Encoding method and decoding method, bitstream, encoder, decoder, and storage medium

Abstract

Embodiments of the present application disclose an encoding method and a decoding method, a bitstream, an encoder, a decoder, and a storage medium. The method includes: analyzing a bitstream to determine a value for a first syntactic identifier; if the first syntactic identifier indicates that the current block uses a cross-component predictive merge mode, analyzing the bitstream to determine a value for a second syntactic identifier; if the second syntactic identifier indicates that the current block uses a cross-component predictive merge fusion mode, analyzing the bitstream to determine at least one fusion type identifier corresponding to the current block; determining at least one chromatic prediction mode corresponding to the current block based on at least one fusion type identifier; performing an intra-chromatic prediction for the current block using at least one chromatic prediction mode to determine at least one first predicted value; performing an intra-chromatic prediction for the current block using a cross-component predictive merge mode to determine a second predicted value; and determining a chromatic prediction value corresponding to the current block based on at least one first and second predicted values. In this way, the prediction accuracy of the chromatic fusion mode can be improved, thereby improving the encoding and decoding efficiency.

Description

[Technical Field]

[0001] The embodiments of this application relate to the video encoding and decoding technology, and more particularly to encoding methods and decoding methods, bitstreams, encoders, decoders, and storage media. [Background technology]

[0002] Based on the reference software test platform for the latest video coding standard, H.266 / Versatile Video Coding (VVC), the Joint Video Experts Team (JVET) proposed a new generation of reference software model, namely the Enhanced Compression Model (ECM).

[0003] In ECM, the intra-prediction portion may include luminance intra-prediction and chromaticity intra-prediction. Here, chromaticity intra-prediction includes a prediction method for the cross-component prediction merge fusion mode. The cross-component prediction merge fusion mode fuses the cross-component prediction merge mode with the default cross-component prediction mode, and because the fusion method is single, it does not fully realize the advantages of the fusion mode, resulting in low coding and decoding efficiency. [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] Embodiments of the present invention provide an encoding method and a decoding method, a bitstream, an encoder, a decoder, and a storage medium that can improve the prediction accuracy of a cross-component predictive merge fusion mode, thereby improving encoding and decoding efficiency. [Means for solving the problem]

[0005] The technical solution of the embodiment of the present application can be realized as follows.

[0006] In a first embodiment, the embodiment of the present application provides a decoding method applicable to a decoder, the method being: The bitstream is analyzed to determine the value of the first syntactic identifier, If the first syntactic identifier indicates that the current block uses cross-component predictive merge mode, the bitstream is parsed and the value of the second syntactic identifier is determined. If the second syntactic identification information indicates that the current block uses a cross-component predictive merge fusion mode, the bitstream is analyzed to determine at least one fusion type identification value corresponding to the current block. Based on the at least one fusion type identification value, determine at least one chromaticity prediction mode corresponding to the current block, Using the aforementioned at least one chromaticity prediction mode, intrachromatic prediction is performed for the current block, and at least one first predicted value is determined. Using the cross-component prediction merge mode, intra-chromaticity prediction is performed on the current block to determine the second predicted value, The method includes determining a chromaticity prediction value corresponding to the current block based on the at least one first prediction value and the second prediction value.

[0007] In a second embodiment, an embodiment of the present application provides an encoding method applicable to an encoder, the method being: Determining the value of the first syntactic identifier, If the first syntactic identifier indicates that the current block uses cross-component predictive merge mode, then the value of the second syntactic identifier is determined. If the second syntactic identification information indicates that the current block uses a cross-component predictive merge fusion mode, the decoder determines at least one chromaticity prediction mode corresponding to the current block and determines at least one fusion type identification value corresponding to the at least one chromaticity prediction mode, wherein the at least one fusion type identification value is used by the decoder to determine at least one first prediction value in chromaticity intra-prediction based on the cross-component predictive merge fusion mode of the current block.

[0008] In a third embodiment, the embodiment of the present application provides a bitstream generated by bit encoding based on information to be encoded, wherein the information to be encoded is at least: The first syntactic identifier value, the second syntactic identifier value, and at least one of the at least one fusion type identifier value, Here, the first syntactic identifier is used to indicate whether the current block uses a cross-component predictive merge mode, the second syntactic identifier is used to indicate whether the current block uses a cross-component predictive merge fusion mode, and the at least one fusion type identifier is used to indicate at least one chromaticity prediction mode corresponding to the current block.

[0009] In a fourth embodiment, an embodiment of the present application provides an encoder comprising a first determination unit configured to determine a value of a first syntactic identifier and, if the first syntactic identifier indicates that the current block uses a cross-component predictive merge mode, to determine a value of a second syntactic identifier. The first determination unit is further configured to determine at least one chromaticity prediction mode corresponding to the current block and at least one fusion type identifier corresponding to the at least one chromaticity prediction mode if the second syntax identifier indicates that the current block uses a cross-component predictive merge fusion mode, the at least one fusion type identifier is used by the decoder to determine at least one first prediction value in chromaticity intra prediction based on the cross-component predictive merge fusion mode of the current block.

[0010] In a fifth embodiment, the present invention provides an encoder comprising a first memory and a first processor. The first memory is configured to store computer programs that can be executed by the first processor. The first processor is configured to execute the encoding method described in the second embodiment by executing a computer program.

[0011] In a sixth embodiment, the present invention provides a decoder comprising an analysis unit, a second determination unit, and a second prediction unit. The analysis unit is configured to analyze the bitstream, determine the value of a first syntax identifier, and if the first syntax identifier indicates that the current block uses a cross-component predictive merge mode, analyze the bitstream and determine the value of a second syntax identifier, and if the second syntax identifier indicates that the current block uses a cross-component predictive merge fusion mode, analyze the bitstream and determine at least one fusion type identifier corresponding to the current block. The second determination unit is configured to determine at least one chromaticity prediction mode corresponding to the current block based on the at least one fusion type identification value, The second prediction unit is configured to perform an intrachromatic prediction for the current block using the at least one chromaticity prediction mode and determine at least one first predicted value, perform an intrachromatic prediction for the current block using the cross-component prediction merge mode and determine a second predicted value, and determine a chromaticity prediction value corresponding to the current block based on the at least one first predicted value and the second predicted value.

[0012] In a seventh embodiment, the present invention provides a decoder comprising a second memory and a second processor. The second memory is configured to store computer programs that can be executed by the second processor. The second processor is configured to execute the decoding method described in the first embodiment by executing a computer program.

[0013] In the eighth embodiment, the embodiment of the present application provides a storage medium for storing a computer program for implementing the decoding method described in the first embodiment or the encoding method described in the second embodiment. [Effects of the Invention]

[0014] Embodiments of the present application provide an encoding method, a decoding method, a bitstream, an encoder, a decoder, and a storage medium. On the decoding side, the bitstream is parsed to determine the value of first syntax identification information; when the first syntax identification information indicates that the current block uses a cross-component prediction merge mode, the bitstream is parsed to determine the value of second syntax identification information; when the second syntax identification information indicates that the current block uses a cross-component prediction merge fusion mode, the bitstream is parsed to determine at least one fusion type identification value corresponding to the current block. At least one chroma intra prediction mode corresponding to the current block is determined based on the at least one fusion type identification value, chroma intra prediction is performed on the current block using the at least one chroma intra prediction mode to determine at least one first prediction value, chroma intra prediction is performed on the current block using the cross-component prediction merge mode to determine a second prediction value, and a chroma prediction value corresponding to the current block is determined based on the at least one first prediction value and the second prediction value. In this way, when it is determined that the current block uses the cross-component prediction merge mode, by further determining that the current block uses the cross-component prediction merge fusion mode, at least one fusion type identification value corresponding to the current block is further parsed from the bitstream, at least one chroma intra prediction mode corresponding to the current block is determined based on the at least one fusion type identification value, and the chroma prediction value corresponding to the current block can be determined by fusing the at least one first prediction value obtained by prediction using the at least one chroma intra prediction mode and the second prediction value obtained by prediction in the cross-component prediction merge mode. That is, the fusion mode at the decoding side can be flexibly selected based on the at least one fusion type identification value, and by providing multiple options for the cross-component prediction merge fusion mode, the prediction accuracy of the cross-component prediction merge fusion mode can be improved, and further the decoding efficiency can be improved. [BRIEF DESCRIPTION OF THE DRAWINGS]

[0015] [Figure 1] It is a schematic diagram of a current block, adjacent reconstructed chroma pixels and reconstructed luma pixels. [Figure 2A] It is a schematic diagram of a linear model based on the CCLM mode. [Figure 2B] It is a schematic diagram of a linear model based on the CCLM-SLOPE mode. [Figure 3] It is a schematic diagram of a multi-model based on the MMLM mode. [Figure 4] It is a schematic diagram of convolution filter spatial components based on the CCCM mode. [Figure 5] It is a schematic diagram of a reference template region based on the CCCM mode. [Figure 6] It is a schematic diagram of candidate positions of spatially adjacent blocks. [Figure 7] It is a schematic diagram of candidate positions of spatially non-adjacent blocks. [Figure 8] It is an exemplary block diagram of a configuration of an encoder according to an embodiment of the present application. [Figure 9] It is an exemplary block diagram of a configuration of a decoder according to an embodiment of the present application. [Figure 10] It is a schematic diagram of a network architecture of an encoding and decoding system according to an embodiment of the present application. [Figure 11] It is a first exemplary flowchart of a decoding method according to an embodiment of the present application. [Figure 12] It is a second exemplary flowchart of a decoding method according to an embodiment of the present application. [Figure 13] It is an exemplary flowchart of an encoding method according to an embodiment of the present application. [Figure 14] It is an exemplary structural diagram of a configuration of an encoder according to an embodiment of the present application. [Figure 15] It is a schematic diagram of a specific hardware structure of an encoder according to an embodiment of the present application. [Figure 16] It is an exemplary structural diagram of a configuration of a decoder according to an embodiment of the present application. [Figure 17] It is a schematic diagram of a specific hardware structure of a decoder according to an embodiment of the present application. [Figure 18] This is an illustrative structural diagram of the configuration of the coding and decoding system according to an embodiment of the present invention. [Modes for carrying out the invention]

[0016] In order to provide a more detailed understanding of the features and technical content of the embodiments of this application, the implementation of the embodiments will be described in detail below with reference to the drawings. The drawings are for reference and explanatory purposes only and are not intended to limit the embodiments of this application.

[0017] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art. The terms used herein are for illustrative purposes only and are not intended to limit the application.

[0018] In the following description, the term “several embodiments” refers to a subset of all possible embodiments, and to make it clear, “several embodiments” can be the same subset or different subsets of all possible embodiments, and these can be combined with each other as long as they do not conflict.

[0019] The terms “first / second / third” as used in the embodiments of this application are merely for distinguishing similar objects and do not represent a specific order of objects. It should be understood that “first / second / third” may, in some cases, be interchangeable in terms of a specific order or sequence, and that the embodiments of this application described herein may be carried out in an order other than that shown or described.

[0020] With the aim of exploring next-generation digital video compression technologies, a new generation of reference software models, namely the Enhanced Compression Model (ECM), is being developed based on the latest video coding standard H.266 / VVC Reference Software Test Platform (VTM: VVC Test Model). Currently, video compression technologies are also conventional coding and decoding performed on a block basis and may include multiple modules such as block partitioning, intra-prediction, inter-prediction, transformation, quantization, entropy coding, loop filtering, and post-processing filtering. The embodiment of this application mainly improves the prediction portion to enhance the coding performance of the ECM.

[0021] Here, the prediction part may include multiple techniques, including luminance prediction mode and chromaticity prediction mode. Chromaticity intra-prediction can be further classified into two types: cross-component prediction mode and non-cross-component prediction mode. Non-cross-component prediction mode typically includes planar mode, direct current (DC) mode, and decoder-side intra-mode derivation (DIMD) mode. Regarding the cross-component linear model (CCLM) prediction mode, the central idea is to perform cross-component prediction to reduce redundancy between cross-components. This primarily involves constructing predicted chromaticity pixel values ​​using reconstructed luminance pixels from the same coding block, and the linear relationship is shown in equation (1) below.

[0022] Nod c (i,j)=a·rec L '(i,j)+b (1) Here, pred c (i,j) represents the chromaticity prediction pixel of the current block, and rec L′(i,j) represents the downsampled reconstructed luminance pixels of the current block, and a and b are called linear model parameters, where a is the scaling parameter and b is the offset parameter. a and b can be derived computationally from adjacent chromaticity and luminance pixels. This linear model can be derived computationally on both the encoding and decoding sides and does not need to be written to the bitstream. Exemplarily, Figure 1 shows a schematic diagram of the current block and adjacent reconstructed chromaticity and reconstructed luminance pixels in CCLM mode. As shown in Figure 1, the grid-like filled circles represent the reconstructed reference pixels adjacent to the current block, which may include the left reference pixel and the upper reference pixel. Furthermore, N represents the side length corresponding to the chromaticity component of the current block, and 2N represents the side length corresponding to the luminance component of the current block.

[0023] Here, in addition to calculating the linear model parameters using all upper and left reference pixels, there are two further calculation methods for the model parameters. In other words, CCLM has two further modes, called CCLM-T and CCLM-L modes, which are as follows:

[0024] In CCLM-T mode, the linear model parameters are calculated using only the upper reference pixels.

[0025] In CCLM-L mode, the linear model parameters are calculated using only the left-hand reference pixel.

[0026] To further improve the coding efficiency of CCLM, ECM has made many improvements to CCLM, including slope-based CCLM models (CCLM_SLOPE), multi-model linear models (MMLM), convolutional cross-component models (CCCM), and gradient linear models (GLM). Below, we will briefly introduce some of these linear models.

[0027] CCLM_SLOPE allows you to adjust the calculated linear model parameters. The adjustment method is as follows:

[0028] a′=a+u, b′=bu*yr (2) Here, the predicted pixels are calculated using the updated linear model parameters a' and b'. This improvement causes the mapping function to tilt or rotate around a point where the luminance value is yr, where yr is generally the average value of the reference luminance pixels. Exemplarily, Figure 2A is a schematic diagram of a linear model based on the CCLM mode, and Figure 2B is a schematic diagram of a linear model based on the CCLM-SLOPE mode. Here, the horizontal axis represents the reconstructed luminance information (Y), the vertical axis represents the chromaticity prediction information (Cb / Cr), the model parameters in Figure 2A are a and b, and the model parameters in Figure 2B are a' and b'. Furthermore, the model parameters a' and b' in Figure 2B can be obtained by adjusting the model parameters a and b.

[0029] In CCLM, there is only one linear model between luminance and chromaticity in the same coding block. In MMLM, multiple models can be provided for the same coding block. Adjacent luminance and chromaticity pixels are classified into different categories based on a classification threshold, and each pixel within each category is used to determine different model parameters. Exemplarily, Figure 3 is a schematic diagram of a multi-model based on the MMLM mode. As shown in Figure 3, here we can classify adjacent reference pixels based on a classification threshold and construct two linear models, the model parameters of the first linear model are α1=2, β1=1, and the model parameters of the second linear model are α2=1 / 2, β2=-1.

[0030] In the cross-component prediction mode of CCCM, a set of convolutional filters is used to obtain the predicted pixels. Exemplarily, a 7-tap convolutional filter typically includes five spatial components, one nonlinear term, and one offset term, as shown in Figure 4. The generation of the predicted pixels may be as shown in equation (3).

[0031] Nod c (i,j)=c0C+c1N+c2S+c3E+c4W+c5P+c6B (3) Here, C represents the luminance pixel at pixel position (i,j), and N, S, W, and E represent the pixels above, below, to the left, and to the right of the corresponding pixel, respectively. The nonlinear term P is expressed as the square of the central luminance sample C and is scaled to the sample value range of the content. B is the offset term and is set to the midpoint of the chromaticity value, i.e., B = midVal. The value of P can be determined by equation (4) and is as follows:

[0032] P=(C*C+midVal)≫bitDepth (4) Here, bitDepth represents the bit depth, and the value of midVal is determined based on the bit depth value. For example, if the bit depth is 10, the value of midVal is 512.

[0033] In equation (3), the coefficients c0 to c6 of the convolution filter are determined by the adjacent reconstructed pixels. Unlike CCLM, the reference template region of CCCM includes the 6x6 reconstructed pixels around the current block, as well as the upper right and lower left extension regions, as shown in Figure 5. In Figure 5, the shaded region outside the reference template region represents the extension portion of the spatial component in the convolution filter. The coefficients of the convolution filter can be determined by minimizing the Mean-Square Error (MSE) between the predicted chromaticity sample and the reconstructed chromaticity sample in the reference template region. Here, minimizing the MSE can be achieved by calculating the autocorrelation matrix of the luminance input and the cross-correlation vector between the luminance input and the chromaticity output.

[0034] Cross-component prediction modes based on convolutional models have various derivative variations, including GLM. Similar to CCLM, CCCM can be used with the selection of different reference template region shapes, i.e., CCCM-T and CCCM-L modes exist. Similarly, CCCM can be used with the selection of multiple parameter models, i.e., the Multi-Model Convolutional Cross-Component Model (MM-CCCM) mode. In MM-CCCM mode, the current input sample determines the specific convolutional filter to use based on a threshold, and obtains the final predicted pixel value.

[0035] To further understand the cross-component prediction merge mode, in the various cross-component linear model prediction modes described above, all cross-component model parameters (ccmParam) are calculated using adjacent reconstructed luminance pixels and adjacent reconstructed chromaticity pixels. Based on this, we now propose the technique of the cross-component prediction merge mode (CCMerge). In this mode, the ccmParam of the current block can be directly inherited from the reconstructed block rather than being obtained by computation. The flag cclmMrgFlag indicates whether the current block uses the cross-component prediction merge mode. If the flag cclmMrgFlag is true, i.e., the current block is in CCMerge mode, a list of model parameters (ccmParam) can be created for the current block, and this list can be represented as ccmList[NUM_LMC_MERGE_CANDS]. This list is filled with existing ccmParam obtained from spatially adjacent candidate blocks and spatially non-adjacent candidate blocks. By default, the upper limit for the number of candidates in the list, NUM_LMC_MERGE_CANDS, is 6. If the list is not full after the above process, it can be filled according to the specified default parameters. The candidate index cclmMrgIdx then indicates the specific model parameters to be used.

[0036] In some embodiments, the method for filling the candidate list is as follows:

[0037] Step 1: Spatial adjacency candidates.

[0038] First, spatially adjacent blocks are checked. The positions of the adjacent blocks are as shown in Figure 6, and the checking order is B1 → A1 → B0 → A0 → B2.

[0039] Step 2: Spatially non-adjacent candidates.

[0040] After checking all spatially adjacent blocks, spatially non-adjacent blocks are considered. Their positional relationships are shown in Figure 7, where each point represents one non-adjacent block, and each point is used to indicate the position of the upper-left corner of that non-adjacent block. It should be noted that the grid in Figure 7 is merely an illustrative representation of the pixel coordinate grid and does not represent a specific block division.

[0041] Step 3: Select default CCLM parameters.

[0042] If the list is not full, after checking for spatially adjacent and non-adjacent candidates, CCLM candidates with default scaling parameters are considered, where the default scaling parameters are {0, 1 / 8, -1 / 8, 2 / 8, -2 / 8, 3 / 8}. In the construction process described above, if a CCLM type candidate exists, the scaling parameter a of the first added CCLM type candidate is considered. first Adjustments are made to it and it is added to the candidate list. In this case, the scaling parameter is {0,a first +{1 / 8,-1 / 8,2 / 8,-2 / 8,3 / 8,-3 / 8,4 / 8,-4 / 8,5 / 8,-5 / 8,6 / 8}}

[0043] The inheritance rules for model parameters are as follows:

[0044] (1) When inheriting a CCLM candidate, the scaling parameter and offset parameter are inherited.

[0045] (2) When inheriting an MMLM candidate, the scaling parameters and classification thresholds are inherited.

[0046] (3) When inheriting a CCCM candidate, all convolution parameters and classification thresholds are inherited.

[0047] (4) When inheriting a GLM candidate, if the GLM is in 3-parameter mode, all gradient indices and model parameters are inherited; otherwise, if the GLM is in 2-parameter mode, only the scaling parameters are inherited, and the offset parameters need to be recalculated.

[0048] (5) When inheriting the chromaticity fusion mode, the MMLM parameters derived in the cross-component prediction part are inherited as candidates.

[0049] (6) When inheriting a CCMerge candidate, the inheritance method depends on the candidate mode it inherits.

[0050] In the cross-component prediction merge mode described above, the predicted values ​​obtained by calculating based on the derived cross-component prediction model are used as the final predicted pixel values. On the other hand, in the fusion mode of the cross-component prediction merge mode, the above predicted values ​​need to be weighted and merged with the predicted values ​​obtained by calculating in MM-CCCM mode to obtain the final predicted values. The default MM-CCCM mode calculates and obtains a set of cross-component prediction models based on the reconstructed luminance and reconstructed chromaticity values ​​adjacent to the current block, calculates and obtains predicted values ​​based on the cross-component prediction model and the pixel values ​​of the luminance block corresponding to the current block, and then weights and merges with the predicted values ​​generated by the cross-component prediction merge mode to obtain the final predicted values.

[0051] As can be seen from this, currently, the fusion mode of the cross-component prediction merge mode simply weights and fuses the predicted values ​​obtained by the derived cross-component model with the predicted values ​​obtained by the default MM-CCCM setting. As a result, there is only one fusion mode, and the effect of the fusion mode cannot be fully utilized, leading to a decrease in coding and decoding efficiency.

[0052] Based on this, embodiments of the present application provide an encoding method and a decoding method, wherein the encoding side can determine at least one chromaticity prediction mode to be fused with a cross-component prediction merge mode based on the encoding cost, and transmit at least one fusion type identifier corresponding to at least one chromaticity prediction mode to the decoding side. On the decoding side, if it is decided to use the cross-component prediction merge fusion mode for the current block, it further analyzes at least one fusion type identifier from the bitstream, performs intra-chromaticity prediction based on at least one chromaticity prediction mode corresponding to at least one fusion type identifier, and fuses the obtained prediction value with the prediction value of the cross-component prediction merge mode to obtain the chromaticity prediction value corresponding to the current block. This allows for flexible selection of the fusion mode on the decoding side using at least one fusion type identifier, provides a variety of options for the cross-component prediction merge fusion mode, improves the prediction accuracy of the cross-component prediction merge fusion mode, and further improves the encoding and decoding efficiency.

[0053] In the following sections, each embodiment of the present invention will be described in detail with reference to the drawings.

[0054] Referring to Figure 8, an exemplary block diagram of the encoder configuration according to an embodiment of the present invention is shown. As shown in Figure 8, the encoder 100 includes a transform and quantization unit 101, an intra-estimation unit 102, an intra-prediction unit 103, a motion compensation unit 104, a motion estimation unit 105, an inverse transform and inverse quantization unit 106, a filter control analysis unit 107, a filtering unit 108, an encoding unit 109, and a decoded image buffer unit 110, where the filtering unit 108 can implement deblocking filtering and sample adaptive offset (SAO) filtering, and the encoding unit 109 can implement header information encoding and context-based adaptive binary arithmetic coding (CABAC). For the input original video signal, a video coding block can be obtained by dividing it into a Coding Tree Unit (CTU). Then, the residual pixel information obtained by intra-prediction or inter-prediction is transformed by the transformation and quantization unit 101, which includes transforming the residual information from the pixel region to the transformation region and quantizing the resulting transformation coefficients, thereby further reducing the bitrate. The intra-estimation unit 102 and the intra-prediction unit 103 are configured to perform intra-prediction on the video coding block. Specifically, the intra-estimation unit 102 and the intra-prediction unit 103 are configured to determine the intra-prediction mode used to encode the video coding block. The motion compensation unit 104 and the motion estimation unit 105 are configured to perform inter-prediction coding on the received video coding block for one or more blocks in one or more reference frames to provide time prediction information.Motion estimation performed by the motion estimation unit 105 is a process that generates motion vectors, which are used to estimate the motion of the video coding block, and the motion compensation unit 104 performs motion compensation based on the motion vectors determined by the motion estimation unit 105. After the intra-prediction mode is determined, the intra-prediction unit 103 is further configured to provide selected intra-prediction data to the coding unit 109, and the motion estimation unit 105 is configured to send the computationally determined motion vector data to the coding unit 109. Furthermore, the inverse transform and inverse quantization unit 106 is configured to reconstruct the video coding block. The residual block is reconstructed in the pixel region, the reconstructed residual block has blocking artifacts removed by the filter control analysis unit 107 and the filtering unit 108, and the reconstructed residual block is added to one prediction block in the frame of the decoded image buffer unit 110 to generate the reconstructed video coding block. The encoding unit 109 is configured to encode various encoding parameters and quantized transformation coefficients, and in a CABAC-based encoding algorithm, the context content is based on adjacent encoding blocks and can encode information indicating the determined intra-prediction mode and be used to output the bitstream of the video signal, and the decoding image buffer unit 110 is configured to store reconstructed video encoding blocks used for prediction reference. As the encoding of the video image progresses, newly reconstructed video encoding blocks are continuously generated, and all of these reconstructed video encoding blocks are stored in the decoding image buffer unit 110.

[0055] Referring to Figure 9, an exemplary block diagram of the decoder configuration according to an embodiment of the present invention is shown. As shown in Figure 9, the decoder 200 includes a decoding unit 201, an inverse transform and inverse quantization unit 202, an intra-prediction unit 203, a motion compensation unit 204, a filtering unit 205, and a decoded image buffer unit 206, where the decoding unit 201 can perform header information decoding and CABAC decoding, and the filtering unit 205 can perform deblocking filtering and SAO filtering. After performing the encoding process shown in Figure 8 on the input video signal, a bitstream of the video signal is output and input to the decoder 200. First, the decoding unit 201 processes the decoded transformation coefficients, which are then processed by the inverse transform and inverse quantization unit 202 to generate residual blocks in the pixel region. The intra-prediction unit 203 is configured to generate prediction data for the current video decoded block based on the determined intra-prediction mode and data from previous decoded blocks from the current frame or picture. The motion compensation unit 204 is configured to determine prediction information for a video decoding block by analyzing motion vectors and other relevant syntactic elements, and to use this prediction information to generate a prediction block for the video decoding block currently being decoded. The decoded video block is formed by adding the residual block from the inverse transform and inverse quantization unit 202 with the corresponding prediction block generated by the intra-prediction unit 203 or the motion compensation unit 204. The decoded video signal can then be filtered by the filtering unit 205 to remove blocking artifacts and improve video quality. The decoded video block is then stored in the decoded image buffer unit 206, which stores a reference image used for subsequent intra-prediction or motion compensation, and is also used to output the video signal, i.e., to obtain the restored original video signal.

[0056] Furthermore, embodiments of the present application provide a network architecture for an encoding / decoding system comprising an encoder and a decoder, where Figure 10 shows a schematic diagram of the network architecture of the encoding / decoding system according to embodiments of the present application. As shown in Figure 10, the network architecture includes one or more electronic devices 13 to 1N and a communication network 01, where the electronic devices 13 to 1N can perform video interaction through the communication network 01. In implementation, the electronic devices may be various types of devices equipped with video encoding / decoding functions, for example, the electronic devices may include smartphones, tablet computers, personal computers, personal information terminals, navigation devices, digital telephones, video telephones, televisions, sensing devices, servers, etc., and embodiments of the present application are not particularly limited thereto. Here, the decoder or encoder described in embodiments of the present application may be the above-mentioned electronic devices.

[0057] The method of the embodiment of this application is mainly applied to the prediction portion shown in Figure 8 and the prediction portion shown in Figure 9. In other words, the embodiment of this application may be applied to an encoder, or to a decoder, or even to both an encoder and a decoder simultaneously, but the embodiment of this application is not limited to these. Furthermore, the prediction portion here may include an intra-prediction portion and an inter-prediction portion.

[0058] Furthermore, it should be noted that on the encoding side, "current block" specifically refers to the encoded block currently being predicted for chromaticity, and on the decoding side, "current block" specifically refers to the decoded block currently being predicted for chromaticity. The current block here may be a coding unit (CU), a coding tree unit (CTU), a prediction unit (PU), or a transform unit (TU), but is not specifically limited to these.

[0059] In one embodiment of the present application, with reference to Figure 11, an illustrative flowchart of the decoding method according to the embodiment of the present application is shown. As shown in Figure 11, the method may include the following steps.

[0060] In step S101, the bitstream is analyzed and the value of the first syntactic identifier is determined.

[0061] In step S102, if the first syntactic identifier indicates that the current block uses cross-component predictive merge mode, the bitstream is parsed and the value of the second syntactic identifier is determined.

[0062] The decoding method in the embodiment of this application is applied to a decoder. Furthermore, the decoding method may specifically refer to a chromaticity prediction method. Here, the focus is on technical improvements to the cross-component prediction merge mode, mainly in the chromaticity intra-prediction mode, and more specifically, on improvements to the fusion mode of cross-component prediction derivation in the cross-component prediction merge mode, thereby improving the coding performance of the ECM.

[0063] Furthermore, it should be noted that in the embodiments of this application, the first syntactic identifier is used to indicate whether the current block uses cross-component predictive merge mode (CCMerge). In some embodiments, if the value of the first syntactic identifier is a first value, it is determined that the first syntactic identifier indicates that the current block does not use cross-component predictive merge mode, and if the value of the first syntactic identifier is a second value, it is determined that the first syntactic identifier indicates that the current block uses cross-component predictive merge mode. In the embodiments of this application, the first and second values ​​are different. Here, the first and second values ​​may be in parameter form or numerical form. Specifically, the first syntactic identifier here may be a parameter written in a profile or a flag value, and is not specifically limited herein.

[0064] Exemplary, the first syntactic identifier can be represented by cclmMrgFlag. The first value can be set to 0 and the second value to 1, or the first value can be set to false and the second value to true. If cclmMrgFlag is 0, it indicates that the current block does not use cross-component predictive merge mode. If cclmMrgFlag is 1, it indicates that the current block uses cross-component predictive merge mode.

[0065] In other words, in the embodiments of the present application, if the value of the first syntactic identifier is a first value, it can be determined that the current block does not use the cross-component predictive merge mode. In some embodiments, if the first syntactic identifier indicates that the current block does not use the cross-component predictive merge mode, for example, if the value of the first syntactic identifier is a first value, the cross-component predictive mode performs chromatic intra-prediction on the current block to determine the chromatic predictive value corresponding to the current block. The cross-component predictive mode in the embodiments of the present application may include at least one of the cross-component linear model predictive mode, MMLM mode, convolutional cross-component model mode, GLM mode, and chromatic fusion mode. Here, the cross-component linear model predictive mode includes at least one of the CCLM mode, CCLM-T mode, and CCLM-L mode, and the convolutional cross-component model mode includes at least one of the CCCM mode, CCCM-T mode, and CCCM-L mode. Specifically, the modes can be selected depending on the actual situation, and the embodiments of the present application are not limited.

[0066] In embodiments of the present invention, if the value of the first syntactic identifier is the second value, it can be determined that the current block is using cross-component predictive merge mode, and the decoder further analyzes the bitstream to determine the value of the second syntactic identifier.

[0067] In step S103, if the second syntactic identifier indicates that the current block uses a cross-component predictive merge fusion mode, the bitstream is parsed to determine at least one fusion type identifier corresponding to the current block.

[0068] In embodiments of the present application, the second syntactic identifier is used to indicate whether the current block uses the cross-component predictive merge fusion mode. In some embodiments, if the value of the second syntactic identifier is the third value, it is determined that the second syntactic identifier indicates that the current block does not use the cross-component predictive merge fusion mode, and if the value of the second syntactic identifier is the fourth value, it is determined that the second syntactic identifier indicates that the current block uses the cross-component predictive merge fusion mode. In embodiments of the present application, the third and fourth values ​​are different. The third and first values ​​may be the same or different, and the fourth and second values ​​may be the same or different. Here, the third and fourth values ​​may be in parameter form or numerical form. Specifically, the second syntactic identifier here may be a parameter written in a profile or a flag value, and is not specifically limited herein.

[0069] Exemplary, the second syntactic identifier can be represented by ccpMergeFusionFlag, where the third value can be set to 0 and the fourth value to 1, or the third value can be set to false and the fourth value to true. If ccpMergeFusionFlag is 0, it indicates that the block is not currently using cross-component predictive merge fusion mode. If cclmMrgFlag is 1, it indicates that the block is currently using cross-component predictive merge fusion mode.

[0070] In some embodiments, if the second syntactic identifier indicates that the current block does not use the cross-component predictive merge fusion mode, for example, if ccpMergeFusionFlag is 0, the decoder performs a chromatic intra-prediction for the current block using the cross-component predictive merge mode and determines the chromatic prediction value corresponding to the current block.

[0071] In other words, in the embodiments of the present application, if the first syntactic identifier indicates that the current block uses the cross-component predictive merge mode, and the second syntactic identifier indicates that the current block uses the cross-component predictive merge fusion mode, then it can be determined to perform chromaticity intra-prediction using the cross-component predictive merge fusion mode for the current block. The decoder further analyzes the bitstream to determine at least one fusion type identifier corresponding to the current block, where the index identifier indicates at least one chromaticity prediction mode for performing chromaticity intra-prediction for the current block and is used to weight-fuse the prediction results of the at least one chromaticity prediction mode with the prediction results of the cross-component predictive merge mode.

[0072] In step S104, at least one chromaticity prediction mode corresponding to the current block is determined based on at least one fusion type identification value.

[0073] In embodiments of the present invention, the decoder can define a predetermined correspondence between a fusion type identifier and a chromaticity prediction mode with respect to the encoder. Here, the predetermined correspondence between a fusion type identifier and a chromaticity prediction mode includes at least one predetermined fusion type identifier corresponding to at least one predetermined chromaticity prediction mode. In this way, the decoder can determine at least one chromaticity prediction mode corresponding to the current block in the predetermined correspondence based on at least one fusion type identifier.

[0074] For example, at least one predetermined chromaticity prediction mode can be identified by at least one predetermined fusion type identifier value in numerical form. The MM-CCCM mode and the Derived Mode (DM) mode are pre-set as at least one predetermined chromaticity prediction mode, and the predetermined fusion type identifier value corresponding to the MM-CCCM mode is set to 0, and the predetermined fusion type identifier value corresponding to the DM mode is set to 1. In this case, when the decoder analyzes the bitstream and obtains that at least one fusion type identifier value is 1, it determines the DM mode as at least one chromaticity prediction mode and performs fusion of the cross-component prediction merge mode and the prediction result.

[0075] In embodiments of the present application, at least one predetermined chromaticity mode may include a cross-component prediction mode and a non-cross-component prediction mode. In some embodiments, at least one predetermined chromaticity prediction mode includes at least one of the following: a cross-component linear model prediction mode, an MMLM mode, a convolutional cross-component model mode, a GLM mode, a DIMD mode, and a DM mode. Specifically, these can be selected depending on the actual situation, and embodiments of the present application are not limited.

[0076] In step S105, intrachromatic prediction is performed for the current block using at least one chromaticity prediction mode, and at least one first predicted value is determined.

[0077] In step S106, a chromaticity intra-prediction is performed on the current block using the cross-component prediction merge mode to determine the second predicted value.

[0078] In step S107, a chromaticity prediction value corresponding to the current block is determined based on at least one first prediction value and a second prediction value.

[0079] In the embodiment of the present application, the decoder performs chroma intra prediction on the current block by using each chroma prediction mode in the at least one chroma prediction mode, and determines a first prediction value corresponding to each chroma prediction mode, thereby determining at least one first prediction value. The decoder performs chroma intra prediction on the current block by using the CCMerge mode, and determines a second prediction value corresponding to the CCMerge mode. The decoder performs weighted fusion based on the at least one first prediction value and the second prediction value, and determines a chroma prediction value corresponding to the current block.

[0080] In some embodiments, the decoder performs weighted addition on the at least one first prediction value and the second prediction value based on at least two predetermined weights, determines a weighted addition value, determines a shift factor based on the at least two predetermined weights, shifts the weighted addition value based on the shift factor, and determines the chroma prediction value.

[0081] For illustration, taking one first prediction value and one second prediction value as an example, fusion can be realized by formula (5), which is as follows.

[0082] pred final =(w1*pred ccpMerge +w2*pred fusionMode )≫shift (5) Here, the at least one weight is w1 and w2, shift represents a shift factor, and the relationship w1+w2=2shift is satisfied. For illustration, w1 and w2 can be defaulted to 2, and in this case shift is 2. pred ccpMerge represents the second prediction value corresponding to the cross-component prediction merge mode, and pred fusionMode represents the first prediction value corresponding to the chroma prediction mode determined based on the fusion type identification value.

[0083] Furthermore, multiple chromaticity prediction modes can be determined based on multiple fusion type identification values. Similar to equation (5), weighted addition and shift processing can be performed on multiple second and first prediction values ​​corresponding to multiple chromaticity prediction modes using multiple weights to determine the chromaticity prediction value corresponding to the current block. In other words, the embodiment of the present application can realize the fusion of various chromaticity prediction modes.

[0084] Exemplary, the fusion type identifier may be at least one value corresponding to the fusion type flag in the bitstream. The fusion type flag may be ccpMergeFusionMode. At least one predetermined chromaticity prediction mode may include a first predetermined chromaticity prediction mode and a second predetermined chromaticity prediction mode. The predetermined fusion type identifier corresponding to the first predetermined chromaticity prediction mode is 0, and the predetermined fusion type identifier corresponding to the second predetermined chromaticity prediction mode is 1. If the value of the second syntactic identifier ccpMergeFusionFlag is 1, i.e., the second syntactic identifier indicates that a cross-component predictive merge fusion mode should be used for the current block, then the corresponding fusion scheme must be selected based on the value of ccpMergeFusionMode. If the value of ccpMergeFusionMode is 0, the first predetermined chromaticity prediction mode is selected to generate a first prediction value, which is then fused with the second prediction value of the CCMerge mode to generate the final chromaticity prediction value. If the value of ccpMergeFusionMode is 1, the second predetermined chromaticity prediction mode is selected to generate a first prediction value, which is then fused with the second prediction value of the CCMerge mode to generate the final chromaticity prediction value.

[0085] If the value of the second syntactic identifier ccpMergeFusionFlag is 0, it indicates that the cross-component predictive merge fusion mode is not used and that there is no need to decode the ccpMergeFusionMode flag.

[0086] In some possible embodiments, the first predetermined chromaticity prediction mode described above may be an MM-CCCM mode, and the second predetermined chromaticity prediction mode described above may be an MMLM mode. In this case, an example of how the embodiment of the present application acts on the cross-component prediction merge fusion mode is as follows.

[0087] If the decoder analyzes that the value of ccpMergeFusionFlag for the current block is 1, it determines at least one chromaticity prediction mode for fusing the CCMerge mode and prediction results based on the value of the flag ccpMergeFusionMode.

[0088] If the value of ccpMergeFusionMode is 0, the chromaticity prediction mode to be fused with the CCMerge mode is set to MM-CCCM. Intra-chromaticity prediction is performed according to the steps of the MM-CCCM mode to determine the first predicted value. The first predicted value and the second predicted value generated by the CCMerge mode are weighted and fused to obtain the chromaticity prediction value for the current block.

[0089] If the value of ccpMergeFusionMode is 1, the chromaticity prediction mode to be fused with the CCMerge mode is set to MMLM. An intra-chromaticity prediction is performed according to the steps of the MMLM mode to determine the first predicted value. The first predicted value and the second predicted value generated by the CCMerge mode are weighted and fused to obtain the chromaticity prediction value for the current block.

[0090] In some other possible embodiments, the first predetermined chromaticity prediction mode described above may be the MM-CCCM mode, and the second predetermined chromaticity prediction mode may be the DIMD mode. In this case, an example of how the embodiment of the present application acts on the cross-component prediction merge fusion mode is as follows.

[0091] If the decoder analyzes that the value of ccpMergeFusionFlag for the current block is 1, it determines at least one chromaticity prediction mode for fusing the CCMerge mode and prediction results based on the value of the flag ccpMergeFusionMode.

[0092] If the value of ccpMergeFusionMode is 0, the chromaticity prediction mode to be fused with the CCMerge mode is set to MM-CCCM. Intra-chromaticity prediction is performed according to the steps of the MM-CCCM mode to determine the first predicted value. The first predicted value and the second predicted value generated by the CCMerge mode are weighted and fused to obtain the chromaticity prediction value for the current block.

[0093] If the value of ccpMergeFusionMode is 1, the chromaticity prediction mode to be fused with the CCMerge mode is set to DIMD mode. Following the steps of DIMD mode, the corresponding intra-prediction angle mode is derived and used to generate the first prediction value. The first prediction value and the second prediction value generated by the CCMerge mode are weighted and fused to obtain the chromaticity prediction value for the current block.

[0094] To understand this, the decoder can determine the chromaticity prediction value for the current block by further analyzing the bitstream for at least one fusion type identifier corresponding to the current block, determining at least one chromaticity prediction mode corresponding to the current block based on at least one fusion type identifier, and further fusing at least one first prediction value obtained by predicting using at least one chromaticity prediction mode with a second prediction value obtained by predicting in the cross-component predictive merge mode. In other words, the decoder can flexibly select the fusion mode based on at least one fusion type identifier, and by providing a variety of choices for predicting the cross-component predictive merge mode, it is possible to improve the prediction accuracy of the cross-component predictive merge mode and further improve the decoding efficiency.

[0095] In some embodiments, as shown in Figure 12 based on Figure 11, steps S101 can be performed after step S101, before step S102, and further steps S201 to S203 can be performed as follows.

[0096] In step S201, if the first syntactic identification information indicates that the current block uses the cross-component predictive merge mode, then intrachromatic prediction is performed based on the template region of the current block, using the cross-component predictive merge mode and the cross-component predictive merge fusion mode, respectively, and a first cost value corresponding to the cross-component predictive merge mode and a second cost value corresponding to the cross-component predictive merge fusion mode are determined.

[0097] In embodiments of the present invention, if the first syntactic identifier indicates that the current block uses a cross-component predictive merge mode, a template region corresponding to the current block can be determined. Exemplarily, the template region can consist of T rows and T columns of pixels in a reconstructed region surrounding the current block (where T is an integer greater than or equal to 1, e.g., T is equal to 3). It can be understood that the template region includes the reconstructed block surrounding the current block. The decoder performs chromaticity intra-prediction in the template region based on the cross-component predictive merge mode and the cross-component predictive merge fusion mode, respectively.

[0098] In the embodiments of the present invention, the encoder makes predictions in the template region using a cross-component prediction merge mode and determines a first cost value corresponding to the cross-component prediction merge mode based on the predicted value corresponding to the cross-component prediction merge mode and the reconstructed value of the prediction block in the template region.

[0099] In the embodiments of the present invention, the process of performing intrachromatic prediction on a template region based on a cross-component prediction merge fusion mode involves a decoder that performs predictions based on the template region using at least one predetermined chromatic prediction mode, and obtains predicted values ​​corresponding to each predetermined chromatic prediction mode. The decoder fuses the predicted values ​​corresponding to each predetermined chromatic prediction mode with the predicted values ​​corresponding to the above-mentioned cross-component prediction merge mode, and obtains predicted values ​​corresponding to each fusion scheme. Here, each fusion scheme refers to a combination method of each predetermined chromatic prediction mode and the cross-component prediction merge mode. The decoder compares the predicted values ​​corresponding to each fusion scheme with the reconstructed values ​​of the prediction blocks in the template region and determines a second cost value corresponding to the cross-component prediction merge fusion mode.

[0100] In step S202, based on the first cost value and the second cost value, it is determined whether the current block uses the cross-component predictive merge fusion mode.

[0101] In embodiments of the present invention, the decoder determines whether the current block uses the cross-component predictive merge fusion mode based on a comparison of the magnitudes of a first cost value and a second cost value. Exemplarily, if the second cost value is smaller than the first cost value, the decoder decides that the current block uses the cross-component predictive merge fusion mode, explaining that the predictive effect of the cross-component predictive merge fusion mode is better. If the first cost value is smaller than the second cost value, the decoder decides that the current block does not use the cross-component predictive merge fusion mode, explaining that the predictive effect of the cross-component predictive merge fusion mode is better.

[0102] In step S203, if it is determined that the current block uses the cross-component predictive merge fusion mode, the bitstream is analyzed to determine at least one fusion type identifier corresponding to the current block.

[0103] In the embodiments of the present invention, if the decoder has determined that the current block uses the cross-component predictive merge fusion mode, it further analyzes the bitstream to determine at least one fusion type identifier, and then performs the method in steps S104 to S107 above to realize intra-chromaticity prediction in the cross-component predictive merge fusion mode according to the embodiments of the present invention.

[0104] Understandably, the embodiments of this application adaptively select whether or not to use the cross-component predictive merge fusion mode according to the template matching method, eliminating the need to transmit second syntactic identification information in the bitstream to determine whether or not to use the cross-component predictive merge fusion mode, thereby improving bitrate and coding / decoding efficiency.

[0105] In some embodiments, when the current block uses a cross-component predictive merge fusion mode, the decoder can determine at least one chromaticity prediction mode corresponding to the current block based on the chromaticity intra-prediction in the template region of the current block.

[0106] In embodiments of the present application, the decision that the current block uses the cross-component predictive merge fusion mode may include deciding that the current block uses the cross-component predictive merge fusion mode based on the indication of the second syntactic identification information in the bitstream, or deciding that the current block uses the cross-component predictive merge fusion mode according to the prediction method based on the template region in steps S201 to S202 above.

[0107] In some embodiments, for situations where the current block is determined to use a cross-component predictive merge fusion mode based on the indication of a second syntactic identification information in the bitstream, the decoder can determine a template region corresponding to the current block, make predictions on the template region using the cross-component predictive merge mode and at least one predetermined chromaticity prediction mode, and determine a cost value corresponding to each fusion scheme. This process is consistent with the process corresponding to steps S201-S202 and will not be repeated here. The decoder can determine at least one fusion scheme with a small cost value based on the cost value corresponding to each fusion scheme, and further determine at least one chromaticity prediction mode based on a predetermined chromaticity prediction mode in at least one fusion scheme.

[0108] In some embodiments, for situations in which the current block is determined to use a cross-component predictive merge fusion mode according to the prediction method based on the template region in steps S201 to S202 above, the decoder can directly utilize the cost values ​​corresponding to each fusion scheme already predicted to determine at least one fusion scheme with a smaller cost value, and further determine at least one chromaticity prediction mode based on a predetermined chromaticity prediction mode in at least one fusion scheme.

[0109] Understandably, the embodiments of the present invention adaptively select at least one chromaticity prediction mode according to a template matching method and fuse it with a cross-component prediction merge mode, eliminating the need to transmit a fusion type identifier in the bitstream to determine which chromaticity prediction mode to use for fusion with the cross-component prediction merge mode, thereby improving bitrate and coding / decoding efficiency.

[0110] In some embodiments, the decoder performs a chromaticity intra-prediction using a cross-component predictive merge mode for the current block, and the process of determining a second predicted value is as follows: This may include determining the index identifier of the current block and constructing a list of candidate parameters for the current block; determining the model parameters of the current block based on the list of candidate parameters and the index identifier; and determining a second predicted value based on the model parameters and the reconstructed luminance pixels corresponding to the current block.

[0111] In the embodiments of this application, the index identifier is used to specify the model parameter corresponding to the current block in the current block's parameter candidate list.

[0112] In some embodiments, if the first syntactic identifier indicates that the current block uses a cross-component predictive merge mode, the decoder can determine the index identifier of the current block by parsing the bitstream. Exemplarily, the index identifier may be cclmMrgIdx.

[0113] In some embodiments, the idxNonLocalCCP flag can also be used as the index identifier, where the value of idxNonLocalCCP is an integer between 0 and 12, with a minimum of 0 and a maximum of 12. If the value of idxNonLocalCCP is 0, the current block does not use the cross-component predictive merge mode; if the value of idxNonLocalCCP is not 0, the model parameters for the current block are obtained from a constructed list of candidate parameters based on the value of idxNonLocalCCP. Exemplarily, the model parameters may be ccmList[idxNonLocalCCP-1].

[0114] In the embodiments of this application, the process of constructing the parameter candidate list for the current block described above is: This may include determining the adjacent blocks of the current block, determining the model parameters of at least one block in the adjacent block if at least one block uses the cross-component prediction mode or the cross-component prediction merge mode to obtain at least one set of first candidate model parameters, and filling the parameter candidate list with at least one set of first candidate model parameters.

[0115] In the embodiments of this application, adjacent blocks may include blocks that are spatially adjacent to the current block, and / or blocks that are temporally adjacent to the current block. That is, adjacent blocks here can be spatially adjacent blocks or temporally adjacent blocks. Here, spatially adjacent blocks are located in the same frame as the current block, and temporally adjacent blocks are located in a different frame from the current block. Exemplaryly, in the case of interpretation, adjacent blocks may refer to temporally adjacent blocks located in the reference frame.

[0116] Furthermore, it should be noted that, taking spatial adjacency as an example, the positions of adjacent blocks to the current block may be as shown in Figure 6, the checking order can be B1→A1→B0→A0→B2, and at least one set of first candidate model parameters is determined according to this order.

[0117] Furthermore, if the parameter candidate list is not full after filling it with at least one set of first candidate model parameters, in some embodiments, constructing the parameter candidate list for the current block may further include determining the non-adjacent blocks of the current block, determining the model parameters for at least one of the blocks if at least one of the non-adjacent blocks uses a cross-component prediction mode or a cross-component prediction merge mode to obtain at least one set of second candidate model parameters, and then subsequently filling the parameter candidate list with at least one set of second candidate model parameters.

[0118] Furthermore, it should be noted that in the embodiments of this application, the number of candidates in the parameter candidate list is represented by NUM_LMC_MERGE_CANDS. By default, the value of NUM_LMC_MERGE_CANDS is set to 12. If the number of first candidate model parameters is less than 12, it indicates that the parameter candidate list is not full, and in this case, at least one set of second candidate model parameters must be determined based on the non-adjacent blocks of the current block, and then at least one set of second candidate model parameters must be subsequently filled into the parameter candidate list. Exemplarily, the positions of the spatially non-adjacent blocks of the current block may be as shown in Figure 7.

[0119] Furthermore, if the parameter candidate list is not full after filling it with at least one pair of second candidate model parameters, in some embodiments, constructing the parameter candidate list for the current block may further include determining at least one pair of third candidate model parameters from the historical parameter candidate list and subsequently filling the parameter candidate list with at least one pair of third candidate model parameters.

[0120] In the embodiments of this invention, the decoder maintains a history parameter candidate list, which includes recently used model parameters (ccmParam), and resets the table at the beginning of each CTU row. If the list is not currently full after including spatially adjacent and non-adjacent candidates, parameters based on ccmParam in the history parameter candidate list are added to the parameter candidate list.

[0121] Furthermore, if the parameter candidate list is not full after filling it with at least one set of second candidate model parameters, or after filling it with at least one set of third candidate model parameters, in some embodiments, constructing the parameter candidate list for the current block may further include determining at least one set of fourth candidate model parameters based on predetermined parameter information, and then subsequently filling the parameter candidate list with at least one set of fourth candidate model parameters.

[0122] In the embodiments of this application, the predetermined parameter information may include at least a predetermined value of the first model parameter, and the predetermined value of the first model parameter is at least one of 0, 1 / 8, -1 / 8, 2 / 8, -2 / 8, and 3 / 8.

[0123] Furthermore, it should be noted that in some embodiments, the model parameters of the current block may include a first model parameter and a second model parameter, where the first model parameter can be used to indicate the scaling parameter when the current block uses a cross-component prediction mode or a cross-component prediction merge mode, and the second model parameter can be used to indicate the offset parameter when the current block uses a cross-component prediction mode or a cross-component prediction merge mode.

[0124] In other words, after constructing a list of parameter candidates based on the adjacent and non-adjacent blocks of the current block, if the constructed list of parameter candidates is not full, a CCLM candidate with default scaling parameters can be considered. Here, the default scaling parameters may be {0, 1 / 8, -1 / 8, 2 / 8, -2 / 8, 3 / 8}. It should be noted that these default scaling parameters can be added to the list of parameter candidates in the order of 0, 1 / 8, -1 / 8, 2 / 8, -2 / 8, 3 / 8.

[0125] To further clarify, in embodiments of the present application, the cross-component prediction mode may include at least one of the cross-component linear model prediction mode, MMLM mode, convolutional cross-component model mode, GLM mode, and chromaticity fusion mode. Here, the cross-component linear model prediction mode includes at least one of the CCLM mode, CCLM-T mode, and CCLM-L mode, and the convolutional cross-component model mode includes at least one of the CCCM mode, CCCM-T mode, and CCCM-L mode. In other words, the inheritance mode here may be, but is not specifically limited to, any one of the cross-component linear model prediction mode, MMLM mode, convolutional cross-component model mode, GLM mode, chromaticity fusion mode, and CCMerge mode.

[0126] In some embodiments, determining the model parameters of the current block based on a list of candidate parameters and index identifiers may include determining a set of candidate model parameters corresponding to index identifiers in the list of candidate parameters, determining the inheritance mode of the current block and its corresponding candidate model parameters based on a set of candidate mode parameters, and determining the model parameters of the current block based on the inheritance mode of the current block and its candidate model parameters.

[0127] Furthermore, in some embodiments, the model parameters of the current block are determined based on the inheritance mode of the current block and the candidate model parameters. If the inheritance mode of the current block is the cross-component linear model prediction mode, then the first and second model parameters in the candidate model parameters are determined to be the model parameters of the current block; that is, it is determined that the current block inherits the first and second model parameters in the candidate model parameters, where the first model parameter is used to represent the scaling parameter of the cross-component prediction mode or the cross-component prediction merge mode (e.g., a in equation (1)), and the second model parameter is used to represent the offset parameter of the cross-component prediction mode or the cross-component prediction merge mode (e.g., b in equation (1)). If the current block's inheritance mode is MMLM mode, then the first model parameter and classification threshold within the candidate model parameters are determined to be the model parameters of the current block; that is, it is determined that the current block inherits the first model parameter and classification threshold within the candidate model parameters. If the current block's inheritance mode is CCCM mode, then the convolution parameters and classification thresholds within the candidate model parameters are determined to be the model parameters of the current block; that is, it is determined that the current block inherits the convolution parameters and classification thresholds within the candidate model parameters. If the current block's inheritance mode is GLM mode, and the GLM mode is a 3-parameter mode, then the gradient index value, the first model parameter, and the second model parameter within the candidate model parameters are determined to be the model parameters of the current block; or, if the GLM mode is a 2-parameter mode, then the first model parameter within the candidate model parameters is determined to be the model parameter of the current block; that is, if the GLM mode is a 3-parameter mode, then it is determined that the current block inherits the gradient index value, the first model parameter, and the second model parameter within the candidate model parameters; or, if the GLM mode is a 2-parameter mode, then it is determined that the current block inherits the first model parameter within the candidate model parameters. If the current block's inheritance mode is chromatic fusion mode, and the chromatic fusion mode is chromatic fusion derivation mode, then determine the prediction mode that the current block will inherit, and determine the current block's model parameters based on the prediction mode and candidate model parameters inherited by the current block; or, if the chromatic fusion mode is not chromatic fusion derivation mode, then determine that the current block will use MMLM mode, and determine that the current block will inherit the first model parameter and classification threshold within the candidate model parameters. If the current block's inheritance mode is CCMerge mode, this may include determining the prediction mode that the current block inherits, and determining the model parameters of the current block based on the prediction mode inherited by the current block and the candidate model parameters.

[0128] Specifically, in the embodiments of this application, a source of cross-component model parameters can be added, providing multiple options for the cross-component predictive merge mode. Hereinheritance rules may be as follows:

[0129] (1) When inheriting CCLM mode, the scaling parameter and offset parameter are inherited.

[0130] (2) When inheriting MMLM mode, the scaling parameters and classification thresholds are inherited.

[0131] (3) When inheriting CCCM mode, all convolution parameters and classification thresholds are inherited.

[0132] (4) When inheriting the GLM mode, if the GLM is in 3-parameter mode, all gradient indices and model parameters are inherited; otherwise, if the GLM is in 2-parameter mode, only the scaling parameters are inherited, and the offset parameters need to be recalculated.

[0133] (5) When inheriting the chromaticity fusion mode, the MMLM parameters derived in the cross-component prediction part are inherited as candidates.

[0134] (6) When inheriting a CCMerge mode, the inheritance method depends on the candidate mode it inherits.

[0135] To further clarify, in the embodiments of this application, the size and construction process of the parameter candidate list can be determined using a separate set of rules rather than sharing the rules of the cross-component prediction merge mode, and are not specifically limited thereto. Thus, after determining the model parameters of the current block based on the inheritance rules described above, the target predicted values ​​of the current block can be determined.

[0136] In another embodiment of the present application, with reference to Figure 13, an exemplary flowchart of the encoding method according to an embodiment of the present application is shown. As shown in Figure 13, the method may include the following steps:

[0137] In step S301, the value of the first syntactic identification information is determined.

[0138] The encoding method of the embodiment of this application is applied to an encoder. Furthermore, the encoding method may specifically refer to a chromaticity prediction method. Here, the invention focuses on technical improvements to the cross-component prediction merge mode in the chromaticity intra-prediction mode, and more specifically, on improvements to the fusion mode of cross-component prediction derivation in the cross-component prediction merge mode, thereby improving the encoding performance of the ECM.

[0139] Furthermore, it should be noted that in the embodiments of this application, the first syntactic identifier is used to indicate whether the current block is using the cross-component predictive merge mode. Also, different values ​​of the first syntactic identifier will result in different mode conditions indicated therein.

[0140] In some embodiments, if the value of the first syntactic identifier is a first value, it is determined that the first syntactic identifier is used to indicate that the current block does not use cross-component predictive merge mode, and if the value of the first syntactic identifier is a second value, it is determined that the first syntactic identifier is used to indicate that the current block uses cross-component predictive merge mode. In embodiments of the present application, the first and second values ​​are different. Here, the first and second values ​​may be in parameter form or numerical form. Specifically, the first syntactic identifier here may be a parameter written to a profile or a flag value, and is not specifically limited herein.

[0141] For example, the first syntactic identifier can be represented by cclmMrgFlag. The first value can be set to 0 and the second value to 1, or the first value can be set to false and the second value to true. When cclmMrgFlag is 0, it is used to indicate to the decoder that the current block does not use cross-component predictive merge mode. When cclmMrgFlag is 1, it is used to indicate to the decoder that the current block uses cross-component predictive merge mode.

[0142] In embodiments of the present invention, the encoder performs chromaticity intraprediction on the current block using a cross-component predictive merge mode and at least one cross-component predictive mode, respectively, and obtains a predicted value corresponding to the cross-component predictive merge mode and at least one predicted value corresponding to at least one cross-component predictive mode. The encoder can determine whether or not to use the cross-component predictive merge mode for the current block by comparing the predicted value corresponding to the cross-component predictive merge mode with at least one predicted value corresponding to at least one cross-component predictive mode, and further determine first syntactic identification information. Here, the cross-component predictive mode may include at least one of the cross-component linear model predictive mode, MMLM mode, convolutional cross-component model mode, GLM mode, and chromaticity fusion mode.

[0143] Furthermore, in some embodiments, the method may further include encoding the value of the first syntactic identifier and writing the resulting encoded bits to a bitstream.

[0144] In the embodiment of this invention, the encoding side writes the value of the first syntactic identifier to the bitstream, allowing the decoding side to directly determine the value of the first syntactic identifier by decoding the bitstream, and furthermore, to determine whether or not the current block uses cross-component predictive merge mode.

[0145] In some embodiments, the encoder determines, by comparing the coding costs between a cross-component predictive merge mode and at least one cross-component predictive mode, that the predictive value corresponding to the cross-component predictive mode with the smaller corresponding coding cost among the at least one cross-component predictive mode is the chromaticity predictive value corresponding to the current block when it is determined that the current block does not use a cross-component predictive merge mode.

[0146] In step S302, if the first syntactic identifier indicates that the current block uses the cross-component predictive merge mode, the value of the second syntactic identifier is determined.

[0147] In embodiments of the present invention, if the first syntactic identifier indicates that the current block uses the cross-component predictive merge mode, that is, if the encoder decides to use the cross-component predictive merge mode for the current block, the encoder further determines whether the current block uses the cross-component predictive merge fusion mode by comparing coding costs, and further determines the value of the second syntactic identifier.

[0148] In embodiments of the present application, the second syntactic identifier is used to indicate whether the current block uses the cross-component predictive merge fusion mode. In some embodiments, if the value of the second syntactic identifier is the third value, it is determined that the second syntactic identifier is used to indicate that the current block does not use the cross-component predictive merge fusion mode, and if the value of the second syntactic identifier is the fourth value, it is determined that the second syntactic identifier is used to indicate that the current block uses the cross-component predictive merge fusion mode. In embodiments of the present application, the third and fourth values ​​are different. The third and first values ​​may be the same or different, and the fourth and second values ​​may be the same or different. Here, the third and fourth values ​​may be in parameter form or numerical form. Specifically, the second syntactic identifier here may be a parameter written in a profile or a flag value, and is not specifically limited herein.

[0149] For example, the second syntactic identifier can be represented by ccpMergeFusionFlag, where the third value can be set to 0 and the fourth value to 1, or the third value can be set to false and the fourth value to true. When ccpMergeFusionFlag is 0, it is used to indicate to the decoder that the current block does not use cross-component predictive merge fusion mode. When cclmMrgFlag is 1, it is used to indicate to the decoder that the current block uses cross-component predictive merge fusion mode.

[0150] In the embodiments of the present invention, the encoder can determine whether to use the cross-component predictive merge mode for the current block by comparing the coding costs of the cross-component predictive merge mode and the cross-component predictive merge fusion mode, and further determine a second syntactic identifier.

[0151] Furthermore, in some embodiments, the method may further include encoding the value of the second syntactic identifier and writing the resulting encoded bits to a bitstream.

[0152] In some embodiments, if the encoder determines, through a comparison of encoding costs, that the current block does not use the cross-component predictive merge fusion mode, the encoder determines the predicted value obtained by performing chromaticity intra-prediction on the current block using the cross-component predictive merge mode as the chromaticity predicted value corresponding to the current block.

[0153] In step S303, if the second syntactic identification information indicates that the current block uses a cross-component predictive merge fusion mode, then at least one chromaticity prediction mode corresponding to the current block is determined, and at least one fusion type identification value corresponding to the at least one chromaticity prediction mode is determined.

[0154] In embodiments of the present invention, when second syntactic identifiers indicate that the current block uses the cross-component predictive merge fusion mode, the encoder determines to use the cross-component predictive merge fusion mode for the current block by comparing the coding costs of the cross-component predictive merge mode and the cross-component predictive merge fusion mode. Here, the process by which the encoder compares the coding costs of the cross-component predictive merge mode and the cross-component predictive merge fusion mode is as follows: This may include: performing intrachromatic prediction on the current block using a cross-component prediction merge mode and determining a predicted value corresponding to the cross-component prediction merge mode; performing intrachromatic prediction on the current block using at least one predetermined chromatic prediction mode and determining at least one predicted value corresponding to at least one predetermined chromatic prediction mode; merging each predicted value in the at least one predicted value with the predicted value corresponding to the cross-component prediction merge mode to obtain at least one fused predicted value; and determining at least one coding cost based on the at least one fused predicted value and the chromatic value of the current block.

[0155] Here, the encoder determines a first chromaticity prediction value corresponding to each predetermined chromaticity prediction mode in at least one predetermined chromaticity prediction mode, and determines an encoding cost corresponding to each predetermined chromaticity prediction mode based on the first chromaticity prediction value corresponding to each predetermined chromaticity prediction mode and the chromaticity value of the current block, thereby determining at least one encoding cost.

[0156] Here, since at least one coding cost is obtained by fusing each predicted value with the predicted value corresponding to the cross-component prediction merge mode, at least one coding cost corresponds to at least one predetermined chromaticity prediction mode. Based on at least one coding cost, the decoder can determine the coding cost corresponding to the cross-component prediction merge fusion mode. Exemplarily, the minimum of the at least one coding cost can be determined as the coding cost corresponding to the cross-component prediction merge fusion mode, and then the current block can be determined whether to use the cross-component prediction merge fusion mode by comparing the coding cost corresponding to the cross-component prediction merge fusion mode with the coding cost of the cross-component prediction merge mode.

[0157] In embodiments of the present invention, once the encoder has determined a cross-component predictive merge fusion mode, it can determine at least one chromaticity prediction mode from among at least one predetermined chromaticity prediction modes based on at least one coding cost already calculated. Exemplarily, at least one chromaticity prediction mode can be determined as the predetermined chromaticity prediction mode corresponding to the first n coding costs with the smallest coding cost, where n is an integer greater than or equal to 1.

[0158] In embodiments of the present invention, the encoder can determine at least one fusion type identifier corresponding to the current block in a predetermined correspondence between a fusion type identifier and a chromaticity prediction mode, based on at least one chromaticity prediction mode, where the predetermined correspondence between a fusion type identifier and a chromaticity prediction mode includes at least one predetermined fusion type identifier corresponding to at least one predetermined chromaticity prediction mode. In this way, the decoder can use at least one fusion type identifier to determine at least one first prediction value for chromaticity intra-prediction based on the cross-component prediction merge fusion mode of the current block.

[0159] In embodiments of the present application, at least one predetermined chromaticity mode may include a cross-component prediction mode and a non-cross-component prediction mode. In some embodiments, at least one predetermined chromaticity prediction mode includes at least one of the following: a cross-component linear model prediction mode, an MMLM mode, a convolutional cross-component model mode, a GLM mode, a DIMD mode, and a DM mode. Here, the cross-component linear model prediction mode includes at least one of the CCLM mode, a CCLM-T mode, and a CCLM-L mode, and the convolutional cross-component model mode includes at least one of the CCCM mode, a CCCM-T mode, and a CCCM-L mode. Specifically, the modes can be selected according to the actual situation, and embodiments of the present application are not limited.

[0160] In some embodiments, after step S303, the encoder further determines at least one first chromaticity prediction value corresponding to at least one chromaticity prediction mode based on the first chromaticity prediction value corresponding to each predetermined chromaticity prediction mode obtained in the coding cost comparison process, performs chromaticity intra prediction for the current block using the cross-component prediction merge mode to determine a second prediction value, and determines the chromaticity prediction value corresponding to the current block based on at least one first prediction value and the second prediction value, thereby completing the processing of the cross-component prediction merge fusion mode on the encoder side and obtaining the chromaticity prediction value corresponding to the current block. Furthermore, the encoder determines the residual corresponding to the current block based on the chromaticity prediction value corresponding to the current block and the chromaticity value of the current block, generates coding information corresponding to the current block based on the residual, first syntax identifier information, second syntax identifier information, and at least one fusion type identifier value, and writes it to the bitstream.

[0161] It can be understood that when the encoder decides to use the cross-component predictive merge mode in the current block, it further decides that the current block will use the cross-component predictive merge fusion mode, determines at least one chromaticity prediction mode to fuse with the cross-component predictive merge mode based on the coding cost, determines at least one fusion type identifier corresponding to the at least one chromaticity prediction mode and sends it to the decoder, thereby flexibly specifying the fusion mode on the decoding side based on the at least one fusion type identifier, providing a variety of choices for the cross-component predictive merge fusion mode, thereby improving the accuracy of intra-chromaticity prediction and further improving coding efficiency.

[0162] In some embodiments, if the first syntactic identifier indicates that the current block uses the cross-component predictive merge mode, then a chromaticity intra-prediction is performed based on the template region of the current block, based on the cross-component predictive merge mode and the cross-component predictive merge fusion mode, respectively, to determine a first cost value corresponding to the cross-component predictive merge mode and a second cost value corresponding to the cross-component predictive merge fusion mode, and based on the first and second cost values, it is determined whether or not the current block uses the cross-component predictive merge fusion mode, and if it is determined that the current block uses the cross-component predictive merge fusion mode, then at least one fusion type identifier corresponding to the current block is determined.

[0163] In the embodiments of the present invention, the encoder can further adaptively select whether or not to use the cross-component predictive merge fusion mode according to the template matching method, eliminating the need to transmit a second syntactic identification information in the bitstream to determine whether or not to use the cross-component predictive merge fusion mode, thereby improving bitrate and coding efficiency. This process is consistent with the description of the processes in steps S201 to S203 in the decoder and will not be repeated here.

[0164] In some embodiments, when the current block uses a cross-component predictive merge fusion mode, at least one fusion type identifier corresponding to the current block is determined based on chromaticity intra-prediction in the template region of the current block.

[0165] In embodiments of the present invention, the encoder can further adaptively select at least one chromaticity prediction mode according to a template matching method and merge it with a cross-component prediction merge mode, eliminating the need to transmit a merge type identifier in the bitstream to determine which chromaticity prediction mode to use for merging with the cross-component prediction merge mode, thereby improving bitrate and coding efficiency. The process is consistent with the description of the same process in the decoder and will not be repeated here.

[0166] In short, the embodiments of the present application primarily provide a novel fusion scheme for the cross-component predictive merge fusion mode, in which at least one chromaticity prediction mode for fusion with the cross-component predictive merge fusion mode can be specified by at least one fusion type identifier, thereby providing a variety of choices for the fusion scheme and improving the efficiency of coding-decoding intra-prediction. Exemplarily, Table 1 shows the test results of the embodiments of the present application. As can be seen from this, the embodiments of the present application can improve coding-decoding efficiency and further improve coding-decoding performance.

[0167] [Table 1]

[0168] In the embodiments of this application, the specific implementation of the embodiments described above has been explained in detail through the embodiments described above. As can be seen therefrom, the technical solution in the embodiments described above allows for flexible selection of the chromaticity prediction mode that can be used for fusion via at least one fusion type identifier for the cross-component prediction merge fusion mode, providing a variety of options for the cross-component prediction merge fusion mode, thereby improving the accuracy of intra-chromaticity prediction and further improving the coding and decoding efficiency.

[0169] In another embodiment of the present application, based on the same inventive concept as the above embodiment, a schematic diagram illustrating the configuration of an encoder according to an embodiment of the present application is shown with reference to Figure 14. As shown in Figure 14, the encoder 130 may include a first determination unit 1301.

[0170] The first determination unit 1301 is configured to determine the value of the first syntax identifier, and if the first syntax identifier indicates that the current block uses the cross-component predictive merge mode, it determines the value of the second syntax identifier. The first determination unit 1301 is further configured to determine at least one chromaticity prediction mode corresponding to the current block and at least one fusion type identifier corresponding to the at least one chromaticity prediction mode if the second syntax identification information indicates that the current block uses a cross-component predictive merge fusion mode, the at least one fusion type identifier is used by the decoder to determine at least one first prediction value in the chromaticity intra prediction based on the cross-component predictive merge fusion mode of the current block.

[0171] In some embodiments, the first determination unit 1301 is further configured to determine at least one coding cost corresponding to the at least one predetermined chromaticity prediction mode, and to determine the at least one chromaticity prediction mode from among the at least one predetermined chromaticity prediction modes based on the at least one coding cost.

[0172] In some embodiments, the at least one predetermined chromaticity prediction mode includes at least one of the following: cross-component linear model prediction mode, MMLM mode, convolutional cross-component model mode, GLM mode, DIMD mode, and DM mode.

[0173] In some embodiments, the first determination unit 1301 is further configured to determine, based on the at least one chromaticity prediction mode, at least one fusion type identification value corresponding to the current block in a predetermined correspondence between fusion type identification values ​​and chromaticity prediction modes, wherein the predetermined correspondence includes at least one predetermined fusion type identification value corresponding to at least one predetermined chromaticity prediction mode.

[0174] In some embodiments, the first determination unit 1301 is configured to further determine a first chromaticity prediction value corresponding to each of the at least one predetermined chromaticity prediction modes, and to determine an encoding cost corresponding to each of the predetermined chromaticity prediction modes based on the first chromaticity prediction value corresponding to each of the predetermined chromaticity prediction modes and the chromaticity value of the current block, thereby determining the at least one encoding cost.

[0175] In some embodiments, referring to Figure 14, the encoder 130 may further include a first prediction unit 1303.

[0176] The first prediction unit 1303 is configured to determine at least one first chromaticity prediction value corresponding to at least one chromaticity prediction mode based on the first chromaticity prediction value corresponding to each predetermined chromaticity prediction mode, perform intra-chromaticity prediction for the current block using the cross-component prediction merge mode to determine a second prediction value, and determine a chromaticity prediction value corresponding to the current block based on the at least one first prediction value and the second prediction value.

[0177] In some embodiments, the first prediction unit 1303 is further configured to perform weighted addition on the at least one first prediction value and the second prediction value based on at least two predetermined weights to determine a weighted addition value, determine a shift factor based on the at least two predetermined weights, perform a shift on the weighted addition value based on the shift factor to determine the chromaticity prediction value.

[0178] In some embodiments, the first prediction unit 1303 is further configured to perform a chromaticity intra-prediction based on the template region of the current block, based on the cross-component prediction merge mode and the cross-component prediction merge fusion mode, respectively, if the first syntax identification information indicates that the current block uses the cross-component prediction merge mode, to determine a first cost value corresponding to the cross-component prediction merge mode and a second cost value corresponding to the cross-component prediction merge fusion mode, to determine whether the current block uses the cross-component prediction merge fusion mode based on the first cost value and the second cost value, and to determine at least one fusion type identification value corresponding to the current block if it is determined that the current block uses the cross-component prediction merge fusion mode.

[0179] In some embodiments, the first prediction unit 1303 is further configured to determine at least one fusion type identifier corresponding to the current block based on chromaticity intra-prediction in the template region of the current block, when the current block uses a cross-component prediction merge fusion mode.

[0180] In some embodiments, the first prediction unit 1303 is further configured to determine, if it is determined that the current block does not use the cross-component prediction merge mode, the predicted value obtained by performing a chromaticity intra-prediction on the current block using the cross-component prediction mode as the chromaticity predicted value corresponding to the current block.

[0181] In some embodiments, the first prediction unit 1303 is further configured to determine, if it is determined that the current block does not use the cross-component prediction merge fusion mode, the predicted value obtained by performing chromaticity intra prediction on the current block using the cross-component prediction merge mode as the chromaticity predicted value corresponding to the current block.

[0182] In some embodiments, referring to Figure 14, the encoder 130 may further include an encoding unit 1302.

[0183] The encoding unit 1302 is configured to determine the residual corresponding to the current block based on the chromaticity prediction value and the chromaticity value of the current block, and to generate a bitstream based on the residual, the first syntax identification information, the second syntax identification information, and the at least one fusion type identification value.

[0184] The description of the above-described embodiment of the apparatus is similar to the description of the above-described embodiment of the method, and has similar advantageous effects. Technical details not disclosed in the embodiment of the apparatus of the present invention should be understood by referring to the description of the embodiment of the method of the present invention.

[0185] In the embodiments of this application, "part" may refer to a part of a circuit, a part of a processor, a part of a program or software, and may be a module or a non-modular component. Furthermore, each component in these embodiments may be integrated into a single processing unit, each unit may be a separate, independent physical unit, or two or more units may be integrated into a single unit. The integrated unit may be implemented in hardware form or in the form of a software functional module.

[0186] If the integrated unit is implemented in the form of a software function module rather than being sold or used as an independent product, it can be stored on a single computer-readable storage medium. Based on this understanding, an essential part of the technical solution of this embodiment, i.e., a part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a computer software product, which is stored on a single storage medium and contains several instructions for causing a single computer device (which may be a personal computer, server, or network device, etc.) or processor to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage mediums include a variety of media capable of storing program code, such as U disks, mobile hard disks, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0187] Accordingly, the embodiments of the present application provide a storage medium (i.e., a computer-readable storage medium) to be applied to the encoder 130, the computer-readable storage medium storing a computer program for implementing the encoding method described in any one of the above embodiments when executed by the first processor.

[0188] Referring to Figure 15, based on the above-described encoder 130 configuration and computer-readable storage medium, a schematic diagram of the specific hardware structure of the encoder 130 according to an embodiment of the present application is shown. As shown in Figure 15, the encoder 130 may comprise a first communication interface 1401, a first memory 1402, and a first processor 1403, each component being coupled to one another by a first bus system 1404. To make it clear, the first bus system 1404 is configured to enable connection communication between these components. In addition to the data bus, the first bus system 1404 also includes a power bus, a control bus, and a status signal bus. However, for clarity of explanation, in Figure 15, the various buses are denoted as the first bus system 1404.

[0189] The first communication interface 1401 is configured to send and receive signals in the process of sending and receiving information with an external network element.

[0190] The first memory 1402 is configured to store a computer program that can be executed by the first processor 1403.

[0191] The first processor 1403 is configured to execute the following process by running the computer program, and the process is as follows: Determining the value of the first syntactic identifier, If the first syntactic identifier indicates that the current block uses cross-component predictive merge mode, then the value of the second syntactic identifier is determined. If the second syntactic identification information indicates that the current block uses a cross-component predictive merge fusion mode, the decoder determines at least one chromaticity prediction mode corresponding to the current block and determines at least one fusion type identification value corresponding to the at least one chromaticity prediction mode, wherein the at least one fusion type identification value is used by the decoder to determine at least one first prediction value in chromaticity intra-prediction based on the cross-component predictive merge fusion mode of the current block.

[0192] It should be understood that the first memory 1402 in the embodiments of this application may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. Here, non-volatile memory may be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory may be random access memory (RAM) used as an external cache. To the extent that this is not an exhaustive description, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linkage dynamic random access memory (SLDRAM), and direct Rambus random access memory (DRRAM). The first memory 1402 in the systems and methods described herein includes, but is not limited to, these and any other suitable types of memory.

[0193] The first processor 1403 may be an integrated circuit chip with signal processing capabilities. In implementation, each step of the above method can be performed by a hardware-type integrated logic circuit or a software-type instruction in the first processor 1403. The first processor 1403 may be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gates, or transistor logic devices, discrete hardware components, etc., which can implement or execute each method, step and logic block diagram disclosed in the embodiments of this application. The general-purpose processor may be a microprocessor, or the processor may be any conventional processor, etc. The steps of the method disclosed in the embodiments of this application may be performed directly by a hardware encoding processor, or by a combination of hardware and software modules within the encoding processor. The software module can be located in a conventional storage medium such as random access memory, flash memory, read-only memory, programmable read-only memory, or electrically erasable programmable memory, or registers. The storage medium is located in the first memory 1402, and the first processor 1403 reads the information in the first memory 1402 and performs the steps of the method described above in combination with its hardware.

[0194] To ensure understanding, these embodiments described herein can be implemented in hardware, software, firmware, middleware, microcode, or a combination thereof. Regarding hardware implementations, the processing unit can be one or more application-specific integrated circuits (ASICs), digital signal processing (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), general-purpose processors, controllers, microcontrollers, microprocessors, other electronic units configured to perform the functions described herein, or a combination thereof. Regarding software implementations, the technology described herein can be implemented by modules (processes, functions, etc.) that perform the functions described herein. The software code can be stored in memory and executed by a processor. The memory may be implemented within or outside the processor.

[0195] Exemplary, in another embodiment, the first processor 1403 is further configured to execute the encoding method in any of the above embodiments by executing the computer program.

[0196] In another embodiment of the present application, based on the same inventive concept as the above embodiment, a schematic diagram illustrating the configuration of a decoder according to the embodiment of the present application is shown with reference to Figure 16. As shown in Figure 16, the decoder 150 may include an analysis unit 1501, a second determination unit 1502, and a second prediction unit 1503.

[0197] The analysis unit 1501 is configured to analyze the bitstream, determine the value of a first syntax identifier, and if the first syntax identifier indicates that the current block uses a cross-component predictive merge mode, analyze the bitstream and determine the value of a second syntax identifier, and if the second syntax identifier indicates that the current block uses a cross-component predictive merge fusion mode, analyze the bitstream and determine at least one fusion type identifier corresponding to the current block.

[0198] The second determination unit 1502 is configured to determine at least one chromaticity prediction mode corresponding to the current block based on the at least one fusion type identification value.

[0199] The second prediction unit 1503 is configured to perform an intrachromatic prediction for the current block using the at least one chromaticity prediction mode and determine at least one first predicted value, perform an intrachromatic prediction for the current block using the cross-component prediction merge mode and determine a second predicted value, and determine a chromaticity prediction value corresponding to the current block based on the at least one first predicted value and the second predicted value.

[0200] In some embodiments, the second determination unit 1502 is further configured to determine, based on the at least one fusion type identification value, at least one chromaticity prediction mode corresponding to the current block in a predetermined correspondence between the fusion type identification value and the chromaticity prediction mode, wherein the predetermined correspondence includes at least one predetermined fusion type identification value corresponding to at least one predetermined chromaticity prediction mode.

[0201] In some embodiments, the at least one predetermined chromaticity prediction mode includes at least one of the following: cross-component linear model prediction mode, MMLM mode, convolutional cross-component model mode, GLM mode, DIMD mode, and DM mode.

[0202] In some embodiments, the second prediction unit 1503 is further configured to perform a chromaticity intra-prediction on the current block using the cross-component prediction mode and determine a chromaticity prediction value corresponding to the current block if the first syntax identification information indicates that the current block does not use the cross-component prediction merge mode.

[0203] In some embodiments, the second prediction unit 1503 is further configured to perform a chromaticity intra-prediction on the current block using the cross-component prediction merge mode and determine a chromaticity prediction value corresponding to the current block, if the second syntax identification information indicates that the current block does not use the cross-component prediction merge mode.

[0204] In some embodiments, the second prediction unit 1503 is further configured to perform weighted addition on the at least one first prediction value and the second prediction value based on at least two predetermined weights to determine a weighted addition value, determine a shift factor based on the at least two predetermined weights, perform a shift on the weighted addition value based on the shift factor to determine the chromaticity prediction value.

[0205] In some embodiments, the second determination unit 1502 is further configured to perform a chromaticity intra prediction based on the template region of the current block, based on the cross-component predictive merge mode and the cross-component predictive merge fusion mode, respectively, if the first syntactic identification information indicates that the current block uses the cross-component predictive merge mode, determine a first cost value corresponding to the cross-component predictive merge mode and a second cost value corresponding to the cross-component predictive merge fusion mode, determine whether the current block uses the cross-component predictive merge fusion mode based on the first cost value and the second cost value, and if it is determined that the current block uses the cross-component predictive merge fusion mode, analyze the bitstream and determine at least one fusion type identification value corresponding to the current block.

[0206] In some embodiments, the second determination unit 1502 is further configured to determine at least one chromaticity prediction mode corresponding to the current block, based on chromaticity intra-prediction in the template region of the current block, when the current block uses a cross-component predictive merge fusion mode.

[0207] The description of the above-described embodiment of the apparatus is similar to the description of the above-described embodiment of the method, and has similar advantageous effects. Technical details not disclosed in the embodiment of the apparatus of the present invention should be understood by referring to the description of the embodiment of the method of the present invention.

[0208] In this embodiment, "part" may refer to a part of a circuit, a part of a processor, a part of a program or software, and may be a module or a non-modular component. Furthermore, each component in this embodiment may be integrated into a single processing unit, each unit may be a separate, independent physical unit, or two or more units may be integrated into a single unit. The integrated unit may be implemented in hardware form or in the form of a software functional module.

[0209] If the integrated unit is implemented in the form of a software function module rather than being sold or used as an independent product, it can be stored in a single computer-readable storage medium. Based on this understanding, this embodiment provides a storage medium (i.e., a computer-readable storage medium) to be applied to the decoder 150, which stores a computer program for implementing the decoding method described in any one of the above embodiments when executed by a second processor.

[0210] Based on the above configuration of the decoder 150 and the computer-readable storage medium, Figure 17 shows a schematic diagram of the specific hardware structure of the decoder 150 according to an embodiment of the present invention. As shown in Figure 17, the decoder 150 may comprise a second communication interface 1601, a second memory 1602, and a second processor 1603, each component being coupled to one another by a second bus system 1604. To make it clear, the second bus system 1604 is configured to enable connection communication between these components. In addition to the data bus, the second bus system 1604 also includes a power bus, a control bus, and a status signal bus. However, for clarity of explanation, the various buses are labeled as the second bus system 1604 in Figure 17.

[0211] The second communication interface 1601 is configured to send and receive signals in the process of sending and receiving information with other external network elements.

[0212] The second memory 1602 is configured to store computer programs that can be executed by the second processor 1603.

[0213] The second processor 1603 is configured to execute the following process by running the computer program, and the process is as follows: The bitstream is analyzed to determine the value of the first syntactic identifier, If the first syntactic identifier indicates that the current block uses cross-component predictive merge mode, the bitstream is parsed and the value of the second syntactic identifier is determined. If the second syntactic identification information indicates that the current block uses a cross-component predictive merge fusion mode, the bitstream is analyzed to determine at least one fusion type identification value corresponding to the current block. Based on the at least one fusion type identification value, determine at least one chromaticity prediction mode corresponding to the current block, Using the aforementioned at least one chromaticity prediction mode, intrachromatic prediction is performed for the current block, and at least one first predicted value is determined. Using the cross-component prediction merge mode, intra-chromaticity prediction is performed on the current block to determine the second predicted value, The method includes determining a chromaticity prediction value corresponding to the current block based on the at least one first prediction value and the second prediction value.

[0214] Exemplary, in another embodiment, the second processor 1603 is further configured to execute the decoding method in any of the above embodiments by executing the computer program.

[0215] It can be understood that the second memory 1602 has similar hardware functionality to the first memory 1402, and the second processor 1603 has similar hardware functionality to the first processor 1403, and therefore, a detailed explanation will not be repeated here.

[0216] In another embodiment of the present application, with reference to Figure 18, an exemplary structural diagram of the configuration of the coding-decoding system according to an embodiment of the present application is shown. As shown in Figure 18, the coding-decoding system 170 may comprise an encoder 1701 and a decoder 1702.

[0217] In the embodiments of the present application, the encoder 1701 may be an encoder described in any one of the above embodiments, and the decoder 1702 may be a decoder described in any one of the above embodiments.

[0218] In the embodiments of this application, the terms “equipment,” “includes,” or any other variation thereof are intended to be non-exclusive, meaning that a process, method, article, or apparatus comprising a set of elements includes not only those elements but also other elements not expressly enumerated, as well as elements inherent to that process, method, article, or apparatus. Unless otherwise specified, an element limited by the expression “includes one…” does not preclude the presence of other similar elements in a process, method, part, or apparatus comprising that element.

[0219] The numbering of the embodiments in the present application above does not indicate any ranking of the embodiments, but is merely for the convenience of explanation.

[0220] The methods disclosed in some embodiments of the methods provided herein can be arbitrarily combined without conflict to obtain new embodiments of the methods.

[0221] The features disclosed in the examples of some of the products provided in this application can be arbitrarily combined without conflict to obtain new examples of products.

[0222] The features disclosed in some of the examples of methods or apparatus provided herein can be arbitrarily combined without conflict to obtain new examples of methods or apparatus.

[0223] The above describes only specific embodiments of the present application, and the scope of protection of this application is not limited thereto. All modifications or substitutions that a person skilled in the art could easily conceive of within the technical scope disclosed herein should be included within the scope of protection of this application. Accordingly, the scope of protection of this application shall be subject to the scope of protection of the claims. [Industrial applicability]

[0224] In the embodiments of the present invention, the decoding side can determine that the current block uses the cross-component predictive merge fusion mode when the current block uses the cross-component predictive merge fusion mode, analyze at least one fusion type identifier corresponding to the current block transmitted from the encoding side to the bitstream, determine at least one chromaticity prediction mode corresponding to the current block based on at least one fusion type identifier, and further determine the chromaticity prediction value corresponding to the current block by fusing at least one first prediction value obtained by prediction using at least one chromaticity prediction mode with a second prediction value obtained by prediction in the cross-component predictive merge mode. In other words, the decoding side can flexibly select the fusion mode based on at least one fusion type identifier, and by providing a variety of options for the cross-component predictive merge fusion mode, the prediction accuracy of the chromaticity fusion mode can be improved, and the decoding efficiency can be improved.

Claims

1. A decoding method applied to a decoder, The bitstream is analyzed to determine the value of the first syntactic identifier, If the first syntactic identifier indicates that the current block uses cross-component predictive merge mode, the bitstream is parsed and the value of the second syntactic identifier is determined. If the second syntactic identification information indicates that the current block uses a cross-component predictive merge fusion mode, the bitstream is analyzed to determine at least one fusion type identification value corresponding to the current block. Based on the at least one fusion type identification value, determine at least one chromaticity prediction mode corresponding to the current block, Using the aforementioned at least one chromaticity prediction mode, intrachromatic prediction is performed for the current block, and at least one first predicted value is determined. Using the cross-component prediction merge mode, intra-chromaticity prediction is performed on the current block to determine the second predicted value. A decoding method comprising determining a chromaticity prediction value corresponding to the current block based on the at least one first prediction value and the second prediction value.

2. Determining at least one chromaticity prediction mode corresponding to the current block based on the at least one fusion type identification value is: The process includes determining at least one chromaticity prediction mode corresponding to the current block in a predetermined correspondence between the fusion type identification value and the chromaticity prediction mode, where the predetermined correspondence includes at least one predetermined fusion type identification value corresponding to at least one predetermined chromaticity prediction mode. The decoding method according to claim 1.

3. The at least one predetermined chromaticity prediction mode includes at least one of the following: cross-component linear model prediction mode, MMLM mode, convolutional cross-component model mode, GLM mode, DIMD mode, and DM mode. The decoding method according to claim 2.

4. The aforementioned decoding method is If the first syntactic identification information indicates that the current block does not use the cross-component prediction merge mode, the cross-component prediction mode is used to perform a chromaticity intra prediction on the current block and to determine the chromaticity prediction value corresponding to the current block. The decoding method according to any one of claims 1 to 3.

5. The aforementioned decoding method is If the second syntactic identification information indicates that the current block does not use the cross-component predictive merge fusion mode, the cross-component predictive merge mode is used to perform chromaticity intra prediction on the current block and to determine the chromaticity prediction value corresponding to the current block. The decoding method according to any one of claims 1 to 3.

6. Determining the chromaticity prediction value corresponding to the current block based on the at least one first prediction value and the second prediction value is: Based on at least two predetermined weights, a weighted sum is applied to the at least one first predicted value and the second predicted value to determine the weighted sum. The process includes determining a shift factor based on at least two predetermined weights, performing a shift on the weighted sum based on the shift factor, and determining the chromaticity prediction value. The decoding method according to any one of claims 1 to 3.

7. The aforementioned decoding method is If the first syntactic identification information indicates that the current block uses the cross-component predictive merge mode, then, based on the template region of the current block, intra-chromaticity prediction is performed based on the cross-component predictive merge mode and the cross-component predictive merge fusion mode, respectively, and a first cost value corresponding to the cross-component predictive merge mode and a second cost value corresponding to the cross-component predictive merge fusion mode are determined. Based on the first cost value and the second cost value, it is determined whether the current block uses the cross-component predictive merge fusion mode, If it is determined that the current block uses the cross-component predictive merge fusion mode, the bitstream is further analyzed to determine at least one fusion type identifier corresponding to the current block. The decoding method according to claim 1.

8. The aforementioned decoding method is If the current block uses a cross-component predictive merge fusion mode, the further includes determining at least one chromaticity prediction mode corresponding to the current block based on chromaticity intra-prediction in the template region of the current block. The decoding method according to claim 1 or 7.

9. An encoding method applied to an encoder, The first is to determine the value of the syntactic identification information, If the first syntactic identifier indicates that the current block uses cross-component predictive merge mode, then the value of the second syntactic identifier is determined. An encoding method comprising: determining at least one chromaticity prediction mode corresponding to the current block if the second syntactic identification information indicates that the current block uses a cross-component predictive merge fusion mode; determining at least one fusion type identifier value corresponding to the at least one chromaticity prediction mode, wherein the at least one fusion type identifier value is used by the decoder to determine at least one first prediction value in chromaticity intra prediction based on the cross-component predictive merge fusion mode of the current block.

10. Determining at least one chromaticity prediction mode corresponding to the current block is: Determining at least one encoding cost corresponding to the at least one predetermined chromaticity prediction mode, This includes determining the at least one chromaticity prediction mode from among the at least one predetermined chromaticity prediction modes based on the at least one encoding cost, The encoding method according to claim 9.

11. The at least one predetermined chromaticity prediction mode includes at least one of the following: cross-component linear model prediction mode, MMLM mode, convolutional cross-component model mode, GLM mode, DIMD mode, and DM mode. The encoding method according to claim 9 or 10.

12. Determining at least one fusion type identification value corresponding to the at least one chromaticity prediction mode is: The process includes determining at least one fusion type identifier corresponding to the current block in a predetermined correspondence between a fusion type identifier and a chromaticity prediction mode, based on the at least one chromaticity prediction mode, wherein the predetermined correspondence includes at least one predetermined fusion type identifier corresponding to at least one predetermined chromaticity prediction mode. The encoding method according to claim 11.

13. Determining at least one coding cost corresponding to the at least one predetermined chromaticity prediction mode is: Determining a first chromaticity prediction value corresponding to each predetermined chromaticity prediction mode in the at least one predetermined chromaticity prediction mode, The process includes determining the coding cost corresponding to each predetermined chromaticity prediction mode based on the first chromaticity prediction value corresponding to each predetermined chromaticity prediction mode and the chromaticity value of the current block, thereby determining the at least one coding cost, The encoding method according to claim 10.

14. The aforementioned encoding method is Based on the first chromaticity prediction values ​​corresponding to each of the predetermined chromaticity prediction modes, at least one first chromaticity prediction value corresponding to at least one of the chromaticity prediction modes is determined. Using the cross-component prediction merge mode, intra-chromaticity prediction is performed on the current block to determine the second predicted value. The process includes determining a chromaticity prediction value corresponding to the current block based on the at least one first prediction value and the second prediction value, The encoding method according to claim 13.

15. Determining the chromaticity prediction value corresponding to the current block based on the at least one first prediction value and the second prediction value is: Based on at least two predetermined weights, a weighted sum is applied to the at least one first predicted value and the second predicted value to determine the weighted sum. The process includes determining a shift factor based on at least two predetermined weights, performing a shift on the weighted sum based on the shift factor, and determining the chromaticity prediction value. The encoding method according to claim 14.

16. The aforementioned encoding method is If the first syntactic identification information indicates that the current block uses the cross-component predictive merge mode, then, based on the template region of the current block, intra-chromaticity prediction is performed based on the cross-component predictive merge mode and the cross-component predictive merge fusion mode, respectively, and a first cost value corresponding to the cross-component predictive merge mode and a second cost value corresponding to the cross-component predictive merge fusion mode are determined. Based on the first cost value and the second cost value, it is determined whether the current block uses the cross-component predictive merge fusion mode, If it is determined that the current block uses the cross-component predictive merge fusion mode, further comprising determining at least one fusion type identifier corresponding to the current block, The encoding method according to claim 9.

17. The aforementioned encoding method is If the current block uses a cross-component predictive merge fusion mode, the further includes determining at least one fusion type identifier corresponding to the current block based on chromaticity intra-prediction in the template region of the current block. The encoding method according to claim 9 or 16.

18. The aforementioned encoding method is If it is determined that the current block does not use the cross-component prediction merge mode, the predicted value obtained by performing a chromaticity intra-prediction on the current block using the cross-component prediction mode is further determined as the chromaticity predicted value corresponding to the current block. The encoding method according to claim 9.

19. The aforementioned encoding method is If it is determined that the current block does not use the cross-component predictive merge fusion mode, the predicted value obtained by performing chromaticity intra-prediction on the current block using the cross-component predictive merge mode is further determined as the chromaticity predicted value corresponding to the current block. The encoding method according to claim 9.

20. The aforementioned encoding method is Based on the predicted chromaticity value and the chromaticity value of the current block, the residual corresponding to the current block is determined. The further includes generating a bitstream based on the residual, the first syntactic identification information, the second syntactic identification information, and the at least one fusion type identification value, The encoding method according to any one of claims 9, 10, 12 to 16.

21. It is an encoder, The system includes a first determination unit configured to determine the value of a first syntactic identification information, and to determine the value of a second syntactic identification information if the first syntactic identification information indicates that the current block uses a cross-component predictive merge mode. The first determination unit is further configured to determine at least one chromaticity prediction mode corresponding to the current block and to determine at least one fusion type identifier corresponding to the at least one chromaticity prediction mode, wherein the second syntax identifier indicates that the current block uses a cross-component predictive merge fusion mode, and the encoder is configured to determine at least one first predictive value in chromaticity intra prediction based on the cross-component predictive merge fusion mode of the current block.

22. It is a decoder, An analysis unit is configured to analyze a bitstream, determine the value of a first syntactic identifier, and if the first syntactic identifier indicates that the current block uses a cross-component predictive merge mode, analyze the bitstream and determine the value of a second syntactic identifier, and if the second syntactic identifier indicates that the current block uses a cross-component predictive merge fusion mode, analyze the bitstream and determine at least one fusion type identifier corresponding to the current block. A second determination unit is configured to determine at least one chromaticity prediction mode corresponding to the current block based on the at least one fusion type identification value, A decoder comprising: a second prediction unit configured to perform intrachromatic prediction on the current block using the at least one chromaticity prediction mode and determine at least one first predicted value; perform intrachromatic prediction on the current block using a cross-component prediction merge mode and determine a second predicted value; and determine a chromaticity predicted value corresponding to the current block based on the at least one first predicted value and the second predicted value.

23. An encoder comprising a first memory and a first processor, The first memory is configured to store a computer program that can be executed by the first processor. The first processor is configured to execute the encoding method described in any one of claims 9 to 20 by executing the computer program, wherein the first processor is an encoder.

24. A decoder comprising a second memory and a second processor, The second memory is configured to store a computer program that can be executed by the second processor. A decoder wherein the second processor is configured to execute the decoding method described in any one of claims 1 to 8 by executing the computer program.

25. A bitstream generated by performing bit encoding based on the information to be encoded, The information to be encoded is at least: The first syntactic identifier value, the second syntactic identifier value, and at least one of the at least one fusion type identifier value, A bitstream in which the first syntactic identifier is used to indicate whether the current block uses a cross-component predictive merge mode, the second syntactic identifier is used to indicate whether the current block uses a cross-component predictive merge fusion mode, and the at least one fusion type identifier is used to indicate at least one chromaticity prediction mode corresponding to the current block.

26. A storage medium storing a computer program for implementing the decoding method described in any one of claims 1 to 8, or the encoding method described in any one of claims 9 to 20.

Images