Improvements in spatial geometric partition modes for video coding

Abstract

Disclosed are a video encoding / decoding method and system for improving a spatial geometry partition mode. A video encoding / decoding method includes encoding / decoding a candidate index code into / from a code stream, where the candidate index code is associated with an intra partition prediction and a template, the template including a reference line specified by one or more indexes of a plurality of reference lines having a plurality of reconstructed samples, the plurality of reconstructed samples are spatially adjacent to a block associated with a Spatial Geometric Partitioning Mode (SGPM).

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the priority benefit of U.S. Provisional Application No. 63 / 380,943, filed on October 25, 2022, entitled "INTRA FUSION AND MULTIPLE REFERENCE LINES FOR SPATIAL GEOMETRIC PARTITIONING MODE", which is hereby incorporated by reference in its entirety. Technical Field

[0003] The present disclosure generally relates to computer - implemented methods and systems for video processing, and more particularly to improvements to spatial geometric partitioning modes for video coding. Background Art

[0004] Video coding has been used in a wide range of applications. For example, in terms of the spatial geometric partitioning mode (SGPM), an intra - mode is used for each partition of an SGPM block, and a fixed reference is used to generate predictions for a given mode. Therefore, there is a need to further improve video coding performance. Summary of the Invention

[0005] The object of the present disclosure is to propose video processing methods and systems to improve video coding performance.

[0006] In a first aspect of the present disclosure, a video coding method includes: encoding a candidate index code into a bitstream, where the candidate index code is associated with intra - partition prediction and a template, and the template includes one or more index - specified reference lines among multiple reference lines having multiple reconstructed samples, and the multiple reconstructed samples are spatially adjacent to a block associated with a spatial geometric partitioning mode (SGPM).

[0007] In a second aspect of the present disclosure, a video coding system includes: a processor; and a memory coupled to the processor, where the processor is configured to execute program instructions stored in the memory to perform any of the video coding methods described above.

[0008] In a third aspect of the present disclosure, a non - transitory computer - readable medium stores program code that can be executed by a processor to perform any of the video coding methods described above.

[0009] In a fourth aspect of the present disclosure, a video decoding method includes: decoding a candidate index code from a bitstream, where the candidate index code is associated with intra-partition prediction and a template, the template includes one or more reference rows specified by an index among a plurality of reference rows having a plurality of reconstructed samples, and the plurality of reconstructed samples are spatially adjacent to a block associated with a spatial geometric partitioning pattern (SGPM).

[0010] In a fifth aspect of the present disclosure, a video decoding system includes: a processor; and a memory coupled to the processor, where the processor is configured to execute program instructions stored in the memory to perform any one of the video decoding methods described above.

[0011] In a sixth aspect of the present disclosure, a non-transitory computer-readable medium stores program code thereon, and the program code is executable by a processor to perform any one of the video decoding methods described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] To more clearly illustrate the embodiments of the present disclosure or related technologies, the following drawings briefly introduced will be described in the embodiments. Apparently, the drawings are only some embodiments of the present disclosure, and those of ordinary skill in the art can obtain other drawings based on these drawings without making any assumptions.

[0013] Figure 1 is a schematic diagram showing a picture divided into blocks applicable to an embodiment of the present disclosure, and the blocks are called coding tree units (CTUs).

[0014] Figure 2 is a schematic diagram showing a coding tree unit of a coding unit (CU) applicable to an embodiment of the present disclosure.

[0015] Figure 3 is a schematic diagram showing an example of a current block (such as a CU) applicable to an embodiment of the present disclosure and reconstructed samples that are spatially adjacent and non-adjacent to the current block.

[0016] Figure 4 is a schematic diagram showing examples of an angular mode and a wide-angle intra prediction (WAIP) mode applicable to an embodiment of the present disclosure.

[0017] Figure 5 is a schematic diagram showing an example of a spatial geometric partitioning mode (SGPM) signaling applicable to an embodiment of the present disclosure.

[0018] Figure 6It is a schematic diagram showing examples of template shapes and extended weights applicable to embodiments of the present disclosure.

[0019] Figure 7 It is a schematic diagram showing examples of geometric partitioning modes (GPM) with inter - frame and intra - frame prediction and SGPM with intra - frame and intra - frame prediction related to available intra prediction mode (IPM) candidates applicable to embodiments of the present disclosure.

[0020] Figure 8 It is a schematic diagram showing examples of hybrid weights applicable to embodiments of the present disclosure.

[0021] Figure 9 It is a flowchart showing a video encoding method according to an embodiment of the present disclosure.

[0022] Figure 10 It is a flowchart showing a video decoding method according to an embodiment of the present disclosure.

[0023] Figure 11 It is a schematic block diagram showing an example of a computing device according to an embodiment of the present disclosure. Detailed implementation manners

[0024] The embodiments of the present disclosure are described in detail below with reference to the accompanying drawings in terms of technical solutions, structural features, achieved purposes, and effects. Specifically, the terms in the embodiments of the present disclosure are only for the purpose of describing specific embodiments and do not limit the present disclosure.

[0025] Video coding has been used in a wide range of applications. For example, in terms of the spatial geometric partitioning mode (SGPM), one intra - frame mode is used for each partition of the SGPM block, and a fixed reference is used to generate the prediction for a given mode. Therefore, there is a need to further improve video coding performance.

[0026] In the present disclosure, encoding and decoding refer to encoding methods and systems as well as decoding methods and systems.

[0027] For example, in the present disclosure, intra - frame fusion and multiple reference lines can be applied to the geometric partitioning mode (GPM) of video coding. The methods provided in the present disclosure can be used for future video coding standards. By implementing the provided methods, modifications to the bit - stream structure, syntax, constraints, and mapping used to generate decoded pictures can be considered for standardization. The relevant descriptions are provided below.

[0028] For example, similar to other video coding schemes such as High Efficiency Video Coding (HEVC), Versatile Video Coding (VVC) is a block-based hybrid spatial and temporal predictive coding scheme. During encoding, as Figure 1 shown, the input picture is first divided into square blocks, which are called Coding Tree Units (CTUs) 100. For example, the CTU 100 can be a block of 128×128 pixels or a block of other pixels.

[0029] For example, as Figure 2 shown, Figure 2 is a schematic diagram of a coding tree unit divided into Coding Units (CUs) that can be applied to embodiments of the present disclosure, where solid lines indicate quadtree partitioning and dashed lines indicate binary tree partitioning. In Figure 2 a picture, a CTU 200 can be divided into one or more Coding Units (CUs) 202, and the CUs 202 can be used for prediction and transformation. Different from HEVC, in VVC, the CUs 202 can be rectangular or square, and can be encoded without further dividing into prediction units or transformation units. In one example, each CU 202 can be as large as its root CTU 200, or can be a subdivision of its root CTU 200, as small as a 4×4 block. In addition, examples of prediction are provided as follows.

[0030] Intra Prediction in VVC and ECM

[0031] For example, in an intra CU, spatially adjacent reconstructed samples will be used to predict the current block, and the intra mode is signaled once for the entire CU. Intra prediction and transform coding are performed at the CU level and the Transform Block (TB) level respectively. Each CU consists of a single TB, except in the case of Intra Sub-Partitioning (ISP) mode and implicit partitioning prediction. For a luma CU, the maximum side length of the TB is 64, and the minimum side length is 4. In addition, the luma TB is further specified as a W×H rectangular block with width W and height H, where W, H ∈ {4, 8, 16, 32, 64}. For a chroma CU, the maximum TB side length is 32, and the chroma TB is a W×H rectangular block with width W and height H, where W, H ∈ {2, 4, 8, 16, 32}, but blocks of 2×H and 4×2 shapes have been excluded to meet memory architecture and throughput requirements.

[0032] For example, in VVC, reference samples obtained from the reconstructed samples of adjacent blocks (e.g., the left block and the upper block of the current block) are used to generate the intra prediction samples of the current block. As Figure 3As shown, for the W×H block 300, reference samples (e.g., the top and left reconstructed samples) are spatially adjacent to the current block (e.g., CU) 302. For example, the reference samples consist of a vertical row formed by 2×H reconstructed samples located on the left side of the block and extending downward, and a horizontal row formed by 2×W reconstructed samples located above the current block and extending to the right. In the present disclosure, this inverted “L” - shaped set of samples can be referred to as the “reference row” 302. One of the multiple reference rows 302 that is directly adjacent to the current block 302 is shown as the row indexed 0, while the other reference rows among the multiple reference rows 302 that are not adjacent to the current block 302 are shown as rows indexed 1, 2, 3, 4, 5, 6, 7,....

[0033] For example, similar to AVC and HEVC, VVC also supports angular intra - prediction modes. Angular intra - prediction is a directional intra - prediction method. Compared with HEVC, the angular intra - prediction in VVC has been modified by improving the prediction accuracy and adapting to the new partitioning framework. The improvement in prediction accuracy is achieved by increasing the number of angular prediction directions and by using a more accurate interpolation filter, while the adaptation to the new partitioning framework is achieved by introducing the wide - angle intra - prediction mode. In VVC, the number of available directional modes for a given block is increased from 33 directions in HEVC to 65 directions. A schematic diagram of the graph 400 showing different angular modes in VVC is depicted in Figure 4 which. The directions with even indices between 2 and 66 are equivalent to the directions of the angular modes supported in HEVC. For square blocks, an equal number of angular modes are assigned to the top and left sides of the block. On the other hand, rectangular intra - blocks that do not exist in HEVC are a core part of the VVC partitioning scheme, where additional intra - prediction directions are assigned to the long side of the block. The additional modes assigned along the longer side are called wide - angle intra - prediction (WAIP) modes because, relative to the horizontal or vertical modes, the WAIP modes correspond to prediction directions with angles greater than 45 degrees (°). The WAIP mode for a given mode index is defined by mapping the original directional mode to a mode with the opposite direction and an index offset equal to 1, as Figure 4 shown. For a given rectangular block, the aspect ratio (i.e., the ratio of width to height) is used to determine which corner modes will be replaced by the corresponding wide - angle modes.

[0034] In VVC, both square blocks and rectangular blocks can use one non - adjacent reference line, called the multiple reference line (MRL). For example, predictions are formed by using row 2 or row 3 located on the left and above the block, instead of always using row 1 to form predictions.

[0035] For example, as Figure 3As shown, in addition to the directly adjacent lines of adjacent samples (e.g., line 0), one of two non-adjacent reference lines (e.g., line 1 and line 2) may include the input for intra prediction in VVC. For an enhanced compression model (ECM), more non-adjacent reference lines can be used. The use of adjacent and non-adjacent reference samples is called multi-reference line (MRL) prediction.

[0036] For example, the intra modes that can be used for MRL are the DC mode and the angular prediction mode. On the other hand, for a given block, not all of these modes can be combined with MRL. The MRL mode is always coupled with the most probable mode (MPM) in VVC. This coupling means that if non-adjacent reference lines are used, the intra prediction mode is one of the MPMs. The motivation for this design of the MRL prediction mode based on MPM is the following observation: non-adjacent reference lines are mainly beneficial for texture patterns with sharp and strongly directed edges. In these cases, the selection of the MPM is much more frequent because there is usually a strong correlation between the texture patterns of adjacent blocks and the texture pattern of the current block. On the other hand, the selection of a non-MPM for intra prediction indicates that the edges are not continuously distributed in adjacent blocks, so in this case the MRL prediction mode is expected to be of little use.

[0037] In addition, it has been observed that when the intra prediction mode is the planar mode, MRL does not provide additional coding gain because the planar mode is usually used for smooth regions. Therefore, MRL excludes the planar mode, and the planar mode is always one of the MPMs. The angular or DC prediction process in MRL is very similar to the case of directly adjacent reference lines. On the other hand, for angular modes with non-integer slopes, a DCT-based interpolation filter (DCTIF) is always used. This design choice is both justified by experimental results and consistent with empirical observations (i.e., MRL is most beneficial for sharp and strongly directed edges), where DCTIF is more appropriate because it retains more high frequencies compared to a smoothing interpolation filter (SIF).

[0038] In one example, from a hardware design perspective, applying the multiple reference lines provided in the method requires additional line buffer costs, where the line buffer is used to store the additional reference lines. In a typical hardware design, the line buffer is part of the on-chip memory architecture for image and video encoding, and it is very important to minimize the on-chip area of ​​the line buffer. To address this issue, MRL is disabled and not signaled for coding units attached to the top boundary of the CTU. In this way, the additional buffer for storing non-adjacent reference lines is limited to 128 (which is the width of the maximum unit size).

[0039] Intra Fusion

[0040] For example, an intra-frame prediction fusion method is provided to improve the accuracy of intra-frame prediction. More specifically, if the current block is a luminance block and the current block is encoded using a non-integer slope angle mode (rather than an ISP mode), and the block size (width×height) is greater than 16, then the two prediction blocks generated from two different reference lines will be "fused", where the fused prediction is a weighted sum of the two prediction blocks. Specifically, the first reference line (line 1) at index i is specified using a method represented by a signal in the bitstream (e.g., as provided above). i ), and the prediction block generated from the reference line using the selected intra prediction mode is denoted as p(line i ), where p(·) represents the operation of generating a prediction block from a reference line using a given intra prediction mode. In the intra prediction fusion method, the reference line line is implicitly selected. i+1 is the second reference line. That is, relative to the first reference line, the second reference line is an index position farther away from the current block. Similarly, the prediction block generated from the second reference line using the same given intra prediction mode is represented as p(line i+1 ). The weighted sum of the two predicted blocks is obtained as follows and used as the predictor for the current block.

[0041] p fusion =w 0 *p(line i )+w 1 *p(line i+1 ),

[0042] Among them, p fusion represents the fusion prediction, w 0 and w 1 are two weighting factors, which are set to 3 / 4 and 1 / 4 respectively in the experiment.

[0043] Spatial Geometry Partition Mode

[0044] For example, a Spatial Geometry Partitioning Mode (SGPM) is provided. The SGPM allows a CU to be partitioned into two parts, and the two parts can use different intra prediction modes. The new mode is conceptually similar to the Geometry Partitioning Mode (GPM) applicable to inter prediction in VVC. On the other hand, since there may be a large number of combinations of partitioning and intra prediction modes, the SGPM uses a different signaling mechanism. To more efficiently express the required partitioning and prediction information in the bitstream, a candidate list is adopted, and only the candidate index is signaled in the bitstream. Each candidate in the list can derive a combination of a partitioning mode and two intra prediction modes, as Figure 5 shown.

[0045] For example, as Figure 5 shown, the CU 510 can be partitioned into two parts (shown as part 512 and part 513) with different intra prediction modes (e.g., "Intra_pred_mode0" and "Intra_pred_model") using a partitioning mode (shown as 511, e.g., "Partition_mode"), which can be represented as a syntax structure 520 with a partitioning mode index (e.g., "partition_mode_idx") and two intra prediction modes (e.g., "intra_pred_mode0_idx" and "intra_pred_mode0_idx"). On the other hand, another syntax structure 530 is also provided to indicate a combination 540 with one candidate index (e.g., "sgpm_cand_idx"), and the combination 540 indicates a combination of a partitioning mode (e.g., "partition_mode_idx") and two intra prediction modes (e.g., "intra_pred_mode0_idx" and "intra_pred_mode0_idx").

[0046] For example, a template is used to generate a candidate list. In one example, a diagram 600 with a CU 610 and a template 620 (shown as two template components 620a and 620b) is shown in Figure 6 where the width of the template 620 is set to 4. On the other hand, for the SGPM adopted for ECM, the template width is set to 1. For each possible combination of a partitioning mode and two intra prediction modes, predictions are generated for the template using partitioning weights extended to the template, as Figure 6As shown. These combinations are arranged in ascending order of their sum of absolute transform differences (SATD) cost between the prediction and reconstruction of the template. For example, the size of the candidate list is set to be equal to 16, and these candidates are regarded as the most likely SGPM combinations for the current block. Both the encoder and the decoder use the template to construct the same candidate list. To reduce the complexity of constructing the candidate list, the number of possible partition patterns and the number of possible intra prediction modes (IPMs) are both limited. For example, the number of possible partition patterns in the current version of SGPM adopted for ECM can be limited to a predetermined set formed by 26 partitions, which covers various partition directions and positions. In one example, multiple templates associated with the 26 partitions can be tried to find the partition with the lowest cost among the 26 partitions.

[0047] For example, two IPM candidate lists corresponding to two SGPM partitions are both constructed by adding available IPM candidates, and then trimmed to a predetermined limit formed by 3 candidates if necessary. Some IPM candidates are inherited from the intra-inter GPM modes already adopted in ECM. As Figure 7 shown, a GPM with inter and intra prediction is shown, where an inter-frame angular mode parallel to the GPM partition boundary (e.g., parallel mode), an inter-frame angular mode perpendicular to the GPM partition boundary (e.g., perpendicular mode), and an inter-frame prediction plane mode (as shown in (a) to (c) in Figure 7 ) can be added respectively as available IPM candidates for SGPM; an SGPM with intra and intra prediction is shown, as shown in (d) in Figure 7 . For example, as Figure 7 shown, the available IPM candidate 710 includes a region 711 with reconstructed samples, a region 713 for intra prediction, and a region 715 for inter prediction; the available IPM candidate 720 includes a region 721 with reconstructed samples, a region 723 for intra prediction, and a region 725 for inter prediction; the available IPM candidate 730 includes a region 731 with reconstructed samples, a region 733 for intra prediction, and a region 735 for inter prediction; the SGPM candidate 740 includes a region 741 with reconstructed samples, a region 743 for intra prediction, and a region 745 for inter prediction.

[0048] In addition, template-based intra mode derivation (TIMD) can be used to derive an intra prediction mode, which is used as an available IPM candidate for SGPM. For example, only the neighbors in the horizontal and vertical directions (e.g., using the top template or the left template) are used to derive the TIMD intra prediction mode to form the IPM of SGPM.

[0049] For example, for certain CU block sizes, the SGPM is implicitly disabled. The range of block sizes for which the SGPM can be used (i.e., the CU-level flag can be signaled to indicate whether to use the SGPM) is initially inherited from the intra-inter GPM mode. In the SGPM adopted for ECM, the range of block sizes is further extended to smaller blocks of sizes 4×8, 8×4, 4×16, and 16×4. In summary, the block sizes for which the SGPM can be used are one of the following size limits, for example, 4 <= width <= 64, 4 <= height <= 64, width < height × 8, height < width × 8, or width × height >= 32, where "width" and "height" represent the width and height of the current block.

[0050] For example, as Figure 8 shown, the adaptive SGPM hybrid scheme 800 can be used to better predict those pixels in the boundary PB (e.g., the GPM division boundary) between two prediction parts, where the weighted average of the two prediction parts is used in the transition region around the SGPM partition. The width of the transition region is called the hybrid width. The hybrid width is adaptively determined according to the block size. Adaptive hybridization does not require signaling. Additionally, as Figure 8 shown, (x, y) are the coordinates of the pixels in the normal direction perpendicular to the boundary PB; d is the distance between the coordinates of the pixels and the boundary PB; the angle and the distance ρ j ; ω 0 indicates the region related to the boundary PB. For example, ω 0 indicates the transition region. Additionally, as Figure 8 shown, let the hybrid width specified for the GPM tool in VVC and ECM be τ. Then, the adaptive SGPM hybrid width can be determined according to the CU block width and height as follows. If min(width, height) == 4, then (l / 2)τ is selected; otherwise, if min(width, height) == 8, then τ is selected; otherwise, if min(width, height) == 16, then 2τ is selected; otherwise, if min(width, height) == 32, then 4τ is selected; otherwise, 8τ is selected.

[0051] Note that in the prior art, one intra mode is used for each partition of the SGPM block, and a single fixed reference (e.g., reference row 0) is used to generate the prediction for a given intra mode. In the present disclosure, the coding performance can be further improved to allow the SGPM block to use intra fusion and MRL. Examples are provided below.

[0052] In the present disclosure, a video coding method for spatial geometric partitioning mode coding is provided. Examples are provided below.

[0053] For example, a flowchart of a video encoding method according to an embodiment of the present disclosure is shown in Figure 9 and an example of a video encoding method 900 is provided therein. The video encoding method 900 includes: block 910, encoding a candidate index code into a bitstream, where the candidate index code is associated with intra-partition prediction and a template, the template includes one or more index-specified reference rows among a plurality of reference rows having a plurality of reconstructed samples, and the plurality of reconstructed samples are spatially adjacent to a block associated with a spatial geometry partitioning mode (SGPM). For example, an index can be used to specify one index-specified reference row to indicate which reference row is used for one or two partitions of the SGPM, rather than using a fixed reference row.

[0054] Correspondingly, a video decoding method for spatial geometry partitioning mode encoding is provided, and an example is provided as follows.

[0055] For example, a flowchart of a video decoding method according to an embodiment of the present disclosure is shown in Figure 10 and an example of a video decoding method 1000 is provided therein. The video decoding method 1000 includes: block 1010, decoding a candidate index code from the bitstream, where the candidate index code is associated with intra-partition prediction and a template, the template includes one or more index-specified reference rows among a plurality of reference rows having a plurality of reconstructed samples, and the plurality of reconstructed samples are spatially adjacent to a block associated with a spatial geometry partitioning mode (SGPM).

[0056] In some embodiments, as shown in block 910 as Figure 9 shown and block 1010 as Figure 10 shown, the candidate index code is associated with a combination of a partitioning mode index, a first intra-prediction mode index, and a second intra-prediction mode index. The first intra-prediction mode index indicates a first intra-prediction mode of a first partition of a block based on a single reference row (e.g., a single reference row having an index (instead of a fixed index) indicated by an encoder / decoder), and the second intra-prediction mode index indicates a second intra-prediction mode of a second partition of the block based on a single reference row. An example is provided as follows.

[0057] Example 1:

[0058] The present disclosure stipulates that MRL can be applied to SGPM blocks. As an example, an index (e.g., i) can be specified to indicate which reference row is used for two partitions of an SGPM block, rather than always using row 0. As another example, two row indices i and j can be specified for two partitions of an SGPM block respectively to indicate which reference row is used for each partition of the SGPM block.

[0059] Specifically, the SGPM block has two partitions. The first partition can use a first intra mode, which is represented by a valid intra mode index intra_mode1. The second partition can use a second intra mode, which is represented by a valid intra mode index intra_mode2. For a given reference row and intra prediction mode of a certain partition of the SGPM block, an intra prediction can be generated, and this intra prediction is called an intra partition prediction.

[0060] In some embodiments, as Figure 9 shown in block 910 and Figure 10 shown in block 1010, a candidate index code is associated with a combination of a partition mode index, a first intra prediction mode index, and a second intra prediction mode index. The first intra prediction mode index indicates the first intra prediction mode of the first partition of the block based on a single reference row guided by a row index signaled in the bitstream, and the second intra prediction mode index indicates the second intra prediction mode of the second partition of the block based on a single reference row. An example is provided below.

[0061] For the first example, the reference row line_i and the intra prediction mode intra_mode1 will be used to generate an intra partition prediction for the first partition of the SGPM block. The reference row line_i and the intra prediction mode intra_mode2 will be used to generate an intra partition prediction for the second partition of the SGPM block.

[0062] The reference row index i can be signaled through the existing syntax signaling syntax of MRL. Alternatively, the SGPM candidate list construction process can be extended to all available combinations of the partition mode, the two IPM modes of the corresponding partitions, and the reference row index.

[0063] In some embodiments, as Figure 9 shown in block 910 and Figure 10 shown in block 1010, a candidate index code is associated with a combination of a partition mode index, a first intra prediction mode index, and a second intra prediction mode index. The first intra prediction mode index indicates the first intra prediction mode of the first partition of the block based on a first reference row guided by a first row index signaled in the bitstream, and the second intra prediction mode index indicates the second intra prediction mode of the second partition of the block based on a second reference row guided by a second row index signaled in the bitstream. Another example is provided below.

[0064] For the second example, the intra-partition prediction for the first partition of the SGPM block will be generated using reference line line_i and intra prediction mode intra_mode1; the intra-partition prediction for the second partition of the SGPM block will be generated using reference line line_j and intra prediction mode intra_mode2. The reference line indices i and j can be signaled through the existing signaling syntax of the MRL. Alternatively, the SGPM candidate list construction can be extended to all available combinations of the partition mode, the two IPM modes for the corresponding partitions, and the two reference line indices for the corresponding partitions.

[0065] Example 2:

[0066] The present disclosure also provides that intra-frame fusion can be used for the SGPM block. More specifically, there are two partitions in the SGPM block.

[0067] In some embodiments, as Figure 9 shown in block 910 and Figure 10 shown in block 1010, the candidate index code is associated with a combination of a partition mode index, a first intra prediction mode index, and a second intra prediction mode index, where the first intra prediction mode index and the second intra prediction mode index indicate two given intra prediction modes for two partitions of the block associated with the fused intra-partition prediction, and the fused intra-partition prediction is expressed as: p fusion_partition = w 0 * p_partition(line i ) + w 1 * p_partition(line i+1 ), where p fusion_partition represents the fused intra-partition prediction for each of the two partitions, w 0 and w 1 are two weighting factors, the sum of the two weighting factors being equal to 1, p_partition(·) represents an operation function that generates an intra-partition prediction based on a given reference line among multiple reference lines in one of two given intra prediction modes, line i and line i+1 are two given reference lines among multiple reference lines directed by two indices i and i + 1. For example, the index i can be encoded in the bitstream or inferred as a default value, e.g., 0 in the case of not being encoded.

[0068] For example, two reference lines (e.g., line 0 and line 1 as Figure 3 shown) can be used to generate two corresponding intra-partition predictions for each partition in a given intra prediction mode. Once two intra-partition predictions are generated for a partition, the fused prediction for the current partition can be obtained by using the following formula: p fusion_partition = w 0*p_partition(line i ) + w 1 *p_partition(line i+1 ), where p fusion_partition represents the intra-partition prediction fusion for the current partition, and w 0 and w 1 are two weighting factors that can be set to 3 / 4 and 1 / 4. The first reference line (line i ) at index i is specified using the method signaled in the bitstream as described above, and the intra-partition prediction generated from this reference line using the selected intra-prediction mode is denoted as p_partition(line i ), where p_partition(·) represents the operation of generating an intra-partition prediction from a given reference line using a given intra-prediction mode. The above process can be referred to as SGPM intra-prediction fusion. This SGPM intra-prediction fusion can be applicable to all allowed intra-modes, limited to all allowed angular intra-modes, or some angular intra-modes with some restrictions, e.g., non-integer slope angular intra-modes. The SGPM intra-prediction fusion may also be limited to certain CU block sizes.

[0069] In some embodiments, as shown in block 910 as Figure 9 shown and block 1010 as Figure 10 shown, the index i is pre-determined to be zero or signaled in the bitstream.

[0070] As an example, the reference line line i may not be specified, and the default reference line is 0. In other words, the SGPM intra-prediction fusion will always fuse two intra-partition predictions based on line 0 and line 1.

[0071] In some embodiments, as shown in block 910 as Figure 9 shown and block 1010 as Figure 10 shown, the index i and the candidate index code are signaled jointly or separately in one or more syntax structures of the bitstream. Examples are provided below.

[0072] In another example, enabling MRL and the intra-fusion method for the SGPM block can be signaled jointly or separately on different levels of syntax structures (e.g., Sequence Parameter Set (SPS), Picture Header (PH), Picture Parameter Set (PPS), and Slice Header (SH)).

[0073] Example 3:

[0074] The present disclosure proposes to generate SGPM prediction fusion using two sets of a combination of a partitioning pattern and two intra prediction modes (e.g., two partitioning patterns and four intra prediction modes in total), wherein each combination set generates a separate CU / block prediction by an existing SGPM method, and the final SGPM prediction fusion is a weighted sum of the two separate predictions.

[0075] In some embodiments, as Figure 9 shown in block 910 and Figure 10 shown in block 1010, the candidate index code is associated with two sets of combinations of a partitioning pattern index and two intra prediction mode indexes, the two sets are associated with the SGPM prediction fusion of the block, the SGPM prediction fusion is expressed as a weighted sum of the two sets and two weighting parameters, the two weighting parameters are two different fixed numbers, and the sum of the two different fixed numbers is equal to 1. Examples are provided below.

[0076] For example, the weighting parameters can be fixed numbers such as 1 / 2 and 1 / 2, or 1 / 4 and 3 / 4, etc. Alternatively, other fixed numbers can be used in specific scenarios.

[0077] In some embodiments, as Figure 9 shown in block 910 and Figure 10 shown in block 1010, each of the two weighting parameters is expressed as a function of the distance between the pixels in the block and the reference pixels in the template. Examples are provided below.

[0078] For example, the weighting parameter can also be a function of the relative distance between the current pixel and the reference pixel.

[0079] In some embodiments, as Figure 9 shown in block 910 and Figure 10 shown in block 1010, the candidate index code is associated with two combined candidate index components, the two combined candidate index components indicate two sets of combinations of a partitioning pattern index and two intra prediction mode indexes. Examples are provided below.

[0080] As an example, the two combined sets can be signaled in the bitstream by two combined candidate indexes, and the two combined candidate indexes can be determined by the encoder RDO process.

[0081] In some embodiments, as Figure 9 shown in block 910 and Figure 10As shown in the block 1010, a candidate index code is associated with a single combined candidate index component, the single combined candidate index component indicating a first set of two sets of combinations of a partitioning mode index and two intra prediction mode indices, the second set of the two sets of combinations of the partitioning mode index and the two intra prediction mode indices being a combination of a specific partitioning mode index and two specific intra prediction mode indices, the specific partitioning mode index being set to the partitioning mode index associated with the single combined candidate index component, and the two specific intra prediction mode indices being two intra prediction mode indices adjacent to the two intra prediction mode indices associated with the single combined candidate index component, the single combined candidate index component being one candidate index in a list. Examples are provided below.

[0082] As another example, with the current SGPM method, only one candidate index is sent in the bitstream to signal the first combined set. Then, the second combined set uses the same partitioning mode derived from the signaled candidate index and two intra modes adjacent to the intra mode derived from the signaled candidate index (e.g., two intra modes derived from the signaled candidate index +1 or -1).

[0083] In some embodiments, as Figure 9 shown in block 910 and Figure 10 shown in block 1010, the two specific intra prediction mode indices are a fixed offset apart from the two intra prediction mode indices associated with the single combined candidate index component. Examples are provided below.

[0084] For example, these two adjacent intra modes can be within or outside the candidate list and can be on either side by adding a fixed offset, as long as the encoder and decoder both follow the same predefined rule.

[0085] In some embodiments, as Figure 9 shown in block 910 and Figure 10 shown in block 1010, a candidate index code is associated with a single combined candidate index component, the single combined candidate index component indicating a first set of two sets of combinations of a partitioning mode index and two intra prediction mode indices, the second set of the two sets of combinations of the partitioning mode index and the two intra prediction mode indices being a combination of a specific partitioning mode index and two specific intra prediction mode indices, the specific partitioning mode index being set to the partitioning mode index associated with the single combined candidate index component, and the two specific intra prediction mode indices being set to two intra prediction mode indices associated with another candidate index in the list, the partitioning mode index of the another candidate index being equal to the partitioning mode index associated with the single combined candidate index component. Examples are provided below.

[0086] As another example, two intra modes can be set to any candidate intra mode in the list, and the arbitrary candidate partitioning mode is the same as the partitioning mode associated with the combined index signaled in the bitstream.

[0087] In some embodiments, as Figure 9 shown in block 910 and Figure 10 shown in block 1010, in response to determining that there are more than one candidate indices in the list and the partitioning mode indices of the more than one candidate indices are equal to the partitioning mode index associated with a single combined candidate index component, two specific intra prediction mode indices are set to the two intra prediction mode indices associated with one candidate index in the list, and this one candidate index minimizes the sum of absolute transform differences (SATD) cost between the prediction and reconstruction of the template. An example is provided below.

[0088] For example, if more than one candidate has the same partitioning mode, the candidate with the minimum SATD cost will contribute two intra modes to the second combined set.

[0089] In some embodiments, as Figure 9 shown in block 910 and Figure 10 shown in block 1010, the candidate index code is associated with a single combined candidate index component, the single combined candidate index component indicates the first set of two sets of combinations of a partitioning mode index and two intra prediction mode indices, the second set of two sets of combinations of a partitioning mode index and two intra prediction mode indices is a combination of a specific partitioning mode index and two specific intra prediction mode indices, the specific partitioning mode index is a partitioning mode index adjacent to the partitioning mode index associated with the single combined candidate index component, the single combined candidate index component serves as one candidate index in the list, and the two specific intra prediction mode indices are set to the two intra prediction mode indices associated with the single combined candidate index component. An example is provided below.

[0090] As another example, with the current SGPM method, only one candidate index is sent in the bitstream to signal the first combined set. Then, the second combined set uses the same intra modes derived from the signaled candidate index and a partitioning mode adjacent to the partitioning mode derived from the signaled candidate index (e.g., a partitioning mode derived from the signaled candidate index +1 or -1).

[0091] In some embodiments, as Figure 9 shown in block 910 and Figure 10 shown in block 1010, the specific partitioning mode index is offset by a fixed amount from the partitioning mode index associated with the single combined candidate index component. An example is provided below.

[0092] For example, these two adjacent partitioning patterns can be located within or outside the candidate list, and can be located on either side by adding a fixed offset, as long as both the encoder and the decoder follow the same predetermined rules.

[0093] In some embodiments, as Figure 9 shown in block 910 and Figure 10 shown in block 1010, a candidate index code is associated with a single combined candidate index component that indicates a first set of two sets of a combination of a partitioning pattern index and two intra prediction mode indices, and a second set of two sets of a combination of a partitioning pattern index and two intra prediction mode indices is a combination of a specific partitioning pattern index and two specific intra prediction mode indices, the specific partitioning pattern index is set to a partitioning pattern index associated with another candidate index in the list, the two intra prediction mode indices of the other candidate index are equal to the two intra prediction mode indices associated with the single combined candidate index component, and the two specific intra prediction mode indices are set to the two intra prediction mode indices associated with the single combined candidate index component. Examples are provided below.

[0094] As another example, the partitioning pattern can be set to the partitioning pattern of any candidate in the list, and the intra mode of the any candidate is the same as the intra mode associated with the combined index signaled in the bitstream.

[0095] In some embodiments, as Figure 9 shown in block 910 and Figure 10 shown in block 1010, in response to determining that there is more than one candidate index in the list and the two intra prediction mode indices of the more than one candidate index are equal to the partitioning pattern index associated with a single combined candidate index component, the specific partitioning pattern index is set to a partitioning pattern index associated with a candidate index in the list, and this candidate index minimizes the sum of absolute transform differences (SATD) cost between the prediction and reconstruction of the template. Examples are provided below.

[0096] For example, if more than one candidate has the same prediction mode, the candidate with the minimum SATD cost will contribute the partitioning pattern to the second combined set.

[0097] In some embodiments, as Figure 9 shown in block 910 and Figure 10As shown in the box 1010, the candidate index code is associated with a single combined candidate index component, which indicates the first set among two sets of combinations of a partition mode index and two intra prediction mode indices, and the second set among two sets of combinations of a partition mode index and two intra prediction mode indices is a combination of a specific partition mode index and two specific intra prediction mode indices. The combination of the specific partition mode index and the two specific intra prediction mode indices is associated with one candidate index in the list, and this one candidate index minimizes the sum of absolute transform differences (SATD) cost between the prediction and reconstruction of the template. An example is provided as follows.

[0098] As another example, with the current SGPM method, only one candidate index is sent in the bitstream to signal the first combination set. Then, the second combination set always uses the candidate with the minimum SATD in the list.

[0099] In addition, any suitable computing system can be used to perform video encoding operations (such as the operations of the video encoder described herein) or video decoding operations (such as the operations of the video decoder described herein). For example, Figure 11 An example of a computing device 1100 is depicted. The computing device 1100 has a processor 1110, and the processor 1110 is coupled to a memory 1120, which can implement the methods herein (such as a video encoding method or a video decoding method).

[0100] In some embodiments, the computing device includes a processor, which is coupled to a memory and configured to execute program instructions stored in the memory to perform operations for implementing a video encoding method associated with an encoder or a video decoding method associated with a decoder.

[0101] For example, the processor may include a microprocessor, an application specific integrated circuit (“ASIC”), a state machine, or other processing devices. For example, the processor includes one or more processing units. Such a processor may include a computer-readable medium storing instructions, or may communicate with a computer-readable medium storing instructions. When the instructions are executed by the processor, the instructions cause the processor to perform the operations described herein. The memory includes any suitable non-transitory computer-readable medium.

[0102] For example, a computer-readable medium includes any electronic, optical, magnetic, or other storage device capable of providing computer-readable instructions or other program code to a processor. Non-limiting examples of computer-readable media include magnetic disks, memory chips, ROM, RAM, ASICs, configured processors, optical memories, magnetic tapes, or any other medium from which a computer processor can read instructions. The instructions may include processor-specific instructions generated by a compiler and / or interpreter from code written in any suitable computer programming language, including, for example, C, C++, C#, Visual Basic, Java, Python, Perl, JavaScript, and ActionScript.

[0103] In some embodiments, the present disclosure provides a video encoding system, the video encoding system including: a processor; and a memory coupled to the processor, wherein the processor is configured to execute program instructions stored in the memory to perform any one of the video encoding methods described above.

[0104] In some embodiments, the present disclosure provides a non-transitory computer-readable medium having program code stored thereon, the program code being executable by a processor to perform any one of the video encoding methods described above.

[0105] In some embodiments, the present disclosure provides a video decoding system, the video decoding system including: a processor; and a memory coupled to the processor, wherein the processor is configured to execute program instructions stored in the memory to perform any one of the video decoding methods described above.

[0106] In some embodiments, the present disclosure provides a non-transitory computer-readable medium having program code stored thereon, the program code being executable by a processor to perform any one of the video decoding methods described above.

[0107] Those of ordinary skill in the art should understand that the various units, algorithms, and steps described and disclosed in the embodiments of the present disclosure are implemented using electronic hardware, or a combination of computer software and electronic hardware. Whether these functions run on hardware or software depends on the application conditions and design requirements of the technical solution. Those of ordinary skill in the art can implement the functions in different ways for each specific application, and such implementation should not exceed the scope of the present disclosure. Those of ordinary skill in the art should understand that since the working processes of the systems, devices, and units in the above embodiments are basically the same, he / she can refer to the working processes of the above systems, devices, and units. For the sake of convenience of description and simplicity, these working processes will not be described in detail.

[0108] It should be understood that the systems, devices, and methods disclosed in the embodiments of the present disclosure can be implemented in other ways. The above embodiments are merely exemplary. The division of units is only based on logical functions, and there are other division methods when implemented. It is feasible to combine or integrate multiple units or components into another system. It is also feasible to omit or skip some features. On the other hand, the shown or discussed mutual coupling, direct coupling, or communication coupling operates through some ports, devices, or units, either indirectly or through electrical, mechanical, or other forms of communication.

[0109] The units that are shown as separate components for illustration purposes are physically separate units or not physically separate units. The units for display are physical units or not physical units, that is, located in one place or distributed over multiple network units. Some or all of these units are used according to the purposes of the embodiments. Additionally, each functional unit in each embodiment can be integrated in a processing unit, can be a physically independent unit, or can be integrated in a processing unit having two or more units.

[0110] If a software functional unit is implemented and used and sold as a product, the software functional unit can be stored in a readable storage medium in a computer. Based on this understanding, the technical solution provided by the present disclosure can be basically implemented in the form of a software product, or partially implemented in the form of a software product. Or, a part of the technical solution beneficial to the prior art can be implemented in the form of a software product. The software product in the computer is stored in the storage medium and includes multiple commands for a computing device (such as a personal computer, a server, or a network device) to execute all or some of the steps disclosed in the embodiments of the present disclosure. The storage medium includes a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a floppy disk, or other media capable of storing program codes.

[0111] Although the present disclosure has been described in connection with the embodiments that are considered to be the most practical and preferred, it should be understood that the present disclosure is not limited to the disclosed embodiments, but is intended to cover various arrangements made without departing from the scope of the broadest interpretation of the appended claims.

Claims

1. A video coding method, comprising: encoding a candidate index code into a bitstream, wherein the candidate index code is associated with intra-partition prediction and a template, the template including one or more reference rows specified by indexes among a plurality of reference rows having a plurality of reconstructed samples, the plurality of reconstructed samples being spatially adjacent to a block associated with a spatial geometry partition mode (SGPM).

2. The method according to claim 1, wherein, the candidate index code is associated with a combination of a partition mode index, a first intra-prediction mode index, and a second intra-prediction mode index, the first intra-prediction mode index indicating a first intra-prediction mode of a first partition of the block based on a single reference row guided by a row index signaled in the bitstream, and the second intra-prediction mode index indicating a second intra-prediction mode of a second partition of the block based on the single reference row.

3. The method according to claim 1, wherein, the candidate index code is associated with a combination of a partition mode index, a first intra-prediction mode index, and a second intra-prediction mode index, the first intra-prediction mode index indicating a first intra-prediction mode of a first partition of the block based on a first reference row guided by a first row index signaled in the bitstream, and the second intra-prediction mode index indicating a second intra-prediction mode of a second partition of the block based on a second reference row guided by a second row index signaled in the bitstream.

4. The method according to claim 1, wherein, the candidate index code is associated with a combination of a partition mode index, a first intra-prediction mode index, and a second intra-prediction mode index, the first intra-prediction mode index and the second intra-prediction mode index indicating two given intra-prediction modes of two partitions of the block associated with a merged intra-partition prediction, the merged intra-partition prediction being represented as follows: p fusion_partition = w 0 * p_partition(line i ) + w 1 * p_partition(line i+1 ), where p fusion_pattition represents the combined intra-partition prediction for each of the two partitions, w 0 and w 1 are two weighting factors, the sum of the two weighting factors being equal to 1, p_partition(·) represents an operation function for generating an intra-partition prediction in one of the two given intra-prediction modes based on a given reference line among the plurality of reference lines, line i and line i+1 are two given reference lines among the plurality of reference lines directed by two indices i and i + 1.

5. The method according to claim 4, wherein, the index i is predetermined to be zero or signaled in the bitstream.

6. The method according to claim 5, wherein, the index i and the candidate index code are signaled jointly or separately in one or more syntax structures of the bitstream.

7. The method according to claim 1, wherein, the candidate index code is associated with two sets of a combination of a partition mode index and two intra-prediction mode indexes, the two sets being associated with an SGPM prediction merge of the block, the SGPM prediction merge being represented as a weighted sum of the two sets and two weighting parameters, the two weighting parameters being two different fixed numbers, and the sum of the two different fixed numbers being equal to 1.

8. The method according to claim 7, wherein, each of the two weighting parameters is represented as a function of a distance between pixels within the block and reference pixels within the template.

9. The method according to claim 7, wherein, the candidate index code is associated with two combined candidate index components, the two combined candidate index components indicating the two sets of the combination of the partition mode index and the two intra-prediction mode indexes.

10. The method according to claim 7, wherein, the candidate index code is associated with a single combined candidate index component, the single combined candidate index component indicating a first set of the two sets of combinations of the partitioning mode index and the two intra prediction mode indexes, a second set of the two sets of combinations of the partitioning mode index and the two intra prediction mode indexes being a combination of a specific partitioning mode index and two specific intra prediction mode indexes, the specific partitioning mode index being set to the partitioning mode index associated with the single combined candidate index component, and the two specific intra prediction mode indexes being two intra prediction mode indexes adjacent to the two intra prediction mode indexes associated with the single combined candidate index component, the single combined candidate index component being one of the candidates in the list.

11. The method according to claim 10, wherein, the two specific intra prediction mode indexes are at a fixed offset from the two intra prediction mode indexes associated with the single combined candidate index component.

12. The method according to claim 7, wherein, the candidate index code is associated with a single combined candidate index component, the single combined candidate index component indicating a first set of the two sets of combinations of the partitioning mode index and the two intra prediction mode indexes, a second set of the two sets of combinations of the partitioning mode index and the two intra prediction mode indexes being a combination of a specific partitioning mode index and two specific intra prediction mode indexes, the specific partitioning mode index being set to the partitioning mode index associated with the single combined candidate index component, and the two specific intra prediction mode indexes being set to two intra prediction mode indexes associated with another candidate index in the list, the partitioning mode index of the another candidate index being equal to the partitioning mode index associated with the single combined candidate index component.

13. The method according to claim 12, wherein, in response to determining that there are more than one candidate indexes in the list and the partitioning mode indexes of the more than one candidate indexes are equal to the partitioning mode index associated with the single combined candidate index component, the two specific intra prediction mode indexes are set to two intra prediction mode indexes associated with a candidate index in the list, the candidate index minimizing the absolute transform difference and SATD cost between the prediction and reconstruction of the template.

14. The method according to claim 7, wherein, The candidate index code is associated with a single combined candidate index component that indicates a first set of the two sets of combinations of the partition mode index and the two intra prediction mode indices. The second set of the two sets of combinations of the partition mode index and the two intra prediction mode indices is a combination of a specific partition mode index and two specific intra prediction mode indices. The specific partition mode index is a partition mode index adjacent to the partition mode index associated with the single combined candidate index component. The single combined candidate index component is a candidate index in a list, and the two specific intra prediction mode indices are set to the two intra prediction mode indices associated with the single combined candidate index component.

15. The method according to claim 14, wherein, the specific partition mode index is at a fixed offset from the partition mode index associated with the single combined candidate index component.

16. The method according to claim 7, wherein, the candidate index code is associated with a single combined candidate index component that indicates a first set of the two sets of combinations of the partition mode index and the two intra prediction mode indices. The second set of the two sets of combinations of the partition mode index and the two intra prediction mode indices is a combination of a specific partition mode index and two specific intra prediction mode indices. The specific partition mode index is set to be a partition mode index associated with another candidate index in the list. The two intra prediction mode indices of the other candidate index are equal to the two intra prediction mode indices associated with the single combined candidate index component, and the two specific intra prediction mode indices are set to the two intra prediction mode indices associated with the single combined candidate index component.

17. The method according to claim 16, wherein, in response to determining that there are more than one candidate index in the list and the two intra prediction mode indices of the more than one candidate index are equal to the partition mode index associated with the single combined candidate index component, the specific partition mode index is set to be a partition mode index associated with a candidate index in the list, and the candidate index minimizes the absolute transform difference and the SATD cost between the prediction and reconstruction of the template.

18. The method according to claim 7, wherein, The candidate index code is associated with a single combined candidate index component, the single combined candidate index component indicating a first set of the two sets of the combination of the partition mode index and the two intra prediction mode indexes, and a second set of the two sets of the combination of the partition mode index and the two intra prediction mode indexes being a combination of a specific partition mode index and two specific intra prediction mode indexes, the combination of the specific partition mode index and the two specific intra prediction mode indexes being associated with one candidate index in a list, the one candidate index minimizing the absolute transform difference and the SATD cost between the prediction and the reconstruction of the template.

19. A video coding system, comprising: a processor; and a memory coupled to the processor, wherein the processor is configured to execute program instructions stored in the memory to perform the method according to any one of claims 1 to 18.

20. A non - transitory computer - readable medium having program code stored thereon, the program code being executable by a processor to perform the method according to any one of claims 1 to 18.

21. A video decoding method, comprising: decoding a candidate index code from a bitstream, wherein the candidate index code is associated with an intra - partition prediction and a template, the template including one or more reference rows specified by indexes in a plurality of reference rows having a plurality of reconstructed samples, the plurality of reconstructed samples being spatially adjacent to a block associated with a spatial geometric partition mode SGPM.

22. The method according to claim 21, wherein the candidate index code is associated with a combination of a partition mode index, a first intra prediction mode index, and a second intra prediction mode index, the first intra prediction mode index indicating a first intra prediction mode of a first partition of the block based on a single reference row guided by a row index signaled in the bitstream, and the second intra prediction mode index indicating a second intra prediction mode of a second partition of the block based on the single reference row.

23. The method according to claim 21, wherein the candidate index code is associated with a combination of a partition mode index, a first intra prediction mode index, and a second intra prediction mode index, the first intra prediction mode index indicating a first intra prediction mode of a first partition of the block based on a first reference row guided by a first row index signaled in the bitstream, and the second intra prediction mode index indicating a second intra prediction mode of a second partition of the block based on a second reference row guided by a second row index signaled in the bitstream.

24. The method according to claim 21, wherein the candidate index code is associated with a combination of a partition mode index, a first intra prediction mode index, and a second intra prediction mode index, the first intra prediction mode index and the second intra prediction mode index indicating two given intra prediction modes of two partitions of the block associated with a fused intra - partition prediction, the fused intra - partition prediction being represented as follows: p fusion_partition = w 0 * p_partition(line i ) + w 1 * p_partition(line i+1 ), Among them, p fusion_partition represents the combined intra-partition prediction for each of the two partitions, w 0 and w 1 are two weighting factors, the sum of the two weighting factors is equal to 1, p_partition(·) represents an operation function, and the operation function is used to generate an intra-partition prediction based on a given reference line among the multiple reference lines in one of the two given intra-prediction modes, line i and line i+1 are two given reference lines among the multiple reference lines guided by two indices i and i + 1.

25. The method according to claim 24, wherein The index i is pre-determined to be zero or signaled in the bitstream.

26. The method according to claim 25, wherein, the index i and the candidate index code are signaled jointly or separately in one or more syntax structures of the bitstream.

27. The method according to claim 21, wherein, the candidate index code is associated with two sets of a combination of a partitioning mode index and two intra prediction mode indexes, the two sets are associated with the SGPM prediction fusion of the block, the SGPM prediction fusion is expressed as a weighted sum of the two sets and two weighting parameters, the two weighting parameters are two different fixed numbers, and the sum of the two different fixed numbers is equal to 1.

28. The method according to claim 27, wherein, each of the two weighting parameters is expressed as a function of the distance between the pixels in the block and the reference pixels in the template.

29. The method according to claim 27, wherein, the candidate index code is associated with two combined candidate index components, and the two combined candidate index components indicate the two sets of the combination of the partitioning mode index and the two intra prediction mode indexes.

30. The method according to claim 27, wherein, the candidate index code is associated with a single combined candidate index component, the single combined candidate index component indicates the first set of the two sets of the combination of the partitioning mode index and the two intra prediction mode indexes, the second set of the two sets of the combination of the partitioning mode index and the two intra prediction mode indexes is a combination of a specific partitioning mode index and two specific intra prediction mode indexes, the specific partitioning mode index is set to be the partitioning mode index associated with the single combined candidate index component, and the two specific intra prediction mode indexes are two intra prediction mode indexes adjacent to the two intra prediction mode indexes associated with the single combined candidate index component, and the single combined candidate index component is a candidate index in a list.

31. The method according to claim 30, wherein, the two specific intra prediction mode indexes are offset by a fixed distance from the two intra prediction mode indexes associated with the single combined candidate index component.

32. The method according to claim 27, wherein, The candidate index code is associated with a single combined candidate index component that indicates a first set of the two sets of combinations of the partition mode index and the two intra prediction mode indexes. A second set of the two sets of combinations of the partition mode index and the two intra prediction mode indexes is a combination of a specific partition mode index and two specific intra prediction mode indexes. The specific partition mode index is set to the partition mode index associated with the single combined candidate index component, and the two specific intra prediction mode indexes are set to two intra prediction mode indexes associated with another candidate index in the list, where the partition mode index of the another candidate index is equal to the partition mode index associated with the single combined candidate index component.

33. The method according to claim 32, wherein, in response to determining that there are more than one candidate indexes in the list and the partition mode indexes of the more than one candidate indexes are equal to the partition mode index associated with the single combined candidate index component, the two specific intra prediction mode indexes are set to two intra prediction mode indexes associated with a candidate index in the list, and the candidate index minimizes the absolute transform difference and the SATD cost between the prediction and the reconstruction of the template.

34. The method according to claim 27, wherein, the candidate index code is associated with a single combined candidate index component that indicates a first set of the two sets of combinations of the partition mode index and the two intra prediction mode indexes. A second set of the two sets of combinations of the partition mode index and the two intra prediction mode indexes is a combination of a specific partition mode index and two specific intra prediction mode indexes. The specific partition mode index is a partition mode index adjacent to the partition mode index associated with the single combined candidate index component. The single combined candidate index component serves as a candidate index in the list, and the two specific intra prediction mode indexes are set to the two intra prediction mode indexes associated with the single combined candidate index component.

35. The method according to claim 34, wherein, the specific partition mode index and the partition mode index associated with the single combined candidate index component are separated by a fixed offset.

36. The method according to claim 27, wherein, The candidate index code is associated with a single combined candidate index component that indicates a first set of the two sets of combinations of the partitioning mode index and the two intra prediction mode indices, and a second set of the two sets of combinations of the partitioning mode index and the two intra prediction mode indices is a combination of a specific partitioning mode index and two specific intra prediction mode indices. The specific partitioning mode index is set to be a partitioning mode index associated with another candidate index in a list, the two intra prediction mode indices of the other candidate index being equal to the two intra prediction mode indices associated with the single combined candidate index component, and the two specific intra prediction mode indices being set to the two intra prediction mode indices associated with the single combined candidate index component.

37. The method according to claim 36, wherein, in response to determining that there are more than one candidate index in the list and the two intra prediction mode indices of the more than one candidate index are equal to the partitioning mode index associated with the single combined candidate index component, the specific partitioning mode index is set to be a partitioning mode index associated with a candidate index in the list, the candidate index minimizing the absolute transform difference and the SATD cost between the prediction and the reconstruction of the template.

38. The method according to claim 27, wherein, the candidate index code is associated with a single combined candidate index component that indicates a first set of the two sets of combinations of the partitioning mode index and the two intra prediction mode indices, and a second set of the two sets of combinations of the partitioning mode index and the two intra prediction mode indices is a combination of a specific partitioning mode index and two specific intra prediction mode indices, and the combination of the specific partitioning mode index and the two specific intra prediction mode indices is associated with a candidate index in a list, the candidate index minimizing the absolute transform difference and the SATD cost between the prediction and the reconstruction of the template.

39. A video decoding system, comprising: a processor; and a memory coupled to the processor, wherein the processor is configured to execute program instructions stored in the memory to perform the method according to any one of claims 21 to 38.

40. A non-transitory computer-readable medium having program code stored thereon that can be executed by a processor to perform the method according to any one of claims 21 to 38.

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