Adaptive color difference Quantization offset derivation unit 222 Switch 301, 302, 303 Video encoding device 311 Adaptive color difference quantization offset derivation unit 312 Inverse quantization unit 313 Color space selection notification unit 314 Quantization offset information transmission unit 401,402,403 Video decoding device 411 Adaptive color difference quantization offset derivation unit 412 Inverse quantization unit 413 Color space selection decoding unit 414 Color difference quantization Set decoding portion 1001 processor 1002 program memory 1003 storing medium 1004 storage medium
102 色空間変換器
103 スイッチ
104 周波数変換/量子化器
105 逆量子化/逆周波数変換器
106 スイッチ
107 逆色空間変換器
108 スイッチ
109 バッファ
110 予測器
111 予測パラメータ決定器
112 エントロピー符号化器
115 減算器
116 加算器
121 適応色差量子化オフセット導出器
122 スイッチ
205 逆量子化/逆周波数変換器
206 スイッチ
207 逆色空間変換器
208 スイッチ
209 バッファ
210 予測器
212 エントロピー復号器
216 加算器
221 適応色差量子化オフセット導出器
222 スイッチ
301,302,303 映像符号化装置
311 適応色差量子化オフセット導出部
312 逆量子化部
313 色空間選択通知部
314 量子化オフセット情報伝送部
401,402,403 映像復号装置
411 適応色差量子化オフセット導出部
412 逆量子化部
413 色空間選択解読部
414 色差量子化オフセット解読部
1001 プロセッサ
1002 プログラムメモリ
1003 記憶媒体
1004 記憶媒体 101
Claims (24)
- 複数の色空間から、符号化のブロック単位で予測誤差信号の色空間を選択可能な映像符号化装置であって、
色空間毎の色差量子化オフセットを導出する適応色差量子化オフセット導出手段と、
異なるダイナミックレンジで表現されうる色空間毎の色差量子化オフセットを使用して量子化係数画像を逆量子化する逆量子化手段とを含む
ことを特徴とする映像符号化装置。 A video encoding device capable of selecting a color space of a prediction error signal in units of encoding blocks from a plurality of color spaces,
Adaptive color difference quantization offset deriving means for deriving a color difference quantization offset for each color space;
A video encoding apparatus comprising: inverse quantization means for inversely quantizing a quantization coefficient image using a color difference quantization offset for each color space that can be expressed in different dynamic ranges. - 適応色差量子化オフセット導出手段は、一方の色空間の色差量子化オフセットに他方の色空間用のオフセットを加算するとともに、加算結果を前記他方の色空間用のダイナミックレンジ内に収める請求項1記載の映像符号化装置。
請求項1 The adaptive color difference quantization offset deriving means adds the offset for the other color space to the color difference quantization offset of one color space, and stores the addition result within the dynamic range for the other color space. Video encoding device.
Claim 1 - ブロック単位で予測誤差信号の色空間を選択する旨をシグナリングする色空間選択通知手段をさらに含む
請求項1又は請求項2記載の映像符号化装置。 The video encoding device according to claim 1, further comprising color space selection notifying means for signaling that the color space of the prediction error signal is selected in units of blocks. - 色空間毎の色差量子化オフセットの値を特定可能な情報をシグナリングする色差量子化オフセット情報伝送手段をさらに含む
請求項3記載の映像符号化装置。 The video encoding apparatus according to claim 3, further comprising color difference quantization offset information transmission means for signaling information capable of specifying a value of a color difference quantization offset for each color space. - 複数の色空間から、符号化のブロック単位で予測誤差信号の色空間を選択可能な映像復号装置であって、
色空間毎の色差量子化オフセットを導出する適応色差量子化オフセット導出手段と、
異なるダイナミックレンジで表現されうる色空間毎の色差量子化オフセットを使用して量子化係数画像を逆量子化する逆量子化手段とを含む
ことを特徴とする映像復号装置。 A video decoding device capable of selecting a color space of a prediction error signal in units of encoding blocks from a plurality of color spaces,
Adaptive color difference quantization offset deriving means for deriving a color difference quantization offset for each color space;
A video decoding device comprising: inverse quantization means for inversely quantizing a quantization coefficient image using a color difference quantization offset for each color space that can be expressed in different dynamic ranges. - 適応色差量子化オフセット導出手段は、一方の色空間の色差量子化オフセットに他方の色空間用のオフセットを加算するとともに、加算結果を前記他方の色空間用のダイナミックレンジ内に収める請求項5記載の映像復号装置。 6. The adaptive color difference quantization offset deriving unit adds an offset for the other color space to the color difference quantization offset of one color space, and stores the addition result within the dynamic range for the other color space. Video decoding device.
- 受信したビットストリームからブロック単位で予測誤差信号の色空間を選択する旨を解読する色空間選択解読手段をさらに含む
請求項5又は請求項6記載の映像復号装置。 The video decoding device according to claim 5 or 6, further comprising color space selection decoding means for decoding that the color space of the prediction error signal is selected in units of blocks from the received bit stream. - 受信したビットストリームから解読される情報に基づいて色空間毎の量子化オフセットの値を特定する色差量子化オフセット解読手段をさらに含む
請求項7記載の映像復号装置。 The video decoding apparatus according to claim 7, further comprising color difference quantization offset decoding means for specifying a quantization offset value for each color space based on information decoded from the received bitstream. - 複数の色空間から、符号化のブロック単位で予測誤差信号の色空間を選択可能な映像符号化方法であって、
色空間毎の量子化オフセットを導出し、
異なるダイナミックレンジで表現されうる色空間毎の色差量子化オフセットを使用して量子化係数画像を逆量子化する
ことを特徴とする映像符号化方法。 A video encoding method capable of selecting a color space of a prediction error signal in units of encoding blocks from a plurality of color spaces,
Deriving the quantization offset for each color space,
A video coding method comprising: dequantizing a quantized coefficient image using a color difference quantization offset for each color space that can be expressed in different dynamic ranges. - 色空間毎の量子化オフセットを導出するときに、一方の色空間の色差量子化オフセットに他方の色空間用のオフセットを加算するとともに、加算結果を前記他方の色空間用のダイナミックレンジ内に収める請求項9記載の映像符号化方法。 When deriving the quantization offset for each color space, the offset for the other color space is added to the color difference quantization offset of one color space, and the addition result falls within the dynamic range for the other color space. The video encoding method according to claim 9.
- ブロック単位で予測誤差信号の色空間を選択する旨をシグナリングする
請求項9又は請求項10記載の映像符号化方法。 The video encoding method according to claim 9 or 10, wherein signaling is performed to select a color space of a prediction error signal in units of blocks. - 色空間毎の色差量子化オフセットの値を特定可能な情報をシグナリングする
請求項11記載の映像符号化方法。 The video encoding method according to claim 11, wherein information capable of specifying a value of a color difference quantization offset for each color space is signaled. - 複数の色空間から、符号化のブロック単位で予測誤差信号の色空間を選択可能な映像復号方法であって、
色空間毎の色差量子化オフセットを導出し、
異なるダイナミックレンジで表現されうる色空間毎の色差量子化オフセットを使用して量子化係数画像を逆量子化する
ことを特徴とする映像復号方法。 A video decoding method capable of selecting a color space of a prediction error signal in units of encoding blocks from a plurality of color spaces,
Deriving color difference quantization offset for each color space,
A video decoding method, comprising: dequantizing a quantized coefficient image using a color difference quantization offset for each color space that can be expressed in different dynamic ranges. - 色空間毎の量子化オフセットを導出するときに、一方の色空間の色差量子化オフセットに他方の色空間用のオフセットを加算するとともに、加算結果を前記他方の色空間用のダイナミックレンジ内に収める請求項13記載の映像復号方法。 When deriving the quantization offset for each color space, the offset for the other color space is added to the color difference quantization offset of one color space, and the addition result falls within the dynamic range for the other color space. The video decoding method according to claim 13.
- 受信したビットストリームからブロック単位で予測誤差信号の色空間を選択する旨を解読する
請求項13又は請求項14記載の映像復号方法。 The video decoding method according to claim 13 or 14, wherein the fact that the color space of the prediction error signal is selected in units of blocks from the received bit stream is decoded. - 受信したビットストリームから解読される情報に基づいて色空間毎の色差量子化オフセットの値を特定する
請求項15記載の映像復号方法。 The video decoding method according to claim 15, wherein a value of a color difference quantization offset for each color space is specified based on information decoded from the received bit stream. - 複数の色空間から、符号化のブロック単位で予測誤差信号の色空間を選択可能な映像符号化方法を実施する映像符号化プログラムであって、
コンピュータに、
色空間毎の色差量子化オフセットを導出する処理と、
異なるダイナミックレンジで表現されうる色空間毎の色差量子化オフセットを使用して量子化係数画像を逆量子化する処理と
を実行させるための映像符号化プログラム。 A video encoding program for implementing a video encoding method capable of selecting a color space of a prediction error signal from a plurality of color spaces in units of encoding blocks,
On the computer,
A process for deriving a color difference quantization offset for each color space;
A video encoding program for performing a process of dequantizing a quantization coefficient image using a color difference quantization offset for each color space that can be expressed in different dynamic ranges. - コンピュータに、
色空間毎の量子化オフセットを導出するときに、一方の色空間の色差量子化オフセットに他方の色空間用のオフセットを加算するとともに、加算結果を前記他方の色空間用のダイナミックレンジ内に収める処理を実行させる請求項17記載の映像符号化プログラム。 On the computer,
When deriving the quantization offset for each color space, the offset for the other color space is added to the color difference quantization offset of one color space, and the addition result falls within the dynamic range for the other color space. The video encoding program according to claim 17, wherein the processing is executed. - コンピュータに、ブロック単位で予測誤差信号の色空間を選択する旨をシグナリングする処理を実行させる
請求項17又は請求項18記載の映像符号化プログラム。 The video encoding program according to claim 17 or 18, wherein the computer executes a process of signaling that the color space of the prediction error signal is selected in units of blocks. - コンピュータに、色空間毎の色差量子化オフセットの値を特定可能な情報をシグナリングする処理を実行させる
請求項19記載の映像符号化プログラム。 The video encoding program according to claim 19, wherein the computer executes a process of signaling information capable of specifying a color difference quantization offset value for each color space. - 複数の色空間から、符号化のブロック単位で予測誤差信号の色空間を選択可能な映像復号方法を実施する映像復号プログラムであって、
コンピュータに、
色空間毎の色差量子化オフセットを導出する処理と、
異なるダイナミックレンジで表現されうる色空間毎の色差量子化オフセットを使用して量子化係数画像を逆量子化する処理と
を実行させるための映像復号プログラム。 A video decoding program for implementing a video decoding method capable of selecting a color space of a prediction error signal from a plurality of color spaces in units of encoding blocks,
On the computer,
A process for deriving a color difference quantization offset for each color space;
A video decoding program for executing a process of dequantizing a quantization coefficient image using a color difference quantization offset for each color space that can be expressed in different dynamic ranges. - コンピュータに、
色空間毎の量子化オフセットを導出するときに、一方の色空間の色差量子化オフセットに他方の色空間用のオフセットを加算するとともに、加算結果を前記他方の色空間用のダイナミックレンジ内に収める処理を実行させる請求項21記載の映像復号プログラム。 On the computer,
When deriving the quantization offset for each color space, the offset for the other color space is added to the color difference quantization offset of one color space, and the addition result falls within the dynamic range for the other color space. The video decoding program according to claim 21, wherein the video decoding program causes the processing to be executed. - コンピュータに、受信したビットストリームからブロック単位で予測誤差信号の色空間を選択する旨を解読する処理を実行させる
請求項21又は請求項22記載の映像復号プログラム。 The video decoding program according to claim 21 or 22, wherein the computer executes a process of decoding that the color space of the prediction error signal is selected in units of blocks from the received bit stream. - コンピュータに、受信したビットストリームから解読される情報に基づいて色空間毎の色差量子化オフセットの値を特定する処理を実行させる
請求項23記載の映像復号プログラム。 The video decoding program according to claim 23, wherein the computer executes a process of specifying a color difference quantization offset value for each color space based on information decoded from the received bit stream.
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