WO2020253810A1 - Outils de codage pour composantes de chrominance - Google Patents

Outils de codage pour composantes de chrominance Download PDF

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WO2020253810A1
WO2020253810A1 PCT/CN2020/097021 CN2020097021W WO2020253810A1 WO 2020253810 A1 WO2020253810 A1 WO 2020253810A1 CN 2020097021 W CN2020097021 W CN 2020097021W WO 2020253810 A1 WO2020253810 A1 WO 2020253810A1
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transform
video
block
coding
mts
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PCT/CN2020/097021
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English (en)
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Kai Zhang
Li Zhang
Hongbin Liu
Zhipin DENG
Yue Wang
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Beijing Bytedance Network Technology Co., Ltd.
Bytedance Inc.
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Priority to CN202080045375.3A priority Critical patent/CN114026865A/zh
Publication of WO2020253810A1 publication Critical patent/WO2020253810A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/12—Selection from among a plurality of transforms or standards, e.g. selection between discrete cosine transform [DCT] and sub-band transform or selection between H.263 and H.264
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/134—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or criterion affecting or controlling the adaptive coding
    • H04N19/157—Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/169—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
    • H04N19/17—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object
    • H04N19/176—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object the region being a block, e.g. a macroblock
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/169—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
    • H04N19/186—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being a colour or a chrominance component

Definitions

  • This patent document relates to video coding techniques, devices and systems.
  • Devices, systems and methods related to digital video coding, and specifically, coding tools for chroma components are described.
  • the described methods may be applied to both the existing video coding standards (e.g., High Efficiency Video Coding (HEVC) ) and future video coding standards (e.g., Versatile Video Coding (VVC) ) or codecs.
  • HEVC High Efficiency Video Coding
  • VVC Versatile Video Coding
  • the disclosed technology may be used to provide an example method for video processing.
  • This method includes applying, as part of a conversion between a current block of a video and a bitstream representation of the video, a coding tool to one or more chroma components of the video based on a selective application of the coding tool to a corresponding luma component of the video, and performing the conversion.
  • the disclosed technology may be used to provide an example method for video processing.
  • This method includes applying, as part of a conversion between a current block of a first chroma component of a video and a bitstream representation of the video, a coding tool to the current block based on a selective application of the coding tool to one or more corresponding blocks of other chroma components of the video, and performing the conversion.
  • the disclosed technology may be used to provide an example method for video processing.
  • This method includes applying, as part of a conversion between a current block of a video and a bitstream representation of the video, a coding tool to a luma component of the video based on a selective application of the coding tool to one or more corresponding chroma components of the video, and performing the conversion.
  • the disclosed technology may be used to provide an example method for video processing.
  • This method includes performing a conversion between a current block of a video and a bitstream representation of the video, wherein whether a multiple transform set (MTS) index and/or a transform skip flag is signaled in the bitstream representation is based on an enablement of a block differential pulse-code modulation (BDPCM) -based coding tool for the current block.
  • MTS multiple transform set
  • BDPCM block differential pulse-code modulation
  • the disclosed technology may be used to provide an example method for video processing.
  • This method includes selecting, based on a type of a multiple transform set (MTS) for a current block of a video, a coding type with a plurality of bins, and applying, as part of a conversion between the current block and a bitstream representation of the video, the coding type to an indication of the type of the MTS.
  • MTS multiple transform set
  • the above-described method is embodied in the form of processor-executable code and stored in a computer-readable program medium.
  • a device that is configured or operable to perform the above-described method.
  • the device may include a processor that is programmed to implement this method.
  • a video decoder apparatus may implement a method as described herein.
  • FIG. 1 shows an example of an encoder block diagram.
  • FIG. 2 shows an example of 67 intra prediction modes.
  • FIGS. 3A and 3B show examples of reference samples for wide-angle intra prediction modes for non-square blocks.
  • FIG. 4 shows an example of a discontinuity when using wide-angle intra prediction.
  • FIGS. 5A-5D show examples of samples used by a position-dependent intra prediction combination (PDPC) method.
  • PDPC position-dependent intra prediction combination
  • FIG. 6 shows an example of divisions of 4 ⁇ 8 and 8 ⁇ 4 blocks.
  • FIG. 7 shows an example of divisions all blocks except 4 ⁇ 8, 8 ⁇ 4 and 4 ⁇ 4.
  • FIG. 8 shows an example of dividing a block of 4x8 samples into two independently decodable areas.
  • FIG. 9 shows an example of the order of processing of the rows of pixels to maximize throughput for 4xN blocks with vertical predictor.
  • FIG. 10 shows an example of a secondary transform in JEM.
  • FIG. 11 shows an example of the proposed reduced secondary transform (RST) .
  • FIG. 12 shows examples of the forward and inverse reduced transforms.
  • FIG. 13 shows an example of a forward RST 8 ⁇ 8 process with a 16 ⁇ 48 matrix.
  • FIG. 14 shows an example of scanning positions 17 through 64 in an 8 ⁇ 8 block for a non-zero element.
  • FIG. 15 shows an example of sub-block transform modes SBT-V and SBT-H.
  • FIGS. 16A-16E show flowcharts of example methods for multiple transforms, in accordance with the disclosed technology.
  • FIG. 17 is a block diagram of an example of a hardware platform for implementing a visual media decoding or a visual media encoding technique described in the present document.
  • FIG. 18 is a block diagram of an example video processing system in which disclosed techniques maybe implemented.
  • Video codecs typically include an electronic circuit or software that compresses or decompresses digital video, and are continually being improved to provide higher coding efficiency.
  • a video codec converts uncompressed video to a compressed format or vice versa.
  • the compressed format usually conforms to a standard video compression specification, e.g., the High Efficiency Video Coding (HEVC) standard (also known as H. 265 or MPEG-H Part 2) , the Versatile Video Coding (VVC) standard to be finalized, or other current and/or future video coding standards.
  • HEVC High Efficiency Video Coding
  • VVC Versatile Video Coding
  • Embodiments of the disclosed technology may be applied to existing video coding standards (e.g., HEVC, H. 265) and future standards to improve runtime performance.
  • Section headings are used in the present document to improve readability of the description and do not in any way limit the discussion or the embodiments (and/or implementations) to the respective sections only.
  • Color space also known as the color model (or color system)
  • color model is an abstract mathematical model which simply describes the range of colors as tuples of numbers, typically as 3 or 4 values or color components (e.g. RGB) .
  • color space is an elaboration of the coordinate system and sub-space.
  • YCbCr, Y′CbCr, or Y Pb/Cb Pr/Cr also written as YCBCR or Y'CBCR, is a family of color spaces used as a part of the color image pipeline in video and digital photography systems.
  • Y′ is the luma component and CB and CR are the blue-difference and red-difference chroma components.
  • Y′ (with prime) is distinguished from Y, which is luminance, meaning that light intensity is nonlinearly encoded based on gamma corrected RGB primaries.
  • Chroma subsampling is the practice of encoding images by implementing less resolution for chroma information than for luma information, taking advantage of the human visual system's lower acuity for color differences than for luminance.
  • 4: 2: 0 the horizontal sampling is doubled compared to 4: 1: 1, but as the Cb and Cr channels are only sampled on each alternate line in this scheme, the vertical resolution is halved. The data rate is thus the same.
  • Cb and Cr are each subsampled at a factor of 2 both horizontally and vertically.
  • 4: 2: 0 schemes having different horizontal and vertical siting.
  • Cb and Cr are co-sited horizontally.
  • Cb and Cr are sited between pixels in the vertical direction (sited interstitially) .
  • Cb and Cr are sited interstitially, halfway between alternate luma samples.
  • Cb and Cr are co-sited in the horizontal direction. In the vertical direction, they are co-sited on alternating lines.
  • FIG. 1 shows an example of encoder block diagram of VVC, which contains three in-loop filtering blocks: deblocking filter (DF) , sample adaptive offset (SAO) and ALF.
  • DF deblocking filter
  • SAO sample adaptive offset
  • ALF utilize the original samples of the current picture to reduce the mean square errors between the original samples and the reconstructed samples by adding an offset and by applying a finite impulse response (FIR) filter, respectively, with coded side information signaling the offsets and filter coefficients.
  • FIR finite impulse response
  • ALF is located at the last processing stage of each picture and can be regarded as a tool trying to catch and fix artifacts created by the previous stages.
  • the number of directional intra modes is extended from 33, as used in HEVC, to 65.
  • the additional directional modes are depicted as red dotted arrows in FIG. 2, and the planar and DC modes remain the same.
  • These denser directional intra prediction modes apply for all block sizes and for both luma and chroma intra predictions.
  • Conventional angular intra prediction directions are defined from 45 degrees to -135 degrees in clockwise direction as shown in FIG. 1.
  • VTM2 several conventional angular intra prediction modes are adaptively replaced with wide-angle intra prediction modes for the non-square blocks.
  • the replaced modes are signaled using the original method and remapped to the indexes of wide angular modes after parsing.
  • the total number of intra prediction modes is unchanged (e.g., 67) , and the intra mode coding is unchanged.
  • every intra-coded block has a square shape and the length of each of its side is a power of 2. Thus, no division operations are required to generate an intra-predictor using DC mode.
  • blocks can have a rectangular shape that necessitates the use of a division operation per block in the general case. To avoid division operations for DC prediction, only the longer side is used to compute the average for non-square blocks.
  • conventional angular intra prediction directions are defined from 45 degrees to -135 degrees in clockwise direction.
  • VTM2 several conventional angular intra prediction modes are adaptively replaced with wide-angle intra prediction modes for non-square blocks.
  • the replaced modes are signaled using the original method and remapped to the indexes of wide angular modes after parsing.
  • the total number of intra prediction modes for a certain block is unchanged, e.g., 67, and the intra mode coding is unchanged.
  • top reference with length 2W+1 and the left reference with length 2H+1, are defined as shown in the examples in FIGS. 3A and 3B.
  • the mode number of replaced mode in wide-angular direction mode is dependent on the aspect ratio of a block.
  • the replaced intra prediction modes are illustrated in Table 1.
  • two vertically-adjacent predicted samples may use two non- adjacent reference samples in the case of wide-angle intra prediction.
  • low-pass reference samples filter and side smoothing are applied to the wide-angle prediction to reduce the negative effect of the increased gap ⁇ p ⁇ .
  • PDPC position dependent intra prediction combination
  • PDPC is an intra prediction method which invokes a combination of the un-filtered boundary reference samples and HEVC style intra prediction with filtered boundary reference samples.
  • PDPC is applied to the following intra modes without signaling: planar, DC, horizontal, vertical, bottom-left angular mode and its eight adjacent angular modes, and top-right angular mode and its eight adjacent angular modes.
  • the prediction sample pred (x, y) is predicted using an intra prediction mode (DC, planar, angular) and a linear combination of reference samples according to the Equation as follows:
  • pred (x, y) (wL ⁇ R -1, y + wT ⁇ R x, -1 –wTL ⁇ R -1, -1 + (64 –wL–wT+wTL) ⁇ pred (x, y) +32) >>shift
  • R x, -1 , R -1, y represent the reference samples located at the top and left of current sample (x, y) , respectively, and R -1, -1 represents the reference sample located at the top-left corner of the current block.
  • additional boundary filters are not needed, as required in the case of HEVC DC mode boundary filter or horizontal/vertical mode edge filters.
  • FIGS. 5A-5D illustrate the definition of reference samples (R x, -1 , R -1, y and R -1, -1 ) for PDPC applied over various prediction modes.
  • the prediction sample pred (x’ , y’) is located at (x’, y’) within the prediction block.
  • Table 2 Examples of PDPC weights according to prediction modes
  • Diagonal top-right 16 >> ( (y’ ⁇ 1) >> S) 16 >> ( (x’ ⁇ 1) >> S) 0
  • Diagonal bottom-left 16 >> ( (y’ ⁇ 1) >> S) 16 >> ( (x’ ⁇ 1) >> S) 0
  • Adjacent diag. top-right 32 >> ( (y’ ⁇ 1) >> S) 0
  • Adjacent diag. bottom-left 0 32 >> ( (x’ ⁇ 1) >> S) 0
  • JVET-M0102 ISP is proposed, which divides luma intra-predicted blocks vertically or horizontally into 2 or 4 sub-partitions depending on the block size dimensions, as shown in Table 3.
  • FIG. 6 and FIG. 7 show examples of the two possibilities. All sub-partitions fulfill the condition of having at least 16 samples.
  • a residual signal is generated by entropy decoding the coefficients sent by the encoder and then invert quantizing and invert transforming them. Then, the sub-partition is intra predicted and finally the corresponding reconstructed samples are obtained by adding the residual signal to the prediction signal. Therefore, the reconstructed values of each sub-partition will be available to generate the prediction of the next one, which will repeat the process and so on. All sub-partitions share the same intra mode.
  • the first sub-partition to be processed is the one containing the top-left sample of the CU and then continuing downwards (horizontal split) or rightwards (vertical split) .
  • reference samples used to generate the sub-partitions prediction signals are only located at the left and above sides of the lines.
  • the reverse processing order either starts with the sub-partition containing the bottom-left sample of the CU and continues upwards or starts with sub-partition containing the top-right sample of the CU and continues leftwards.
  • BDPCM Block differential pulse-code modulation coding
  • BDPCM is proposed in JVET-M0057. Due to the shape of the horizontal (resp. vertical) predictors, which use the left (A) (resp. top (B) ) pixel for prediction of the current pixel, the most throughput-efficient way of processing the block is to process all the pixels of one column (resp. line) in parallel, and to process these columns (resp. lines) sequentially.
  • a block of width 4 is divided into two halves with a horizontal frontier when the predictor chosen on this block is vertical
  • a block of height 4 is divided into two halves with a vertical frontier when the predictor chosen on this block is horizontal.
  • Table 4 summarizes the number of cycles required to process the block, depending on the block size. It is trivial to show that any block which has both dimensions larger or equal to 8 can be processed in 8 pixels per cycle or more.
  • JVET-N0413 quantized residual domain BDPCM (denote as RBDPCM hereinafter) is proposed.
  • the intra prediction is done on the entire block by sample copying in prediction direction (horizontal or vertical prediction) similar to intra prediction.
  • the residual is quantized and the delta between the quantized residual and its predictor (horizontal or vertical) quantized value is coded.
  • the residual quantized samples are sent to the decoder.
  • the invert quantized residuals, Q -1 (Q (r i, j ) ) are added to the intra block prediction values to produce the reconstructed sample values.
  • Transform skip is always used in quantized residual domain BDPCM.
  • VTM4 large block-size transforms, up to 64 ⁇ 64 in size, are enabled, which is primarily useful for higher resolution video, e.g., 1080p and 4K sequences.
  • High frequency transform coefficients are zeroed out for the transform blocks with size (width or height, or both width and height) equal to 64, so that only the lower-frequency coefficients are retained.
  • M size
  • N the block height
  • transform skip mode is used for a large block, the entire block is used without zeroing out any values.
  • a Multiple Transform Selection (MTS) scheme is used for residual coding both inter and intra coded blocks. It uses multiple selected transforms from the DCT8/DST7.
  • the newly introduced transform matrices are DST-VII and DCT-VIII.
  • the Table 4 below shows the basis functions of the selected DST/DCT.
  • Table 4 Basis functions of transform matrices used in VVC
  • the transform matrices are quantized more accurately than the transform matrices in HEVC.
  • the transform matrices are quantized more accurately than the transform matrices in HEVC.
  • MTS In order to control MTS scheme, separate enabling flags are specified at SPS level for intra and inter, respectively.
  • a CU level flag is signaled to indicate whether MTS is applied or not.
  • MTS is applied only for luma.
  • the MTS CU level flag is signalled when the following conditions are satisfied.
  • ⁇ CBF flag is equal to one
  • MTS CU flag is equal to zero, then DCT2 is applied in both directions. However, if MTS CU flag is equal to one, then two other flags are additionally signaled to indicate the transform type for the horizontal and vertical directions, respectively.
  • Transform and signaling mapping table as shown in Table 5.
  • 8-bit primary transform cores are used. Therefore, all the transform cores used in HEVC are kept as the same, including 4-point DCT-2 and DST-7, 8-point, 16-point and 32-point DCT-2. Also, other transform cores including 64-point DCT-2, 4-point DCT-8, 8-point, 16-point, 32-point DST-7 and DCT-8, use 8-bit primary transform cores.
  • High frequency transform coefficients are zeroed out for the DST-7 and DCT-8 blocks with size (width or height, or both width and height) equal to 32. Only the coefficients within the 16x16 lower-frequency region are retained.
  • the residual of a block can be coded with transform skip mode.
  • the transform skip flag is not signaled when the CU level MTS_CU_flag is not equal to zero.
  • the block size limitation for transform skip is the same to that for MTS in JEM4, which indicate that transform skip is applicable for a CU when both block width and height are equal to or less than 32.
  • secondary transform is applied between forward primary transform and quantization (at encoder) and between de-quantization and invert primary transform (at decoder side) .
  • 4x4 (or 8x8) secondary transform is performed depends on block size.
  • 4x4 secondary transform is applied for small blocks (i.e., min (width, height) ⁇ 8) and 8x8 secondary transform is applied for larger blocks (i.e., min (width, height) > 4) per 8x8 block.
  • non-separable transform Application of a non-separable transform is described as follows using input as an example. To apply the non-separable transform, the 4x4 input block X
  • the non-separable transform is calculated as where indicates the transform coefficient vector, and T is a 16x16 transform matrix.
  • the 16x1 coefficient vector is subsequently re-organized as 4x4 block using the scanning order for that block (horizontal, vertical or diagonal) .
  • the coefficients with smaller index will be placed with the smaller scanning index in the 4x4 coefficient block.
  • the mapping from the intra prediction mode to the transform set is pre-defined.
  • the selected non-separable secondary transform (NSST) candidate is further specified by the explicitly signalled secondary transform index.
  • the index is signalled in a bit-stream once per Intra CU after transform coefficients.
  • the RST (a.k.a. Low Frequency Non-Separable Transform (LFNST) ) was introduced in JVET-K0099 and 4 transform set (instead of 35 transform sets) mapping introduced in JVET-L0133.
  • LNNST Low Frequency Non-Separable Transform
  • 16x64 further reduced to 16x48
  • 16x16 matrices are employed.
  • RST8x8 the 16x16 one as RST4x4.
  • FIG. 11 shows an example of RST.
  • RT Reduced Transform
  • the RT matrix is an R ⁇ N matrix as follows:
  • the invert transform matrix for RT is the transpose of its forward transform.
  • the forward and invert RT are depicted in FIG. 12.
  • the RST8x8 with a reduction factor of 4 (1/4 size) is applied.
  • 64x64 which is conventional 8x8 non-separable transform matrix size
  • 16x64 direct matrix is used instead of 64x64, which is conventional 8x8 non-separable transform matrix size.
  • the 64 ⁇ 16 invert RST matrix is used at the decoder side to generate core (primary) transform coefficients in 8 ⁇ 8 top-left regions.
  • the forward RST8x8 uses 16 ⁇ 64 (or 8x64 for 8x8 block) matrices so that it produces non-zero coefficients only in the top-left 4 ⁇ 4 region within the given 8 ⁇ 8 region. In other words, if RST is applied then the 8 ⁇ 8 region except the top-left 4 ⁇ 4 region will have only zero coefficients.
  • 16x16 (or 8x16 for 4x4 block) direct matrix multiplication is applied.
  • An invert RST is conditionally applied when the following two conditions are satisfied:
  • width (W) and height (H) of a transform coefficient block is greater than 4, then the RST8x8 is applied to the top-left 8 ⁇ 8 region of the transform coefficient block. Otherwise, the RST4x4 is applied on the top-left min (8, W) ⁇ min (8, H) region of the transform coefficient block.
  • RST index is equal to 0, RST is not applied. Otherwise, RST is applied, of which kernel is chosen with the RST index.
  • the RST selection method and coding of the RST index are explained later.
  • RST is applied for intra CU in both intra and inter slices, and for both Luma and Chroma. If a dual tree is enabled, RST indices for Luma and Chroma are signaled separately. For inter slice (the dual tree is disabled) , a single RST index is signaled and used for both Luma and Chroma.
  • ISP Intra Sub-Partitions
  • a RST matrix is chosen from four transform sets, each of which consists of two transforms. Which transform set is applied is determined from intra prediction mode as the following:
  • transform set 0 is selected.
  • transform set selection is performed according to the following table:
  • IntraPredMode The index to access the above table, denoted as IntraPredMode, have a range of [-14, 83], which is a transformed mode index used for wide angle intra prediction.
  • 16x48 matrices are applied instead of 16x64 with the same transform set configuration, each of which takes 48 input data from three 4x4 blocks in a top-left 8x8 block excluding right-bottom 4x4 block (as shown in FIG. 13) .
  • any coefficient in the 4 ⁇ 4 sub-block may be non-zero. However, it is constrained that in some cases, some coefficients in the 4 ⁇ 4 sub-block must be zero before invert RST is applied on the sub-block.
  • nonZeroSize be a variable. It is required that any coefficient with the index no smaller than nonZeroSize when it is rearranged into a 1-D array before the invert RST must be zero.
  • nonZeroSize is set equal to 8 (that is, coefficients with the scanning index in the range [8, 15] as show in FIG. 14, shall be 0) .
  • nonZeroSize is set equal to 16.
  • sps_st_enabled_flag 1 specifies that st_idx may be present in the residual coding syntax for intra coding units.
  • sps_st_enabled_flag 0 specifies that st_idx is not present in the residual coding syntax for intra coding units.
  • st_idx [x0] [y0] specifies which secondary transform kernel is applied between two candidate kernels in a selected transform set.
  • st_idx [x0] [y0] equal to 0 specifies that the secondary transform is not applied.
  • the array indices x0, y0 specify the location (x0, y0) of the top-left sample of the considered transform block relative to the top-left sample of the picture.
  • st_idx [x0] [y0] is inferred to be equal to 0.
  • a luma location (xTbY, yTbY) specifying the top-left sample of the current luma transform block relative to the top-left luma sample of the current picture
  • nTbW specifying the width of the current transform block
  • nTbH specifying the height of the current transform block
  • nStSize log2StSize, numStX, numStY, and nonZeroSize are derived as follows:
  • log2StSize is set to 3 and nStOutSize is set to 48.
  • log2StSize is set to 2 and nStOutSize is set to 16.
  • nStSize is set to (1 ⁇ log2StSize) .
  • nTbH is equal to 4 and nTbW is greater than 8, numStX set equal to 2.
  • numStX set equal to 1.
  • nTbW is equal to 4 and nTbH is greater than 8, numStY set equal to 2.
  • numStY set equal to 1.
  • nonZeroSize is set equal to 8.
  • nonZeroSize set equal to 16.
  • the variable stPredModeIntra is set to the predModeIntra specified in clause 8.4.4.2.1.
  • stPredModeIntra is less than or equal to 34, or equal to INTRA_LT_CCLM, INTRA_T_CCLM, or INTRA_L_CCLM, the following applies:
  • variable stIdx specifying the index for transform selection in a set.
  • the transformation matrix derivation process as specified in clause 8.7.4.5 is involved with the transform output length nTrS, the index for transform set selection stPredModeIntra, and the index for transform selection in a transform set stIdx as inputs, and the transformation matrix secTransMatrix as output.
  • variable stTrSetIdx is derived as follows:
  • the transformation matrix secTransMatrix is derived based on nTrS, stTrSetIdx, and stIdx as follows:
  • nTrS 48
  • stTrSetIdx 0
  • nTrS 48
  • stTrSetIdx 0
  • nTrS 48
  • stTrSetIdx 1
  • nTrS 48
  • stTrSetIdx 1
  • nTrS 48
  • stTrSetIdx 2
  • nTrS 48
  • stTrSetIdx 2
  • nTrS 48
  • stTrSetIdx 3
  • nTrS 48
  • stTrSetIdx 3
  • the scaled transform coefficient d’ is calculated as
  • d is the scaled transform coefficient before clipping.
  • coeffMin CoeffMinC
  • coeffMax CoeffMaxC
  • CoeffMinY - (1 ⁇ (extended_precision_processing_flag ? Max (15, BitDepthY +6) : 15) )
  • CoeffMinC - (1 ⁇ (extended_precision_processing_flag ? Max (15, BitDepthC +6) : 15) )
  • CoeffMaxY (1 ⁇ (extended_precision_processing_flag ? Max (15, BitDepthY +6) : 15) ) -1
  • CoeffMaxC (1 ⁇ (extended_precision_processing_flag ? Max (15, BitDepthC + 6 ) :15) ) –1
  • extended_precision_processing_flag is a syntax element signaled in SPS.
  • Affine linear weighted intra prediction (ALWIP, or matrix based intra prediction)
  • Affine linear weighted intra prediction (ALWIP, or matrix based intra prediction (MIP) is proposed in JVET-N0217.
  • test 1 ALWIP is designed with a memory restriction of 8K bytes and at most 4 multiplications per sample.
  • Test 2 is similar to test 1, but further simplifies the design in terms of memory requirement and model architecture.
  • cu_sbt_flag may be signaled to indicate whether the whole residual block or a sub-part of the residual block is decoded.
  • inter MTS information is further parsed to determine the transform type of the CU.
  • a part of the residual block is coded with inferred adaptive transform and the other part of the residual block is zeroed out.
  • the SBT is not applied to the combined inter-intra mode.
  • sub-block transform position-dependent transform is applied on luma transform blocks in SBT-V and SBT-H (chroma TB always using DCT-2) .
  • the two positions of SBT-H and SBT-V are associated with different core transforms.
  • the horizontal and vertical transforms for each SBT position is specified in FIG. 15.
  • the horizontal and vertical transforms for SBT-V position 0 is DCT-8 and DST-7, respectively.
  • the sub-block transform jointly specifies the TU tiling, cbf, and horizontal and vertical transforms of a residual block, which may be considered a syntax shortcut for the cases that the major residual of a block is at one side of the block.
  • the signaled index may cause overhead bits.
  • Some combinations of transforms may not be efficient in MTS and SBT.
  • the transform skip (TS) flag is coded regardless whether the current block is coded with QR-BDPCM mode or not.
  • QR-BDPCM when QR-BDPCM is enabled, there is no need to apply transforms. Therefore, the signaling of TS flag is redundant when one block is coded with QR-BDPCM.
  • the transform skip flag is context coded with one context which may be also utilized for coding the bin which indicates whether the transform matric is DCT2.
  • the shared context may be less efficient.
  • QR-BDPCM/TS may be also applicable to chroma blocks. How to better determine the usage of QR-BDPCM/TS need to be further studied.
  • Embodiments of the presently disclosed technology overcome drawbacks of existing implementations, thereby providing video coding with higher coding efficiencies but lower computational complexity.
  • Methods for multiple transforms, and as described in the present document, may enhance both existing and future video coding standards, is elucidated in the following examples described for various implementations.
  • the examples of the disclosed technology provided below explain general concepts, and are not meant to be interpreted as limiting. In an example, unless explicitly indicated to the contrary, the various features described in these examples may be combined.
  • ⁇ Max (x, y) returns the larger one of x and y
  • ⁇ Min (x, y) returns the smaller one of x and y.
  • the decoded coefficients may be associated with one or multiple representative blocks in the same color component as the current block or different color component.
  • the determination on the transform of a first block may depend on the decoded coefficients of the first block.
  • the determination on the transform of a first block may depend on the decoded coefficients of a second block which may be different to the first block.
  • the second block may be in the same color component, such as the luma component, as the color component of the first block.
  • the second block may be neighboring to the first block.
  • the second block may be with the same intra prediction mode as the first block.
  • the second block may be with the same block dimensions as the first block.
  • the second block may be the last decoded block satisfying certain conditions, such as the same intra-prediction mode or the same dimensions, before the first block in the decoding order.
  • the second block may be in a different color component from that of the first block.
  • the first block may be in the luma component
  • the second block may be in a chroma component (e.g., the Cb/Cr, B/R component) .
  • the three blocks are in the same coding unit.
  • the first block in the first color component and the second block in the second color component may be at the corresponding locations of a picture with each other.
  • the determination on the transform of a first block may depend on the decoded coefficients of multiple blocks comprising at least one block not identical to the first block.
  • multiple blocks may comprise the first block.
  • multiple blocks may comprise one block or plurality of neighboring to the first block.
  • multiple blocks may comprise one block or plurality of blocks with the same block dimensions as the first block.
  • multiple blocks may comprise may comprise last N decoded block satisfying certain conditions, such as the same intra-prediction mode or the same dimensions, before the first block in the decoding order.
  • N is an integer larger than 1.
  • multiple blocks may comprise one block or plurality of blocks not in the same color component as the first block.
  • the first block may be in the luma component.
  • Multiple blocks may comprise blocks in chroma components (e.g., a second block in the Cb/B component, and a third block in the Cr/R component) .
  • the three blocks are in the same coding unit.
  • the first block in the first color component and the plurality of blocks not in the first component color component comprised in the multiple blocks may be at the corresponding locations of a picture with the first block.
  • representative coefficients are those decoded significant coefficients which are smaller than or no greater than a threshold
  • representative coefficients may be those at a predefined location in a block.
  • representative coefficients may comprise only one coefficient located at (xPos, yPos) coordinate relative to the representative block.
  • the positions may depend on the dimensions of the block.
  • representative coefficients may be those at a predefined position in the coefficient scanning order.
  • representative coefficients may also comprise those zero coefficients.
  • V is derived as the number of representative coefficients.
  • V is derived as the sum of representative coefficients.
  • the first kind of transform is different to the second kind of transform.
  • the first and second kinds of transforms are DCT-2 and when V is odd, the third and fourth kinds of transforms are DST-7.
  • V is smaller than a threshold T1
  • a fifth kind of transform is selected as the horizontal transform and a sixth kind of transform is selected as the vertical transform.
  • T1 1 or 2.
  • the threshold may depend on the dimensions of the block.
  • the threshold may depend on the QP.
  • the fifth/sixth kind of transform is a specific transform such as DCT-X or DST-Y.
  • X may be an integer such as 2 or 8.
  • Y may be an integer such as 7 or 8.
  • the transform determination may further depend on the coded information of current block.
  • DST-7 may be applied to current block and when V is odd, DCT-2 may be applied to current block.
  • the horizontal and vertical transform sets may be not identical.
  • the horizontal and vertical transform sets may be not identical.
  • the transform set may include DCT-2 and DST-7.
  • the transform set may include DCT-2, DST-7 and identify transform.
  • the transform set may be dependent on coded information, color component, partitioning structure (e.g., dual tree/single tree; quadtree/binary tree/ternary tree/extended quadtree) , slice/picture types etc. al.
  • partitioning structure e.g., dual tree/single tree; quadtree/binary tree/ternary tree/extended quadtree
  • the transform set may be dependent on block dimension.
  • DCT-2 and DST-7 may be included.
  • DST-7 and identity transform may be included.
  • bullet 1-bullet 5 can only be applied to specific blocks.
  • bullet 1-bullet 5 can only be applied to intra-coded blocks.
  • DCT-2 in horizontal transform and DCT-2 in vertical transform if the flag is equal to 0, DCT-2 in horizontal transform and DCT-2 in vertical transform; if the flag is equal to 1, DST-7 in horizontal transform and DST-7 in vertical transform.
  • transforms excluding DST-8 can be applied in a block coded with SBT.
  • DCT-2 and DST-7 can be applied in a block coded with SBT.
  • transform block width and height are W and H, respectively.
  • the selection of transforms for a block coded with SBT may depend on transform block dimensions, wherein the transform block may be smaller than the coding block when SBT is applied.
  • coefficients in one TU e.g., the first or the last TU
  • partial or all TUs may be utilized to determine the transform matrix.
  • CU-level solution Whether to use the CU-level solution or TU-level solution may depend on the block size and/or VPDU size and/or maximum CTU size and/or coded information of one block.
  • CU-level determination method may be applied.
  • the coefficients or representative coefficients may be quantized or dequantized.
  • Transform skip may also be determined by the coefficients or representative coefficients implicitly with any disclosed method in the document.
  • a coefficient or representative coefficients may be scaled before being used to derive the transforms.
  • a coefficient or representative coefficients may be added by an offset before being used to derive the transforms.
  • coefficients or representative coefficients may be filtered before being used to derive the transforms.
  • the disclosed methods in the document may also be used to derive other coding modes/information by the coefficients or representative coefficients implicitly.
  • the representative coefficients are from those corresponding to the sub-region instead of the whole block.
  • the above-mentioned implicit MTS method may be applied.
  • Picture or slice type (such as I-frame or P/B-frame, I-slice or P/B-slice)
  • the above-mentioned implicit MTS method may be applied.
  • e. Coding mode (such as inter mode/intra mode/IBC mode etc.)
  • the above-mentioned implicit MTS method may be applied.
  • f. Coding methods such as Intra Sub-block partition, Derived Tree (DT) method, etc.
  • the above-mentioned implicit MTS method may be applied while for chroma blocks, it is not applied.
  • Intra-prediction mode (such as DC, vertical, horizontal, etc.)
  • Motion information (such as MV and reference index) .
  • the usage of the coding tool X for a chroma block is derived from the information of whether the coding tool is applied to the corresponding luma block. Therefore, no additional signaling of usage of coding tool X for chroma blocks are needed.
  • a coding tool X may be applied on chroma components of a block if it is applied on the corresponding luma block; and it is not applied on chroma components of a block if it is not applied on the corresponding luma block.
  • coding tool X may be applied in the same manner on the luma component and the chroma components when it is applied on the corresponding luma block.
  • a message (such as a flag or an index) may be conditionally signaled to indicate whether coding tool X is applied on chroma components of a block.
  • the condition may be defined as whether it is applied on the corresponding luma blocks. Alternatively, furthermore, it is not applied on chroma components of a block without signaling if it is not applied on the corresponding luma blocks.
  • coding tool X may be applied in the same manner on the luma component and the chroma components when it is applied on the corresponding luma block and the message indicates that it is also applied on the chroma components.
  • coding tool X may be applied in a differnt manner on the luma component and the chroma components.
  • a “corresponding luma block” may refer to a luma block which covers at least one “corresponding sample” of the chroma block.
  • the sample positions may be scaled according to the color format such as 4: 4: 4 or 4: 2: 0.
  • the top-left position of the chroma block is (x0, y0)
  • the width and height of the chroma block are W and H, all of which are scaled to the luma sample unit.
  • the corresponding sample may be at (x0, y0) ;
  • the corresponding sample may be at (x0+W-1, y0+H-1) ;
  • the corresponding sample may be at (x0+W/2-1, y0+H/2-1) ;
  • the corresponding sample may be at (x0+W/2, y0+H/2) ;
  • the corresponding sample may be at (x0+W/2, y0+H/2-1) ;
  • the corresponding sample may be at (x0+W/2-1, y0+H/2) ;
  • a coding tool X could be applied on one chroma component of a block depending on whether it is applied on one or multiple corresponding blocks of the other chroma component.
  • the usage of the coding tool X for a chroma block is derived from the information of whether the coding tool is applied to the corresponding blocks of the other chroma component. Therefore, no additional signaling of usage of coding tool X for chroma blocks are needed.
  • a coding tool X could be applied on luma component of a block depending on whether it is applied on one or multiple corresponding blocks of the chroma components.
  • the usage of the coding tool X for a luma block is derived from the information of whether the coding tool is applied to the corresponding blocks of the chroma components. Therefore, no additional signaling of usage of coding tool X for luma blocks are needed.
  • a message (such as a flag) may be conditionally signaled to indicate whether coding tool X is applied on luma components of a block.
  • the condition may be defined as whether it is applied on the corresponding blocks of the chroma components. Alternatively, furthermore, it is not applied on luma components of a block without signaling if it is not applied on the corresponding blocks of the chroma components.
  • the coding tool X mentioned above may be defined as follows.
  • coding tool X may be transform skip.
  • the MTS indices and/or transform skip flag may be conditionally signaled, depending on the usage of BDPCM or QR-BDPCM or any variance of BDPCM.
  • the MTS indices and/or transform skip flag may not be signaled for a block in the bitstream when the BDPCM or QR-BDPCM or any variance of BDPCM is enabled for the block (such as intra_bdpcm_flag equal to true) .
  • the transform skip flag for a block may be inferred to be true when BDPCM or QR-BDPCM or any variance of BDPCM is enabled in the block.
  • the MTS index may be inferred to be 0 for a block when the BDPCM or QR-BDPCM or any variance of BDPCM is enabled in the block.
  • Fixed-length coding may be applied to code different MTS types (such as DST7-DST7, DCT8-DST7, DST7-DCT8, DCT8-DCT8 in VVC spec) excluding TS and DCT-2.
  • each bin may be context coded.
  • the first or the last bin may be context coded, and the remaining bins are bypass coded.
  • all bins are bypass coded.
  • transform matrix index (e.g., TS, DCT-2, other transform matrices) may depend on coded mode, transform block size and/or QT depth and/or MTT depth and/or BT depth and/or TT depth.
  • the context modeling for transform matrix index may depend on the coding mode of the block, such as whether the block is coded with intra/inter/IBC mode.
  • the context modeling for transform matrix index may depend on a function of multiple partition depths which may include QT depth, MTT depth, BT depth, TT depth.
  • the context modeling for transform matrix index may depend on the transform depth of a TU/TB relative to the CU/PU.
  • the context index increasement may be set to a function of TU/TB dimension.
  • the context index increasement mentioned above may be further clipped to a range, such as [k0, k1] , wherein k0 and k1 are integers.
  • the context index increasement may be set to a function of TU/TB width or height.
  • the context index increasement may be set to a function of MTT depth.
  • the context index increasement may be set to min (K, quad tree depth) , wherein the function min (a, b) returns the smaller value between a and b, K is an integer such as 4 or 5.
  • the above methods may be applied to code specific bins used in the matrix index coding.
  • the bin which is used to indicate whether it is DCT2 or not is context coded and context modeling is based on above methods, such as the first bin of tu_mts_idx.
  • context modeling i.e., how to select a context index
  • first bin oftu_mts_idx may be the same.
  • a single context may be used for the first bin of tu_mts_idx.
  • a single context may be used for all bins except the first bin of tu_mts_idx.
  • the first bin of tu_mts_idx may be context coded using the context modeling method mentioned in bullet 24.
  • the first and the second bins of tu_mts_idx may be context coded, and all the remaining bins may be bypass coded.
  • the binarization of transform matrices may be defined in the following ways:
  • the table below shows the mapped bins and corresponding matrix.
  • the table below shows the mapped bins and corresponding matrix.
  • the table below shows the mapped bins and corresponding matrix.
  • MTS have only two candidate combination of transforms: DCT2-DCT2 and DST7-DST7.
  • method 1610, 1620, 1630, 1640 and 1650 may be implemented at a video encoder and/or decoder.
  • the method 1610 includes, at operation 1614, performing the conversion.
  • the method 1620 includes, at operation 1624, performing the conversion.
  • the method 1630 includes, at operation 1634, performing the conversion.
  • FIG. 16D shows a flowchart of an exemplary method for video processing.
  • the method 1640 includes, at operation 1642, performing a conversion between a current block of a video and a bitstream representation of the video.
  • whether a multiple transform set (MTS) index and/or a transform skip flag is signaled in the bitstream representation is based on an enablement of a block differential pulse-code modulation (BDPCM) -based coding tool for the current block.
  • BDPCM block differential pulse-code modulation
  • FIG. 16E shows a flowchart of an exemplary method for video processing.
  • the method 1650 includes, at operation 1652, selecting, based on a type of a multiple transform set (MTS) for a current block of a video, a coding type with a plurality of bins.
  • MTS multiple transform set
  • the method 1650 includes, at operation 1654, applying, as part of a conversion between the current block and a bitstream representation of the video, the coding type to an indication of the type of the MTS.
  • additions are indicated using bolded double braces, e.g., ⁇ ⁇ a ⁇ ⁇ indicates that “a” has been added, whereas deletions are indicated using bolded double brackets, e.g., [ [a]] indicates that “a” has been deleted.
  • JVET-N1001-v7 The working draft specified in JVET-N1001-v7 may be changed as below.
  • JVET-N1001-v8 The working draft specified in JVET-N1001-v8 may be changed as below.
  • Input to this process is a request for a binarization for the syntax element tu_mts_idx. Output of this process is the binarization of the syntax element.
  • JVET-N1001-v8 The working draft specified in JVET-N1001-v8 may be changed as below.
  • JVET-N1001-v8 The working draft specified in JVET-N1001-v8 may be changed as below.
  • JVET-N1001-v8 The working draft specified in JVET-N1001-v8 may be changed as below.
  • JVET-N1001-v8 The working draft specified in JVET-N1001-v8 may be changed as below.
  • JVET-N1001-v8 The working draft specified in JVET-N1001-v8 may be changed as below.
  • FIG. 17 is a block diagram of a video processing apparatus 1700.
  • the apparatus 1700 may be used to implement one or more of the methods described herein.
  • the apparatus 1700 may be embodied in a smartphone, tablet, computer, Internet of Things (IoT) receiver, and so on.
  • the apparatus 1700 may include one or more processors 1702, one or more memories 1704 and video processing hardware 1706.
  • the processor (s) 1702 may be configured to implement one or more methods (including, but not limited to, methods 1610, 1620, 1630, 1640 and 1650) described in the present document.
  • the memory (memories) 1704 may be used for storing data and code used for implementing the methods and techniques described herein.
  • the video processing hardware 1706 may be used to implement, in hardware circuitry, some techniques described in the present document.
  • the video coding methods may be implemented using an apparatus that is implemented on a hardware platform as described with respect to FIG. 17.
  • Some embodiments of the disclosed technology include making a decision or determination to enable a video processing tool or mode.
  • the encoder when the video processing tool or mode is enabled, the encoder will use or implement the tool or mode in the processing of a block of video, but may not necessarily modify the resulting bitstream based on the usage of the tool or mode. That is, a conversion from the block of video to the bitstream representation of the video will use the video processing tool or mode when it is enabled based on the decision or determination.
  • the decoder when the video processing tool or mode is enabled, the decoder will process the bitstream with the knowledge that the bitstream has been modified based on the video processing tool or mode. That is, a conversion from the bitstream representation of the video to the block of video will be performed using the video processing tool or mode that was enabled based on the decision or determination.
  • Some embodiments of the disclosed technology include making a decision or determination to disable a video processing tool or mode.
  • the encoder will not use the tool or mode in the conversion of the block of video to the bitstream representation of the video.
  • the decoder will process the bitstream with the knowledge that the bitstream has not been modified using the video processing tool or mode that was enabled based on the decision or determination.
  • FIG. 18 is a block diagram showing an example video processing system 1800 in which various techniques disclosed herein may be implemented.
  • the system 1800 may include input 1802 for receiving video content.
  • the video content may be received in a raw or uncompressed format, e.g., 8 or 10 bit multi-component pixel values, or may be in a compressed or encoded format.
  • the input 1802 may represent a network interface, a peripheral bus interface, or a storage interface. Examples of network interface include wired interfaces such as Ethernet, passive optical network (PON) , etc. and wireless interfaces such as Wi-Fi or cellular interfaces.
  • PON passive optical network
  • the system 1800 may include a coding component 1804 that may implement the various coding or encoding methods described in the present document.
  • the coding component 1804 may reduce the average bitrate of video from the input 1802 to the output of the coding component 1804 to produce a coded representation of the video.
  • the coding techniques are therefore sometimes called video compression or video transcoding techniques.
  • the output of the coding component 1804 may be either stored, or transmitted via a communication connected, as represented by the component 1806.
  • the stored or communicated bitstream (or coded) representation of the video received at the input 1802 may be used by the component 1808 for generating pixel values or displayable video that is sent to a display interface 1810.
  • the process of generating user-viewable video from the bitstream representation is sometimes called video decompression.
  • certain video processing operations are referred to as “coding” operations or tools, it will be appreciated that the coding tools or operations are used at an encoder and corresponding decoding tools or operations that reverse the results of the coding will be performed by
  • peripheral bus interface or a display interface may include universal serial bus (USB) or high definition multimedia interface (HDMI) or Displayport, and so on.
  • storage interfaces include SATA (serial advanced technology attachment) , PCI, IDE interface, and the like.
  • a method for video processing comprising performing a conversion between a current block of a video and a bitstream representation of the video, wherein whether a multiple transform set (MTS) index and/or a transform skip flag is signaled in the bitstream representation is based on an enablement of a block differential pulse-code modulation (BDPCM) -based coding tool for the current block.
  • MTS multiple transform set
  • BDPCM block differential pulse-code modulation
  • a method for video processing comprising applying, as part of a conversion between a current block of a video and a bitstream representation of the video, a coding tool to one or more chroma components of the video based on a selective application of the coding tool to a corresponding luma component of the video; and performing the conversion.
  • a method for video processing comprising applying, as part of a conversion between a current block of a first chroma component of a video and a bitstream representation of the video, a coding tool to the current block based on a selective application of the coding tool to one or more corresponding blocks of other chroma components of the video; and performing the conversion.
  • condition comprises the application of the coding tool to the one or more corresponding blocks of other chroma components.
  • a method for video processing comprising applying, as part of a conversion between a current block of a video and a bitstream representation of the video, a coding tool to a luma component of the video based on a selective application of the coding tool to one or more corresponding chroma components of the video; and performing the conversion.
  • coding tool is selected from the group consisting of a multiple transform set (MTS) , a transform skip, a reduced secondary transform (RST) , a block differential pulse-code modulation (BDPCM) , and a quantized residual domain BDPCM (QR-BDPCM) .
  • MTS multiple transform set
  • RST reduced secondary transform
  • BDPCM block differential pulse-code modulation
  • QR-BDPCM quantized residual domain BDPCM
  • a method for video processing comprising selecting, based on a type of a multiple transform set (MTS) for a current block of a video, a coding type with a plurality of bins; and applying, as part of a conversion between the current block and a bitstream representation of the video, the coding type to an indication of the type of the MTS.
  • MTS multiple transform set
  • the coding tree is a quaternary tree (QT) , a multi-type tree (MTT) , a ternary tree (TT) , or a binary tree (BT) .
  • QT quaternary tree
  • MTT multi-type tree
  • TT ternary tree
  • BT binary tree
  • the type of the MTS is a transform skip (TS) , DCT2-DCT2, DST7-DST7, DCT8-DST7, DST7-DCT8, or DCT8-DCT8, wherein DST#is a Discrete Sine Transform of Type #and DCT#is a Discrete Cosine Transform of Type #, and wherein the coding type is a binarization based on a table defined as:
  • An apparatus in a video system comprising a processor and a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to implement the method in any one of solutions 1 to 42.
  • a computer program product stored on a non-transitory computer readable media including program code for carrying out the method in any one of solutions 1 to 42.
  • Implementations of the subject matter and the functional operations described in this patent document can be implemented in various systems, digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. Implementations of the subject matter described in this specification can be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a tangible and non-transitory computer readable medium for execution by, or to control the operation of, data processing apparatus.
  • the computer readable medium can be a machine-readable storage device, a machine-readable storage substrate, a memory device, a composition of matter effecting a machine-readable propagated signal, or a combination of one or more of them.
  • data processing unit or “data processing apparatus” encompasses all apparatus, devices, and machines for processing data, including by way of example a programmable processor, a computer, or multiple processors or computers.
  • the apparatus can include, in addition to hardware, code that creates an execution environment for the computer program in question, e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them.
  • 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 multiple coordinated files (e.g., files that store one or more modules, sub programs, or portions of code) .
  • a computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network.
  • the processes and logic flows described in this specification can 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 can also be performed by, and apparatus can also be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit) .
  • processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer.
  • 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 performing instructions and one or more memory devices for storing instructions and data.
  • a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto optical disks, or optical disks.
  • mass storage devices for storing data, e.g., magnetic, magneto optical disks, or optical disks.
  • a computer need not have such devices.
  • Computer readable media suitable for storing computer program instructions and data include all forms of nonvolatile memory, media and memory devices, including by way of example semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices.
  • semiconductor memory devices e.g., EPROM, EEPROM, and flash memory devices.
  • the processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

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Abstract

La présente invention concerne des dispositifs, des systèmes et des procédés de codage vidéo numérique qui comprennent des outils de codage pour des composantes de chrominance. Dans un aspect représentatif, un procédé de traitement vidéo comprend la réalisation d'une conversion entre un bloc courant d'une vidéo et une représentation de flux binaire de la vidéo, la signalisation d'un indice d'ensemble de transformées multiples (MTS) et/ou d'un indicateur de saut de transformée dans la représentation de flux binaire dépendant de l'activation d'un outil de codage basé sur une modulation de code d'impulsion différentiel de bloc (BDPCM) pour le bloc courant.
PCT/CN2020/097021 2019-06-21 2020-06-19 Outils de codage pour composantes de chrominance WO2020253810A1 (fr)

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