Sub-partitioning in intra coding

Abstract

To provide a method, a device, and a system related to video processing.SOLUTION: In an exemplary embodiment, a method for processing video includes executing conversion between a current picture block of video and a coded expression of the video by using an intra sub-block partitioning (ISP) mode. By using the ISP mode, prediction is determined for each sub-partition by using an intra-prediction process based on a sample in a current picture. The block is partitioned in a plurality of sub-partitions including a first sub-partition located on the same upper left corner position as the upper left corner position of the block.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] This application is a divisional application of Patent Application No. 2023-188074 filed on November 2, 2023, which is based on Patent Application No. 2022-513061 filed on February 25, 2022, which is a national phase application of International Patent Application No. PCT / CN2020 / 112425 filed on August 31, 2020, which claims priority to and the benefit of International Patent Application No. PCT / CN2019 / 103762 filed on August 30, 2019. The entire disclosures of the aforementioned applications are incorporated by reference as part of the disclosure of this application.

[0002] This patent document relates to video coding and decoding. [Background technology]

[0003] Despite advances in video compression, digital video still accounts for the largest bandwidth usage in the Internet and other digital communications networks. As the number of connected user devices capable of receiving and displaying video increases, the bandwidth demands for digital video usage are expected to continue to increase. Summary of the Invention

[0004] Devices, systems and methods relating to digital video coding, and in particular to video and image coding and decoding, in which an intra sub-partition mode is used for coding or decoding video blocks.

[0005] In one exemplary aspect, a method of video processing is disclosed. The method includes performing a conversion between a block of a current picture of a video and a coded representation of the video using an intra sub-block partitioning (ISP) mode. Using the ISP mode, a prediction is determined for each sub-partition using an intra prediction process based on samples in the current picture. The block is partitioned into a plurality of sub-partitions, including a first sub-partition having an upper-left corner location that is the same as the upper-left corner location of the block.

[0006] In yet another aspect, a method of video processing is disclosed. The method includes determining whether a wide-angle intra-prediction mode mapping is valid for a transformation between a block of a video and a coded representation of the video based on a rule. The wide-angle intra-prediction mode is a mode in which a reference sample and a predicted sample form an obtuse angle with respect to an upper-left direction. The rule specifies that if the coding tool is valid for the transformation of the block, a dimension of a prediction unit is used for the determination. The method also includes performing the transformation based on the determination.

[0007] In yet another aspect, a method of video processing is disclosed. The method includes performing a conversion between a coding unit of a video domain of a video and a coded representation of the video. The coding unit is partitioned into one or more partitions, and the coding unit is coded into the coded representation using a quantized residual signal obtained by an intra prediction process of each of the one or more partitions. The coded representation includes a syntax element indicating a quantization parameter used for quantization. The syntax element is included in the coded representation at most once for a coding unit and indicates a difference between a value of the quantization parameter and another quantization value based on a previously processed coding unit of the video.

[0008] In yet another aspect, a method of video processing is disclosed. The method includes determining whether a transform operation is skipped during encoding or an inverse transform operation is skipped during decoding for a transformation between a block of a video including one or more partitions and a coded representation of the video using an intra sub-block partitioning (ISP) mode based on characteristics of the block or the ISP mode. Using the ISP mode, a prediction is determined for each sub-partition using an intra prediction process based on samples in a current picture. The method also includes performing the transformation based on the determination.

[0009] In yet another aspect, a method of video processing is disclosed. The method includes, for a conversion between a block of a video including one or more partitions and a coded representation of the video, determining a type of transform to be used during the conversion based on whether an intra sub-block partitioning (ISP) mode is used for the conversion. Using the ISP mode, a prediction is determined for each sub-partition using an intra prediction process based on samples in the current picture. The conversion includes applying the transform before encoding to the coded representation during encoding, or applying an inverse transform of the transform to coefficient values ​​parsed from the coded representation before reconstructing sample values ​​of the block. The method also includes performing the conversion based on the determination.

[0010] In yet another aspect, a method of video processing is disclosed. The method includes determining a restriction on an intra sub-block partitioning (ISP) mode based on whether a lossless coding process is applied to a block of a video including one or more partitions and a coded representation of the video. Using the ISP mode, a prediction is determined for each sub-partition using an intra prediction process based on samples in a current picture. The method also includes performing the conversion based on the determination.

[0011] In yet another aspect, a method of video processing is disclosed. The method includes performing a transformation between a video domain coding unit of a video and a coded representation of the video according to a rule. The coding unit is divided into a plurality of transform units. The rule specifies a relationship between a quantization parameter (QP) for the coding unit and one or more quantization parameters of the plurality of transform units.

[0012] In yet another aspect, a method of video processing is disclosed. The method includes determining whether and / or how to apply a deblocking filter to an edge based on a quantization parameter (QP) of a transform unit related to the edge for a transformation between a video domain and a coded representation of the video domain. The video domain includes one or more coding units and one or more transform units. The method also includes performing the transformation based on the determination.

[0013] In yet another aspect, a method of video processing is disclosed that includes determining, for a conversion between a video unit including one or more sub-partitions and a coded representation of the video unit, that the conversion uses an intra sub-block partitioning mode, and, based on the determination, performing the conversion such that an intra prediction process is used for the conversion of each of the one or more sub-partitions.

[0014] In yet another exemplary aspect, another method of video processing is disclosed. The method includes: determining whether wide-angle intra-prediction mapping is used during conversion between the video block and a coded representation of the video block based on applicability of a coding tool and / or a size of a prediction unit of the video block without using a coding unit size of the video block, and performing the conversion based on a result of the determination.

[0015] In yet another exemplary aspect, another method of video processing is disclosed, the method including, for transforming between a video domain including a coding unit, the coding unit including intra sub-block partitions, and a coded representation of the video domain, determining a delta quantization parameter (delta QP) applicable to transforming all intra sub-block partitions of the coding unit, and performing the transform using the delta QP, the delta QP being signaled to the coding unit in the coded representation.

[0016] In yet another exemplary aspect, another method of video processing is disclosed, the method including, for transforming between the video domain and a coded representation in the video domain, determining a quantization parameter (QP) used for transforming a coding unit (CU) in the video domain based on a QP of a transform unit (TU) in the video domain, and performing the transform using the QP of the TU and / or the QP of the CU.

[0017] In yet another exemplary aspect, another method of video processing is disclosed, the method including: determining whether to apply a deprotection filter to an edge of a video block for conversion between a video domain including one or more coding units and one or more transform units based on the transform unit to which the edge belongs; and performing the conversion based on the determination.

[0018] In yet another example aspect, another method of video processing is disclosed that includes determining, for a conversion between a video block and a coded representation of the video block using an intra sub-partitioning mode, whether a transform operation is to be skipped based on a dimension of a coding block, a prediction block, or a transform, and performing the conversion based on the determination.

[0019] In yet another example aspect, another method of video processing is disclosed that includes determining a type of transform to be applied based on whether an intra-subpartitioning mode or a lossless coding mode is used for converting between a video block and a coded representation of the video block, and performing the conversion based on the determination.

[0020] In yet another exemplary aspect, another method of video processing is disclosed that includes performing a transformation between a video block and a coded representation of the video block with a rule of exclusivity according to whether a lossless coding mode is used for the transformation or an intra-subpartitioning mode is used for the transformation, the coded representation including an indication of whether the lossless coding mode or the intra-subpartitioning mode is used.

[0021] In yet another representative aspect, the above-described methods are embodied in the form of processor executable code and stored on a computer readable program medium.

[0022] In yet another representative aspect, a device configured or operable to perform the above-mentioned method is disclosed. The device may include a processor programmed to implement the method.

[0023] In yet another representative aspect, a video decoder device may implement the methods described herein.

[0024] These and other aspects and features of the disclosed technology are described in more detail in the drawings, specification and claims. [Brief description of the drawings]

[0025] [Figure 1] FIG. 2 is a block diagram illustrating an example of sub-partitioning.

[0026] [Diagram 2] FIG. 2 is a block diagram illustrating an example of sub-partitioning.

[0027] [Diagram 3] FIG. 1 is a block diagram of an example implementation of a hardware platform for video processing.

[0028] [Figure 4] 1 is a flowchart of an exemplary method for video processing.

[0029] [Diagram 5] 1 is a block diagram of an example video processing system in which the disclosed techniques may be implemented.

[0030] [Figure 6] 1 is a flowchart representation of a method for video processing in accordance with the present technology.

[0031] [Figure 7] 4 is a flowchart representation of another method for video processing in accordance with the present technology.

[0032] [Figure 8] 4 is a flowchart representation of another method for video processing in accordance with the present technology.

[0033] [Figure 9] 4 is a flowchart representation of another method for video processing in accordance with the present technology.

[0034] [Figure 10] 4 is a flowchart representation of another method for video processing in accordance with the present technology.

[0035] [Figure 11] 4 is a flowchart representation of another method for video processing in accordance with the present technology.

[0036] [Figure 12] 4 is a flowchart representation of another method for video processing in accordance with the present technology.

[0037] [Figure 13] 11 is a flowchart representation of yet another method for video processing in accordance with the present technology. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] This document relates to video coding techniques. Specifically, it relates to intra sub-partitioning prediction in video coding. It may be applied to existing video / image coding standards such as HEVC, or to a standard to be finalized (Versatile Video Coding). It may also be applicable to future video coding standards or video codecs.

[0039] Embodiments of the disclosed techniques may be applied to existing video coding standards (e.g., HEVC, H.265) and future standards to improve compression performance. Section headings are used in this document to improve readability of the specification, but in no way limit the description or embodiments (and / or implementations) to only the respective sections.

[0040] 1. Initial discussion

[0041] Video coding standards have evolved primarily through the development of well-known ITU-T and ISO / IEC standards. ITU-T produced H.261 and H.263, ISO / IEC produced MPEG-1 and MPEG-4 Visual, and the two organizations jointly produced H.262 / MPEG-2 Video and H.264 / MPEG-4 AVC (Advanced Video Coding) and H.265 / HEVC standards. Starting with H.262, video coding standards are based on a hybrid video coding structure where temporal prediction plus transform coding is utilized. In order to explore future video coding technologies beyond HEVC, the Joint Video Exploration Team (JVET) was jointly established by VCEG and MPEG in 2015. Since then, many new methods have been adopted by JVET and put into reference software named the Joint Exploration Model (JEM). In April 2018, the JVET (Joint Video Expert Team) was established by VCEG (Q6 / 16) and ISO / IEC JTC1 SC29 / WG11 (MPEG) to work on the VVC standard, which aims to reduce the bit rate by 50% compared to HEVC.

[0042] 1.1 Exemplary Intra-Subpartition (ISP) Implementation

[0043] In some embodiments, the ISP tool divides the luma intra-prediction block into two or four sub-partitions vertically or horizontally depending on the dimension of the block size, as shown in Table 1. Figures 1 and 2 show examples of two possibilities. Figure 1 shows an example of partitioning 4x8 and 8x4 blocks. Figure 2 shows an example of partitioning all blocks except 4x8, 8x4, and 4x4. All sub-partitions meet the condition of having at least 16 samples. [Table 1]

[0044] For each of these subpartitions, a residual signal is generated by entropy decoding the coefficients transmitted by the encoder, then inverse quantizing and inverse transforming them. The subpartitions are then intra predicted, and finally, the corresponding reconstructed samples are obtained by adding the residual signal to the prediction signal. Thus, the reconstructed values ​​of each subpartition are available to generate a prediction for the next subpartition, which repeats the process, and so on. All subpartitions share the same intra mode.

[0045] Based on the intra mode and the split used, two different classes of processing orders are used, which are called normal order and reverse order. In normal order, the first processed subpartition is the one that contains the top-left sample of the CU and continues downward (horizontal split) or right (vertical split). As a result, the reference samples used to generate the subpartition prediction signal are located only to the left and above the line. On the other hand, the reverse order is the one that starts with the subpartition that contains the bottom-left sample of the CU and continues upward, or starts with the subpartition that contains the top-right sample of the CU and continues leftward.

[0046] Exemplary ISP-related syntax, semantics, and processes are presented below. [Table 2] TIFF2025026531000004.tif238161TIFF2025026531000005.tif187161TIFF202502653100 0006.tif220168TIFF2025026531000007.tif161168TIFF2025026531000008.tif237168TI FF2025026531000009.tif237168TIFF2025026531000010.tif232166TIFF20250265310000 11.tif238166TIFF2025026531000012.tif238166TIFF2025026531000013.tif188166[Outer 1] TIFF2025026531000014.tif231170TIFF2025026531000015.tif501708.4.5 Decoding process for intra blocks 8.4.5.1 General Decoding Process for Intra Blocks The inputs to this process are as follows: - A sample position (xTb0, yTb0) that specifies the top-left sample of the current transform block relative to the top-left sample of the current picture. - variable nTbW that specifies the width of the current transform block - Variable nTbH that specifies the height of the current transform block - variable predModeIntra that specifies the intra prediction mode - variable cIdx that specifies the color component of the current block The output of this process is a modified, reconstructed picture before in-loop filtering. The maximum transform block width, maxTbWidth, and height, maxTbHeight, are derived as follows:

number

number

number

number

number

number

number

number

number

number

number

[0047] 2. Examples of technical problems solved by the technical solutions provided in this document

[0048] Some example problems are listed as follows:

[0049] (1) In some scenarios, xPartIdx and yPartIdx are incremented by xPardInc and yPartInc before invoking the intra-sample prediction process for the first TU. Therefore, when ISP is applied, e.g., xPartInc or yPartInc is not equal to zero, the first part of the CU cannot be predicted properly.

[0050] (2) Wide-angle intra-prediction mode mapping is performed according to CU dimensions instead of TU dimensions when ISP is applied.

[0051] (3) Delta QP is signaled to the CU coded by the ISP. However, there may be a delay during which the delta QP is not signaled in the first TU of the ISP.

[0052] (4) Transform skip is not allowed for ISP-coded blocks.

[0053] (5) Depending on whether the current block is ISP coded, intra-prediction reference samples are fetched.

[0054] (6) The implicit transform selection approach does not consider the case where the TU is not the prediction unit when the ISP is applied.

[0055] (7) The deblocking filter needs access to the QP used to encode / decode the coding block that covers the samples at the edge. However, when one CU contains multiple TUs (eg, when ISP is enabled), the QP of a coding block (eg, a CU) is undefined.

[0056] 3. List of Exemplary Embodiments and Techniques

[0057] The following list should be considered as examples to illustrate the general concept. These items should not be interpreted narrowly. Furthermore, these items can be combined in any manner.

[0058] In the following description, the term "ISP" may not be interpreted narrowly. Any kind of tool that can split one CU into multiple TU / PUs may also be treated as an ISP. 1. When ISP is used, the intra prediction process should be applied to each subpartition, including the first subpartition that has the same top-left position as the current CU. In one example, the variables xPartIdx, yPartIdx and xPartPbIdx defined in section 8.4.5.1 (of the VVC standard) may be updated after intra prediction processing and / or scaling / transform processing and / or reconstruction processes. 2. When a certain coding tool is applied, wide-angle intra-prediction mode mapping is performed depending on the prediction unit dimension instead of the CU dimension. Alternatively, when a particular coding tool is applied, wide-angle intra prediction is not applied. i. In one example, wide-angle intra-prediction mapping is not invoked when a particular coding tool is applied. ii. In one example, when a particular coding tool is applied, the wide-angle intra-prediction mapping is the same mapping, eg, any mode M is preserved at M after mapping. b. In one example, the particular coding tool may be an ISP. 3. When ISP is applied, the delta QP may be signaled only once for the entire CU. In one example, it may be signaled in the first TU. b. Alternatively, when an ISP is applied, the delta QP is always signaled in the last TU. c. Alternatively, when the ISP applies, the delta QP is not signaled. d. In one example, the delta QP is signaled with a particular TU (first / last), regardless of whether it contains non-zero coefficients (luma block or multiple luma and chroma blocks). i. Alternatively, delta QP is signaled with a particular TU (first / last) only when it contains non-zero coefficients (luma block or multiple luma and chroma blocks). 1) Alternatively, furthermore, if there are no non-zero coefficients, delta QP is inferred to be 0. 4. It is proposed to define the QP of a CU as the QP associated with the TUs in the CU. In one example, the QP of a CU may be defined as the QP associated with the first / last TU in the CU. b. Alternatively, the QP of a CU may be defined as the QP before adding the delta QP for the different TUs in the current CU. c. Alternatively, the QP of a CU may be defined as a QP derived from a function (eg, average) of the QPs of multiple TUs with a delta QP applied. d. In one example, how to apply the deblocking filter may use the QP of the CU defined above. 5. Whether / how to apply a deblocking filter (e.g. luma / chroma block edge determination) may depend on the QP used for the transform block / transform unit covering the corresponding samples instead of the coding unit. Alternatively, when one block is coded in ISP mode, the check of the QP of the CU may be modified to check the QP of the TU. b. Alternatively, when one block is larger than the VPDU / maximum transform block size, the check of the QP of the CU may be modified to check the QP of the TU. 6. Transform skip may be used when an ISP is applied. In one example, whether transform skip is used when ISP is applied may depend on the dimensions of the coding block / prediction block / transform block. b. In one example, whether a transform skip is used when an ISP is applied may depend on whether a vertical ISP or a horizontal ISP is applied. 7. The same intra-prediction reference samples are fetched regardless of whether the current block is ISP coded or not. a. In one example, assume that the width and height of the current transform block are W and H, respectively, and then when the current block is ISP coded, 2×W upper neighboring samples and 2×H left neighboring samples are fetched. 8. Implicit transform selection is performed differently depending on whether an ISP is used or not. In one example, the horizontal transform and / or the vertical transform may be selected depending on whether the transform block width is greater than K, where K is an integer such as 1 or 2. 9. The horizontal transform and / or the vertical transform may be selected depending on whether the transform block height is greater than K, where K is an integer such as 1 or 2. When lossless coding is applied, certain transforms may be restricted for ISP coded blocks. a. When lossless coding is applied, the 4x4 transform may be constrained for ISP coded blocks. b. In one example, when lossless coding is applied, a transform size restriction may be applied to the ISP coded block that forces the transform size to P×Q, such as 4×4. i. In one example, if an M×N block is split vertically into four M / 4×N subpartitions by ISP mode, for each subpartition, the M / 4×N block may be made into a 4×4 transform block to perform transformation and quantization. c. In one example, when lossless coding is applied, coding block size restrictions may be applied to the ISP block. i. In one example, the width of each ISP sub-partition may be no less than 4. ii. In one example, the height of each ISP sub-partition may be no less than 4. d. In one example, when lossless coding is applied, the ISP split flag (such as intra_subpartitions_split_flag) may depend on the coding block dimension. i. In one example, any split direction (horizontal or vertical) that causes the width or height of an ISP subpartition to be less than 4 is not allowed. ii. In one example, for an 8x16 ISP coded block, the split flag may be inferred to be split horizontally, and therefore, the ISP split flag (such as intra_subpartitions_split_flag) is not signaled but is inferred. 10. When lossless coding is applied, the ISP may be disabled. a. Alternatively, lossless coding may be disabled in ISP coded blocks. b. In one example, when a CU / CTU / VPDU / slice / picture / sequence level trans-quant bypass enabled flag is true, the ISP may not be allowed for the current video unit (current CU / CTU / VPDU / slice / picture / sequence, etc.). 11. None of the TUs split by the ISP are allowed to have non-zero coefficients. a. Any TU split by the ISP is allowed to have only zero coefficients. b. The Cbf flag may be signaled for all TUs that are split by the ISP.

[0059] 4. Additional Exemplary Embodiments

[0060] In the following example, new additions are shown in bold italic font, and removals are shown between [[]].

[0061] 4.1 Exemplary Modifications of the General Decoding Process for Intra Blocks 8.4.5.1 General Decoding Process for Intra Blocks The inputs to this process are as follows: - A sample position (xTb0, yTb0) that specifies the top-left sample of the current transform block relative to the top-left sample of the current picture. - variable nTbW that specifies the width of the current transform block - Variable nTbH that specifies the height of the current transform block - variable predModeIntra that specifies the intra prediction mode - variable cIdx that specifies the color component of the current block The output of this process is a modified, reconstructed picture before in-loop filtering. The maximum transform block width, maxTbWidth, and height, maxTbHeight, are derived as follows:

number

number

number

number

number

[0062] 4.2 Exemplary Modifications in Wide-Angle Intra-Prediction Mapping for Intra Blocks Wide-angle intra-prediction mode mapping process The inputs to this process are as follows: - variable predModeIntra that specifies the intra prediction mode - Variable nTbW that specifies the transform block width - Variable nTbH that specifies the transform block height - variable cIdx that specifies the color component of the current block The output of this process is a modified intra-prediction mode predModeIntra. The output of this process is a modified intra-prediction mode predModeIntra. The variables nW and nH are derived as follows. - [[If IntraSubPartitionsSplitType is equal to ISP_NO_SPLIT or cIdx is not equal to 0, the following applies. ]]

number

number

number

number

number

number

number

number

[0063] 4.3 Example Modifications for Delta QP [Table 5] TIFF2025026531000052.tif237168TIFF2025026531000053.tif237168TIFF2025026531000054.tif57168

[0064] 4.4 Exemplary Modified Deblocking Filter Luma block edge decision processing The inputs to this process are as follows: - Picture sample array recPicture - A position (xCb, yCb) that specifies the top-left sample of the current coding block relative to the top-left luma sample of the current picture. - Position (xBl, yBl) that specifies the top-left sample of the current block relative to the top-left luma sample of the current coding. - The edgeType variable specifies whether to filter vertically (EDGE_VER) or horizontally (EDGE_HOR). - Variable bS that specifies the boundary filtering strength - Variable maxFilterLengthP that specifies the maximum filter length - variable maxFilterLengthQ that specifies the maximum filter length The output of this process is as follows: - Variables containing the decision dE, dEp and dEq - Modified filter length variables maxFilterLengthP and maxFilterLengthQ - variable t C Sample value p for i=0..maxFilterLengthP, j=0..maxFilterLengthQ and k=0,3 i,k , q j,k is derived as follows: - If edgeType is equal to EDGE_VER, the following applies:

number

number

number

number

number

number

number

number

number

number

number

number

[0065] FIG. 3 is a block diagram of a video processing device 300. The device 300 may be used to implement one or more of the methods described herein. The device 300 may be embodied in a smartphone, a tablet, a computer, an Internet of Things (IoT) receiver, etc. The device 300 may include one or more processors 302, one or more memories 304, and video processing hardware 306. The processor 302 may be configured to implement one or more of the methods described herein. The memory(s) 304 may be used to store data and code used to implement the methods and techniques described herein. The video processing hardware 306 may be used to implement some of the techniques described herein in a hardware circuit. In some embodiments, the hardware 306 may be at least partially within the processor 302, for example, within a graphics co-processor.

[0066] The following solution may be implemented as a preferred solution in some embodiments.

[0067] The following solutions may be implemented in conjunction with additional techniques described in the items listed in the previous section (e.g., item 1).

[0068] Solution 1. A method of video processing (e.g., method 400 shown in FIG. 4), comprising: determining (402) that for a transformation between a video unit including one or more sub-partitions and a coded representation of the video unit, that the transformation uses an intra sub-block partitioning mode; and, based on the determination, performing the transformation such that an intra prediction process is used for the transformation of each of the one or more sub-partitions (404).

[0069] Solution 2. The method according to Solution 1, wherein the intra prediction process includes updating the x partition index variable and the y partition index variable at the end of the intra prediction process.

[0070] The following solutions may be implemented in conjunction with additional techniques described in the items listed in the previous section (e.g., item 2).

[0071] Solution 3. A method of video processing, comprising: determining whether wide-angle intra-prediction mapping is used during conversion between a video block and a coded representation of the video block based on the applicability of a coding tool and / or a size of a prediction unit of the video block, without using a coding unit size of the video block, and performing the conversion based on a result of the determination.

[0072] Solution 4. The method according to Solution 3, wherein the determination is performed such that the wide-angle intra-prediction mapping is disabled due to the coding tool being a particular coding tool.

[0073] Solution 5. The method according to Solution 3, wherein the determination is performed such that the wide-angle intra-prediction mapping is an identity mapping due to the coding tool being a particular coding tool.

[0074] Solution 6. The method according to solutions 4-5, wherein the particular coding tool is an intra-subpartitioning tool.

[0075] The following solutions may be implemented in conjunction with additional techniques described in the items listed in the previous section (e.g., item 3).

[0076] Solution 7. A method of video processing, comprising: for transforming between a video domain including a coding unit, the video domain including intra sub-block partitions, and a coded representation of the video domain, determining a delta quantization parameter (delta QP) applicable to transforming all intra sub-block partitions of the coding unit, and performing the transformation using the delta QP, wherein the delta QP is signaled to the coding unit in the coded representation.

[0077] Solution 8. The method according to solution 7, wherein the delta QP is signaled together with the first transform unit in the video domain.

[0078] Solution 9. The method according to solution 7, wherein the delta QP is signaled together with the last transform unit in the video domain.

[0079] Solution 10. The method according to Solution 7, wherein the delta QP is signaled together with the transform unit having a predefined position in the video domain.

[0080] The following solutions may be implemented in conjunction with additional techniques described in the items listed in the previous section (e.g., item 4).

[0081] Solution 11. A method of video processing, comprising, for conversion between a video domain and a coded representation in the video domain, determining a quantization parameter (QP) to be used for conversion of a coding unit (CU) in the video domain based on a QP of a transform unit (TU) in the video domain, and performing the conversion using the QP of the TU and / or the QP of the CU.

[0082] Solution 12. The method according to Solution 11, wherein the QP for a CU is determined to be equal to the QP of a TU that is the last or first TU of a video region.

[0083] Solution 13. The method according to any of Solutions 11 to 12, wherein the QP of the CU is determined to be the QP of the TU before adding the delta QP to the QP of the TU.

[0084] Solution 14. The method according to any of Solutions 11 to 13, wherein performing the transformation further comprises selectively applying a deblocking filter to video regions during the transformation based on the QP of the CU.

[0085] The following solutions may be implemented in conjunction with additional techniques described in the items listed in the previous section (e.g., item 5).

[0086] Solution 15. A method of video processing, comprising: determining whether to apply a deprotection filter to an edge of a video block for transformation between a video domain including one or more coding units and one or more transform units, the application of which is based on the transform unit to which the edge belongs; and performing the transformation based on the determination.

[0087] Solution 16. The method according to Solution 15, further comprising using an intra sub-partition mode for transforming the video block, wherein the decision based on the transform unit is performed by checking a quantization parameter of the transform unit.

[0088] Solution 17. The method of Solution 15, wherein determining that the video block is of a size larger than a virtual pipeline data unit or a maximum transform block size and a base further comprises determining based on a quantization parameter of a coding unit to which the edge belongs.

[0089] The following solutions may be implemented in conjunction with additional techniques described in the items listed in the previous section (e.g., item 6).

[0090] Solution 18. A method of video processing, comprising: for a conversion between a video block and a coded representation of the video block using an intra sub-partitioning mode, determining whether a transform operation is to be skipped based on dimensions of a coding block, a prediction block, or a transform; and performing the conversion based on the determination.

[0091] Solution 19. The method according to Solution 18, wherein the intra-subpartitioning mode is a vertical intra-subpartitioning mode.

[0092] Solution 20. The method according to Solution 18, wherein the intra-subpartitioning mode is a horizontal intra-subpartitioning mode.

[0093] The following solutions may be implemented in conjunction with additional techniques described in the items listed in the previous section (e.g., item 7).

[0094] Solution 21. The method according to any of Solutions 1 to 20, wherein the transform using the intra subpartitioning mode includes using 2*W upper neighbouring samples and 2*H left neighbouring samples for transforms for a WxH transform block size.

[0095] The following solutions may be implemented in conjunction with additional techniques described in the items listed in the previous section (e.g., items 8 and 9).

[0096] Solution 22. A method of video processing comprising: determining a type of transform to be applied based on whether an intra-subpartitioning mode or a lossless coding mode is used for converting between a video block and a coded representation of the video block; and performing the conversion based on the determination.

[0097] Solution 23. The method according to Solution 22, wherein the determining further uses a transform block width in determining the type of transform.

[0098] Solution 24. The method according to any of Solutions 22-23, wherein the type of transform is a horizontal transform or a vertical transform.

[0099] Solution 25. A method according to any of Solutions 22 to 24, wherein if a lossless coding mode is used, determining the type of transform comprises determining to use a 4x4 transform.

[0100] Solution 26. A method according to any of Solutions 22 to 24, wherein if an intra-subpartition mode and a lossless coding mode are used, determining includes determining a type of transform to be a PxQ transform, where P and / or Q are integers depending on the size of the video block.

[0101] The following solutions may be implemented in conjunction with additional techniques described in the items listed in the previous section (e.g., item 10).

[0102] Solution 27. A video processing method comprising: performing a transformation between a video block and a coded representation of the video block with a rule of exclusivity according to which either a lossless coding mode is used for the transformation or an intra-subpartitioning mode is used for the transformation, the coded representation including an indication of whether a lossless coding mode or an intra-subpartitioning mode is used.

[0103] Solution 28. The method according to Solution 27, wherein the exclusivity rules further define that the lossless coding mode is disabled by the video block belonging to a coding unit, coding tree unit, virtual pipeline data unit, slice, picture or sequence level bypass enable flag mode.

[0104] The following solutions may be implemented in conjunction with additional techniques described in the items listed in the previous section (e.g., item 11).

[0105] Solution 29. A method according to any of Solutions 1 to 28, wherein a given transform unit split by partitioning in the intra-subpartitioning tool is not allowed to have all zero coefficients.

[0106] Solution 30. The method according to any of solutions 1 to 29, wherein converting comprises encoding the video into a coded representation.

[0107] Solution 31. A method according to any of Solutions 1 to 29, wherein converting comprises decoding the coded representation to generate pixel values ​​of the video.

[0108] Solution 32. A video decoding device comprising a processor configured to implement the methods defined in one or more of solutions 1 to 31.

[0109] Solution 33. A video encoding device comprising a processor configured to implement the methods defined in one or more of solutions 1 to 31.

[0110] Solution 34. A computer program product storing computer code which, when executed by a processor, causes the processor to implement a method according to any one of solutions 1 to 31.

[0111] Solution 35. A method, apparatus or system as described herein.

[0112] In the above solutions, performing a transformation involves using the results of previous decision steps during the encoding or decoding operation to arrive at a transformation result.

[0113] FIG. 5 is a block diagram illustrating an example video processing system 500 in which various techniques disclosed herein can be implemented. Various implementations may include some or all of the components of system 500. System 500 may include an input 502 for receiving video content. The video content may be received in raw or uncompressed format, e.g., 8 or 10 bit multi-component pixel values, or may be in a compressed or encoded format. Input 502 may represent a network interface, a peripheral bus interface, or a storage interface. Examples of network interfaces include wired interfaces such as Ethernet, passive optical network (PON), and wireless interfaces such as Wi-Fi or cellular interfaces.

[0114] The system 500 may include a coding component 504 that may implement various coding or encoding methods described in this document. The coding component 504 may reduce the average bit rate of the video from the input 502 to the output of the coding component 504 to generate a coded representation of the video. Thus, the coding techniques may be referred to as video compression or video transcoding techniques. The output of the coding component 504 may be stored or transmitted via a connected communication, as represented by component 506. The stored or communicated bitstream (or coded) representation of the video received at the input 502 may be used by component 508 to generate pixel values ​​or displayable video that are sent to a display interface 510. The process of generating a user-viewable video from the bitstream representation may be referred to as video decompression. Additionally, although certain video processing operations are referred to as "coding" operations or tools, it will be understood that the coding tools or operations are used in an encoder, or that corresponding decoding tools or operations that reverse the results of the coding are performed by a decoder.

[0115] Examples of peripheral bus interfaces or display interfaces include universal serial bus (USB), high definition multimedia interface (HDMI), or display port, etc. Examples of storage interfaces include serial advanced technology attachment (SATA), PCI, IDE interfaces, etc. The techniques described herein may be embodied in various electronic devices, such as mobile phones, laptops, smartphones, or other devices capable of performing digital data processing and / or video display.

[0116] 6 is a flow chart representation of a method 600 for video processing according to the present technology. The method 600 includes, at operation 610, performing a conversion between a block of a current picture of the video and a coded representation of the video using an intra sub-block partitioning (ISP) mode. Using the ISP mode, a prediction is determined for each sub-partition using an intra prediction process based on samples in the current picture. The block is partitioned into multiple sub-partitions, including a first sub-partition having the same upper left corner position as the upper left corner position of the block. In some embodiments, after the reconstruction process is invoked for one sub-partition, the x partition index variable and the y partition index variable are updated.

[0117] 7 is a flowchart representation of a method 700 for video processing according to the present technology. The method 700 includes, at operation 710, determining whether a wide-angle intra-prediction mode mapping is valid for a transform between a block of video and a coded representation of the video based on a rule. The wide-angle intra-prediction mode is a mode in which a reference sample and a predicted sample form an obtuse angle with respect to an upper-left direction. The rule specifies that if the coding tool is valid for transforming the block, the dimension of the prediction unit is used for the determination. The method 700 also includes, at operation 720, performing the transform based on the determination.

[0118] In some embodiments, the wide-angle intra-prediction mode mapping is not used when the coding tool is enabled for transforming the block. In some embodiments, the wide-angle intra-prediction mapping is the same mapping when the coding tool is enabled for transforming the block. In some embodiments, the coding tool includes an intra-sub-block partitioning (ISP) mode in which prediction is determined for each sub-partition using an intra-prediction process based on samples in the current picture.

[0119] 8 is a flowchart representation of a method 800 for video processing according to the present technology. The method 800 includes, at operation 810, performing a conversion between a coding unit of a video domain of the video and a coded representation of the video. The coding unit is partitioned into one or more partitions, and the coding unit is coded into the coded representation using a quantized residual signal obtained by an intra prediction process of each of the one or more partitions. The coded representation includes a syntax element indicating a quantization parameter used for quantization. The syntax element is included at most once in the coded representation for a coding unit, and the syntax element indicates a difference between a value of the quantization parameter and another quantization value based on a previously processed coding unit of the video.

[0120] In some embodiments, the difference in the value of the quantization parameter is omitted in the coded representation when an intra-sub-block partitioning process based on one or more partitions is used. In some embodiments, the difference in the value of the quantization parameter is signaled with the first transform unit in the video domain. In some embodiments, the difference in the value of the quantization parameter is signaled with the last transform unit in the video domain.

[0121] In some embodiments, the quantization parameter value difference is signaled with a particular transform unit regardless of whether the particular transform unit includes non-zero coefficients. In some embodiments, the quantization parameter value difference is signaled with a particular transform unit if the particular transform unit includes non-zero coefficients. In some embodiments, the quantization parameter value difference defaults to zero if the particular transform unit includes only zero coefficients. In some embodiments, the particular transform unit includes the first or last transform unit of a video region.

[0122] 9 is a flowchart representation of a method 900 for video processing according to the present technology. The method 900 includes, at operation 910, determining whether a transform operation is skipped during encoding or an inverse transform operation is skipped during decoding for a conversion between a block of a video including one or more partitions and a coded representation of the video using an intra sub-block partitioning (ISP) mode based on characteristics of the block or the ISP mode. Using the ISP mode, a prediction is determined for each sub-partition using an intra prediction process based on samples in the current picture. The method 900 also includes, at operation 920, performing a conversion based on the determination.

[0123] In some embodiments, the characteristics of the block include dimensions of the block. In some embodiments, the block includes a coding block, a prediction block, or a transform block. In some embodiments, the characteristics of the ISP mode include a direction in which the ISP is applied, the direction including vertical or horizontal. In some embodiments, the same reference samples are used for the transformation regardless of whether the ISP mode is used. In some embodiments, the block includes a transform block having a width W and a height H, and the transformation of the block uses 2×W neighboring samples above the block and 2×H neighboring samples to the left of the block.

[0124] FIG. 10 is a flow chart representation of a method 1000 for video processing according to the present technology. The method 1000 includes, at operation 1010, determining a type of transform to be used during the transformation for a transformation between a block of video including one or more partitions and a coded representation of the video based on whether an intra sub-block partitioning (ISP) mode is used for the transformation. Using the ISP mode, a prediction is determined for each sub-partition using an intra prediction process based on samples in the current picture. The transformation includes applying the transform before encoding to the coded representation during encoding, or applying an inverse transform of the transform to coefficient values ​​parsed from the coded representation before reconstructing sample values ​​of the block. The method 1000 also includes, at operation 1020, performing the transformation based on the determination.

[0125] In some embodiments, the type of transform includes a horizontal transform or a vertical transform. In some embodiments, the determining is further based on whether a width of the transform block is greater than a threshold K, where K is an integer equal to 1 or 2. In some embodiments, the determining is further based on whether a height of the transform block is greater than a threshold K, where K is an integer equal to 1 or 2.

[0126] 11 is a flowchart representation of a method 1100 for video processing according to the present technology. The method 1100 includes, at operation 1110, determining a restriction on an intra sub-block partitioning (ISP) mode based on whether a lossless coding process is applied to the block for conversion between a block of the video including one or more partitions and a coded representation of the video. Using the ISP mode, a prediction is determined for each sub-partition using an intra prediction process based on samples in the current picture. The method 1100 also includes, at operation 1120, performing the conversion based on the determination.

[0127] In some embodiments, the restriction includes enforcing a transform size restriction for a block coded using an ISP mode if a lossless coding mode is applied to the block. In some embodiments, the transform size restriction includes a 4×4 transform size. In some embodiments, the block has dimensions of M×N and includes four partitions, each having dimensions of (M / 4)×N, and each partition is split into 4×4 transform blocks to perform transform and / or quantization operations. In some embodiments, the restriction includes enforcing a coding block size restriction for a block coded using an ISP mode if a lossless coding mode is applied to the block. In some embodiments, the block includes one or more partitions, and a width of each of the one or more partitions is greater than or equal to 4. The block includes one or more partitions, and a height of each of the one or more partitions is greater than or equal to 4.

[0128] In some embodiments, when a lossless coding mode is applied to the block, the restriction specifies that the signaling of the syntax element in the coded representation depends on the dimensions of the individual partitions. The syntax element specifies the direction in which the block is split into one or more partitions. In some embodiments, the direction specified by the syntax element is not allowed if the width or height of an individual partition is smaller than 4. In some embodiments, the signaling of the syntax element is omitted in the coded representation and the value of the syntax element is derived based on the shape of the block.

[0129] In some embodiments, the restriction specifies that the ISP mode is disabled if a lossless coding process is applied to the block. In some embodiments, the restriction specifies that the ISP mode is enabled if a lossless coding process is not applied to the block. In some embodiments, the ISP mode is disabled for a video unit if a transquant bypass enabled syntax flag in the coded representation indicates that a lossless coding process is enabled at the video unit level. The video unit includes a coding unit, a coding tree unit, a virtual pipeline data unit, a slice, a picture, or a sequence. In some embodiments, none of the transform units determined using the ISP mode include non-zero coefficients. In some embodiments, all transform units determined using the ISP mode include only zero coefficients. In some embodiments, a syntax flag for all transform units indicating non-zero transform coefficients is signaled in the coded representation.

[0130] 12 is a flowchart representation of a method 1200 for video processing according to the present technology. The method 1200 includes, at operation 1210, performing a conversion between a coding unit of a video domain of the video and a coded representation of the video according to a rule. The coding unit is divided into a plurality of transform units. The rule specifies a relationship between a quantization parameter (QP) for the coding unit and one or more quantization parameters of the plurality of transform units.

[0131] In some embodiments, the QP of the coding unit is equal to the QP of the first transform unit or the last transform unit of the coding unit. In some embodiments, the QP of the coding unit is determined to be the QP of at least one transform unit in the coding unit before the difference between the value of the quantization parameter and another quantization value based on a previously processed coding unit of the video is added. In some embodiments, the QP of the coding unit is derived using a function of the QP of the one or more transform units to which the at least one delta QP has been applied, the delta QP being the difference between the value of the quantization parameter and another quantization value based on a previously processed coding unit of the video. In some embodiments, performing the transformation further includes selectively applying a deblocking filter to the coding unit during the transformation based on the QP of the coding unit.

[0132] 13 is a flowchart representation of a method 1300 for video processing according to the present technology. The method 1300 includes, at operation 1310, determining whether and / or how to apply a deblocking filter to an edge for a transformation between a video domain and a coded representation of the video domain that includes one or more coding units and one or more transform units based on a quantization parameter (QP) of a transform unit related to the edge. The method 1300 also includes, at operation 1320, performing the transformation based on the determination.

[0133] In some embodiments, the QP for the transform unit is used when an intra-subblock partitioning process is used to transform the video region. In some embodiments, the QP for the transform unit is used instead of the QP of the coding unit when the size of the video region is larger than the virtual pipeline data unit or the maximum transform block size.

[0134] In some embodiments, the transforming includes encoding the video into a coded representation, hi some implementations, the transforming includes decoding the coded representation to generate pixel values ​​for the video.

[0135] Some embodiments of the disclosed techniques include making a decision or determination to enable a video processing tool or mode. In one example, when a video processing tool or mode is enabled, an encoder uses or implements the tool or mode in processing blocks of video, but may not necessarily modify the resulting bitstream based on the use of the tool or mode. That is, conversion of blocks of video to a bitstream representation of video uses the video processing tool or mode when enabled based on the decision or determination. In another example, when a video processing tool or mode is enabled, a decoder processes the bitstream knowing that the bitstream has been modified based on the video processing tool or mode. That is, conversion of a bitstream representation of video to blocks of video is performed using the video processing tool or mode enabled based on the decision or determination.

[0136] Some embodiments of the disclosed techniques include making a decision or determination to disable a video processing tool or mode. In one example, when a video processing tool or mode is disabled, an encoder does not use the tool or mode in converting blocks of video to a bitstream representation of the video. In another example, when a video processing tool or mode is disabled, a decoder processes the bitstream knowing that the bitstream has not been modified using the video processing tool or mode that was enabled based on the decision or determination.

[0137] The disclosed and other solutions, examples, embodiments, modules, and functional operations described in this document can be implemented in digital electronic circuitry, or computer software, firmware, or hardware, including the structures disclosed in this document and their structural equivalents, or in a combination of one or more of them. The disclosed and other embodiments can be implemented as one or more computer program products, e.g., one or more modules of computer program instructions encoded on a computer-readable medium for executing or controlling the operation of a data processing device. The computer-readable medium can be a machine-readable storage device, a machine-readable storage substrate, a memory device, a composition affecting a machine-readable propagated signal, or a combination of one or more of them. The term "data processing device" encompasses all apparatus, devices, and machines for processing data, including, by way of example, a programmable processor, a computer, or multiple processors or computers. In addition to hardware, an apparatus can include code that creates an execution environment for the computer program in question, e.g., code that constitutes a processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them. A propagated signal is an artificially generated signal, for example a machine-generated electrical, optical, or electromagnetic signal generated to encode information for transmission to a suitable receiver device.

[0138] A computer program (also known as a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in several coordinated files (e.g., files that store one or more modules, subprograms, or portions of code). A computer program can be deployed to be executed on several computers that are located on one computer or at one site, or distributed across several sites and interconnected by a communications network.

[0139] The processes and logic flows described herein may be performed by one or more programmable processors executing one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows may also be performed by, and an apparatus may be implemented as, special purpose logic circuitry, such as an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit).

[0140] Processors suitable for executing computer programs include, by way of example, both general purpose and special purpose microprocessors, and any one or more processors of any kind of digital computer. Typically, a processor will receive instructions and data from a read-only memory or a random access memory or both. The essential elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Typically, a computer will also include, or be operatively coupled to receive and / or transfer data from, one or more mass storage devices for storing data, e.g., magnetic disks, magneto-optical disks, or optical disks. However, a computer need not have such devices. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, including, by way of example, semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices, magnetic disks, magneto-optical disks, e.g., internal hard disks or removable disks, and CD ROM and DVD-ROM disks. The processor and memory may be supplemented by, or incorporated in, special purpose logic circuitry.

[0141] Although this patent document contains many details, these should not be construed as limitations on the scope of any subject matter or what may be claimed, but rather as descriptions of features that may be specific to certain embodiments of a particular technique. Certain features described in this patent document in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Furthermore, although features may be described above as acting in a particular combination and may initially be claimed in their own right, one or more features from a claimed combination may, in some cases, be deleted from the combination, and the claimed combination may be subject to subcombinations or variations of the subcombination.

[0142] Similarly, although the figures depict acts in a particular order, this should not be understood as requiring such acts to be performed in a particular order or sequentially, or to perform all of the acts depicted, to achieve desired results. Further, the separation of various system components in the embodiments described in this patent document should not be understood as requiring such separation in all embodiments.

[0143] Only a few implementations and examples have been described, and other implementations, extensions and variations can be made based on what is described and shown in this patent document.

Claims

1. 1. A method for processing video data, comprising the steps of: determining whether a partitioning mode is used for a current video block of a video for conversion between the current video block and a bitstream of the video; if the partitioning mode is used for the current video block, partitioning the current video block into a plurality of sub-regions; performing the transformation based on the plurality of sub-regions; and The method of claim 1, wherein the multiple sub-regions share a same intra-prediction mode, the multiple sub-regions including a first sub-region having a same top-left corner location as the current video block.

2. if the partitioning mode is used for the current video block and the current video block is a luma transform block, deriving a variable indicative of a width-to-height ratio based on a width of the current video block and a height of the current video block; the variables are used to derive an intra-prediction mode in a mapping process of wide-angle intra-prediction modes for each of the plurality of sub-regions; The method of claim 1 , wherein the wide-angle intra-prediction mode is a mode in which a reference sample and a predicted sample form an obtuse angle with respect to an upper-left direction.

3. The method of claim 2 , wherein if the partitioning mode is not used for the current video block, the variable is derived based on the width of the current video block and the height of the current video block.

4. when the partitioning mode is used for the current video block, syntax elements for sub-regions containing non-zero coefficients are included in the bitstream; The method of claim 1 , wherein the syntax element indicates an absolute value of a difference between a quantization parameter of the subregion and its prediction.

5. The method of claim 1 , wherein if the partitioning mode is used for the current video block, the partitioning depends on a dimension of the current video block.

6. The method of claim 5 , wherein partitioning that reduces the width or height of a sub-region below a predefined value is not allowed.

7. If the current video block has a size of M×2M, then a partition of the current video block is inferred to be different from a partition of a video block having a size different from M×2M. The method of claim 5 , wherein M is a predefined integer.

8. The method of any one of claims 1 to 7, wherein the transforming comprises encoding the current video block into the bitstream.

9. The method of any one of claims 1 to 7, wherein the converting comprises decoding the current video block from the bitstream.

10. 1. An apparatus for processing video data, the apparatus including a processor and a non-transitory memory having instructions that, when executed by the processor, cause the processor to: determining whether a partitioning mode is used for a current video block of a video for conversion between the current video block and a bitstream of the video; if the partitioning mode is used for the current video block, partitioning the current video block into a plurality of sub-regions; performing the transformation based on the plurality of sub-regions; The apparatus, wherein the multiple sub-regions share a same intra-prediction mode, the multiple sub-regions including a first sub-region having a same top-left corner location as the current video block.

11. A non-transitory computer-readable storage medium storing instructions, the non-transitory computer-readable storage medium storing instructions for a processor to: determining whether a partitioning mode is used for a current video block of a video for conversion between the current video block and a bitstream of the video; if the partitioning mode is used for the current video block, partitioning the current video block into a plurality of sub-regions; performing the transformation based on the plurality of sub-regions; 11. The non-transitory computer-readable storage medium, wherein the multiple sub-regions share a same intra-prediction mode, the multiple sub-regions including a first sub-region having a same top-left corner location as the current video block.

12. 1. A method for storing a video bitstream, comprising: determining whether a partitioning mode is being used for a current video block of the video; if the partitioning mode is used for the current video block, partitioning the current video block into a plurality of sub-regions; generating the bitstream based on the plurality of sub-regions; storing the bitstream on a non-transitory computer-readable recording medium; The method of claim 1, wherein the multiple sub-regions share a same intra-prediction mode, the multiple sub-regions including a first sub-region having a same top-left corner location as the current video block.

Images