CN116193118A - LCEVC-based enhancement layer coding method, device, equipment and medium - Google Patents
LCEVC-based enhancement layer coding method, device, equipment and medium Download PDFInfo
- Publication number
- CN116193118A CN116193118A CN202310108746.3A CN202310108746A CN116193118A CN 116193118 A CN116193118 A CN 116193118A CN 202310108746 A CN202310108746 A CN 202310108746A CN 116193118 A CN116193118 A CN 116193118A
- Authority
- CN
- China
- Prior art keywords
- quantization parameter
- enhancement layer
- code rate
- frame
- current frame
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 52
- 238000013139 quantization Methods 0.000 claims abstract description 261
- 238000004590 computer program Methods 0.000 claims description 14
- 230000008859 change Effects 0.000 description 28
- 238000010586 diagram Methods 0.000 description 8
- 230000000694 effects Effects 0.000 description 8
- 230000008569 process Effects 0.000 description 8
- 230000004927 fusion Effects 0.000 description 6
- 230000002123 temporal effect Effects 0.000 description 6
- 230000007423 decrease Effects 0.000 description 5
- 230000006872 improvement Effects 0.000 description 5
- 239000013598 vector Substances 0.000 description 5
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- 230000009466 transformation Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 238000012163 sequencing technique Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000001131 transforming effect Effects 0.000 description 1
Images
Classifications
-
- 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
-
- 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
- H04N19/30—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using hierarchical techniques, e.g. scalability
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Compression Or Coding Systems Of Tv Signals (AREA)
Abstract
The present disclosure relates to a method, an apparatus, a device, and a medium for encoding an enhancement layer based on LCEVC, which are applied to the technical field of video encoding and can improve the encoding quality of video encoding. The method comprises the following steps: under the condition that a to-be-encoded enhancement layer sequence uses time domain prediction, acquiring a code rate of a current frame base layer corresponding to a current frame enhancement layer and an average code rate of a C frame base layer before the current frame base layer, wherein the to-be-encoded enhancement layer sequence comprises a multi-frame enhancement layer, and the current frame enhancement layer is any frame in the multi-frame enhancement layer; under the condition that the code rate of the current frame base layer is smaller than or equal to the average code rate, encoding the current frame enhancement layer based on the first quantization parameter; and under the condition that the code rate of the current frame basic layer is larger than the average code rate, updating the quantization parameter of the current frame enhancement layer from the first quantization parameter to a second quantization parameter, and encoding the current frame enhancement layer based on the second quantization parameter, wherein the second quantization parameter is smaller than the first quantization parameter.
Description
Technical Field
The embodiment of the application relates to the technical field of video coding. And more particularly, to an LCEVC-based enhancement layer encoding method, apparatus, terminal device, and storage medium.
Background
Among the low complexity enhanced video coding (Low Complexity Enhancement VideoCoding, LCEVC) standards are the base layer and the enhancement layer. The base layer is generally encoded by adopting the existing video encoding standards such as H.264/H.265, and relatively mature researches on a frame-level code rate allocation method are carried out on the H.264/H.265. Whereas the enhancement layer is encoded using the tools described in the LCEVC standard, which currently only has a fixed quantization parameter encoding, i.e. the quantization parameters are the same for each frame of a video sequence. The fixed quantization parameter coding ignores the differences from frame to frame of the video.
Because the video picture content is continuously changed, the frames are different, and a certain arithmetic relation exists between the quantization parameter and the coding quality, so that the coding quality of video coding can be influenced by a mode of fixed quantization parameter coding.
Disclosure of Invention
In order to solve the above technical problems or at least partially solve the above technical problems, embodiments of the present application provide a method, an apparatus, a device, and a medium for encoding an enhancement layer based on LCEVC, which can improve the encoding quality of video encoding.
In a first aspect, an embodiment of the present application provides an LCEVC-based enhancement layer encoding method, including:
under the condition that a to-be-encoded enhancement layer sequence uses time domain prediction, acquiring a code rate of a current frame base layer corresponding to a current frame enhancement layer and an average code rate of a C frame base layer before the current frame base layer, wherein the to-be-encoded enhancement layer sequence comprises a multi-frame enhancement layer, the current frame enhancement layer is any frame in the multi-frame enhancement layer, the average code rate is an average value of code rates of each frame base layer in the C frame base layer, and C is an integer larger than 1;
under the condition that the code rate of the current frame base layer is smaller than or equal to the average code rate, encoding the current frame enhancement layer based on a first quantization parameter;
and under the condition that the code rate of the current frame basic layer is larger than the average code rate, updating the quantization parameter of the current frame enhancement layer from a first quantization parameter to a second quantization parameter, and encoding the current frame enhancement layer based on the second quantization parameter, wherein the second quantization parameter is smaller than the first quantization parameter.
In a second aspect, an embodiment of the present application provides an enhancement layer encoding apparatus based on LCEVC, including:
a memory configured to store a computer program;
A processor configured to cause the LCEVC-based enhancement layer encoding apparatus to implement the LCEVC-based enhancement layer encoding method of the first aspect when invoking a computer program.
In a third aspect, an embodiment of the present application provides a terminal device, including: the LCEVC-based enhancement layer encoding apparatus of the second aspect.
In a fourth aspect, embodiments of the present application provide a computer-readable storage medium, comprising: the computer readable storage medium has stored thereon a computer program which, when executed by a processor, implements the LCEVC-based enhancement layer encoding method as shown in the second aspect.
In a fifth aspect, embodiments of the present application provide a computer program product comprising: the computer program product, when run on a computer, causes the computer to implement the LCEVC-based enhancement layer encoding method as shown in the second aspect.
Compared with the related art, the technical scheme provided by the embodiment of the application has the following effects: in some embodiments of the present application, under the condition that a to-be-encoded enhancement layer sequence uses time domain prediction, obtaining a code rate of a current frame base layer corresponding to a current frame enhancement layer of the to-be-encoded enhancement layer sequence, and an average code rate of a C frame base layer before the current frame base layer, and under the condition that the code rate of the current frame base layer is less than or equal to the average code rate, encoding the current frame enhancement layer based on a first quantization parameter (original quantization parameter); and under the condition that the code rate of the current frame basic layer is larger than the average code rate, updating the quantization parameter of the current frame enhancement layer from the first quantization parameter to the second quantization parameter (the second quantization parameter is smaller than the first quantization parameter, namely, the original quantization parameter is reduced, so that the quantization parameter is reduced from the first quantization parameter to the second quantization parameter), and encoding the current frame enhancement layer based on the second quantization parameter. In this way, under the condition that the current frame enhancement layer of the enhancement layer sequence to be coded uses time domain prediction, the coding quality of the current frame is improved by reducing the quantization parameter of the current frame enhancement layer (reducing the quantization parameter can improve the code rate), and under the condition that the coding quality of the current frame enhancement layer is improved due to the fact that the current frame enhancement layer uses time domain prediction (utilizing the correlation between frames), the coding quality of the subsequent multi-frame enhancement layer of the current frame enhancement layer (adopting inter-frame coding) is also improved relatively, and further the average coding quality of video coding is improved.
Drawings
In order to more clearly illustrate the embodiments of the present application or the implementation in the related art, a brief description will be given below of the drawings required for the embodiments or the related art descriptions, and it is apparent that the drawings in the following description are some embodiments of the present application, and other drawings may be obtained according to these drawings for those of ordinary skill in the art.
FIG. 1 illustrates a schematic diagram of a LCEVC encoder in some embodiments of the present application;
FIG. 2 illustrates a schematic block diagram of a temporal prediction process of an LCEVC encoder in some embodiments of the present application;
FIG. 3 is a schematic diagram of motion vectors of a current frame to be encoded block and a previous frame to be encoded block being 0 in some embodiments of the present application;
FIG. 4 illustrates one of the flow diagrams of LCEVC-based enhancement layer encoding methods in some embodiments of the present application;
FIG. 5 illustrates a second flow chart of an LCEVC-based enhancement layer encoding method in some embodiments of the present application;
FIG. 6 illustrates a third flow chart of an LCEVC-based enhancement layer encoding method in some embodiments of the present application;
FIG. 7 illustrates a fourth flow diagram of an LCEVC-based enhancement layer encoding method in some embodiments of the present application;
FIG. 8 illustrates a fifth flow diagram of an LCEVC-based enhancement layer encoding method in some embodiments of the present application;
FIG. 9 illustrates a sixth flow chart of an LCEVC-based enhancement layer encoding method in some embodiments of the present application;
fig. 10 illustrates a schematic structural diagram of an LCEVC-based enhancement layer encoding apparatus in some embodiments of the present application.
Detailed Description
For purposes of clarity and implementation of the present application, the following description will make clear and complete descriptions of exemplary implementations of the present application with reference to the accompanying drawings in which exemplary implementations of the present application are illustrated, it being apparent that the exemplary implementations described are only some, but not all, of the examples of the present application.
It should be noted that the brief description of the terms in the present application is only for convenience in understanding the embodiments described below, and is not intended to limit the embodiments of the present application. Unless otherwise indicated, these terms should be construed in their ordinary and customary meaning.
The terms "first," second, "" third and the like in the description and in the claims and in the above-described figures are used for distinguishing between similar or similar objects or entities and not necessarily for limiting a particular order or sequence, unless otherwise indicated. It is to be understood that the terms so used are interchangeable under appropriate circumstances.
The terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a product or apparatus that comprises a list of elements is not necessarily limited to all elements explicitly listed, but may include other elements not expressly listed or inherent to such product or apparatus.
The enhancement layer coding method based on LCEVC provided by some embodiments of the present application is used to optimize the coding process of the first enhancement layer and the second enhancement layer of the LCEVC coder, so as to improve the coding quality of the enhancement layers of some frames, and further improve the average coding quality of video coding. Therefore, the structure of the LCEVC encoder will be described first.
Referring to fig. 1, the LCEVC encoder includes: a first downsampling layer 11, a second downsampling layer 12, a base layer 13, a first upsampling layer 14, a first enhancement layer 15, an L1 residual reconstruction layer 16, a fusion layer 17, a second upsampling layer 18, and a second enhancement layer 19.
The first downsampling layer 11 is used for downsampling the video to be encoded to reduce the resolution of the video to be encoded.
The second downsampling layer 12 is used for further downsampling the output of the first downsampling layer 11 to further reduce the resolution of video frames of the video to be encoded. It should be noted that, in the LCEVC standard, there are two downsampling processes, and the downsampling method of each layer may be selected or whether to downsample according to actual requirements, which is not limited herein.
The base layer 13 is configured to encode the output of the second downsampling layer 12 by a base layer encoder to generate a base layer bitstream. It should be noted that the base layer encoder may be any encoder, for example: x264, x265, high efficiency video coding (High Efficiency Video Coding, HEVC) encoder, multi-function video coding (Versatile Video Coding, VVC) encoder, etc. The base layer is also referred to as a base layer or an underlayer.
The first upsampling layer 14 is used for upsampling the encoded reconstructed image of the base layer 13 to increase the resolution of the encoded reconstructed image of the base layer 13.
The first enhancement layer 15 is configured to calculate a residual (L1 residual) between the output of the first downsampling layer 11 and the output of the first upsampling layer 14, and sequentially transform, quantize, and entropy encode the L1 residual to obtain an L1 enhancement coefficient.
The L1 residual reconstruction layer 16 is configured to sequentially perform inverse quantization, inverse transformation, and filtering on the data quantized by the first enhancement layer 15, so as to obtain a reconstructed L1 residual, which is an output of the L1 residual reconstruction layer 16.
And a fusion layer 17, configured to perform additive fusion on the output of the L1 residual reconstruction layer 16 and the output of the first upsampling layer 14, so as to obtain an output of the fusion layer 17.
The second upsampling layer 18 is used for upsampling the output of the fusion layer 17 to improve the resolution of the image output by the fusion layer 17, and the resolution of the output of the second upsampling layer 18 is consistent with the resolution of the original video to be encoded.
The second enhancement layer 19 is configured to calculate a difference image between the output of the second upsampling layer 18 and the original video to be encoded, i.e. an L2 residual, perform time domain prediction on the L2 residual as required, compress and transmit the generated prediction coefficient to a terminal device, and transform, quantize and entropy encode the L2 residual in order to obtain an L2 enhancement coefficient.
Temporal prediction in an LCEVC encoder is used to determine whether to encode the L2 residual using intra mode or inter mode. As shown in fig. 2, a schematic diagram of a specific process of time domain prediction mainly includes 21 to 26 parts, and each process in fig. 2 is explained in detail below, where:
specifically, subtracting the L2 residual error of the previous frame from the L2 residual error of the current frame to reconstruct the L2 residual error of the previous frame, thereby obtaining an inter-frame prediction residual error (inter_resi);
22 specifically, transform and quantize inter_resi to obtain inter symbols (inter_symbols); performing inverse quantization and inverse transformation on the inter_symbols to obtain inter-frame residual reconstruction (inter_resi_recon);
23 is specifically inter_resi_recon plus the L2 residual reconstruction of the previous frame and the up-sampled image of the current frame to obtain an inter-frame reconstructed image (inter_recon); calculating an inter-frame rate distortion cost (inter_cost) based on inter_rect and inter_symbols;
24 is specifically to directly transform and quantize the L2 residual error of the current frame to obtain an intra-frame symbol (intra_symbols); performing inverse quantization and inverse transformation on intra_symbols to obtain intra residual reconstruction (intra_resi_recon);
25 is specifically intra_resi_recon added with an up-sampled image of the current frame to obtain an intra-frame reconstructed image (intra_recon); calculating an intra rate distortion cost (intra_cost) based on intra_rect and intra_symbols;
26 is specifically determining whether the inter-frame rate distortion cost is greater than the intra-frame rate distortion cost; under the condition that the inter-frame rate distortion cost is greater than the intra-frame rate distortion cost, determining an intra-frame mode, and then carrying out L2 residual error coding of the current frame based on the intra-frame mode; and under the condition that the inter-frame rate distortion cost is smaller than or equal to the intra-frame rate distortion cost, determining the inter-frame mode, and then carrying out L2 residual coding of the current frame based on the inter-frame mode.
In the case of using time domain prediction, the motion vector of the current frame and the previous frame is always 0. Illustratively, as shown in (B) of fig. 3, the coordinates are (a, B) for the current block to be encoded of the current frame to be encoded, and as shown in (a) of fig. 3, the coordinates are (a, B) for the reference block of the previous frame to be encoded of the current frame to be encoded, so that the current block to be encoded and the reference block are both fast, and in this case, the motion vectors of the current block to be encoded and the reference block are 0. In the LCEVC encoder, when the L2 residual uses temporal prediction, the motion vector of each block to be encoded of the current frame to be encoded and the reference block in the corresponding previous frame to be encoded is 0.
The relationship between quantization parameter, code rate and coding quality of video is described below.
Referring to the existing research on the rate control algorithm, and through experimental research on the LCEVC standard, it is found that the relation between the quantization parameter and the code rate can be described by a logarithmic model, as shown in formula (1).
Q＝λ·lnR+γ (1)
Wherein Q is a quantization parameter, R is a code rate, and lambda and gamma are coefficients of a relation model between the quantization parameter and the code rate. As can be obtained from the formula (1), the quantization parameter is in a linear relationship with the logarithm of the code rate, and λ is a value smaller than 0 in practical situations, so that the quantization parameter decreases with increasing code rate; the quantization parameter increases as the code rate decreases. That is, the quantization parameter increases and the code rate decreases; the quantization parameter is reduced and the code rate is increased.
In addition, the similar relationship between the code rate and the coding quality of the video (measured by an objective index vmaf close to subjective) is found through experimental study, that is, the relationship can also be described by a logarithmic relationship, as shown in a formula (2).
vmaf＝α·lnR+β (2)
Wherein vmaf is coding quality, R is code rate, and alpha and beta are coefficients of a relation model between coding quality and code rate. As can be obtained from the formula (2), the logarithm of the code rate and the coding quality are also in a linear relationship, and in the practical situation, α is a value greater than 0, so that the coding quality increases with the increase of the code rate; the coding quality decreases with decreasing code rate.
Furthermore, we can deduce that the quality of the video frame and the quantization parameter are approximately linear, i.e. can be described by equation (3).
vmaf＝a·Q+b (3)
Wherein vmaf is the coding quality, Q is the quantization parameter, and a, b are coefficients of a relational model between the coding quality and the quantization parameter.
As can be derived from the formula (3), the coding quality and the quantization parameter are also in a linear relationship, in practical cases a is a value smaller than 0, so that the coding quality decreases with increasing quantization parameter; the coding quality increases with decreasing quantization parameters.
The enhancement layer coding method based on LCEVC provided in some embodiments of the present application may be applicable to LCEVC coding schemes with fixed quantization parameters, may also be applicable to LCEVC coding schemes with rate control, such as average rate, and may also be applicable to other LCEVC coding schemes, which is not limited herein.
The standard for LCEVC uses fixed quantization parameter coding, i.e. the quantization parameters are the same for each frame of a video sequence. There is no mature scheme for rate allocation of enhancement layers for LCEVC at present, but with reference to other video coding standards such as h.264/AVC, h.265/HEVC, an average rate allocation scheme can be analogically adopted. But neither the existing fixed quantization parameter coding nor the average rate allocation coding takes into account the frame-to-frame variability.
In order to solve the above technical problems, in some embodiments of the present application, under the condition that an enhancement layer sequence to be encoded uses time domain prediction, obtaining a code rate of a current frame base layer corresponding to a current frame enhancement layer of the enhancement layer sequence to be encoded, and an average code rate of a C frame base layer before the current frame base layer, and under the condition that the code rate of the current frame base layer is less than or equal to the average code rate, encoding the current frame enhancement layer based on a first quantization parameter (original quantization parameter); and under the condition that the code rate of the current frame basic layer is larger than the average code rate, updating the quantization parameter of the current frame enhancement layer from the first quantization parameter to the second quantization parameter (the second quantization parameter is smaller than the first quantization parameter, namely, the original quantization parameter is reduced, so that the quantization parameter is reduced from the first quantization parameter to the second quantization parameter), and encoding the current frame enhancement layer based on the second quantization parameter. In this way, under the condition that the current frame enhancement layer of the enhancement layer sequence to be encoded uses time domain prediction, the encoding quality of the current frame is improved by reducing the quantization parameter of the current frame enhancement layer (reducing the quantization parameter can improve the code rate), and under the condition that the encoding quality of the current frame enhancement layer is improved, the encoding quality of the subsequent multi-frame enhancement layer of the current frame enhancement layer (adopting inter-frame encoding) is also relatively improved due to the fact that the current frame enhancement layer uses time domain prediction (the current frame enhancement layer generally adopts inter-frame mode encoding and utilizes the correlation between frames), and the average encoding quality of video encoding is further improved.
In some embodiments of the present application, the execution body of the LCEVC-based enhancement layer encoding method may be a server or a terminal device, or may be a functional module or a functional entity in the server or the terminal device that can implement the LCEVC-based enhancement layer encoding method, which may be specifically determined according to an actual situation.
The server may be one server cluster, or may be a plurality of server clusters, and may include one or more types of servers. The terminal device may be a television, a smart television, a laser projection device, a display (monitor), an electronic whiteboard (electronic bulletin board), an electronic desktop (electronic table), a mobile phone, a tablet computer, a notebook computer, a palm computer, a vehicle-mounted terminal device, and the like, which is not particularly limited herein.
Fig. 4 is a flowchart of steps for implementing an LCEVC-based enhancement layer encoding method according to one or more embodiments of the present application, which may include S401 to S405 described below.
S401, under the condition that a to-be-encoded enhancement layer sequence uses time domain prediction, acquiring the code rate of a current frame base layer corresponding to a current frame enhancement layer and the average code rate of a C frame base layer before the current frame base layer.
The to-be-coded enhancement layer sequence comprises a multi-frame enhancement layer, the current frame enhancement layer is any frame in the multi-frame enhancement layer, the average code rate is an average value of code rates of each frame of base layer in the C frame base layer, and C is an integer larger than 1.
Wherein, the enhancement layer sequence to be encoded uses time domain prediction, and then the enhancement layer sequence to be encoded belongs to the L2 residual error in FIG. 1.
As can be seen from fig. 1, if the enhancement layer sequence to be encoded uses time domain prediction, the enhancement layer sequence to be encoded is an L2 residual; if the enhancement layer sequence to be encoded uses time domain prediction, the enhancement layer sequence to be encoded may be an L2 residual or an L1 residual.
S402, determining whether the code rate of the current frame basic layer is larger than the average code rate.
In the case where the code rate of the current frame base layer is less than or equal to the average code rate, the following steps S403 and S405 are performed, and in the case where the code rate of the current frame base layer is greater than the average code rate, the following steps S404 and S405 are performed.
S403, under the condition that the code rate of the current frame base layer is smaller than or equal to the average code rate, the current frame enhancement layer is encoded based on the first quantization parameter.
S404, under the condition that the code rate of the current frame basic layer is larger than the average code rate, the quantization parameter of the current frame enhancement layer is updated from the first quantization parameter to the second quantization parameter.
S405, encoding the current frame enhancement layer based on a second quantization parameter, wherein the second quantization parameter is smaller than the first quantization parameter.
In some embodiments of the present application, encoding a current frame enhancement layer based on a quantization parameter (either a first quantization parameter or a second quantization parameter) includes: transforming the current frame enhancement layer, quantizing the transformed output based on the quantization parameter, and entropy coding the quantized output to obtain the enhancement coefficient of the current frame enhancement layer after coding.
It will be appreciated that the first quantization parameter is an original quantization parameter of the enhancement layer of the current frame, and the second quantization parameter is smaller than the first quantization parameter, that is, the enhancement layer of the current frame is encoded with the original quantization parameter in a case where the code rate of the base layer of the current frame is smaller than or equal to the average code rate, and the original quantization parameter is reduced (the first quantization parameter is reduced to the second quantization parameter) in a case where the code rate of the base layer of the current frame is larger than the average code rate, and then the enhancement layer of the current frame is encoded with the reduced quantization parameter.
Correspondingly, according to the time domain prediction result, the current frame enhancement layer is determined to be encoded by adopting an inter-frame mode or an intra-frame mode.
In the encoding of the LCEVC enhancement layer, the temporal prediction mainly uses the correlation between the adjacent frames (the current frame and the previous frame) to further improve the compression performance, and because the temporal prediction in the LCEVC is different from the complex video encoding standards such as h.264/h.265 and the like and mainly is mainly represented by that the motion vector is always 0, the temporal prediction has a good compression effect in the scene with weak motion, and once the picture content has a large change, the algorithm performance is reduced. In the encoding process of the base layer, the code rate of the relevant frames is stable under the condition that the scene movement is not severe, and when scene switching (the scene has large change), the code rate of the relevant frames is generally improved. The rate change of the base layer can be used to adjust the quantization parameters of certain frames of the enhancement layer. That is, in the process of encoding the enhancement layer, it can determine whether the current frame base layer has a large scene change relative to the previous frame base layer by using the magnitude relation between the code rate of the current frame base layer and the average code rate of the C frame base layer before the current frame base layer, thereby determining whether to adjust the quantization parameter of the current frame enhancement layer. Specifically, under the condition that the code rate of the current frame base layer is smaller than or equal to the average code rate of the C frame base layer before the current frame base layer, the current frame base layer is not changed greatly, does not move severely and is not a scene change frame relative to the previous frame base layer, so that the quantization parameter of the current frame enhancement layer is not required to be adjusted, under the condition that the code rate of the current frame base layer is larger than the average code rate of the C frame base layer before the current frame base layer, the current frame base layer is determined to be changed greatly, does move severely and is a scene change frame relative to the previous frame base layer, and therefore the quantization parameter of the current frame enhancement layer is required to be adjusted, namely the quantization parameter of the current frame enhancement layer is required to be reduced to improve the code rate, and the coding quality is improved.
In some embodiments of the present application, under the condition of using time domain prediction, S401 to S405 adaptively improve the code rate of some scene change frames (when the code rate of the current frame base layer corresponding to the current frame enhancement layer is greater than the average code rate of the previous C frame base layer of the current frame base layer, the current frame enhancement layer is an important frame) through a sliding window algorithm, thereby reducing the influence caused by error propagation and further improving the coding quality of video.
In some embodiments of the present application, the code rate of the current frame base layer corresponding to the current frame enhancement layer of the enhancement layer sequence to be encoded and the code rate of the C frame base layer before the current frame base layer may also be obtained under the condition that the enhancement layer sequence to be encoded uses time domain prediction (the code rate of the C frame base layer includes the code rate of each frame base layer in the C frame base layer); determining a target number of bit rates smaller than the bit rate of the current frame base layer in the bit rate of the C frame base layer; when the target number is less than or equal to a number threshold (the number threshold is determined according to practical situations and is not limited herein), encoding the current frame enhancement layer based on the first quantization parameter; when the target number is larger than the number threshold, updating the quantization parameter of the current frame enhancement layer from the first quantization parameter to the second quantization parameter; the current frame enhancement layer is encoded based on a second quantization parameter, the second quantization parameter being less than the first quantization parameter.
It can be appreciated that the number of the code rate of the C frame base layer is smaller than the code rate of the current frame base layer, and it is determined whether the current frame base layer has a large scene change relative to the previous frame base layer, thereby determining whether to adjust the quantization parameter of the current frame enhancement layer. Specifically, when the number of code rates of the C frame base layer is smaller than or equal to the number threshold, it is determined that the current frame base layer is not changed greatly, moves severely, and is not a scene change frame with respect to the previous frame base layer, so that there is no need to adjust the quantization parameter of the current frame enhancement layer.
In some embodiments of the present application, the frame type of the current frame base layer corresponding to the current frame enhancement layer may be obtained under the condition that the enhancement layer sequence to be encoded uses time domain prediction, and then when the frame type of the current frame base layer is a key frame (I frame), the quantization parameter of the current frame enhancement layer is updated from the first quantization parameter to the second quantization parameter; encoding the current frame enhancement layer based on a second quantization parameter, the second quantization parameter being less than the first quantization parameter; when the frame type of the current frame base layer is a non-key frame (P-frame or B-frame), the current frame enhancement layer is encoded based on the first quantization parameter.
It can be understood that, generally, the key frame is a scene change frame, so when the frame type of the current frame base layer is the key frame, the quantization parameter of the current frame enhancement layer needs to be adjusted, that is, the quantization parameter of the current frame enhancement layer needs to be reduced to improve the code rate, thereby improving the coding quality; when the frame type of the current frame base layer is a non-key frame, the quantization parameter of the current frame enhancement layer does not need to be adjusted.
In some embodiments of the present application, whether to adjust quantization parameters of the current frame enhancement layer may be determined according to actual conditions by combining a frame type of the current frame base layer corresponding to the current frame enhancement layer, a code rate of the current frame base layer corresponding to the current frame enhancement layer, and a code rate of the C frame base layer before the current frame base layer.
In some embodiments of the present application, the quantization parameter (the lifting code rate) of some scene change frames is reduced, so that the coding quality is improved, and meanwhile, due to the use of time domain prediction, the coding quality of some scene change frames is improved, and meanwhile, the coding quality of subsequent frames of some scene change frames can also be improved. And because the frames with larger scene changes generally have local characteristics, namely the larger scene changes can not occur in a short time after the larger scene changes occur, the quantity of the enhancement frame frames which need to reduce quantization parameters to improve the coding quality in the enhancement layer sequence to be coded is not large, so that the improvement of the overall code rate of the enhancement layer sequence to be coded is small, namely the influence on the overall code rate is small.
In this embodiment of the present application, in the case where LCEVC-based video coding employs fixed quantization parameter coding, the first quantization parameter is determined before coding, the second quantization parameter may be determined before coding, and the second quantization parameter may also be calculated in real time based on the first quantization parameter when determining to employ reduced quantization parameter coding for the current frame enhancement layer; in the case that rate control coding is adopted in LCEVC-based video coding, the first quantization parameter is determined according to a corresponding rate control method, and the second quantization parameter is calculated in real time based on the first quantization parameter when determining that reduced quantization parameter coding is adopted for the enhancement layer of the current frame.
The second quantization parameter is calculated in real time based on the first quantization parameter, specifically, a difference value between the first quantization parameter and a preset value may be determined as the second quantization parameter, or a product of the first quantization parameter and a preset adjustment coefficient may be determined as the second quantization parameter, or may be calculated according to other methods, which is not limited herein.
In some embodiments of the present application, as shown in fig. 5 in conjunction with fig. 4, S404 may be specifically implemented by S404a and S404b described below.
S404a, determining the product of the first quantization parameter and the adjustment coefficient as the second quantization parameter.
Wherein the adjustment coefficient is greater than 0 and less than 1.
The adjustment coefficient may be determined according to practical situations, and is not limited herein.
Wherein, the formula sw can be used 2 ＝sw 1 ·S 0 And calculating a second quantization parameter from the first quantization parameter.
Wherein sw is 2 For the second quantization parameter sw 1 For the first quantization parameter, S 0 To adjust the coefficients.
S404b, the quantization parameter of the enhancement layer of the current frame is updated from the first quantization parameter to the second quantization parameter.
In some embodiments of the present application, the product of the first quantization parameter and the adjustment coefficient is determined as the second quantization parameter, the adjustment coefficient is greater than 0 and less than 1, and the second quantization parameter after the first quantization parameter is reduced can be determined quickly by multiplying the adjustment coefficient by a certain proportion of the quantization parameter.
In some embodiments of the present application, the adjustment coefficient is greater than or equal to 0.5 and less than or equal to 0.8. Therefore, on one hand, the quantization effect is not affected, on the other hand, the code rate can be improved by reducing the quantization parameter, and the coding quality is further improved.
In some embodiments of the present application, C is k times the size of the encoded group of pictures (Group of pictures, GOP) of the base layer, k being a positive integer.
The value of k is related to the size of GOP, the length of the enhancement layer sequence to be encoded, etc., and may be specifically determined according to practical situations, which is not limited herein. For example, k may take on values of 1, 2, 3, etc.
In some embodiments of the present application, C is the difference between the GOP size and 1.
In some embodiments of the present application, the arbitrary value of C may cause great fluctuation of the effect, where C is an integer multiple or a near integer multiple of the size of the GOP, so that it may be ensured that the average coding quality of video coding is improved under the condition that the number of enhancement frames required to adjust the quantization parameter is relatively small and the improvement of the overall code rate is relatively small.
Since the video picture content is continuously changed, there is a difference between frames, and this difference is also reflected in the relationship between quantization parameter, code rate and coding quality, and the main effect is coefficients (λ, α, a) of several relationship models corresponding to the above formulas (1) to (3). I.e. some video frame contents are more sensitive to changes in the code rate of the encoding (or changes in the quantization parameter), while some frames are comparatively insensitive. For example, for the ith and jth frames, the same code rate ΔR (or ΔQ) varies with unequal code quality, i.e., Δvmaf i ≠Δvmaf j 。
In some embodiments of the present application, the average coding quality of video coding can be improved by properly reducing the quantization parameter of the sensitive frame (increasing the code rate).
Illustratively, as shown in fig. 6, the LCEVC-based enhancement layer encoding method provided in some embodiments of the present application may include S601 to S604 described below.
S601, executing each frame of enhancement layer in the enhancement layer sequence to be coded separately: and performing first precoding based on the first precoding quantization parameter, determining a first coding quality and a first code rate corresponding to the first precoding, performing second precoding based on the second precoding quantization parameter, and determining a second coding quality and a second code rate corresponding to the second precoding.
Wherein the first pre-encoded quantization parameter is different from the second pre-encoded quantization parameter, e.g., the first pre-encoded quantization parameter is smaller than the second pre-encoded quantization parameter. The first precoding quantization parameter and the second precoding quantization parameter may be determined according to actual situations, which are not limited herein. One of the first pre-encoded quantization parameter and the second pre-encoded quantization parameter may be the same as the quantization parameter of the LCEVC encoding of the corresponding one-frame enhancement layer (the third quantization parameter or the fifth quantization parameter described below), or may be different from the quantization parameter of the LCEVC encoding of the corresponding one-frame enhancement layer, and is not limited herein.
For each frame of enhancement layer in the enhancement layer sequence to be encoded, the first precoding quantization parameters may be the same or different; the second precoding quantization parameter may be the same or different for each frame of the enhancement layer in the enhancement layer sequence to be encoded, which is not limited herein.
S602, determining M target frame enhancement layers from the enhancement layer sequence to be encoded based on the first coding quality, the first code rate, the second coding quality and the second code rate of each frame enhancement layer.
The coding quality of each target frame enhancement layer is influenced by the code rate to a degree greater than that of the other frame enhancement layers except the M target frame enhancement layers in the enhancement layer sequence to be coded, and M is an integer greater than 1. The value of M may be determined according to practical situations, and is not limited herein, and may be determined according to the length of the enhancement layer sequence to be encoded, for example.
In some embodiments of the present application, the following formula (4) may be obtained based on the above formula (2).
Wherein vmaf 1 For a first coding quality, R 1 For the first code rate, vmaf 2 For the second coding quality, R 2 Is the second code rate. Therefore, the first coding quality, the first code rate, the second coding quality and the second code rate corresponding to each frame of enhancement layer are respectively substituted into the formula (4), so that the influence degree alpha of the coding quality of each frame of enhancement layer by the code rate can be calculated, then the alpha of each frame of enhancement layer is sequenced, and the M frame of enhancement layer with the largest alpha is determined from the alpha, namely M target frame of enhancement layers.
S603, the quantization parameter of each target frame enhancement layer is updated from the third quantization parameter to the fourth quantization parameter.
Wherein the fourth quantization parameter is smaller than the third quantization parameter.
And S604, encoding each target frame enhancement layer based on the fourth quantization parameter.
In some embodiments of the present application, the code rate is improved by determining M target frame enhancement layers whose coding quality is greatly affected by the code rate (the coding quality is sensitive to the code rate change) from the sequence of enhancement layers to be coded, and then reducing the quantization parameter of each target frame enhancement layer (reducing the third quantization parameter to the fourth quantization parameter), so as to further improve the coding quality of each target frame enhancement layer.
In some embodiments of the present application, other frame enhancement layers except for M target frame enhancement layers in the enhancement layer sequence to be encoded may be encoded based on the original quantization parameter, so that the average encoding quality of video encoding is improved by only reducing the quantization parameter of the target frame enhancement layer whose encoding quality is sensitive to the code rate change, and the influence on the code rate is not great.
In some embodiments of the present application, some specific frame enhancement layers, except for M target frame enhancement layers, whose encoding quality is insensitive to code rate variation, in an enhancement layer sequence to be encoded may be further encoded to reduce the code rate, because the encoding quality of these specific frame enhancement layers is not greatly affected by the code rate, the code rate of properly improving these specific frame enhancement layers has less influence on the overall encoding quality, and may counteract the code rate improved by the target frame enhancement layers, so that by releasing the quantization parameter of the target frame enhancement layers to reduce (improve the code rate of the code quality on the code rate variation sensitive frame), the quantization parameter of the specific frame enhancement layers is improved (reduce the code rate of the code quality on the code rate variation insensitive frame), thereby improving the average encoding quality of video encoding under the condition that the overall video encoding code rate is basically unchanged.
In some embodiments of the present application, as shown in fig. 7 in conjunction with fig. 6, after S601 described above, the LCEVC-based enhancement layer encoding method provided in some embodiments of the present application may further include S605 to S607 described below.
S605, N specific frame enhancement layers are determined from the enhancement layer sequence to be coded based on the first coding quality, the first code rate, the second coding quality and the second code rate of each frame enhancement layer.
The coding quality of each specific frame enhancement layer is affected by the code rate to a degree smaller than that of the other frame enhancement layers except the N specific frame enhancement layers in the enhancement layer sequence to be coded, and N is an integer larger than 1. The value of N may be determined according to practical situations, and is not limited herein, and may be determined according to the length of the enhancement layer sequence to be encoded, for example.
In connection with the above description of S602, after the α of each frame of enhancement layer is ordered, N frame enhancement layers with minimum α are determined therefrom, i.e., N specific frame enhancement layers.
S606, the quantization parameter of each specific frame enhancement layer is updated from the fifth quantization parameter to the sixth quantization parameter.
Wherein the sixth quantization parameter is greater than the fifth quantization parameter;
S607, based on the sixth quantization parameter, each specific frame enhancement layer is encoded.
In some embodiments of the present application, the code rate of each specific frame enhancement layer is reduced by determining N specific frame enhancement layers whose coding quality is less affected by the code rate (the coding quality is insensitive to the code rate change) from the sequence of enhancement layers to be coded, and then by increasing the quantization parameter of each specific frame enhancement layer (increasing the fifth quantization parameter to the sixth quantization parameter), but since each specific frame enhancement layer is a frame whose coding quality is insensitive to the code rate change, the influence on the coding quality of each specific frame enhancement layer is less.
Illustratively, assuming M, N are both 3, the enhancement layer sequence to be encoded includes 20 frame enhancement layers, the following steps are performed for each of the 20 frame enhancement layers: performing first precoding on the ith frame enhancement layer based on the first precoding quantization parameter, and determining vmaf corresponding to the ith (i=0, 1,2,3 … …, 19) frame enhancement layer 1 i And R is 1 i Based on the second precoding quantization parameter, performing second precoding on the ith frame enhancement layer, and determining vmaf corresponding to the ith frame enhancement layer 2 i And R is 2 i Based on vmaf 1 i And R is 1 i ，vmaf 2 i And R is 2 i And the formula (4) calculates alpha corresponding to the i-th frame enhancement layer i The alpha corresponding to each enhancement layer in 20 frames of enhancement layers is obtained 0 、α 1 、α 3 ……α 19 For alpha 0 、α 1 、α 3 ……α 19 And sequencing, namely determining the 3 frame enhancement layer with the largest alpha as a target frame enhancement layer, and determining the 3 frame enhancement layer with the smallest alpha as a specific frame enhancement layer. Then, the quantization parameter of the target frame enhancement layer is reduced, and the quantization parameter of the specific frame enhancement layer is increased.
In some embodiments of the present application, quantization parameters of N specific frame enhancement layers in an enhancement layer sequence to be encoded may be improved by reducing quantization parameters of M target frame enhancement layers in the enhancement layer sequence to be encoded, and encoding other frame enhancement layers in the enhancement layer sequence to be encoded except for the M target frame enhancement layers and the N specific frame enhancement layers based on original quantization parameters, so as to improve the code rate of some encoding quality in the enhancement layer sequence to be encoded for the code rate change sensitive frame, effectively improve (some encoding quality is sensitive to the code rate change) the encoding quality, reduce the code rate of some encoding quality in the enhancement layer sequence to be encoded for the code rate change insensitive frame, and hardly affect (some encoding quality is insensitive to the code rate change frame), so that under the condition that the overall code rate of the enhancement layer sequence to be encoded is basically unchanged, the overall encoding quality (i.e., the average encoding quality) is effectively improved.
In some embodiments of the present application, the fourth quantization parameter is a product of the third quantization parameter and a first adjustment coefficient, and the first adjustment coefficient is a difference between 1 and the target coefficient; the sixth quantization parameter is the product of the fifth quantization parameter and a second adjustment coefficient, the second adjustment coefficient being the sum of 1 and the target coefficient. Therefore, the improvement of the code rate of the M target frame enhancement layers and the reduction of the code rate of the N specific frame enhancement layers can be offset to the greatest extent, so that the overall coding quality (namely the average coding quality) is effectively improved under the condition that the overall code rate of the enhancement layer sequence to be coded is basically unchanged.
Wherein, the formula sw can be described as follows 4 ＝sw 3 (1-S) and third quantization parameter, calculating a fourth quantization parameter, and sw according to the following formula 6 ＝sw 5 And (1+S) and a fifth quantization parameter, a sixth quantization parameter is calculated.
Wherein sw is 3 For the third quantization parameter sw 4 For the fourth quantization parameter sw 5 For the fifth quantization parameter sw 6 For the sixth quantization parameter, S is the target coefficient, (1-S) is the first adjustment coefficient, and (1+S) is the second adjustment coefficient. Where S is greater than 0 and less than 1, and S is greater than or equal to 0.2 and less than or equal to 0.5, as an example.
In some embodiments of the present application, when the enhancement layer sequence to be encoded uses time domain prediction, the quantization parameter of the sensitive frame is properly reduced (the code rate is improved) through S601 to S604, so as to improve the average encoding quality of video encoding; when the enhancement layer sequence to be encoded does not use the time domain prediction, the quantization parameter of the sensitive frame is properly reduced (the code rate is improved) through S601 to S604, so as to improve the average encoding quality of video encoding.
In some embodiments of the present application, the correlation between enhancement layer frames is not utilized without using time domain prediction, but the picture content between frames still has a difference, so that the coding quality of some enhancement layer frames is more sensitive to the change of the code rate, and therefore, the quantization parameters of some enhancement layer frames whose coding quality is greatly affected by the code rate can be adjusted to improve the overall coding quality.
In some embodiments of the present application, as shown in fig. 8 in conjunction with fig. 4 and fig. 6, S608 described below is included before S401 and S601, and S601 described above may be specifically implemented by S601a described below.
S608, determining whether to use time domain prediction.
S601a, when the to-be-encoded enhancement layer sequence does not use time domain prediction, performing, respectively, each frame of enhancement layer in the to-be-encoded enhancement layer sequence: and performing first precoding based on the first precoding quantization parameter, determining a first coding quality and a first code rate corresponding to the first precoding, performing second precoding based on the second precoding quantization parameter, and determining a second coding quality and a second code rate corresponding to the second precoding.
Therefore, under the condition that the enhancement layer sequence to be encoded does not use time domain prediction, the quantization parameter of the code quality to the code rate change sensitive frame is reduced, so that the code rate of the code quality to the code rate change sensitive frame is improved, and further under the condition that the overall code rate of the enhancement layer sequence to be encoded is smaller, the overall coding quality (namely, the average coding quality) is effectively improved. The method adjusts the quantization parameters of some frames, adopts an intra-frame coding mode because the time domain prediction is not used, and the frames do not refer to each other, so that the coding quality of the frames sensitive to the code rate change can only be improved, and the final reaction result is the improvement of the average coding quality.
In some embodiments of the present application, referring to fig. 7 and fig. 8, as shown in fig. 9, in the case that the enhancement layer sequence to be encoded does not use time domain prediction, by reducing the code rate of the frame whose code quality is insensitive to code rate change (increasing the quantization parameter), the code rate of the frame whose code quality is sensitive to code rate change is increased (reducing the quantization parameter), and then in the case that the overall code rate of the enhancement layer sequence to be encoded is basically unchanged, the overall code quality is effectively increased (i.e. the average code quality is increased). The quantization parameters of some frames are adjusted in this way, and because the time domain prediction is not used, the frames do not have mutual reference, only the coding quality of the frames with the coding quality sensitive to the code rate change can be improved, and the final reaction results in the improvement of the average coding quality.
Based on the same inventive concept, as an implementation of the above method, as shown in fig. 10, some embodiments of the present application further provide an enhancement layer encoding apparatus based on LCEVC, including: a memory 1001 configured to store a computer program; the processor 1002 is configured to enable the LCEVC-based enhancement layer encoding apparatus to implement the LCEVC-based enhancement layer encoding method provided by the above method embodiment, and achieve the same technical effects when invoking a computer program. Wherein:
A processor 1002 configured to obtain, in a case where an enhancement layer sequence to be encoded uses time domain prediction, a code rate of a current frame base layer corresponding to a current frame enhancement layer, and an average code rate of a C frame base layer preceding the current frame base layer, where the enhancement layer sequence to be encoded includes multiple frame enhancement layers, the current frame enhancement layer is any frame of the multiple frame enhancement layers, the average code rate is an average value of code rates of each frame base layer in the C frame base layer, and C is an integer greater than 1; under the condition that the code rate of the current frame base layer is smaller than or equal to the average code rate, encoding the current frame enhancement layer based on a first quantization parameter; and under the condition that the code rate of the current frame basic layer is larger than the average code rate, updating the quantization parameter of the current frame enhancement layer from a first quantization parameter to a second quantization parameter, and encoding the current frame enhancement layer based on the second quantization parameter, wherein the second quantization parameter is smaller than the first quantization parameter.
In some embodiments of the present application, under the condition that a current frame enhancement layer of an enhancement layer sequence to be encoded uses time domain prediction, the encoding quality of a current frame is improved by reducing a quantization parameter of the current frame enhancement layer (reducing the quantization parameter can improve the code rate), and because the current frame enhancement layer uses time domain prediction (using correlation between frames), under the condition that the encoding quality of the current frame enhancement layer is improved, the encoding quality of a subsequent multi-frame enhancement layer (adopting inter-frame encoding) of the current frame enhancement layer is also relatively improved, thereby improving the average encoding quality of video encoding.
Some embodiments of the present application further provide a terminal device, including: the enhancement layer coding device based on LCEVC can achieve the same technical effect, and is not repeated here.
The embodiment of the application further provides a computer readable storage medium, on which a computer program is stored, where the computer program when executed by a processor implements each process executed by the above-mentioned LCEVC-based enhancement layer encoding method, and the same technical effects can be achieved, so that repetition is avoided, and no further description is given here.
The computer readable storage medium may be a Read-Only Memory (ROM), a random access Memory (Random Access Memory, RAM), a magnetic disk, an optical disk, or the like.
The present application provides a computer program product comprising: the computer program product, when run on a computer, causes the computer to implement the LCEVC-based enhancement layer encoding method described above.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.
The foregoing description, for purposes of explanation, has been presented in conjunction with specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the embodiments to the precise forms disclosed above. Many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles and the practical application, to thereby enable others skilled in the art to best utilize the embodiments and various embodiments with various modifications as are suited to the particular use contemplated.
Claims (10)
1. An LCEVC-based enhancement layer encoding method, comprising:
under the condition that a to-be-encoded enhancement layer sequence uses time domain prediction, acquiring a code rate of a current frame base layer corresponding to a current frame enhancement layer and an average code rate of a C frame base layer before the current frame base layer, wherein the to-be-encoded enhancement layer sequence comprises a multi-frame enhancement layer, the current frame enhancement layer is any frame in the multi-frame enhancement layer, the average code rate is an average value of code rates of each frame base layer in the C frame base layer, and C is an integer larger than 1;
under the condition that the code rate of the current frame base layer is smaller than or equal to the average code rate, encoding the current frame enhancement layer based on a first quantization parameter;
Under the condition that the code rate of the current frame basic layer is larger than the average code rate, updating the quantization parameter of the current frame enhancement layer from the first quantization parameter to a second quantization parameter, and encoding the current frame enhancement layer based on the second quantization parameter;
wherein the second quantization parameter is smaller than the first quantization parameter.
2. The method according to claim 1, wherein said updating the quantization parameter of the current frame enhancement layer from the first quantization parameter to a second quantization parameter in the case where the code rate of the current frame base layer is greater than the average code rate, comprises:
determining the product of the first quantization parameter and an adjustment coefficient as the second quantization parameter under the condition that the code rate of the current frame base layer is larger than the average code rate, wherein the adjustment coefficient is larger than 0 and smaller than 1;
and updating the quantization parameter of the current frame enhancement layer from the first quantization parameter to the second quantization parameter.
3. The method of claim 2, wherein the adjustment factor is greater than or equal to 0.5 and less than or equal to 0.8.
4. A method according to any one of claims 1 to 3, wherein C is k times the size of the encoded group of pictures of the base layer, and k is a positive integer.
5. The method according to claim 1, wherein the method further comprises:
in the case that the enhancement layer sequence to be encoded does not use time domain prediction, respectively performing, for each frame of enhancement layer in the enhancement layer sequence to be encoded: performing first precoding based on a first precoding quantization parameter, determining a first coding quality and a first code rate corresponding to the first precoding, performing second precoding based on a second precoding quantization parameter, and determining a second coding quality and a second code rate corresponding to the second precoding;
determining M target frame enhancement layers from the enhancement layer sequence to be coded based on the first coding quality, the first code rate, the second coding quality and the second code rate of each frame enhancement layer, wherein the influence degree of the code rate on the coding quality of each target frame enhancement layer is greater than that of the coding quality of other frame enhancement layers except the M target frame enhancement layers in the enhancement layer sequence to be coded, and M is an integer greater than 1;
updating the quantization parameter of each target frame enhancement layer from a third quantization parameter to a fourth quantization parameter, wherein the fourth quantization parameter is smaller than the third quantization parameter;
And encoding each target frame enhancement layer based on the fourth quantization parameter.
6. The method of claim 5, wherein the method further comprises:
determining N specific frame enhancement layers from the enhancement layer sequence to be coded based on the first coding quality, the first code rate, the second coding quality and the second code rate of each frame enhancement layer, wherein the influence degree of the code rate on the coding quality of each specific frame enhancement layer is smaller than that of the coding quality of other frame enhancement layers except for the N specific frame enhancement layers in the enhancement layer sequence to be coded, and N is an integer larger than 1;
updating the quantization parameter of each specific frame enhancement layer from a fifth quantization parameter to a sixth quantization parameter, wherein the sixth quantization parameter is larger than the fifth quantization parameter;
encoding each of the particular frame enhancement layers based on the sixth quantization parameter.
7. The method of claim 6, wherein N = M;
the fourth quantization parameter is the product of the third quantization parameter and a first adjustment coefficient, the first adjustment coefficient being the difference between 1 and a target coefficient;
the sixth quantization parameter is a product of the fifth quantization parameter and a second adjustment coefficient, the second adjustment coefficient being a sum of 1 and the target coefficient.
8. An LCEVC-based enhancement layer encoding apparatus, comprising:
a memory configured to store a computer program;
a processor configured to cause the LCEVC-based enhancement layer encoding apparatus to implement the LCEVC-based enhancement layer encoding method of any one of claims 1-7 when invoking a computer program.
9. A terminal device, comprising: an LCEVC-based enhancement layer encoding apparatus as recited in claim 8.
10. A computer-readable storage medium, comprising: a computer program is stored on a computer readable storage medium, which when executed by a processor implements the LCEVC-based enhancement layer encoding method according to any one of claims 1 to 7.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310108746.3A CN116193118A (en) | 2023-02-13 | 2023-02-13 | LCEVC-based enhancement layer coding method, device, equipment and medium |
| PCT/CN2023/100023 WO2024124835A1 (en) | 2022-12-13 | 2023-06-13 | Video encoding method and device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310108746.3A CN116193118A (en) | 2023-02-13 | 2023-02-13 | LCEVC-based enhancement layer coding method, device, equipment and medium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116193118A true CN116193118A (en) | 2023-05-30 |
Family
ID=86436078
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310108746.3A Pending CN116193118A (en) | 2022-12-13 | 2023-02-13 | LCEVC-based enhancement layer coding method, device, equipment and medium |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116193118A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024124835A1 (en) * | 2022-12-13 | 2024-06-20 | 海信视像科技股份有限公司 | Video encoding method and device |
-
2023
- 2023-02-13 CN CN202310108746.3A patent/CN116193118A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024124835A1 (en) * | 2022-12-13 | 2024-06-20 | 海信视像科技股份有限公司 | Video encoding method and device |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR100781525B1 (en) | Method and apparatus for encoding and decoding FGS layers using weighting factor | |
| CN107071422B (en) | Low complex degree HEVC rate adaption transformation coding method based on image correlation model | |
| CN104320657B (en) | The predicting mode selecting method of HEVC lossless video encodings and corresponding coding method | |
| CN103460700A (en) | Method for decoding image in intra prediction mode | |
| JP2007503776A (en) | Method and apparatus for minimizing the number of reference images used for inter coding | |
| KR20070092179A (en) | Video encoding method, video decoding method, video encoder, and video decoder, which use smoothing prediction | |
| Yuan et al. | Hybrid distortion-based rate-distortion optimization and rate control for H. 265/HEVC | |
| TWI468018B (en) | Video coding using vector quantized deblocking filters | |
| WO2012006304A2 (en) | Motion compensation using vector quantized interpolation filters | |
| CN114915789B (en) | Method, system, device and medium for optimizing Lagrange multiplier between frames | |
| CN116193118A (en) | LCEVC-based enhancement layer coding method, device, equipment and medium | |
| CN110740319A (en) | Video encoding and decoding method and device, electronic equipment and storage medium | |
| CN115118976A (en) | Image coding method, readable medium and electronic device thereof | |
| CN103096064B (en) | The method and relevant device of coding and reconstructed pixel block | |
| WO2022021422A1 (en) | Video coding method and system, coder, and computer storage medium | |
| JP7125559B2 (en) | Video stream adaptive filtering for bitrate reduction | |
| Wang et al. | A low complexity compressed sensing-based codec for consumer depth video sensors | |
| WO2008028333A1 (en) | Method and apparatus for encoding a flash picture occurring in a viedo sequence, and for decoding corresponding data for a flash picture | |
| KR20130032807A (en) | Method and apparatus for encoding a moving picture | |
| CA2800525A1 (en) | Video rate control based on transform-coefficients histogram | |
| Yang et al. | Efficient panoramic video coding for Immersive metaverse experience | |
| Kumar et al. | Inter Frame-Rate Distortion optimisation on scalable video for HEVC | |
| Chen et al. | An Enhanced Video Compression Framework based on Rescaling Networks | |
| CN107749993A (en) | Distributed video coding information source distortion evaluation method based on MMSE reconstruct | |
| CN113132736B (en) | HEVC compression noise level estimation denoising method based on DCT domain |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |