Constraints on Adaptation Parameter Set Syntax Elements

Abstract

Systems, methods, and apparatus for video processing are described. The video processing may include video encoding, video decoding, or video transcoding. An example method of video processing includes performing conversion between a video and a bitstream of the video according to a format rule, wherein the format rule specifies that a first field at a sequence level or a picture level or a slice level controls a value of a second field in an adaptation parameter set.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on international patent application No. PCT / CN2021 / 085009 filed on April 1, 2021, which claims priority and benefits from international patent application No. PCT / CN2020 / 082728 filed on April 1, 2020. All of the above patent applications are hereby incorporated by reference in their entirety. Technical Field

[0003] This application document relates to image and video encoding and decoding. Background Art

[0004] Digital video accounts for the largest use of bandwidth on the Internet and other digital communications networks. As the number of connected user devices capable of receiving and displaying video increases, bandwidth requirements for digital video usage are expected to continue to grow. Summary of the invention

[0005] This document discloses techniques used by video encoders and decoders to process a codec representation of a video using control information useful for decoding the codec representation.

[0006] In one example aspect, a video processing method is disclosed. The method includes: performing a conversion between a video including one or more chroma components and a codec representation of the video, the video including one or more video pictures including one or more slices, wherein the codec representation conforms to a format rule, wherein the format rule specifies that a chroma array type field controls constraints on conversion characteristics of chroma used during the conversion.

[0007] In another example aspect, another video processing method is disclosed. The method includes: performing a conversion between a video including one or more video pictures including one or more video regions and a codec representation of the video, wherein the codec representation conforms to a format rule, the format rule providing for including a deblocking mode indicator for the video region, the deblocking mode indicator indicating applicability of a deblocking filter to the video region during the conversion.

[0008] In another example aspect, another video processing method is disclosed. The method includes performing conversion between a video including one or more video pictures including one or more video slices and / or one or more video sub-pictures and a codec representation of the video, wherein the codec representation complies with a format rule, the format rule specifying a flag indicating whether a single slice per sub-picture mode is enabled for the video picture when picture segmentation is disabled for the video picture.

[0009] In another example aspect, another video processing method is disclosed. The method includes performing conversion between a video including one or more video pictures including one or more video slices and a codec representation of the video, wherein the codec representation complies with a format rule that specifies signaling a picture or slice level chroma quantization parameter offset in a picture header or a slice header.

[0010] In another example aspect, another video processing method is disclosed. The method includes: performing conversion between a video including one or more video pictures including one or more video slices and a codec representation of the video, wherein the codec representation conforms to a format rule, wherein the format rule specifies that a converted chroma quantization parameter (QP) table applicable to a video block of the video is derived as an XOR operation between (delta_qp_in_val_minus1[i][j]+1) and delta_qp_diff_val[i][j], wherein delta_qp_in_val_minus1[i][j] specifies an incremental value for deriving input coordinates of a j-th pivot point of an i-th chroma map table, and delta_qp_diff_val[i][j] specifies an incremental value for deriving output coordinates of a j-th pivot point of an i-th chroma QP map table, wherein i and j are integers.

[0011] In another example aspect, another video processing method is disclosed. The method includes: performing conversion between a video and a bitstream of the video according to a format rule, and wherein the format rule stipulates that a first field at a sequence level or a picture level or a slice level controls a value of a second field in an adaptation parameter set.

[0012] In another example aspect, another video processing method is disclosed. The method includes: performing conversion between a video and a bitstream of the video according to a format rule, and wherein the format rule specifies that a value of a syntax element associated with an adaptive loop filter (ALF) used in the conversion depends on the presence of another syntax element, the other syntax element indicating an identifier of an adaptive parameter set (APS) corresponding to the adaptive loop filter.

[0013] In another example aspect, another video processing method is disclosed. The method includes: performing conversion between a video and a bitstream of the video according to a format rule, and wherein the format rule specifies that a value of a field associated with a chroma component of the video controls whether a syntax element is inferred for the chroma component in a slice header associated with an adaptive loop filter.

[0014] In another example aspect, another video processing method is disclosed. The method includes: performing conversion between a video including one or more pictures including one or more slices and a bitstream of the video according to a format rule, and wherein the format rule provides for including a field in a picture parameter set, the field indicating the presence of a syntax element related to a difference between a luma quantization parameter of a codec unit and a prediction.

[0015] In another example aspect, another video processing method is disclosed. The method includes: performing conversion between a video including one or more pictures including one or more sub-pictures and a bitstream of the video according to a format rule, and wherein the format rule provides that, in response to disabling picture segmentation for the picture, a first flag is enabled for the picture, the first flag indicating whether each sub-picture of the picture includes exactly one rectangular strip.

[0016] In another example aspect, another video processing method is disclosed. The method includes: performing conversion between a video including one or more video regions and a bitstream of the video according to a format rule, and wherein the format rule provides that the bitstream includes a deblocking mode indicator for the video region, the deblocking mode indicator indicating applicability of a deblocking filter to the video region during the conversion.

[0017] In another example aspect, another video processing method is disclosed. The method includes performing conversion between a video including one or more pictures including one or more slices and a bitstream of the video according to a format rule, and wherein the format rule provides that a picture level or slice level chroma quantization parameter offset is always signaled in a picture header or a slice header.

[0018] In another example aspect, another video processing method is disclosed. The method includes performing conversion between a video including one or more pictures including one or more slices and a bitstream of the video according to a format rule, and wherein the format rule specifies that a chroma quantization parameter (QP) table for the conversion applied to a video block of the video is derived as an XOR operation between two syntax elements.

[0019] In yet another exemplary aspect, a video encoder apparatus is disclosed. The video encoder includes a processor configured to implement the above method.

[0020] In yet another exemplary aspect, a video decoder apparatus is disclosed, wherein the video decoder comprises a processor configured to implement the above method.

[0021] In yet another example aspect, a computer readable medium having code stored thereon is disclosed. The code embodies one of the methods described herein in the form of processor executable code.

[0022] These and other features are described in this document. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A block diagram of an example of a video processing system is shown.

[0024] Figure 2 A block diagram showing a video processing apparatus

[0025] Figure 3 A flow chart illustrating an example method of video processing is shown.

[0026] Figure 4 is a block diagram illustrating a video encoding and decoding system according to some embodiments of the present disclosure.

[0027] Figure 5 is a block diagram illustrating an encoder according to some embodiments of the present disclosure.

[0028] Figure 6 is a block diagram illustrating a decoder according to some embodiments of the present disclosure.

[0029] Figures 7A-7C is a flowchart of an exemplary video processing method based on some embodiments of the disclosed technology.

[0030] Figures 8A-8E is a flowchart of an exemplary video processing method based on some embodiments of the disclosed technology. DETAILED DESCRIPTION

[0031] In this article, the section titles are used for ease of understanding and do not limit the applicability of the techniques and embodiments disclosed in each section to only that section. In addition, the use of H.266 terminology in some descriptions is only for ease of understanding and is not intended to limit the scope of the disclosed technology. Therefore, the technology described here is also applicable to other video codec protocols and designs.

[0032] 1. Introduction

[0033] This article relates to video codec technology. Specifically, the syntax design of APS, deblocking, sub-picture and QP increment in video codec. These concepts can be applied alone or in various combinations to any video codec standard or non-standard video codec that supports multi-layer video codec, such as the Versatile Video Codec (VVC) under development.

[0034] 2. Abbreviations

[0035] APS (Adaptation Parameter Set) Adaptive Parameter Set

[0036] AU (Access Unit) Access Unit

[0037] AUD (Access Unit Delimiter) Access Unit Delimiter

[0038] AVC (Advanced Video Coding) Advanced Video Codec

[0039] CLVS (Coded Layer Video Sequence) Coded Layer Video Sequence

[0040] CPB (Coded Picture Buffer) Coded Picture Buffer

[0041] CRA (Clean Random Access) Pure Random Access

[0042] CTU (Coding Tree Unit)

[0043] CVS (Coded Video Sequence) Coded Video Sequence

[0044] DPB (Decoded Picture Buffer) Decoded Picture Buffer

[0045] DPS (Decoding Parameter Set) Decoding Parameter Set

[0046] EOB (End Of Bitstream) bitstream end

[0047] EOS (End Of Sequence) sequence end

[0048] GDR (Gradual Decoding Refresh) Gradual Decoding Refresh

[0049] HEVC (High Efficiency Video Coding) High Efficiency Video Coding

[0050] HRD (Hypothetical Reference Decoder) Hypothetical Reference Decoder

[0051] IDR (Instantaneous Decoding Refresh)

[0052] JEM (Joint Exploration Model)

[0053] MCTS (Motion-Constrained Tile Sets)

[0054] NAL (Network Abstraction Layer) Network Abstraction Layer

[0055] OLS (Output Layer Set) Output Layer Set

[0056] PH (Picture Header) Picture Header

[0057] PPS (Picture Parameter Set) Picture Parameter Set

[0058] PROF (Prediction Refinement with Optical Flow)

[0059] PTL (Profile, Tier and Level) Profile, Tier and Level

[0060] PU (Picture Unit)

[0061] RBSP (Raw Byte Sequence Payload)

[0062] SEI (Supplemental Enhancement Information) Supplemental Enhancement Information

[0063] SH (Slice Header) Strip Header

[0064] SPS (Sequence Parameter Set)

[0065] SVC (Scalable Video Coding) Scalable Video Codec

[0066] VCL (Video Coding Layer) Video Coding Layer

[0067] VPS (Video Parameter Set) Video Parameter Set

[0068] VTM (VVC Test Model) VVC Test Model

[0069] VUI (Video Usability Information) Video Usability Information

[0070] VVC (Versatile Video Coding) Multi-functional video codec

[0071] 3. Preliminary Discussion

[0072] Video codec standards have evolved primarily through the development of the known ITU-T and ISO / IEC standards. ITU-T developed H.261 and H.263, ISO / IEC developed MPEG-1 and MPEG-4 video, and the two organizations jointly developed H.262 / MPEG-2 video and H.264 / MPEG-4 Advanced Video Codec (AVC) and H.265 / HEVC standards. Since H.262, video codec standards have been based on a hybrid video codec structure, which uses temporal prediction plus transform codec. In order to explore future video codec technologies beyond HEVC, VCEG and MPEG jointly established the Joint Video Exploration Team (JVET) in 2015. Since then, JVET has adopted many new methods and applied them to reference software called the Joint Exploration Model (JEM). JVET meetings are held simultaneously every quarter, and the goal of the new codec standard is to reduce the bit rate by 50% compared to HEVC. The new video codec standard was officially named Versatile Video Codec (VVC) at the JVET meeting in April 2018, when the first version of the VVC Test Model (VTM) was released. With the continuous efforts of VVC standardization, new codec technologies are adopted into the VVC standard at each JVET meeting. The VVC working draft and test model VTM are updated after each meeting. The VVC project now aims to achieve technical completion (FDIS) at the July 2020 meeting.

[0073] 3.1.PPS Syntax and Semantics

[0074] In the latest VVC draft text, the PPS syntax and semantics are as follows:

[0075]

[0076]

[0077]

[0078]

[0079]

[0080] The PPS RBSP shall be available to the decoding process before being referenced, the PPS RBSP being included in at least one AU (where the TemporalId is less than or equal to the TemporalId of the PPS NAL unit) or provided by external means.

[0081] All PPS NAL units within a PU with a specific value of pps_pic_parameter_set_id shall have the same content.

[0082] pps_pic_parameter_set_id identifies the PPS for reference by other syntax elements. The value of pps_pic_parameter_set_id shall be in the range of 0 to 63, inclusive.

[0083] Regardless of the nuh_layer_id value, PPS NAL units share the same value space of pps_pic_parameter_set_id.

[0084] Let ppsLayerId be the value of nuh_layer_id for a particular PPS NAL unit and vclLayerId be the value of nuh_layer_id for a particular VCL NAL unit. A particular VCL NAL unit shall not reference a particular PPS NAL unit unless ppsLayerId is less than or equal to vclLayerId and the layer with nuh_layer_id equal to ppsLayerId is included in at least one OLS that includes a layer with nuh_layer_id equal to vclLayerId.

[0085] pps_seq_parameter_set_id indicates the value of pps_seq_parameter_set_id of SPS. The value of pps_seq_parameter_set_id shall be in the range of 0 to 15, inclusive. The value of pps_seq_parameter_set_id shall be the same in all PPSs referenced by the coded picture in CLV.

[0086] mixed_nalu_types_in_pic_flag equal to 1 indicates that each picture referencing the PPS has more than one VCL NAL unit, the VCL NAL units do not have the same nal_unit_type value, and the picture is not an IRAP picture. mixed_nalu_types_in_pic_flag equal to 0 indicates that each picture referencing the PPS has one or more VCL NAL units, and the VCL NAL units of each picture referencing the PPS have the same nal_unit_type value.

[0087] When no_mixed_nalu_types_in_pic_constraint_flag is equal to 1, the value of mixed_nalu_types_in_pic_flag shall be equal to 0.

[0088] For each slice with nal_unit_type value nalUnitTypeA in the range IDR_W_RADL to CRA_NUT (inclusive) in a picture picA that also contains one or more slices with another value nal_unit_type (i.e. the value of mixed_nalu_types_in_pic_flag of picture picA is equal to 1), the following applies:

[0089] - The slice shall belong to the sub-picture subpicA whose corresponding subpic_treated_as_pic_flag[i] value is equal to 1.

[0090] - A slice shall not belong to a picA sub-picture containing VCL NAL units with nal_unit_type not equal to nalUnitTypeA.

[0091] —If nalUnitTypeA is equal to CRA, then for all following PUs in CLVS that follow the current picture in decoding order and output order, neither RefPicList[0] nor RefPicList[1] of the slices in subpicA in these PUs shall include in the active entry any pictures that precede picA in decoding order.

[0092] — Otherwise (i.e., nalUnitTypeA is equal to IDR_W_RADL or IDR_N_LP), for all PUs in CLVS that follow the current picture in decoding order, neither RefPicList[0] nor RefPicList[1] of the slices in subpicA in these PUs shall include in the active entry any pictures that precede picA in decoding order.

[0093] NOTE 1 - mixed_nalu_types_in_pic_flag equal to 1 indicates that the picture referencing the PPS includes slices with different NAL unit types, for example, a codec picture originating from a sub-picture bitstream Merge operation, for which the codec picture encoder must ensure further alignment of the parameters matching the bitstream structure and the original bitstream. An example of such alignment is as follows: When the value of sps_idr_rpl_flag is equal to 0 and mixed_nalu_types_in_pic_flag is equal to 1, the picture referencing the PPS cannot have slices with nal_unit_type equal to IDR_W_RADL or IDR_N_LP.

[0094] pic_width_in_luma_samples indicates the width of each decoded picture referencing the PPS in luma sample units. pic_width_in_luma_samples shall not be equal to 0, shall be an integer multiple of Max(8,MinCbSizeY), and shall be less than or equal to pic_width_max_in_luma_samples.

[0095] When res_change_in_clvs_allowed_flag is equal to 0, the value of pic_width_in_luma_samples shall be equal to pic_width_max_in_luma_samples.

[0096] pic_height_in_luma_samples represents the height of each decoded picture referencing the PPS in luma sample units. pic_height_in_luma_samples shall not be equal to 0, shall be an integer multiple of Max(8,MinCbSizeY), and shall be less than or equal to pic_height_max_in_luma_samples.

[0097] When res_change_in_clvs_allowed_flag is equal to 0, the value of pic_height_in_luma_samples shall be equal to pic_height_max_in_luma_samples.

[0098] The derivation of the variables PicWidthInCtbsY, PicHeightInCtbsY, PicSizeInCtbsY, PicWidthInMinCbsY, PicHeightInMinCbsY, PicSizeInMinCbsY, PicSizeInSamplesY, PicWidthInSamplesC, and PicHeightInSamplesC is as follows:

[0099] PicWidthInCtbsY = Ceil(pic_width_in_luma_samples ÷ CtbSizeY) (69)

[0100] PicHeightInCtbsY = Ceil(pic_height_in_luma_samples ÷ CtbSizeY) (70)

[0101] PicSizeInCtbsY = PicWidthInCtbsY * PicHeightInCtbsY (71)

[0102] PicWidthInMinCbsY = pic_width_in_luma_samples / MinCbSizeY (72)

[0103] PicHeightInMinCbsY = pic_height_in_luma_samples / MinCbSizeY (73)

[0104] PicSizeInMinCbsY = PicWidthInMinCbsY * PicHeightInMinCbsY (74)

[0105] PicSizeInSamplesY = pic_width_in_luma_samples * pic_height_in_luma_samples (75)

[0106] PicWidthInSamplesC = pic_width_in_luma_samples / SubWidthC (76)

[0107] PicHeightInSamplesC = pic_height_in_luma_samples / SubHeightC (77)

[0108] pps_conformance_window_flag equal to 1 indicates that the conformance cropping window offset parameter follows immediately in the PPS. pps_conformance_window_flag equal to 0 indicates that the conformance cropping window offset parameter does not exist in the PPS.

[0109] pps_conf_win_left_offset, pps_conf_win_right_offset, pps_conf_win_top_offset, and pps_conf_win_bottom_offset represent samples of the picture in the CLVS output from the decoding process, according to the rectangular area represented in the output picture coordinates. When pps_conformance_window_flag is equal to 0, the values ​​of pps_conf_win_left_offset, pps_conf_win_right_offset, pps_conf_win_top_offset, and pps_conf_win_bottom_offset are inferred to be equal to 0.

[0110] The consistency cropping window contains the luma samples with horizontal picture coordinates from SubWidthC*pps_conf_win_left_offset to pic_width_in_luma_samples — (SubWidthC*pps_conf_win_right_offset+1) and vertical picture coordinates from SubHeightC*pps_conf_win_top_offset to pic_height_in_luma_samples — (SubHeightC*pps_conf_clusive_bottom_offset+1) (inclusive).

[0111] The value of SubWidthC*(pps_conf_win_left_offset+pps_conf_win_right_offset) should be less than pic_width_in_luma_samples, and the value of SubHeightC*(pps_conf_win_top_offset+pps_conf_win_bottom_offset) should be less than pic_height_in_luma_samples.

[0112] When ChromaArrayType is not equal to 0, the corresponding representative samples of the two chroma arrays are samples with picture coordinates (x / SubWidthC, y / SubHeightC), where (x, y) are the picture coordinates representing the luma sample.

[0113] NOTE 2 - The consistency crop window offset parameter is used for output only. All internal decoding processes are used for the uncropped picture size.

[0114] Let ppsA and ppsB refer to any two PPSs of the same SPS. The bitstream conformance requirement is that when ppsA and ppsB have the same values ​​of pic_width_in_luma_samples and pic_height_in_luma_samples, respectively, ppsA and ppsB shall have the same values ​​of pps_conf_win_left_offset, pps_conf_win_right_offset, pps_conf_win_top_offset, and pps_conf_win_bottom_offset, respectively.

[0115] When pic_width_in_luma_samples is equal to pic_width_max_in_luma_samples and picUheight_in_luma_sample is equal to pic_height_max_in_luma_samples, the bitstream conformance requirement is that pps_conf_win_left_offset, pps_conf_win_right_offset, pps_conf_win_top_offset and pps_conf_win_bottom_offset are equal to sps_conf_win_left_offset, sps_conf_win_right_offset, sps_conf_win_top_offset and sps_conf_win_bottom_offset, respectively.

[0116] scaling_window_explicit_signaling_flag equal to 1 indicates that the scaling window offset parameters are present in the PPS. scaling_window_explicit_signaling_flag equal to 0 indicates that the scaling window offset parameters are not present in the PPS. When res_change_in_clvs_allowed_flag is equal to 0, the value of scaling_window_explicit_signaling_flag shall be equal to 0.

[0117] scaling_win_left_offset, scaling_win_right_offset, scaling_win_top_offset, and scaling_win_bottom_offset represent the offsets to the picture size that are applied to the scaling ratio calculation. When not present, the values ​​of scaling_win_left_offset, scaling_win_right_offset, scaling_win_top_offset, and scaling_win_bottom_offset are inferred to be equal to pps_conf_win_left_offset, pps_conf_win_right_offset, pps_conf_win_top_offset, and pps_conf_win_bottom_offset, respectively.

[0118] SubWidthC*(scaling_win_left_offset+scaling _ win_right_offsets) should be less than pic_width_in_luma_samples, and the value of SubHeightC*(scaling_win_top_offset+scaling_win_bottom_offset) should be less than pic_height_in_luma_samples.

[0119] The variables PicOutputWidthL and PicOutputHeightL are derived as follows:

[0120] PicOutputWidthL=pic_width_in_luma_samples- (78)

[0121] SubWidthC*(scaling_win_right_offset+scaling_win_left_offset)PicOutputHeightL=pic_height_in_luma_samples- (79)

[0122] SubWidthC*(scaling_win_bottom_offset+scaling_win_top_offset)

[0123] Let refPicOutputWidthL and refPicOutputHeightL be the PicOutputWidthL and PicOutputHeightL of the reference picture of the current picture that references this PPS. The bitstream conformance requirement is that all of the following conditions are met:

[0124] -PicOutputWidthL*2 should be greater than or equal to refPicWidthInLumaSamples.

[0125] -PicOutputHeightL*2 should be greater than or equal to refPicHeightInLumaSamples.

[0126] -PicOutputWidthL should be less than or equal to refPicWidthInLumaSamples*8.

[0127] -PicOutputHeightL should be less than or equal to refPicHeightInLumaSamples*8.

[0128] - PicOutputWidthL*pic_width_max_in_luma_samples should be greater than or equal to refPicOutputWidthL*(pic_width_in_luma_samples-Max(8,MinCbSizeY)).

[0129] -PicOutputHeightL*pic_height_max_in_luma_samples should be greater than or equal to refPicOutputHeightL*(pic_height_in_luma_samples-Max(8,MinCbSizeY)).

[0130] output_flag_present_flag equal to 1 indicates that the pic_output_flag syntax element is present in the slice header referencing the PPS. output_flag_present_flag equal to 0 indicates that the pic_output_flag syntax element is not present in the slice header referencing the PPS.

[0131] subpic_id_mapping_in_pps_flag equal to 1 indicates that sub-picture ID mapping is signaled in the PPS. subpic_id_mapping_in_pps_flag equal to 0 indicates that sub-picture ID mapping is not signaled in the PPS. If subpic_id_mapping_explicitly_signalled_flag is 0 or subpic_id_mapping_in_sps_flag is equal to 1, the value of subpic_id_mapping_in_pps_flag shall be equal to 0. Otherwise (subpic_id_mapping_explicitly_signalled_flag is equal to 1 and subpic_id_mapping_in_sps_flag is equal to 0), the value of subpic_id_mapping_in_pps_flag shall be equal to 1.

[0132] pps_num_subpics_minus1 shall be equal to sps_num_subpics_minus1.

[0133] pps_subpic_id_len_minus1 shall be equal to sps_subpic_id_len_minus1.

[0134] pps_subpic_id[i] represents the sub-picture ID of the i-th sub-picture. The length of the pps_subpic_id[i] syntax element is pps_subpic_id_len_minus1+1 bits.

[0135] For each value of i in the range from 0 to sps_num_subpics_minus1, the variable SubpicIdVal[i] is derived as follows:

[0136]

[0137] Bitstream conformance requires that both of the following constraints apply:

[0138] - For any two different values ​​of i and j in the range 0 to sps_num_subpics_minus1 (inclusive), SubpicIdVal[i] shall not be equal to SubpicIdVal[j].

[0139] — When the current picture is not the first picture of the CLVS, for each value of i in the range 0 to sps_num_subpics_minus1 (inclusive), if the value of SubpicIdVal[i] is not equal to the value of SubpicIdVal[i] of the preceding picture in decoding order in the same layer, the nal_unit_type of all codec slice NAL units of the subpictures in the current picture with sub-picture index i shall be equal to a specific value in the range IDR_W_RADL to CRA_NUT (inclusive).

[0140] no_pic_partition_flag equal to 1 indicates that picture partitioning is not applied to each picture referencing the PPS. no_pic_partition_flag equal to 0 indicates that each picture referencing the PPS may be partitioned into multiple slices or slices.

[0141] Bitstream conformance requires that the value of no_pic_partition_flag shall be the same for all PPSs referenced by a coded or decoded picture within a CLVS.

[0142] Bitstream conformance requires that when the value of sps_num_subpics_minus1+1 is greater than 1, the value of no_pic_partition_flag shall not be equal to 1.

[0143] pps_log2_ctu_size_minus5 plus 5 represents the size of the luma codec treeblock for each CTU. pps_log2_ctu_size_minus5 shall be equal to sps_log2_ctu_size_minus5.

[0144] num_exp_tile_columns_minus1 plus 1 indicates the number of explicitly provided tile column widths. The value of num_exp_tile_columns_minus1 shall be in the range of 0 to PicWidthInCtbsY-1, inclusive. When no_pic_partition_flag is equal to 1, the value of num_exp_tile_columns_minus1 is inferred to be equal to 0.

[0145] num_exp_tile_rows_minus1 plus 1 indicates the number of explicitly provided tile row heights. The value of num_exp_tile_rows_minus1 shall be in the range of 0 to PicHeightInCtbsY-1, inclusive. When no_pic_partition_flag is equal to 1, the value of num_tile_rows_minus1 is inferred to be equal to 0.

[0146] tile_column_width_minus1[i] plus 1 represents the width of the i-th tile column in CTBs for i in the range of 0 to num_exp_tile_columns_minus1-1, inclusive. As specified in clause 6.5.1, tile_column_width_minus1[num_exp_tile_columns_minus1] is used to derive the width of tile columns with indices greater than or equal to num_exp_tile_columns_minus1. The value of tile_column_width_minus1[i] shall be in the range of 0 to PicWidthInCtbsY-1, inclusive. If not present, the value of tile_column_width_minus1[0] is inferred to be equal to PicWidthInCtbsY-1.

[0147] tile_row_height_minus1[i] plus 1 represents the height of the i-th tile row in CTBs for i in the range of 0 to num_exp_tile_rows_minus1-1, inclusive. As specified in clause 6.5.1, tile_row_height_minus1[num_exp_tile_rows_minus1] is used to derive the height of tile rows with indices greater than or equal to num_exp_tile_rows_minus1. The value of tile_row_height_minus1[i] shall be in the range of 0 to PicHeightInCtbsY-1, inclusive. If not present, the value of tile_row_height_minus1[0] is inferred to be equal to PicHeightInCtbsY-1.

[0148] rect_slice_flag equal to 0 indicates that the slices within each slice are arranged in raster scan order and the slice information is not signaled in the PPS. rect_slice_flag equal to 1 indicates that the slices within each slice cover a rectangular area of ​​the picture and the slice information is signaled in the PPS. When not present, rect_slice_flag is inferred to be equal to 1. When subpic_info_present_flag is equal to 1, the value of rect_slice_flag shall be equal to 1.

[0149] single_slice_per_subpic_flag equal to 1 indicates that each sub-picture consists of one and only one rectangular slice. single_slice_per_subpic_flag equal to 0 indicates that each sub-picture may consist of one or more rectangular slices. When single_slice_per_subpic_flag is equal to 1, num_slices_in_pic_minus1 is inferred to be equal to sps_num_subpics_minus1. When not present, the value of single_slice_per_subpic_flag is inferred to be equal to 0.

[0150] num_slices_in_pic_minus1 plus 1 indicates the number of rectangular slices in each picture referencing the PPS. The value of num_slices_in_pic_minus1 shall be in the range of 0 to MaxSlicesPerPicture-1, inclusive, where MaxSlicesPerPicture is specified in Annex A. When no_pic_partition_flag is equal to 1, the value of num_slices_in_pic_minus1 is inferred to be equal to 0.

[0151] tile_idx_delta_present_flag equal to 0 indicates that tile_idx_delta values ​​are not present in the PPS and all rectangular slices in pictures referencing the PPS are represented in raster order according to the procedure defined in clause 6.5.1. tile_idx_delta_present_flag equal to 1 indicates that tile_idx_delta values ​​may be present in the PPS and all rectangular slices in pictures referencing the PPS are represented in the order indicated by the tile_idx_delta values. When not present, the value of tile_idx_delta_present_flag is inferred to be equal to 0.

[0152] slice_width_in_tiles_minus1[i] plus 1 represents the width of the i-th rectangular strip in units of tile columns. The value of slice_width_in_tiles_minus1[i] should be in the range of 0 to NumTileColumns-1, including the end value.

[0153] When slice_width_in_tiles_minus1[i] is not present, the following applies:

[0154] — If NumTileColumns is equal to 1, the value of slice_width_in_tiles_minus1[i] is inferred to be equal to 0.

[0155] – Otherwise, the value of slice_width_in_tiles_minus1[i] is inferred as specified in clause 6.5.1.

[0156] slice_height_in_tiles_minus1[i] plus 1 represents the height of the i-th rectangular strip in units of tile rows. The value of slice_height_in_tiles_minus1[i] should be in the range of 0 to NumTileRows-1, including the end value.

[0157] When slice_height_in_tiles_minus1[i] is not present, the following applies:

[0158] - If NumTileRows is equal to 1, or tile_idx_delta_present_flag is equal to 0 and tileIdx % NumTileColumns is greater than 0, then the value of slice_height_in_tiles_minus1[i] is inferred to be equal to 0.

[0159] — Otherwise (NumTileRows is not equal to 1, and tile_idx_delta_present_flag is equal to 1 or tileIdx % NumTileColumns is equal to 0), when tile_idx_delta_present_flag is equal to 1 or tileIdx % NumTileColumns is equal to 0, the value of slice_height_in_tiles_minus1[i] is inferred to be equal to slice_height_in_tiles_minus1[i-1].

[0160] num_exp_slices_in_tile[i] represents the number of explicitly provided strip heights in the current tile containing multiple rectangular strips. The value of num_exp_slices_in_tile[i] should be in the range of 0 to RowHeight[tileY]-1, where tileY is the index of the tile row containing the i-th strip. When not present, the value of num_exp_slices_in_tile[i] is inferred to be equal to 0. When num_exp_slices_in_tile[i] is equal to 0, the value of the inferred variable NumSlicesInTile[i] is equal to 1.

[0161] exp_slice_height_in_ctus_minus1[j] plus 1 represents the height of the jth rectangular slice in the current slice in CTU rows. The value of exp_slice_height_in_ctus_minus1[j] shall be in the range of 0 to RowHeight[tileY]-1, inclusive, where tileY is the slice row index of the current slice.

[0162] When num_exp_slices_in_tile[i] is greater than 0, the variables NumSlicesInTile[i] and SliceHeightInCtusMinus1[i+k] for k in the range 0 to NumSlicesInTile[i]-1 are derived as follows:

[0163]

[0164]

[0165] tile_idx_delta[i] represents the difference between the tile index of the first tile in the i-th rectangular strip and the tile index of the first tile in the (i+1)-th rectangular strip. The value of tile_idx_delta[i] shall be in the range of -NumTilesInPic+1 to NumTilesInPic-1, inclusive. If not present, the value of tile_idx_delta[i] is inferred to be equal to 0. If present, the value of tile_idx_delta[i] shall not be equal to 0.

[0166] loop_filter_across_tiles_enabled_flag equal to 1 indicates that loop filtering operations can be performed across slice boundaries in pictures that reference PPS. loop_filter_across_tiles_enabled_flag equal to 0 indicates that loop filtering operations are not performed across slice boundaries in pictures that reference PPS. Loop filtering operations include deblocking filter, sample adaptive offset filter, and adaptive loop filter operations. If not present, the value of loop_filter_across_tiles_enabled_flag is inferred to be equal to 1.

[0167] loop_filter_across_slices_enabled_flag equal to 1 indicates that loop filtering operations can be performed across slice boundaries in pictures that reference PPS. loop_filter_across_slice_enabled_flag equal to 0 indicates that loop filtering operations are not performed across slice boundaries in pictures that reference PPS. Loop filtering operations include deblocking filter, sample adaptive offset filter, and adaptive loop filter operations. If not present, the value of loop_filter_across_slices_enabled_flag is inferred to be equal to 0.

[0168] cabac_init_present_flag equal to 1 indicates that cabac_init_flag is present in the slice header referencing the PPS. cabac_init_present_flag equal to 0 indicates that cabac_init_flag is not present in the slice header referencing the PPS.

[0169] num_ref_idx_default_active_minus1[i] increments by 1 and, when i is equal to 0, represents the inferred value of the variable NumRefIdxActive[0] for a P or B slice with num_ref_idx_active_override_flag equal to 0, and, when i is equal to 1, represents the inferred value of NumRefIdxActive[1] for a B slice with num_ref_idx_active_override_flag equal to 0. The value of num_ref_idx_default_active_minus1[i] shall be in the range of 0 to 14, inclusive.

[0170] rpl1_idx_present_flag equal to 0 indicates that ref_pic_list_sps_flag[1] and ref_pic_list_idx[1] are not present in the PH syntax structure or the slice header of the picture referencing the PPS. rpl1_idx_present_flag equal to 1 indicates that ref_pic_list_sps_flag[1] and ref_pic_list_idx[1] may be present in the PH syntax structure or the slice header of the picture referencing the PPS.

[0171] init_qp_minus26 plus 26 represents the initial value of SliceQpY for each slice that references the PPS. When a non-zero value of ph_qp_delta is decoded, SliceQp Y The initial value of SliceQp is modified at the picture level, or when a non-zero value of slice_qp_delta is decoded. Y The initial value of init_qp_minus26 is modified at the stripe level. The value of init_qp_minus26 should be in the range of -(26+QpBdOffset) to +37, inclusive.

[0172] cu_qp_delta_enabled_flag equal to 1 indicates that the ph_cu_qp_delta_subdiv_intra_slice and ph_cu_qp_delta_subdiv_inter_slice syntax elements are present in the PH referencing the PPS, and cu_qp_delta_abs may be present in the transform unit syntax. cu_qp_delta_enabled_flag equal to 0 indicates that the ph_cu_qp_delta_subdiv_intra_slice and ph_cu_qp_delta_subdiv_inter_slice syntax elements are not present in the PH referencing the PPS, and cu_qp_delta_abs is not present in the transform unit syntax.

[0173] pps_chroma_tool_offsets_present_flag equal to 1 indicates that syntax elements related to chroma tool offsets are present in the PPS RBSP syntax structure. pps_chroma_tool_offsets_present_flag equal to 0 indicates that syntax elements related to chroma tool offsets are not present in the PPS RBSP syntax structure. When ChromaArrayType is equal to 0, the value of pps_chroma_tool_offsets_present_flag shall be equal to 0.

[0174] pps_cb_qp_offset and pps_cr_qp_offset are used to derive Qp' Cb and Qp' Cr The brightness quantization parameter Qp' Y The values ​​of pps_cb_qp_offset and pps_cr_qp_offset shall be in the range -12 to +12, inclusive. When ChromaArrayType is equal to 0, pps_cb_qp_offset and pps_cr_qp_offset are not used during decoding and the decoder shall ignore their values. If not present, the values ​​of pps_cb_qp_offset and pps_cr_qp_offset are inferred to be equal to 0.

[0175] pps_joint_cbcr_qp_offset_present_flag equal to 1 indicates that pps_joint_cbcr_qp_offset_value and joint_cbcr_qp_offset_list[i] are present in the PPS RBSP syntax structure. pps_joint_cbcr_qp_offset_present_flag equal to 0 indicates that pps_joint_cbcr_qp_offset_value and joint_cbcr_qp_offset_list[i] are not present in the PPS RBSP syntax structure. When ChromaArrayType is equal to 0 or sps_joint_cbcr_enabled_flag is equal to 0, the value of pps_joint_cbcr_qp_offset_present_flag shall be equal to 0. When not present, the value of pps_joint_cbcr_qp_offset_present_flag is inferred to be equal to 0.

[0176] pps_joint_cbcr_qp_offset_value is used to derive Qp' CbCr The brightness quantization parameter Qp' YThe value of pps_joint_cbcr_qp_offset_value shall be in the range of -12 to +12, inclusive. When ChromaArrayType is equal to 0 or sps_joint_cbcr_enabled_flag is equal to 0, pps_joint_cbcr_qp_offset_value is not used during decoding and the decoder shall ignore its value. When pps_joint_cbcr_qp_offset_present_flag is equal to 0, pps_joint_cbcr_qp_offset_value is not present and is inferred to be equal to 0.

[0177] pps_slice_chroma_qp_offsets_present_flag equal to 1 indicates that the slice_cb_qp_offset and slice_cr_qp_offset syntax elements are present in the associated slice header. pps_slice_chroma_qp_offsets_present_flag equal to 0 indicates that the slice_cb_qp_offset and slice_cr_qp_offset syntax elements are not present in the associated slice header. When not present, the value of pps_slice_chroma_qp_offsets_present_flag is inferred to be equal to 0.

[0178] pps_cu_chroma_qp_offset_list_enabled_flag equal to 1 indicates that the ph_cu_chroma_qp_offset_subdiv_intra_slice and ph_cu_chroma_qp_offset_subdiv_inter_slice syntax elements are present in the PH referencing the PPS, and cu_chroma_qp_offset_flag may be present in transform unit syntax and palette codec syntax. pps_cu_chroma_qp_offset_list_enabled_flag equal to 0 indicates that the ph_cu_chroma_qp_offset_subdiv_intra_slice and ph_cu_chroma_qp_offset_subdiv_inter_slice syntax elements are not present in the PH referencing the PPS, and cu_chroma_qp_offset_flag is not present in transform unit syntax and palette codec syntax. If not present, the value of pps_cu_chroma_qp_offset_list_enabled_flag is inferred to be equal to 0.

[0179] chroma_qp_offset_list_len_minus1 plus 1 indicates the number of cb_qp_offset_list[i], cr_qp_offset_list[i], and joint_cbcr_qp_offset_list[i] syntax elements present in the PPS RBSP syntax structure. The value of chroma_qp_offset_list_len_minus1 shall be in the range of 0 to 5, inclusive.

[0180] cb_qp_offset_list[i], cr_qp_offset_list[i] and joint_cbcr_qp_offset_list[i] respectively represent the offsets in Qp' Cb , Qp' Cr and Qp' CbCr The values ​​of cb_qp_offset_list[i], cr_qp_offset_list[i], and joint_cbcr_qp_offset_list[i] shall be in the range -12 to +12, inclusive. When pps_joint_cbcr_qp_offset_present_flag is equal to 0, joint_cbcr_qp_offset_list[i] is not present and is inferred to be equal to 0.

[0181] pps_weighted_pred_flag equal to 0 indicates that weighted prediction is not applied to P slices referencing PPS. pps_weighted_pred_flag equal to 1 indicates that weighted prediction is applied to P slices referencing PPS. When sps_weighted_pred_flag is equal to 0, the value of pps_weighted_pred_flag shall be equal to 0.

[0182] pps_weighted_bipred_flag equal to 0 indicates that explicit weighted prediction is not applied to B slices referencing the PPS. pps_weighted_bipred_flag equal to 1 indicates that explicit weighted prediction is applied to B slices referencing the PPS. When sps_weighted_bipred_flag is equal to 0, the value of pps_weighted_bipred_flag shall be equal to 0.

[0183] deblocking_filter_control_present_flag equal to 1 indicates that the deblocking filter control syntax element is present in the PPS. deblocking_filter_control_present_flag equal to 0 indicates that the deblocking filter control syntax element is not present in the PPS.

[0184] deblocking_filter_override_enabled_flag equal to 1 indicates that ph_deblocking_filter_overrid_flag is present in the PH referencing the PPS or slice_deblocking_filter_override_flag is present in the slice header referencing the PPS. deblocking_filter_override_enabled_flag equal to 0 indicates that ph_deblocking_filter_override_flag is not present in the PH referencing the PPS or slice_deblocking_filter_override_flag is not present in the slice header referencing the PPS. If not present, the value of deblocking_filter_override_enabled_flag is inferred to be equal to 0.

[0185] pps_deblocking_filter_disabled_flag equal to 1 indicates that the operation of the deblocking filter is not applied to slices referencing the PPS where slice_deblocking_filter_disabled_flag is not present. pps_deblocking_filter_disabled_flag equal to 0 indicates that the operation of the deblocking filter is applied to slices referencing the PPS where slice_deblocking_filter_disabled_flag is not present. When not present, the value of pps_deblocking_filter_disabled_flag is inferred to be equal to 0.

[0186] pps_beta_offset_div2 and pps_tc_offset_div2 represent the default deblocking parameter offsets for beta and tc (divided by 2) applied to the luma component of the slice referencing the PPS, unless the default deblocking parameter offsets are overridden by the deblocking parameter offsets present in the picture header or in the slice header of the slice referencing the PPS. The values ​​of pps_beta_offset_div2 and pps_tc_offset_div2 shall both be in the range of -12 to 12, inclusive. If not present, the values ​​of pps_beta_offset_div2 and pps_tc_offset_div2 shall both be inferred to be equal to 0.

[0187] pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2 represent the default deblocking parameter offsets for beta and tC (divided by 2) applied to the Cb component of the slice referencing the PPS, unless the default deblocking parameter offsets are overridden by the deblocking parameter offsets present in the picture header or in the slice header of the slice referencing the PPS. The values ​​of pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2 shall both be in the range of -12 to 12, inclusive. If not present, the values ​​of pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2 shall both be inferred to be equal to 0.

[0188] pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2 represent the default deblocking parameter offsets for beta and tC (divided by 2) applied to the Cr components of the slice referencing the PPS, unless the default deblocking parameter offsets are overridden by the deblocking parameter offsets present in the picture header or in the slice header of the slice referencing the PPS. The values ​​of pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2 should both be in the range of -12 to 12, inclusive. When not present, the values ​​of pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2 are both inferred to be equal to 0.

[0189] rpl_info_in_ph_flag equal to 1 indicates that the reference picture list information is present in the PH syntax structure and not in the slice header referencing the PPS that does not contain the PH syntax structure. rpl_info_in_ph_flag equal to 0 indicates that the reference picture list information is not present in the PH syntax structure and may be present in the slice header referencing the PPS that does not contain the PH syntax structure.

[0190] dbf_info_in_ph_flag equal to 1 indicates that the deblocking filter information is present in the PH syntax structure and is not present in the slice headers referencing the PPS that does not contain the PH syntax structure. dbf_info_in_ph_flag equal to 0 indicates that the deblocking filter information is not present in the PH syntax structure and may be present in the slice headers referencing the PPS that does not contain the PH syntax structure. If not present, the value of dbf_info_in_ph_flag is inferred to be equal to 0.

[0191] sao_info_in_ph_flag equal to 1 indicates that the SAO filter information is present in the PH syntax structure and not in the slice headers referencing the PPS that does not contain the PH syntax structure. sao_info_in_ph_flag equal to 0 indicates that the SAO filter information is not present in the PH syntax structure and may be present in the slice headers referencing the PPS that does not contain the PH syntax structure.

[0192] alf_info_in_ph_flag equal to 1 indicates that the ALF information is present in the PH syntax structure and not in the slice headers referencing the PPS that does not contain the PH syntax structure. alf_info_in_ph_flag equal to 0 indicates that the ALF information is not present in the PH syntax structure and may be present in the slice headers referencing the PPS that does not contain the PH syntax structure.

[0193] wp_info_in_ph_flag equal to 1 indicates that the weighted prediction information may be present in the PH syntax structure, but not in the slice headers referencing the PPS that does not contain the PH syntax structure. wp_info_in_ph_flag equal to 0 indicates that the weighted prediction information is not present in the PH syntax structure, and may be present in the slice headers referencing the PPS that does not contain the PH syntax structure. If not present, the value of wp_info_in_ph_flag is inferred to be equal to 0.

[0194] qp_delta_info_in_ph_flag equal to 1 indicates that QP delta information is present in the PH syntax structure and not in slice headers that reference a PPS that does not contain a PH syntax structure. qp_delta_info_in_ph_flag equal to 0 indicates that QP delta information is not present in the PH syntax structure and may be present in slice headers that reference a PPS that does not contain a PH syntax structure.

[0195] pps_ref_wraparound_enabled_flag equal to 1 indicates that horizontal wraparound motion compensation is applied in inter prediction. pps_ref_wraparound_enabled_flag equal to 0 indicates that horizontal wraparound motion compensation is not applied. When the value of CtbSizeY / MinCbSizeY+1 is greater than pic_width_in_luma_samples / MinCbSizeY—1, the value of pps_ref_wraparound_enabled_flag shall be equal to 0. When sps_ref_wraparound_enabled_flag is equal to 0, the value of pps_ref_wraparound_enabled_flag shall be equal to 0.

[0196] pps_ref_wraparound_offset plus (CtbSizeY / MinCbSizeY)+2 represents the offset used to calculate the horizontal wrapping position in units of MinCbSizeY luma samples. The value of pps_ref_wraparound_offset shall be in the range of 0 to (pic_width_in_luma_samples / MinCbSizeY)-(CtbSizeY / MinCbSizeY)-2, inclusive.

[0197] The variable PpsRefWraparoundOffset is set equal to pps_ref_wraparound_offset+(CtbSizeY / MinCbSizeY)+2.

[0198] picture_header_extension_present_flag equal to 0 indicates that the PH extension syntax element is not present in the PH referencing the PPS. picture_header_extension_present_flag equal to 1 indicates that the PH extension syntax element is present in the PH referencing the PPS. In bitstreams conforming to this version of this specification, picture_header_extension_present_flag shall be equal to 0.

[0199] slice_header_extension_present_flag equal to 0 indicates that the slice header extension syntax element is not present in the slice header of the codec picture referencing the PPS. slice_header_extension_present_flag equal to 1 indicates that the slice header extension syntax element is present in the slice header for the codec picture referencing the PPS. slice_header_extension_present_flag shall be equal to 0 in bitstreams conforming to this version of this specification.

[0200] pps_extension_flag equal to 0 indicates that there is no pps_extension_data_flag syntax element in the PPSRBSP syntax structure. pps_extension_flag equal to 1 indicates that there is a pps_extension_data_flag syntax element in the PPSRBSP syntax structure.

[0201] pps_extension_data_flag can have any value. Its presence and value do not affect the conformance of a decoder to the profiles expressed in this version of this specification. Decoders conforming to this version of this specification shall ignore all pps_extension_data_flag syntax elements.

[0202] 3.2.APS Syntax and Semantics

[0203] In the latest VVC draft text, the PPS syntax and semantics are as follows:

[0204]

[0205] The APS RBSP contains the ALF syntax structure, for example, alf_data().

[0206]

[0207]

[0208]

[0209] The APS RBSP contains the LMCS syntax structure, for example, lmcs_data().

[0210]

[0211]

[0212] The APS RBSP contains a scaling list data syntax structure, eg, scaling_list_data().

[0213]

[0214]

[0215] Each APS RBSP shall be available to the decoding process before being referenced, and each APS RBSP shall be included in at least one AU (where the TemporalId is less than or equal to the TemporalId of the codec slice NAL unit that references the AU) or provided by external means.

[0216] All APS NAL units with a specific value of adapt_parameter_set_id and a specific value of aps_params_type in a PU, whether they are prefix or suffix APS NAL units, shall have the same content.

[0217] The adaption_parameter_set_id provides an identifier for the APS to be referenced by other syntax elements.

[0218] When aps_params_type is equal to ALF_APS or SCALING_APS, the value of adaptation_parameter_set_id shall be in the range of 0 to 7, inclusive.

[0219] When aps_params_type is equal to LMCS_APS, the value of adaptation_parameter_set_id shall be in the range of 0 to 3, inclusive.

[0220] Let apsLayerId be the value of nuh_layer_id for a particular APS NAL unit and vclLayerId be the value of nuh_layer_id for a particular VCL NAL unit. A particular VCL NAL unit shall not reference a particular APS NAL unit unless apsLayerId is less than or equal to vclLayerId and the layer with nuh_layer_id equal to apsLayerId is included in at least one OLS that includes a layer with nuh_layer_id equal to vclLayerId.

[0221] aps_params_type indicates the type of APS parameters carried in the APS, as shown in Table 6.

[0222] Table 6 - APS parameter type codes and APS parameter types

[0223] aps_params_type aps_params_type name APS parameter type 0 ALF_APS ALF parameters 1 LMCS_APS LMCS parameters 2 SCALING_APS Scaling list parameters 3..7 Reserved Reserved

[0224] All APS NAL units with a specific value of aps_params_type, regardless of the nuh_layer_id value, share the same value space for adapt_parameter_set_id. APS NAL units with different aps_params_type values ​​use separate value spaces for adapt_parameter_set_id.

[0225] NOTE 1—APS NAL units (with specific values ​​of adaptation_parameter_set_id and specific values ​​of aps_params_type) can be shared between pictures, and different slices within a picture can reference different ALF APSs.

[0226] NOTE 2—A suffix APS NAL unit associated with a particular VCL NAL unit that precedes the suffix APS NAL unit in decoding order is not used for that particular VCL NAL unit, but is used for VCL NAL units that follow the suffix APS NAL unit in decoding order.

[0227] aps_extension_flag equal to 0 indicates that the aps_extension_data_flag syntax element is not present in the APS RBSP syntax structure. aps_extension_flag equal to 1 indicates that the aps_extension_data_flag syntax element is present in the APS RBSP syntax structure.

[0228] aps_extension_data_flag can have any value. Its presence and value do not affect decoder conformance to the profiles represented in this version of this specification. Decoders conforming to this version of this specification shall ignore all aps_extension_data_flag syntax elements.

[0229] alf_luma_filter_signal_flag equal to 1 indicates that the luma filter set is signaled. alf_luma_filter_signal_flag equal to 0 indicates that the luma filter set is not signaled.

[0230] alf_chroma_filter_signal_flag equal to 1 indicates that the chroma filter is signaled. alf_chroma_filter_signal_flag equal to 0 indicates that the chroma filter is not signaled. When ChromaArrayType is equal to 0, alf_chroma_filter_signal_flag shall be equal to 0.

[0231] The value of at least one of alf_luma_filter_signal_flag, alf_chroma_filter_signal_flag, alf_cc_cb_filter_signal_flag, and alf_cc_cr_filter_signal_flag shall be equal to 1.

[0232] The variable NumAlfFilters, which represents the number of different adaptive loop filters, is set equal to 25.

[0233] alf_luma_clip_flag equal to 0 indicates that linear adaptive loop filtering is applied to the luma component. alf_luma_clip_flag equal to 1 indicates that non-linear adaptive loop filtering may be applied to the luma component.

[0234] alf_luma_num_filters_signalled_minus1 plus 1 indicates the number of adaptive loop filter categories that can signal luma coefficients. The value of alf_luma_num_filters_signalled_minus1 should be in the range of 0 to NumAlfFilters — 1, inclusive.

[0235] alf_luma_coeff_delta_idx[filtIdx] represents the index of the signaled adaptive loop filter luma coefficient delta for the filter class indicated by filtIdx, ranging from 0 to NumAlfFilters — 1. When alf_luma_coeff_delta_idx[filtIdx] is not present, it is inferred to be equal to 0. The length of alf_luma_coeff_delta_idx[filtIdx] is Ceil(Log2(alf_luma_num_filters_signalled_minus1+1)) bits. The value of alf_luma_coeff_delta_idx[filtIdx] shall be in the range of 0 to alf_luma_num_filters_signalled_minus1, inclusive.

[0236] alf_luma_coeff_abs[sfIdx][j] represents the absolute value of the j-th coefficient of the signaled luma filter indicated by sfIdx. When alf_luma_coeff_abs[sfIdx][j] is not present, it is inferred to be equal to 0. The value of alf_luma_coeff_abs[sfIdx][j] should be in the range of 0 to 128, inclusive.

[0237] alf_luma_coeff_sign[sfIdx][j] represents the sign of the j-th luma coefficient of the filter indicated by sfIdx, as shown below:

[0238] - If alf_luma_coeff_sign[sfIdx][j] is equal to 0, the corresponding luma filter coefficient is positive.

[0239] Otherwise (alf_luma_coeff_sign[sfIdx][j] is equal to 1), the corresponding luma filter coefficient is negative.

[0240] When alf_luma_coeff_sign[sfIdx][j] is not present, it is inferred to be equal to 0.

[0241] The variable filtCoeff[sfIdx][j] with sfIdx=0..alf_luma_num_filters_signalled_minus1,j=0..11 is initialized as follows:

[0242] filtCoeff[sfIdx][j]=alf_luma_coeff_abs[sfIdx][j]* (93)

[0243] (1-2*alf_luma_coeff_sign[sfIdx][j])

[0244] With element AlfCoeff L [adaptation_parameter_set_id][filtIdx][j] Luma filter coefficient AlfCoeff L [adaptation_parameter_set_id] (where filtIdx=0..NumAlfFilters-1 and j=0..11) is derived as follows:

[0245] Alf Coeff L[adaptation_parameter_set_id][filtIdx][j]=filtCoeff[alf_luma_coeff_delta_idx[filtIdx]][j] (94)

[0246] The fixed filter coefficients AlfFixFiltCoeff[i][j] (where i=0..64, j=0..11) and the class-to-filter map AlfClassToFiltMap[m][n] (where m=0..15 and n=0..24) are derived as follows:

[0247]

[0248]

[0249]

[0250] Bitstream consistency requires AlfCoeff where filtIdx=0..NumAlfFilters-1,j=0..11 L The value of [adaptation_parameter_set_id][filtIdx][j] should be between -2 7 To 2 7 -1, inclusive.

[0251] alf_luma_clip_idx[sfIdx][j] represents the clip index of the clip value to be used before multiplying the j-th coefficient of the signaled luma filter indicated by sfIdx. Bitstream conformance requires that the value of alf_luma_clip_idx[sfIdx][j] with sfIdx=0..alf_luma_num_filters_signalled_minus1 and j=0..11 shall be in the range of 0 to 3, inclusive.

[0252] With element AlfClip L [adaptation_parameter_set_id][filtIdx][j] (where filtIdx = 0..NumAlfFilters-1 and j = 0..11) Luma filter clipping value AlfClip L[adaptation_parameter_set_id] is derived from BitDepth and clipIdx set equal to alf_luma_clip_idx[alf_luma_coeff_delta_idx[filtIdx]][j] as shown in Table 8.

[0253] alf_chroma_clip_flag equal to 0 indicates that linear adaptive loop filtering is applied to chroma components; alf_chroma_clip_flag equal to 1 indicates that non-linear adaptive loop filtering is applied to chroma components. When not present, alf_chroma_clip_flag is inferred to be equal to 0.

[0254] alf_chroma_num_alt_filters_minus1 plus 1 indicates the number of optional filters for chroma components. The value of alf_chroma_num_alt_filters_minus1 should be in the range of 0 to 7, inclusive.

[0255] alf_chroma_coeff_abs[altIdx][j] represents the absolute value of the j-th chroma filter coefficient of the optional chroma filter with index altIdx. When alf_chroma_coeff_abs[altIdx][j] is not present, it is inferred to be equal to 0. The value of alf_chroma_coeff_abs[sfIdx][j] shall be in the range of 0 to 128, inclusive.

[0256] alf_chroma_coeff_sign[altIdx][j] represents the sign of the j-th chroma filter coefficient of the optional chroma filter with index altIdx as follows:

[0257] - If alf_chroma_coeff_sign[altIdx][j] is equal to 0, the corresponding chroma filter coefficient is positive.

[0258] Otherwise (alf_chroma_coeff_sign[altIdx][j] is equal to 1), the corresponding chroma filter coefficient is negative.

[0259] When alf_chroma_coeff_sign[altIdx][j] is not present, it is inferred to be equal to 0.

[0260] With element AlfCoeff C[adaptation_parameter_set_id][altIdx][j] chroma filter coefficient AlfCoeff C [adaptation_parameter_set_id][altIdx] (where altIdx = 0..alf_chroma_num_alt_filters_minus1, j = 0..5) is derived as follows:

[0261] Alf Coeff C [adaptation_parameter_set_id][altIdx][j]=alf_chroma_coeff_abs[altIdx][j]* (97)

[0262] (1-2*alf_chroma_coeff_sign[altIdx][j])

[0263] Bitstream conformance requirement, where alfCoeff altIdx = 0..alf_chroma_num_alt_filters_minus1, j = 0..5 C The value of [adaptation_parameter_set_id][altIdx][j] should be between -2 7 To 2 7 -1, inclusive.

[0264] alf_cc_cb_filter_signal_flag equal to 1 indicates that the cross-component filter of the Cb color component is signaled. alf_cc_cb_filter_signal_flag equal to 0 indicates that the cross-component filter of the Cb color component is not signaled. When ChromaArrayType is equal to 0, alf_cc_cb_filter_signal_flag shall be equal to 0.

[0265] alf_cc_cb_filters_signalled_minus1 plus 1 indicates the number of cross-component filters for the Cb color component signaled in the current ALF APS. The value of alf_cc_cb_filters_signalled_minus1 shall be in the range of 0 to 3, inclusive.

[0266] alf_cc_cb_mapped_coeff_abs[k][j] represents the absolute value of the j-th mapping coefficient of the signaled k-th cross-component filter for the Cb color component. When alf_cc_cb_mapped_coeff_abs[k][j] is not present, it is inferred to be equal to 0.

[0267] alf_cc_cb_coeff_sign[k][j] represents the sign of the j-th coefficient of the k-th cross-component filter signaled for the Cb color component, as shown below:

[0268] - If alf_cc_cb_coeff_sign[k][j] is equal to 0, the corresponding cross-component filter coefficient is positive.

[0269] Otherwise (alf_cc_cb_sign[k][j] is equal to 1), the corresponding cross-component filter coefficient is negative.

[0270] When alf_cc_cb_coeff_sign[k][j] is not present, it is inferred to be equal to 0.

[0271] For the Cb color component CcAlfApsCoeff Cb The k-th cross-component filter coefficient signaled by [adaptation_parameter_set_id][k][j] (where j=0..6) is derived as follows:

[0272] — If alf_cc_cb_mapped_coeff_abs[k][j] is equal to 0, then CcAlfApsCoeff Cb [adaptation_parameter_set_id][k][j] is set equal to 0.

[0273] — Otherwise, CcAlfApsCoeff Cb [adaptation_parameter_set_id][k][j] is set equal to (1-2*alf_cc_cb_coeff_sign[k][j])*2 alf_cc_cb_mapped_coeff_abs[k][j]-1 .

[0274] alf_cc_cr_filter_signal_flag equal to 1 indicates that cross-component filters for Cr color components are signaled. alf_cc_cr_filter_signal_flag equal to 0 indicates that cross-component filters for Cr color components are not signaled. When ChromaArrayType is equal to 0, alf_cc_cr_filter_signal_flag shall be equal to 0.

[0275] alf_cc_cr_filters_signalled_minus1 plus 1 indicates the number of cross-component filters for the Cr color component signaled in the current ALF APS. The value of alf_cc_cr_filters_signalled_minus1 shall be in the range of 0 to 3, inclusive.

[0276] alf_cc_cr_mapped_coeff_abs[k][j] represents the absolute value of the j-th mapping coefficient of the signaled k-th cross-component filter for the Cr color component. When alf_cc_cr_mapped_coeff_abs[k][j] is not present, it is inferred to be equal to 0.

[0277] alf_cc_cr_coeff_sign[k][j] represents the sign of the j-th coefficient of the k-th cross-component filter signaled for the Cr color component, as shown below:

[0278] - If alf_cc_cr_coeff_sign[k][j] is equal to 0, the corresponding cross-component filter coefficient is positive.

[0279] Otherwise (alf_cc_cr_sign[k][j] is equal to 1), the corresponding cross-component filter coefficient is negative.

[0280] When alf_cc_cr_coeff_sign[k][j] is not present, it is inferred to be equal to 0.

[0281] The signaled k-th cross-component filter coefficient for the Cr color component CcAlfApsCoeffCr[adaptation_parameter_set_id][k][j] (where j=0..6) is derived as follows:

[0282] — If alf_cc_cr_mapped_coeff_abs[k][j] is equal to 0, then CcAlfApsCoeff Cr [adaptation_parameter_set_id][k][j] is set equal to 0.

[0283] — Otherwise, CcAlfApsCoeff Cr [adaptation_parameter_set_id][k][j] is set equal to (1-2*alf_cc_cr_coeff_sign[k][j])*2 alf _cc_cr_mapped_coeff_abs[k][j]-1.

[0284] alf_chroma_clip_idx[altIdx][j] represents the clipping index of the clipping value to be used before multiplying the j-th coefficient of the optional chroma filter with index altIdx. Bitstream conformance requires that the value of alf_chroma_clip_idx[altIdx][j] with altIdx=0..alf_chroma_num_alt_filters_minus1, j=0..5 shall be in the range of 0 to 3, inclusive.

[0285] The chroma filter clipping value AlfClipC[adaptation_parameter_set_id][altIdx][j] with the elements AlfClipC[adaptation_parameter_set_id][altIdx][j], where altIdx=0..alf_chroma_num_alt_filters_minus1, j=0..5, is derived from BitDepth and clipIdx is set equal to alf_chroma_clip_idx[altIdx][j] as shown in Table 8.

[0286] Table 8 - AlfClip specification depending on BitDepth and clipIdx

[0287]

[0288] lmcs_min_bin_idx represents the minimum bin index used in the luma map and chroma scaling construction process. The value of lmcs_min_bin_idx should be in the range of 0 to 15, inclusive.

[0289] lmcs_delta_max_bin_idx represents the delta value between 15 and the maximum bin index LmcsMaxBinIdx used for the luma mapping and chroma scaling construction process. The value of lmcs_delta_max_bin_idx shall be in the range of 0 to 15, inclusive. The value of LmcsMaxBinIdx is set equal to 15 - lmcs_delta_max_bin_idx. The value of LmcsMaxBinIdx shall be greater than or equal to lmcs_min_bin_idx.

[0290] lmcs_delta_cw_prec_minus1 plus 1 indicates the number of bits used for the syntax lmcs_delta_abs_cw[i]. The value of lmcs_delta_cw_prec_minus1 shall be in the range of 0 to BitDepth-2, inclusive.

[0291] lmcs_delta_abs_cw[i] represents the absolute incremental codeword value of the i-th bin.

[0292] lmcs_delta_sign_cw_flag[i] indicates the sign of the variable lmcsDeltaCW[i], as shown below:

[0293] - If lmcs_delta_sign_cw_flag[i] is equal to 0, lmcsDeltaCW[i] is a positive value.

[0294] —Otherwise (lmcs_delta_sign_cw_flag[i] is not equal to 0), lmcsDeltaCW[i] is a negative value.

[0295] When lmcs_delta_sign_cw_flag[i] is not present, it is inferred to be equal to 0.

[0296] The variable OrgCW is derived as follows:

[0297] OrgCW=(1< <BitDepth) / 16 (98)

[0298] The variable lmcsDeltaCW[i], where i = lmcs_min_bin_idx..LmcsMaxBinIdx, is derived as follows:

[0299] lmcsDeltaCW[i]=

[0300] (1-2*lmcs_delta_sign_cw_flag[i])*lmcs_delta_abs_cw[i] (99)

[0301] The variable lmcsCW[i] is derived as follows:

[0302] - For i=0..lmcs_min_bin_idx-1, lmcsCW[i] is set equal to 0.

[0303] - For i = lmcs_min_bin_idx..LmcsMaxBinIdx, the following applies:

[0304] lmcsCW[i]=OrgCW+lmcsDeltaCW[i] (100)

[0305] The value of lmcsCW[i] should be in the range of (OrgCW>>3) to (OrgCW<<3-1), inclusive.

[0306] - For i = LmcsMaxBinIdx+1..15, lmcsCW[i] is set to 0.

[0307] Bitstream conformance requires the following to be true:

[0308]

[0309] The variable InputPivot[i], where i = 0..16, is derived as follows:

[0310] InputPivot[i]=i*OrgCW (102)

[0311] The variables LmcsPivot[i] where i=0..16 and ScaleCoeff[i] and InvScaleCoeff[i] where i=0..15 are derived as follows:

[0312]

[0313]

[0314] Bitstream consistency requires that, for i = lmcs_min_bin_idx..LmcsMaxBinIdx, when the value of LmcsPivot[i] is not a multiple of 1<<(BitDepth-5), the value of (LmcsPivot[i]>>(BitDepth-5)) should not be equal to the value of (LmcsPivot[i+1]>>(BitDepth-5)).

[0315] lmcs_delta_abs_crs represents the absolute codeword value of the variable lmcsDeltaCrs. The value of lmcs_delta_abs_crs should be in the range of 0 to 7, inclusive. If not present, lmcs_delta_abs_crs is inferred to be equal to 0.

[0316] lmcs_delta_sign_crs_flag indicates the sign of the variable lmcsDeltaCrs. If not present, lmcs_delta_sign_crs_flag is inferred to be equal to 0.

[0317] The variable lmcsDeltaCrs is derived as follows:

[0318] lmcsDeltaCrs=(1-2*lmcs_delta_sign_crs_flag)*lmcs_delta_abs_crs (104)

[0320] Bitstream consistency requires that when lmcsCW[i] is not equal to 0, (lmcsCW[i]+lmcsDeltaCrs) shall be in the range of (OrgCW>>3) to ((OrgCW<<3)-1), including the end values.

[0321] The variable ChromaScaleCoeff[i], where i = 0…15, is derived as follows:

[0322]

[0323] scaling_matrix_for_lfnst_disabled_flag equal to 1 indicates that the scaling matrix is ​​not applied to blocks coded with LFNST. scaling_matrix_for_lfnst_disabled_flag equal to 0 indicates that the scaling matrix can be applied to blocks coded with LFNST.

[0324] scaling_list_chroma_present_flag equal to 1 indicates that the chroma scaling list is present in scaling_list_data(). scaling_list_chroma_present_flag equal to 0 indicates that the chroma scaling list is not present in scaling_list_data(). Bitstream conformance requirement, when ChromaArrayType is equal to 0, scaling_list_chroma_present_flag must be equal to 0, when ChromaArrayType is not equal to 0, scaling_list_chroma_present_flag must be equal to 1.

[0325] scaling_list_copy_mode_flag[id] equal to 1 indicates that the values ​​of the scaling list are the same as those of the reference scaling list. The reference scaling list is represented by scaling_list_pred_id_delta[id]. scaling_list_copy_mode_flag[id] equal to 0 indicates that scaling_list_pred_mode_flag is present.

[0326] scaling_list_pred_mode_flag[id] equal to 1 indicates that the values ​​of the scaling list can be predicted from the reference scaling list. The reference scaling list is represented by scaling_list_pred_id_delta[id]. scaling_list_pred_mode_flag[id] equal to 0 indicates that the values ​​of the scaling list are explicitly signaled. When not present, the value of scaling_list_pred_mode_flag[id] is inferred to be equal to 0.

[0327] scaling_list_pred_id_delta[id] represents the reference scaling list used to derive the prediction scaling matrix ScalingMatrixPred[id]. When not present, the value of scaling_list_pred_id_delta[id] is inferred to be equal to 0. The value of scaling_list_pred_id_delta[id] should be in the range of 0 to maxIdDelta, where maxIdDelta is derived from id as follows:

[0328] maxIdDelta=(id<2)? id:((id<8)?(id-2):(id-8))(106)

[0329] The variables refId and matrixSize are derived as follows:

[0330] refId=id-scaling_list_pred_id_delta[id] (107)

[0331] matrixSize=(id<2)? 2:((id<8)?4:8) (108)

[0332] The array ScalingMatrixPred[x][y] of (matrixSize)x(matrixSize) (where x=0..matrixSize-1, y=0..matrixSize-1) and the variable ScalingMatrixDCPred are derived as follows:

[0333] —When scaling_list_copy_mode_flag[id] and scaling_list_pred_mode_flag[id] are both equal to 0, all elements of ScalingMatrixPred are set equal to 8 and the value of ScalingMatrixDCPred is set equal to 8.

[0334] Otherwise, when scaling_list_pred_id_delta[id] is equal to 0, all elements of ScalingMatrixPred are set equal to 16 and ScalingMatrixDCPred is set equal to 16.

[0335] Otherwise (scaling_list_copy_mode_flag[id] or scaling_list_pred_mode_flag[id] is equal to 1 and scaling_list_pred_id_delta[id] is greater than 0), ScalingMatrixPred is set equal to ScalingMatrixRec[refId] and the following applies to ScalingMatrixDCPred:

[0336] —If refId is greater than 13, then ScalingMatrixDCPred is set equal to ScalingMatrixDCRec[refId-14].

[0337] Otherwise (refId is less than or equal to 13), ScalingMatrixDCPred is set equal to ScalingMatrixPred[0][0].

[0338] scaling_list_dc_coef[id-14] is used to derive the value of the variable ScalingMatrixDC[id-14] when id is greater than 13, as shown below:

[0339] ScalingMatrixDCRec[id-14]=(ScalingMatrixDCPred+scaling_list_dc_coef[id-14])&255 (109)

[0340] When not present, the value of scaling_list_dc_coef[id-14] is inferred to be equal to 0. The value of scaling_list_dc_coef[id-14] shall be in the range -128 to 127, inclusive. The value of ScalingMatrixDCRec[id-14] shall be greater than 0.

[0341] scaling_list_delta_coef[id][i] represents the difference between the current matrix coefficient ScalingList[id][i] and the previous matrix coefficient ScalingList[id][i-1] when scaling_list_copy_mode_flag[id] is equal to 0. The value of scaling_list_delta_coef[id][i] shall be in the range of -128 to 127, inclusive. When scaling_list_copy_mode_flag[id] is equal to 1, all elements of ScalingList[id] are set equal to 0.

[0342] The (matrixSize)x(matrixSize) array ScalingMatrixRec[id] is derived as follows:

[0343] ScalingMatrixRec[id][x][y]=(ScalingMatrixPred[x][y]+ScalingList[id][k])&255 (110)

[0344] with k=0..(matrixSize*matrixSize-1),

[0345] x=DiagScanOrder[Log2(matrixSize)][Log2(matrixSize)][k][0],and

[0346] y=DiagScanOrder[Log2(matrixSize)][Log2(matrixSize)][k][1]The value of ScalingMatrixRec[id][x][y] should be greater than 0.

[0347] PH Syntax and Semantics

[0348] In the latest VVC draft text, the PH syntax and semantics are as follows:

[0349]

[0350] The PH RBSP contains the PH syntax structure, for example, picture_header_structure().

[0351]

[0352]

[0353]

[0354]

[0355]

[0356] The PH syntax structure contains information common to all slices of the coded picture associated with the PH syntax structure.

[0357] gdr_or_irap_pic_flag equal to 1 indicates that the current picture is a GDR or IRAP picture. gdr_or_irap_pic_flag equal to 0 indicates that the current picture may or may not be a GDR or IRAP picture.

[0358] gdr_pic_flag equal to 1 indicates that the picture associated with the PH is a GDR picture. gdr_pic_flag equal to 0 indicates that the picture associated with the PH is not a GDR picture. When not present, the value of gdr_pic_flag is inferred to be equal to 0. When gdr_enabled_flag is equal to 0, the value of gdr_pic_flag shall be equal to 0.

[0359] ph_inter_slice_allowed_flag equal to 0 indicates that all codec slices of the picture have slice_type equal to 2. ph_inter_slice_allowed_flag equal to 1 indicates that there may or may not be one or more codec slices with slice_type equal to 0 or 1 in the picture.

[0360] ph_intra_slice_allowed_flag equal to 0 indicates that all codec slices of the picture have slice_type equal to 0 or 1. ph_intra_slice_allowed_flag equal to 1 indicates that the picture may or may not have one or more codec slices with slice_type equal to 2. When not present, the value of ph_intra_slice_allowed_flag is inferred to be equal to 1.

[0361] NOTE 1 – For bitstreams that assume that sub-pictures do not need to be modified based on the bitstream merge, the encoder shall set the value of ph_inter_slice_allowed_flag and ph_intra_slice_allowed_flag equal to 1.

[0362] non_reference_picture_flag equal to 1 indicates that the picture associated with the PH is never used as a reference picture. non_reference_picture_flag equal to 0 indicates that the picture associated with the PH may or may not be used as a reference picture.

[0363] ph_pic_parameter_set_id indicates the value of pps_pic_parameter_set_id that the PPS is using. The value of ph_pic_parameter_set_id should be in the range of 0 to 63, inclusive.

[0364] Bitstream conformance requires that the TemporalId value of PH shall be greater than or equal to the TemporalId value of the PPS whose pps_pic_parameter_set_id is equal to ph_pic_parameter_set_id.

[0365] ph_pic_order_cnt_lsb represents the picture order count modulo MaxPicOrderCntLsb of the current picture. The length of the ph_pic_order_cnt_lsb syntax element is log2_max_pic_order_cnt_lsb_minus4+4 bits. The value of ph_pic_order_cnt_lsb shall be in the range of 0 to MaxPicOrderCntLsb-1, inclusive.

[0366] no_output_of_prior_pics_flag affects the output of previously decoded pictures in the DPB after decoding of a CLVSS picture that is not the first picture in the bitstream as represented in Annex C.

[0367] recovery_poc_cnt indicates the recovery point of the decoded picture in the output order. If the current picture is a GDR picture associated with PH, and there is a picture picA in the CLVS that follows the current GDR picture in the decoding order, and its PicOrderCntVal is equal to the PicOrderCntVal of the current GDR picture plus the value of recovery_poc_cnt, the picture picA is called the recovery point picture. Otherwise, the first picture whose PicOrderCntVal is greater than the PicOrderCntVal of the current picture plus the value of recovery_poc_cnt in the output order is called the recovery point picture. The recovery point picture should not be before the current GDR picture in the decoding order. The value of recovery_poc_cnt should be in the range of 0 to MaxPicOrderCntLsb-1, including the end value.

[0368] When the current picture is a GDR picture, the variable RpPicOrderCntVal is derived as follows:

[0369] RpPicOrderCntVal = PicOrderCntVal + recovery_poc_cnt (82)

[0370] NOTE 2—When gdr_enabled_flag is equal to 1 and the PicOrderCntVal of the current picture is greater than or equal to the RpPicOrderCntVal associated with the GDR picture, the current and subsequent decoded pictures in output order exactly match the corresponding pictures produced by starting the decoding process from the preceding IRAP picture (if any, preceding the associated GDR picture in decoding order).

[0371] ph_extra_bit[i] may be equal to 1 or 0. Decoders conforming to this version of this specification shall ignore the value of ph_extra_bit[i]. Its value does not affect the conformance of the decoder to the profile represented in this version of this specification.

[0372] ph_poc_msb_present_flag equal to 1 indicates that the syntax element poc_msb_val is present in the PH. ph_poc_msb_present_flag equal to 0 indicates that the syntax element poc_msb_val is not present in the PH. The value of ph_poc_msb_present_flag shall be equal to 0 when vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id]] is equal to 0 and there is a picture in the current AU in the reference layer of the current layer.

[0373] poc_msb_val represents the POC MSB value of the current picture. The length of the syntax element poc_msb_val is poc_msb_len_minus1+1 bits.

[0374] ph_alf_enabled_flag equal to 1 indicates that the adaptive loop filter is enabled for all slices associated with the PH and may be applied to the Y, Cb, or Cr color components in the slice. ph_alf_enabled_flag equal to 0 indicates that the adaptive loop filter may be disabled for one or more or all slices associated with the PH. When not present, ph_alf_enabled_flag is inferred to be equal to 0.

[0375] ph_num_alf_aps_ids_luma indicates the number of ALF APSs referenced by the slice associated with the PH.

[0376] ph_alf_aps_id_luma[i] represents the adaptation_parameter_set_id of the i-th ALFAPS referenced by the luma component of the slice associated with the PH.

[0377] The value of alf_luma_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_alf_aps_id_luma[i].

[0378] The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_alf_aps_id_luma[i] shall be less than or equal to the TemporalId of the picture associated with the PH.

[0379] ph_alf_chroma_idc equal to 0 indicates that the adaptive loop filter is not applied to the Cb and Cr color components. ph_alf_chroma_idc equal to 1 indicates that the adaptive loop filter is applied to the Cb color component. ph_alf_chroma_idc equal to 2 indicates that the adaptive loop filter is applied to the Cr color component. ph_alf_chroma_idc equal to 3 indicates that the adaptive loop filter is applied to the Cb and Cr color components. When ph_alf_chroma_idc is not present, it is inferred to be equal to 0.

[0380] ph_alf_aps_id_chroma indicates the adaptation_parameter_set_id of the ALF APS referenced by the chroma component of the slice associated with the PH.

[0381] The value of alf_chroma_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_alf_aps_id_chroma.

[0382] The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_alf_aps_id_chroma shall be less than or equal to the TemporalId of the picture associated with the PH.

[0383] ph_cc_alf_cb_enabled_flag equal to 1 indicates that the cross-component filter of the Cb color component is enabled for all slices associated with the PH and may be applied to the Cb color components in the slices. ph_cc_alf_cb_enabled_flag equal to 0 indicates that the cross-component filter of the Cb color component may be disabled for one or more or all slices associated with the PH. When not present, ph_cc_alf_cb_enabled_flag is inferred to be equal to 0.

[0384] ph_cc_alf_cb_aps_id represents the adaptation_parameter_set_id of the ALF APS referenced by the Cb color component of the slice associated with the PH.

[0385] The value of alf_cc_cb_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_cc_alf_cb_aps_id.

[0386] The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_cc_alf_cb_aps_id shall be less than or equal to the TemporalId of the picture associated with the PH.

[0387] ph_cc_alf_cr_enabled_flag equal to 1 indicates that cross-component filters for Cr color components are enabled for all slices associated with the PH and may be applied to Cr color components in the slices. ph_cc_alf_cr_enabled_flag equal to 0 indicates that cross-component filters for Cr color components may be disabled for one or more or all slices associated with the PH. When not present, ph_cc_alf_cr_enabled_flag is inferred to be equal to 0.

[0388] ph_cc_alf_cr_aps_id represents the adaptation_parameter_set_id of the ALF APS referenced by the Cr color component of the slice associated with the PH.

[0389] The value of alf_cc_cr_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_cc_alf_cr_aps_id.

[0390] The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_cc_alf_cr_aps_id shall be less than or equal to the TemporalId of the picture associated with the PH.

[0391] ph_lmcs_enabled_flag equal to 1 indicates that luma mapping and chroma scaling are enabled for all slices associated with the PH. ph_lmcs_enabled_flag equal to 0 indicates that luma mapping and chroma scaling may be disabled for one or more or all slices associated with the PH. If not present, the value of ph_lmcs_enabled_flag is inferred to be equal to 0.

[0392] ph_lmcs_aps_id represents the adaptation_parameter_set_id of the LMCS APS referenced by the slice associated with the PH. The TemporalId of the APS NAL unit with aps_params_type equal to LMCS_APS and adaptation_parameter_set_id equal to ph_lmcs_aps_id shall be less than or equal to the TemporalId of the picture associated with the PH.

[0393] ph_chroma_residual_scale_flag equal to 1 indicates that chroma residual scaling is enabled for all slices associated with PH. ph_chroma_residual_scale_flag equal to 0 indicates that chroma residual scaling may be disabled for one or more or all slices associated with PH. When ph_chroma_residual_scale_flag is not present, it is inferred to be equal to 0.

[0394] ph_scaling_list_present_flag equal to 1 indicates that the scaling list data for the slices associated with the PH is derived based on the scaling list data contained in the reference scaling list APS. ph_scaling_list_present_flag equal to 0 indicates that the scaling list data for the slices associated with the PH is set equal to 16. When not present, the value of ph_scaling_list_present_flag is inferred to be equal to 0.

[0395] ph_scaling_list_aps_id indicates the adaptation_parameter_set_id of the scaling list APS. The TemporalId of the APS NAL unit with aps_params_type equal to SCALING_APS and adaptation_parameter_set_id equal to ph_scaling_list_aps_id shall be less than or equal to the TemporalId of the picture associated with the PH.

[0396] ph_virtual_boundaries_present_flag equal to 1 indicates that information about virtual boundaries is signaled in the PH. ph_virtual_boundaries_present_flag equal to 0 indicates that information about virtual boundaries is not signaled in the PH. When one or more virtual boundaries are signaled in the PH, loop filtering operations are disabled across virtual boundaries in the picture. Loop filtering operations include deblocking filter, sample adaptive offset filter, and adaptive loop filter operations. When not present, the value of ph_virtual_boundaries_present_flag is inferred to be equal to 0.

[0397] Bitstream conformance requires that when subpic_info_present_flag is equal to 1, the value of ph_virtual_boundaries_present_flag shall be equal to 0.

[0398] The variable VirtualBoundariesPresentFlag is derived as follows:

[0399]

[0400] ph_num_ver_virtual_boundaries represents the number of ph_virtual_boundaries_pos_x[i] syntax elements present in the PH. When ph_num_ver_virtual_boundaries does not exist, it is inferred to be equal to 0.

[0401] The variable NumVerVirtualBoundaries is derived as follows:

[0402]

[0403]

[0404] ph_virtual_boundaries_pos_x[i] represents the position of the i-th vertical virtual boundary in units of luma samples divided by 8. The value of ph_virtual_boundaries_pos_x[i] shall be in the range of 1 to Ceil(pic_width_in_luma_samples÷8)-1, inclusive.

[0405] The list VirtualBoundariesPosX[i] (i ranges from 0 to NumVerVirtualBoundaries-1, including the end value) represents the position of the vertical virtual boundary in units of brightness samples, which is derived as follows:

[0406]

[0407] The distance between any two vertical virtual boundaries should be greater than or equal to CtbSizeY luminance samples.

[0408] ph_num_hor_virtual_boundaries represents the number of ph_virtual_boundaries_pos_y[i] syntax elements present in PH. When ph_num_hor_virtual_boundaries does not exist, it is inferred to be equal to 0.

[0409] The parameter NumHorVirtualBoundaries is derived as follows:

[0410]

[0411] When sps_virtual_boundaries_enabled_flag is equal to 1 and ph_virtual_boundaries_present_flag is equal to 1, the sum of ph_num_ver_virtual_boundaries and ph_num_hor_virtual_boundaries shall be greater than zero.

[0412] ph_virtual_boundaries_pos_y[i] represents the position of the i-th horizontal virtual boundary in units of luma samples divided by 8. The value of ph_virtual_boundaries_pos_y[i] shall be in the range of 1 to Ceil(pic_height_in_luma_samples÷8)-1, inclusive.

[0413] The list VirtualBoundariesPosY[i] (i ranges from 0 to NumHorVirtualBoundaries-1, including the end value)) represents the position of the horizontal virtual boundary in units of luminance samples, which is derived as follows:

[0414]

[0415] The distance between any two horizontal virtual boundaries should be greater than or equal to CtbSizeY luminance samples.

[0416] pic_output_flag affects the decoded picture output and removal process specified in Annex C. When pic_output_flag is not present, it is inferred to be equal to 1.

[0417] partition_constraints_override_flag is equal to 1 to indicate that partition constraint parameters exist in the PH. partition_constraints_override_flag is equal to 0 to indicate that partition constraint parameters do not exist in the PH. When not present, the value of partition_constraints_override_flag is inferred to be equal to 0.

[0418] ph_log2_diff_min_qt_min_cb_intra_slice_luma represents the difference between the base 2 logarithm of the minimum size of luma samples of luma leaf blocks resulting from the quadtree partitioning of the CTU and the base 2 logarithm of the minimum decoded block size of luma samples of luma CUs in slices with slice_type equal to 2(I) associated with the PH. The value of ph_log2_diff_min_qt_min_cb_intra_slice_luma shall be in the range of 0 to CtbLog2SizeY-MinCbLog2SizeY, inclusive. When not present, the value of ph_log2_diff_min_qt_min_cb_luma is inferred to be equal to sps_log2_diff_min_qt_min_cb_intra_slice_luma.

[0419] ph_max_mtt_hierarchy_depth_intra_slice_luma indicates the maximum hierarchical depth of a codec unit resulting from a multi-type tree partitioning of quadtree leaves in slices with slice_type equal to 2 (I) associated with the PH. The value of ph_max_mtt_hierarchy_depth_intra_slice_luma shall be in the range of 0 to 2*(CtbLog2SizeY-MinCbLog2SizeY), inclusive. When not present, the value of ph_max_mtt_hierarchy_depth_intra_slice_luma is inferred to be equal to sps_max_mtt_hierarchy_depth_intra_slice_luma.

[0420] ph_log2_diff_max_bt_min_qt_intra_slice_luma represents the difference between the base 2 logarithm of the maximum size (width or height) of the luma samples of a luma codec block that can be partitioned using binary partitioning and the minimum size (width or height) of the luma samples of a luma leaf block resulting from a quadtree partitioning of a CTU in a slice with slice_type equal to 2(I) associated with the PH. The value of ph_log2_diff_max_bt_min_qt_intra_slice_luma shall be in the range of 0 to CtbLog2SizeY-MinQtLog2SizeIntraY, inclusive. When not present, the value of ph_log2_diff_max_bt_min_qt_intra_slice_luma is inferred to be equal to sps_log2_diff_max_bt_min_qt_intra_slice_luma.

[0421] ph_log2_diff_max_tt_min_qt_intra_slice_luma represents the difference between the base 2 logarithm of the maximum dimension (width or height) in the luma samples of a luma codec block that can be partitioned using ternary partitioning and the minimum dimension (width or height) in the luma samples of a luma leaf block resulting from a quadtree partitioning of a CTU in a slice with slice_type equal to 2(I) associated with the PH. The value of ph_log2_diff_max_tt_min_qt_intra_slice_luma shall be in the range of 0 to CtbLog2SizeY-MinQtLog2SizeIntraY, inclusive. When not present, the value of ph_log2_diff_max_tt_min_qt_intra_slice_luma is inferred to be equal to sps_log2_diff_max_tt_min_qt_intra_slice_luma.

[0422] ph_log2_diff_min_qt_min_cb_intra_slice_chroma represents the difference between the base 2 logarithm of the minimum size among the luma samples of the chroma leaf blocks resulting from the quadtree partitioning of the chroma CTU with treeType equal to DUAL_TREE_CHROMA and the base 2 logarithm of the minimum decoded block size among the luma samples of the chroma CUs with treeType equal to DUAL_TREE_CHROMA in the slices with slice_type equal to 2(I) associated with the PH. The value of ph_log2_diff_min_qt_min_cb_intra_slice_chroma shall be in the range of 0 to CtbLog2SizeY-MinCbLog2SizeY, inclusive. When not present, the value of ph_log2_diff_min_qt_min_cb_intra_slice_chroma is inferred to be equal to sps_log2_diff_min_qt_min_cb_intra_slice_chroma.

[0423] ph_max_mtt_hierarchy_depth_intra_slice_chroma indicates the maximum hierarchy depth of a chroma codec unit resulting from a multi-type tree partitioning of the leaves of the chroma quadtree with treeType equal to DUAL_TREE_CHROMA in slices with slice_type equal to 2(I) associated with the PH. The value of ph_max_mtt_hierarchy_depth_intra_slice_chroma shall be in the range of 0 to 2*(CtbLog2SizeY-MinCbLog2SizeY), inclusive. When not present, the value of ph_max_mtt_hierarchy_depth_intra_slice_chroma is inferred to be equal to sps_max_mtt_hierarchy_depth_intra_slice_chroma.

[0424] ph_log2_diff_max_bt_min_qt_intra_slice_chroma represents the difference between the base 2 logarithm of the maximum size (width or height) of the luma samples of a chroma codec block that can be partitioned using binary partitioning and the minimum size (width or height) of the luma samples of a chroma leaf block resulting from a quadtree split of a chroma CTU with treeType equal to DUAL_TREE_CHROMA in a slice with slice_type equal to 2(I) associated with the PH. The value of ph_log2_diff_max_bt_min_qt_intra_slice_chroma shall be in the range of 0 to CtbLog2SizeY-MinQtLog2SizeIntraC, inclusive. When not present, the value of ph_log2_diff_max_bt_min_qt_intra_slice_chroma is inferred to be equal to sps_log2_diff_max_bt_min_qt_intra_slice_chroma.

[0425] ph_log2_diff_max_tt_min_qt_intra_slice_chroma represents the difference between the base 2 logarithm of the maximum dimension (width or height) in the luma samples of a chroma codec block that can be partitioned using ternary partitioning and the minimum dimension (width or height) in the luma samples of a chroma leaf block resulting from a quadtree partitioning of a chroma CTU with treeType equal to DUAL_TREE_CHROMA in a slice with slice_type equal to 2(I) associated with the PH. The value of ph_log2_diff_max_tt_min_qt_intra_slice_chroma shall be in the range of 0 to CtbLog2SizeY-MinQtLog2SizeIntraC, inclusive. When not present, the value of ph_log2_diff_max_tt_min_qt_intra_slice_chroma is inferred to be equal to sps_log2_diff_max_tt_min_qt_intra_slice_chroma

[0426] ph_cu_qp_delta_subdiv_intra_slice indicates the maximum cbSubdiv value of the intra-slice codec unit that transmits cu_qp_delta_abs and cu_qp_delta_sign_flag. The value of ph_cu_qp_delta_subdiv_intra_slice shall be in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeIntraY+ph_max_mtt_hierarchy_depth_intra_slice_luma), inclusive.

[0427] If not present, the value of ph_cu_qp_delta_subdiv_intra_slice is inferred to be equal to 0.

[0428] ph_cu_chroma_qp_offset_subdiv_intra_slice indicates the maximum cbSubdiv value of the intra-slice codec unit that transmits cu_chroma_qp_offset_flag. The value of ph_cu_chroma_qp_offset_subdiv_intra_slice shall be in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeIntraY+ph_max_mtt_hierarchy_depth_intra_slice_luma), inclusive.

[0429] If not present, the value of ph_cu_chroma_qp_offset_subdiv_intra_slice is inferred to be equal to 0.

[0430] ph_log2_diff_min_qt_min_cb_inter_slice represents the difference between the base 2 logarithm of the minimum size of luma samples of luma leaf blocks resulting from a quadtree partitioning of a CTU and the base 2 logarithm of the minimum luma codec block size of luma samples of luma CUs in slices with slice_type equal to 0 (B) or 1 (P) associated with the PH. The value of ph_log2_diff_min_qt_min_cb_inter_slice shall be in the range of 0 to CtbLog2SizeY-MinCbLog2SizeY, inclusive. If not present, the value of ph_log2_diff_min_qt_min_cb_luma is inferred to be equal to sps_log2_diff_min_qt_min_cb_inter_slice.

[0431] ph_max_mtt_hierarchy_depth_inter_slice indicates the maximum hierarchical depth of coding units resulting from multi-type tree partitioning of quadtree leaves in slices with slice_type equal to 0 (B) or 1 (P) associated with PH. The value of ph_max_mtt_hierarchy_depth_inter_slice shall be in the range of 0 to 2*(CtbLog2SizeY - MinCbLog2SizeY), inclusive. When not present, the value of ph_max_mtt_hierarchy_depth_inter_slice is inferred to be equal to sps_max_mtt_hierarchy_depth_inter_slice.

[0432] ph_log2_diff_max_bt_min_qt_inter_slice represents the difference between the base 2 logarithm of the maximum dimension (width or height) in the luma samples of a luma codec block that can be partitioned using binary partitioning and the minimum dimension (width or height) in the luma samples of a luma leaf block resulting from a quadtree partitioning of a CTU in a slice with slice_type associated with PH equal to 0 (B) or 1 (P). The value of ph_log2_diff_max_bt_min_qt_inter_slice shall be in the range of 0 to CtbLog2SizeY - MinQtLog2SizeInterY, inclusive. When not present, the value of ph_log2_diff_max_bt_min_qt_inter_slice is inferred to be equal to sps_log2_diff_max_bt_min_qt_inter_slice.

[0433] ph_log2_diff_max_tt_min_qt_inter_slice represents the difference between the base 2 logarithm of the maximum dimension (width or height) in the luma samples of a luma codec block that can be partitioned using ternary partitioning and the minimum dimension (width or height) in the luma samples of a luma leaf block resulting from a quadtree partitioning of a CTU in a slice with slice_type associated with PH equal to 0 (B) or 1 (P). The value of ph_log2_diff_max_tt_min_qt_inter_slice shall be in the range of 0 to CtbLog2SizeY-MinQtLog2SizeInterY, inclusive. When not present, the value of ph_log2_diff_max_tt_min_qt_inter_slice is inferred to be equal to sps_log2_diff_max_tt_min_qt_inter_slice.

[0434] ph_cu_qp_delta_subdiv_inter_slice indicates the maximum cbSubdiv value of the intra-slice codec unit that transmits cu_qp_delta_abs and cu_qp_delta_sign_flag. The value of ph_cu_qp_delta_subdiv_inter_slice shall be in the range of 0 to 2*(CtbLog2SizeY-MinQtLog2SizeInterY+ph_max_mtt_hierarchy_depth_inter_slice), inclusive.

[0435] If not present, the value of ph_cu_qp_delta_subdiv_inter_slice is inferred to be equal to 0.

[0436] ph_cu_chroma_qp_offset_subdiv_inter_slice indicates the maximum cbSubdiv value of the codec unit within a slice that transmits cu_chroma_qp_offset_flag. The value of ph_cu_chroma_qp_offset_subdiv_inter_slice shall be in the range of 0 to 2*(CtbLog2SizeY - MinQtLog2SizeInterY + ph_max_mtt_hierarchy_depth_inter_slice), inclusive.

[0437] If not present, the value of ph_cu_chroma_qp_offset_subdiv_inter_slice is inferred to be equal to 0.

[0438] ph_temporal_mvp_enabled_flag indicates whether the temporal motion vector predictor can be used for inter prediction of the slices associated with the PH. If ph_temporal_mvp_enabled_flag is equal to 0, the syntax elements of the slices associated with the PH shall be constrained so that the temporal motion vector predictor is not used in the decoding of the slices. Otherwise (ph_temporal_mvp_enabled_flag is equal to 1), the temporal motion vector predictor can be used for decoding the slices associated with the PH. When not present, the value of ph_temporal_mvp_enabled_flag is inferred to be equal to 0. The value of ph_temporal_mvp_enabled_flag shall be equal to 0 when no reference picture in the DPB has the same spatial resolution as the current picture.

[0439] The maximum number of sub-block-based Merge MVP candidates, MaxNumSubblockMergeCand, is derived as follows:

[0440]

[0441] The value of MaxNumSubblockMergeCand should be in the range of 0 to 5, inclusive.

[0442] ph_collocated_from_l0_flag equal to 1 indicates that the collocated picture reference picture used for temporal motion vector prediction is derived from reference picture list 0. Derived from reference picture list 1 ph_collocated_from_l0_flag equal to 0 indicates that the collocated picture reference picture used for temporal motion vector prediction.

[0443] ph_collocated_ref_idx indicates the reference index of the collocated picture used for temporal motion vector prediction.

[0444] When ph_collocated_from_l0_flag is equal to 1, ph_collocated_ref_idx refers to the entry in reference picture list 0, and the value of ph_collocated_ref_idx shall be in the range of 0 to num_ref_entries[0][RplsIdx[0]]-1, inclusive.

[0445] When ph_collocated_from_l0_flag is equal to 0, ph_collocated_ref_idx refers to the entry in reference picture list 1, and the value of ph_collocated_ref_idx shall be in the range of 0 to num_ref_entries[1][RplsIdx[1]]-1, inclusive.

[0446] If not present, the value of ph_collocated_ref_idx is inferred to be equal to 0.

[0447] mvd_l1_zero_flag equal to 1 indicates that the mvd_coding(x0,y0,1) syntax structure is not parsed, and MvdL1[x0][y0][compIdx] and MvdCpL1[x0][y0][cpIdx][compIdx] are set equal to 0, where compIdx=0..1 and cpIdx=0..2. mvd_l1_zero_flag equal to 0 indicates that the mvd_coding(x0,y0,1) syntax structure is parsed.

[0448] ph_fpel_mmvd_enabled_flag equal to 1 indicates that merge mode with motion vector differences uses integer sample precision in slices associated with the PH. ph_fpel_mmvd_enabled_flag equal to 0 indicates that merge mode with motion vector differences may use fractional sample precision in slices associated with the PH. When not present, the value of ph_fpel_mmvd_enabled_flag is inferred to be 0.

[0449] ph_disable_bdof_flag equal to 1 indicates that inter-frame bi-directional prediction based on bidirectional optical flow inter-frame prediction is disabled in the slice associated with PH. ph_disable_bdof_flag equal to 0 indicates that inter-frame bi-directional prediction based on bidirectional optical flow inter-frame prediction may be enabled or not enabled in the slice associated with PH.

[0450] When ph_disable_bdof_flag is not present, the following applies:

[0451] - If sps_bdof_enabled_flag is equal to 1, then the value of ph_disable_bdof_flag is inferred to be equal to 0.

[0452] Otherwise (sps_bdof_enabled_flag is equal to 0), the value of ph_disable_bdof_flag is inferred to be equal to 1.

[0453] ph_disable_dmvr_flag equal to 1 indicates that inter bi-prediction based on decoder motion vector refinement is disabled in slices associated with the PH. ph_disable_dmvr_flag equal to 0 indicates that inter bi-prediction based on decoder motion vector refinement may or may not be enabled in slices associated with the PH.

[0454] When ph_disable_dmvr_flag is not present, the following applies:

[0455] - If sps_dmvr_enabled_flag is equal to 1, then the value of ph_disable_dmvr_flag is inferred to be equal to 0.

[0456] Otherwise (sps_dmvr_enabled_flag is equal to 0), the value of ph_disable_dmvr_flag is inferred to be equal to 1.

[0457] ph_disable_prof_flag equal to 1 indicates that optical flow prediction refinement is disabled in the slice associated with PH. ph_disable_prof_flag equal to 0 indicates that optical flow prediction refinement may or may not be enabled in the slice associated with PH.

[0458] When ph_disable_prof_flag is not present, the following applies:

[0459] - If sps_affine_prof_enabled_flag is equal to 1, then the value of ph_disable_prof_flag is inferred to be equal to 0.

[0460] Otherwise (sps_affine_prof_enabled_flag is equal to 0), the value of ph_disable_prof_flag is inferred to be equal to 1.

[0461] ph_qp_delta indicates the Qp to be used for the codec block in the picture Y The initial value of until it is modified by the value of CuQpDeltaVal in the codec unit layer.

[0462] When qp_delta_info_in_ph_flag is equal to 1, the Qp of all slices of the picture Y The initial value of the quantization parameter SliceQp Y The derivation is as follows:

[0463] SliceQp Y =26+init_qp_minus26+ph_qp_delta (89)

[0464] SliceQp Y The value of should be in the range of -QpBdOffset to +63, inclusive.

[0465] ph_joint_cbcr_sign_flag indicates whether the concatenated residual samples in both chrominance components have inverted signs in the transform unit for which tu_joint_cbcr_residual_flag[x0][y0] is equal to 1. When tu_joint_cbcr_residual_flag[x0][y0] is equal to 1 for the transform unit, ph_joint_cbcr_sign_flag is equal to 0 indicating that the sign of each residual sample of the Cr (or Cb) component is the same as the sign of the concatenated Cb (or Cr) residual sample, and ph_joint_cbcr_sign_flag is equal to 1 indicating that the sign of each residual sample of the Cr (or Cb) component is given by the inverted sign of the concatenated Cb (or Cr) residual sample.

[0466] ph_sao_luma_enabled_flag equal to 1 indicates that SAO is enabled for luma components in all slices associated with the PH; ph_sao_luma_enabled_flag equal to 0 indicates that SAO may be disabled for luma components of one or more or all slices associated with the PH. When ph_sao_luma_enabled_flag is not present, it is inferred to be equal to 0.

[0467] ph_sao_chroma_enabled_flag equal to 1 indicates that SAO is enabled for chroma components in all slices associated with the PH; ph_sao_chroma_enabled_flag equal to 0 indicates that SAO may be disabled for chroma components of one or more or all slices associated with the PH. When ph_sao_chroma_enabled_flag is not present, it is inferred to be equal to 0.

[0468] ph_dep_quant_enabled_flag equal to 0 indicates that dependent quantization is disabled for the current picture. ph_dep_quant_enabled_flag equal to 1 indicates that dependent quantization is enabled for the current picture. When ph_dep_quant_enabled_flag is not present, it is inferred to be equal to 0.

[0469] pic_sign_data_hiding_enabled_flag equal to 0 indicates that sign bit hiding is disabled for the current picture. pic_sign_data_hiding_enabled_flag equal to 1 indicates that sign bit hiding is enabled for the current picture. When pic_sign_data_hiding_enabled_flag is not present, it is inferred to be equal to 0.

[0470] ph_deblocking_filter_override_flag equal to 1 indicates that deblocking parameters are present in PH. ph_deblocking_filter_override_flag equal to 0 indicates that deblocking parameters are not present in PH. If not present, the value of ph_deblocking_filter_override_flag is inferred to be equal to 0.

[0471] ph_deblocking_filter_disabled_flag equal to 1 indicates that the operation of the deblocking filter is not applied to the slices associated with the PH. ph_deblocking_filter_disabled_flag equal to 0 indicates that the operation of the deblocking filter is applied to the slices associated with the PH. When ph_deblocking_filter_disabled_flag is not present, it is inferred to be equal to pps_deblocking_filter_disabled_flag.

[0472] ph_beta_offset_div2 and ph_tc_offset_div2 represent the deblocking parameter offsets of beta and tc (divided by 2) applied to the luma component of the slice associated with the PH. The values ​​of ph_beta_offset_div2 and ph_tc_offset_div2 should both be in the range of -12 to 12, inclusive. When not present, the values ​​of ph_beta_offset_div2 and ph_tc_offset_div2 are inferred to be equal to pps_beta_offset_div2 and pps_tc_offset_div2, respectively.

[0473] ph_cb_beta_offset_div2 and ph_cb_tc_offset_div2 represent the deblocking parameter offsets of beta and tc (divided by 2) applied to the Cb component of the slice associated with the PH. The values ​​of ph_cb_beta_offset_div2 and ph_cb_tc_offset_div2 should both be in the range of -12 to 12, inclusive. When not present, the values ​​of ph_cb_beta_offset_div2 and ph_cb_tc_offset_div2 are inferred to be equal to pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2, respectively.

[0474] ph_cr_beta_offset_div2 and ph_cr_tc_offset_div2 represent the deblocking parameter offsets of beta and tc (divided by 2) applied to the Cr components of the slice associated with the PH. The values ​​of ph_cr_beta_offset_div2 and ph_cr_tc_offset_div2 should both be in the range of -12 to 12, inclusive. When not present, the values ​​of ph_cr_beta_offset_div2 and ph_cr_tc_offset_div2 are inferred to be equal to pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2, respectively.

[0475] ph_extension_length represents the length of the PH extension data in bytes, excluding the bits used to signal the ph_extension_length itself. The value of ph_extension_length shall be in the range of 0 to 256, inclusive. If not present, the value of ph_extension_length is inferred to be equal to 0.

[0476] ph_extension_data_byte can have any value. Decoders conforming to this version of this specification shall ignore the value of ph_extension_data_byte. Its value does not affect the conformance of a decoder to the profiles represented in this version of this specification.

[0477] SH Syntax and Semantics

[0478] In the latest VVC draft text, the SH syntax and semantics are as follows:

[0479]

[0480]

[0481]

[0482]

[0483] The variable CuQpDeltaVal representing the difference between the luma quantization parameter of the codec containing cu_qp_delta_abs and its prediction is set equal to 0. The variable CuQpOffset Cb 、CuQpOffset Cr and CuQpOffset CbCr Indicates that when determining the quantization parameter Qp' of the codec unit containing cu_chroma_qp_offset_flag Cb , Qp' Cr and Qp' CbCr , the value to be used is set equal to 0.

[0484] picture_header_in_slice_header_flag equal to 1 indicates that the PH syntax structure is present in the slice header. picture_header_in_slice_header_flag equal to 0 indicates that the PH syntax structure is not present in the slice header.

[0485] Bitstream conformance requires that the value of picture_header_in_slice_header_flag shall be the same in all codec slices in CLVS.

[0486] When picture_header_in_slice_header_flag is equal to 1 for a codec slice, bitstream conformance requires that VCL NAL units with nal_unit_type equal to PH_NUT shall not appear in the CLVS.

[0487] When picture_header_in_slice_header_flag is equal to 0, all codec slices in the current picture should have picture_header_in_slice_header_flag equal to 0, and the current PU should have a PH NAL unit.

[0488] slice_subpic_id represents the sub-picture ID of the sub-picture containing the slice. If slice_subpic_id exists, the value of the variable CurrSubpicIdx is derived so that SubpicIdVal[CurrSubpicIdx] is equal to slice_subpic_id. Otherwise (slice_subpic_id does not exist), CurrSubpicIdx is derived to be equal to 0. The length of slice_subpic_id is sps_subpic_id_len_minus1+1 bits.

[0489] slice_address indicates the slice address of the slice. When not present, the value of slice_address is inferred to be equal to 0. When rect_slice_flag is equal to 1 and NumSlicesInSubpic[CurrSubpicIdx] is equal to 1, the value of slice_address is inferred to be equal to 0.

[0490] If rect_slice_flag is equal to 0, the following applies:

[0491] —The strip address is the raster scan slice index.

[0492] —The length of slice_address is Ceil(Log2(NumTilesInPic)) bits.

[0493] — The value of slice_address shall be in the range of 0 to NumTilesInPic-1, inclusive. Otherwise (rect_slice_flag is equal to 1), the following applies:

[0494] —The slice address is the sub-picture level slice index of the slice.

[0495] —The length of slice_address is Ceil(Log2(NumSlicesInSubpic[CurrSubpicIdx])) bits.

[0496] —The value of slice_address shall be in the range of 0 to NumSlicesInSubpic[CurrSubpicIdx]-1, inclusive.

[0497] The following constraints apply to the bitstream conformance requirements:

[0498] - If rect_slice_flag is equal to 0 or subpic_info_present_flag is equal to 0, the value of slice_address shall not be equal to the value of slice_address of any other codec slice NAL unit of the same codec picture.

[0499] — Otherwise, the value of the pair of slice_subpic_id and slice_address shall not be equal to the value of the pair of slice_subpic_id and slice_address of any other codec slice NAL unit of the same codec picture.

[0500] - The shape of a picture slice shall be such that the entire left and upper boundaries of each CTU, when decoded, shall consist of either a picture boundary or a boundary of a previously decoded CTU(s).

[0501] sh_extra_bit[i] may be equal to 1 or 0. Decoders conforming to this version of this specification shall ignore the value of sh_extra_bit[i]. Its value does not affect the conformance of the decoder to the profile represented in this version of this specification.

[0502] num_tiles_in_slice_minus1 plus 1, if present, indicates the number of tiles in the slice. The value of num_tiles_in_slice_minus1 should be in the range of 0 to NumTilesInPic-1, inclusive.

[0503] The variable NumCtusInCurrSlice indicates the number of CTUs in the current slice, and the list CtbAddrInCurrSlice[i], where i ranges from 0 to NumCtusInCurrSlice-1, inclusive, indicates the picture raster scan address of the i-th CTB in the slice, derived as follows:

[0504]

[0505]

[0506] The variables SubpicLeftBoundaryPos, SubpicTopBoundaryPos, SubpicRightBoundaryPos, and SubpicBotBoundaryPos are derived as follows:

[0507]

[0508] slice_type indicates the codec type of the slice according to Table 9.

[0509] Table 9 - slice_type name association

[0510] slice_type slice_type name 0 B(B slice) 1 P(P slice) 2 I (I slice)

[0511] If not present, slice_type is inferred to have a value equal to 2.

[0512] When ph_intra_slice_allowed_flag is equal to 0, the value of slice_type shall be equal to 0 or 1. When nal_unit_type is in the range of IDR_W_RADL to CRA_NUT (inclusive) and vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id]] is equal to 1, slice_type shall be equal to 2.

[0513] The variables MinQtLog2SizeY, MinQtLog2SizeC, MinQtSizeY, MinQtSizeC, MaxBtSizeY, MaxBtSizeC, MinBtSizeY, MaxTtSizeY, MaxTtSizeC, MinTtSizeY, MaxMttDepthY, and MaxMttDepthC are derived as follows:

[0514] — If slice_type is equal to 2(I), the following applies:

[0515] MinQtLog2SizeY=MinCbLog2SizeY+ph_log2_diff_min_qt_min_cb_intra_slice_luma (119)

[0516] MinQtLog2SizeC=MinCbLog2SizeY+ph_log2_diff_min_qt_min_cb_intra_slice_chroma (120)

[0517] MaxBtSizeY=1<<(MinQtLog2SizeY+ph_log2_diff_max_bt_min_qt_intra_slice_luma) (121)

[0518] MaxBtSizeC=1<<(MinQtLog2SizeC+ph_log2_diff_max_bt_min_qt_intra_slice_chroma) (122)

[0519] MaxTtSizeY = 1 << (MinQtLog2SizeY + ph_log2_diff_max_tt_min_qt_intra_slice_luma) (123)

[0520] MaxTtSizeC = 1 << (MinQtLog2SizeC + ph_log2_diff_max_tt_min_qt_intra_slice_chroma) (124)

[0521] MaxMttDepthY = ph_max_mtt_hierarchy_depth_intra_slice_luma (125)

[0522] MaxMttDepthC = ph_max_mtt_hierarchy_depth_intra_slice_chroma (126)

[0523] CuQpDeltaSubdiv = ph_cu_qp_delta_subdiv_intra_slice (127)

[0524] CuChromaQpOffsetSubdiv = ph_cu_chroma_qp_offset_subdiv_intra_slice(128)

[0525] — Otherwise (slice_type equals 0 (B) or 1 (P)), the following applies:

[0526] MinQtLog2SizeY = MinCbLog2SizeY + ph_log2_diff_min_qt_min_cb_inter_slice(129)

[0527] MinQtLog2SizeC = MinCbLog2SizeY + ph_log2_diff_min_qt_min_cb_inter_slice(130)

[0528] MaxBtSizeY = 1 << (MinQtLog2SizeY + ph_log2_diff_max_bt_min_qt_inter_slice) (131)

[0529] MaxBtSizeC = 1 << (MinQtLog2SizeC + ph_log2_diff_max_bt_min_qt_inter_slice) (132)

[0530] MaxTtSizeY = 1 << (MinQtLog2SizeY + ph_log2_diff_max_tt_min_qt_inter_slice) (133)

[0531] MaxTtSizeC = 1 << (MinQtLog2SizeC + ph_log2_diff_max_tt_min_qt_inter_slice) (134)

[0532] MaxMttDepthY = ph_max_mtt_hierarchy_depth_inter_slice (135)

[0533] MaxMttDepthC = ph_max_mtt_hierarchy_depth_inter_slice (136)

[0534] CuQpDeltaSubdiv = ph_cu_qp_delta_subdiv_inter_slice (137)

[0535] CuChromaQpOffsetSubdiv = ph_cu_chroma_qp_offset_subdiv_inter_slice(138)

[0536] — The following applies:

[0537] MinQtSizeY = 1 << MinQtLog2SizeY (139)

[0538] MinQtSizeC = 1 << MinQtLog2SizeC (140)

[0539] MinBtSizeY = 1 << MinCbLog2SizeY (141)

[0540] MinTtSizeY = 1 << MinCbLog2SizeY (142)

[0541] slice_alf_enabled_flag equal to 1 indicates that the adaptive loop filter is enabled and can be applied to the Y, Cb or Cr color components in the slice. slice_alf_enabled_flag equal to 0 indicates that the adaptive loop filter is disabled for all color components in the slice. When not present, the value of slice_alf_enabled_flag is inferred to be equal to ph_alf_enabled_flag.

[0542] slice_num_alf_aps_ids_luma indicates the number of ALF APSs referenced by the slice. When slice_alf_enabled_flag is equal to 1 and slice_num_alf_aps_ids_luma is not present, the value of slice_num_alf_aps_ids_luma is inferred to be equal to the value of ph_num_alf_aps_ids_luma.

[0543] slice_alf_aps_id_luma[i] represents the adaptation_parameter_set_id of the i-th ALF APS referenced by the luma component of the slice. The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_alf_aps_id_luma[i] shall be less than or equal to the TemporalId of the coded slice NAL unit. When slice_alf_enabled_flag is equal to 1 and slice_alf_aps_id_luma[i] is not present, the value of slice_alf_aps_id_luma[i] is inferred to be equal to the value of ph_alf_aps_id_luma[i].

[0544] The value of alf_luma_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_alf_aps_id_luma[i].

[0545] slice_alf_chroma_idc equal to 0 indicates that the adaptive loop filter is not applied to the Cb and Cr color components. slice_alf_chroma_idc equal to 1 indicates that the adaptive loop filter is applied to the Cb color component. slice_alf_chroma_idc equal to 2 indicates that the adaptive loop filter is applied to the Cr color component. slice_alf_chroma_idc equal to 3 indicates that the adaptive loop filter is applied to the Cb and Cr color components. When slice_alf_chroma_idc is not present, it is inferred to be equal to ph_alf_chroma_idc.

[0546] slice_alf_aps_id_chroma indicates the adaptation_parameter_set_id of the ALF APS referenced by the chroma components of the slice. The TemporalId of APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_alf_aps_id_chroma shall be less than or equal to the TemporalId of the codec slice NAL unit. When slice_alf_enabled_flag is equal to 1 and slice_alf_aps_id_chroma is not present, the value of slice_alf_aps_id_chroma is inferred to be equal to the value of ph_alf_aps_id_chroma.

[0547] The value of alf_chroma_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_alf_aps_id_chroma.

[0548] slice_cc_alf_cb_enabled_flag equal to 0 indicates that the cross-component filter is not applied to the Cb color component. slice_cc_alf_cb_enabled_flag equal to 1 indicates that the cross-component filter is enabled and may be applied to the Cb color component. When slice_cc_alf_cb_enabled_flag is not present, it is inferred to be equal to ph_cc_alf_cb_enabled_flag.

[0549] slice_cc_alf_cb_aps_id indicates the adaptation_parameter_set_id referenced by the Cb color component of the slice.

[0550] The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_cc_alf_cb_aps_id shall be less than or equal to the TemporalId of the codec slice NAL unit. When slice_cc_alf_cb_enabled_flag is equal to 1 and slice_cc_alf_cb_aps_id is not present, the value of slice_cc_alf_cb_aps_id is inferred to be equal to the value of ph_cc_alf_cb_aps_id.

[0551] The value of alf_cc_cb_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_cc_alf_cb_aps_id.

[0552] slice_cc_alf_cr_enabled_flag equal to 0 indicates that the cross-component filter is not applied to the Cr color components. slice_cc_alf_cb_enabled_flag equal to 1 indicates that the cross-component adaptive loop filter is enabled and may be applied to the Cr color components. When slice_cc_alf_cr_enabled_flag is not present, it is inferred to be equal to ph_cc_alf_cr_enabled_flag.

[0553] slice_cc_alf_cr_aps_id represents the adaptation_parameter_set_id referenced by the Cr color components of the slice. The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_cc_alf_cr_aps_id shall be less than or equal to the TemporalId of the codec slice NAL unit. When slice_cc_alf_cr_enabled_flag is equal to 1 and slice_cc_alf_cr_aps_id is not present, the value of slice_cc_alf_cr_aps_id is inferred to be equal to the value of ph_cc_alf_cr_aps_id.

[0554] The value of alf_cc_cr_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_cc_alf_cr_aps_id.

[0555] colour_plane_id identifies the colour plane associated with the current slice when separate_colour_plane_flag is equal to 1. The value of colour_plane_id shall be in the range 0 to 2, inclusive. colour_plane_id values ​​0, 1 and 2 correspond to the Y, Cb and Cr planes respectively. The value 3 of colour_plane_id is reserved for future use by ITU-T | ISO / IEC.

[0556] NOTE 1 – There is no correlation between the decoding processes of different colour planes of a picture.

[0557] num_ref_idx_active_override_flag equal to 1 indicates that the syntax element num_ref_idx_active_minus1[0] is present in P and B slices, and the syntax element num_ref_idx_active_minus1[1] is present in B slices. num_ref_idx_active_override_flag equal to 0 indicates that the syntax elements num_ref_idx_active_minus1[0] and num_ref_idx_active_minus1[1] are not present. If not present, the value of num_ref_idx_active_override_flag is inferred to be equal to 1.

[0558] num_ref_idx_active_minus1[i] is used to derive the variable NumRefIdxActive[i] as specified by equation 143. The value of num_ref_idx_active_minus1[i] shall be in the range of 0 to 14, inclusive.

[0559] For i equal to 0 or 1, when the current slice is a B slice, num_ref_idx_active_override_flag is equal to 1, and num_ref_idx_active_minus1[i] does not exist, then num_ref_idx_active_minus1[i] is inferred to be equal to 0.

[0560] When the current slice is a P slice, num_ref_idx_active_override_flag is equal to 1, and num_ref_idx_active_minus1[0] does not exist, it is inferred that num_ref_idx_active_minus1[0] is equal to 0.

[0561] The variable NumRefIdxActive[i] is derived as follows:

[0562]

[0563] The value of NumRefIdxActive[i]-1 represents the maximum reference index of reference picture list i that can be used to decode the slice. When the value of NumRefIdxActive[i] is equal to 0, the reference index of reference picture list i may not be used to decode the slice.

[0564] When the current slice is a P slice, the value of NumRefIdxActive[0] should be greater than 0.

[0565] When the current slice is a B slice, both NumRefIdxActive[0] and NumRefIdxActive[1] should be greater than 0.

[0566] cabac_init_flag indicates the method used to determine the initialization table used during context variable initialization. When cabac_init_flag is not present, it is inferred to be equal to 0.

[0567] slice_collocated_from_l0_flag equal to 1 indicates that the collocated picture used for temporal motion vector prediction comes from reference picture list 0. slice_collocated_from_l0_flag equal to 0 indicates that the collocated picture used for temporal motion vector prediction comes from reference picture list 1.

[0568] When slice_type is equal to B or P, ph_temporal_mvp_enabled_flag is equal to 1, and slice_collocated_from_l0_flag is not present, the following applies:

[0569] - If rpl_info_in_ph_flag is equal to 1, slice_collocated_from_l0_flag is inferred to be equal to ph_collocated_from_l0_flag.

[0570] Otherwise (rpl_info_in_ph_flag is equal to 0, slice_type is equal to P), the value of slice_collocated_from_l0_flag is inferred to be equal to 1.

[0571] slice_collocated_ref_idx indicates the reference index of the collocated picture used for temporal motion vector prediction.

[0572] When slice_type is equal to P or slice_type is equal to B and slice_collocated_from_l0_flag is equal to 1, slice_collocated_ref_idx refers to the entry in reference picture list 0, and the value of slice_collocated_ref_idx shall be in the range of 0 to NumRefIdxActive[0]-1, inclusive.

[0573] When slice_type is equal to B and slice_collocated_from_l0_flag is equal to 0, slice_collocated_ref_idx refers to the entry in reference picture list 1, and the value of slice_collocated_ref_idx shall be in the range of 0 to NumRefIdxActive[1]-1, inclusive.

[0574] When slice_collocated_ref_idx is not present, the following applies:

[0575] - If rpl_info_in_ph_flag is equal to 1, the value of slice_collocated_ref_idx is inferred to be equal to ph_collocated_ref_idx.

[0576] Otherwise (rpl_info_in_ph_flag is equal to 0), the value of slice_collocated_ref_idx is inferred to be equal to 0.

[0577] Bitstream conformance requires that the picture referenced by slice_collocated_ref_idx shall be the same for all slices of a codec picture.

[0578] Bitstream conformance requires that the values ​​of pic_width_in_luma_samples and pic_height_in_luma_samples of the reference picture referenced by slice_collocated_ref_idx shall be equal to the values ​​of pic_width_in_luma_samples and pic_height_in_luma_samples of the current picture, respectively, and RprConstraintsActive[slice_collocated_from_l0_flag? 0:1][slice_collocated_ref_idx] shall be equal to 0.

[0579] slice_qp_delta indicates the Qp used for the codec block in the slice. Y The initial value of until it is modified by the value of CuQpDeltaVal in the codec unit layer.

[0580] When qp_delta_info_in_ph_flag is equal to 0, the Qp Y The initial value of the quantization parameter SliceQp Y The derivation is as follows:

[0581] SliceQp Y =26+init_qp_minus26+slice_qp_delta (144)

[0582] SliceQp Y The value of should be in the range of -QpBdOffset to +63, inclusive.

[0583] When any of the following conditions is true:

[0584] —The value of wp_info_in_ph_flag is equal to 1, pps_weighted_pred_flag is equal to 1, and slice_type is equal to P.

[0585] —The value of wp_info_in_ph_flag is equal to 1, pps_weighted_bipred_flag is equal to 1, and slice_type is equal to B.

[0586] The following applies:

[0587] —The value of NumRefIdxActive[0] shall be less than or equal to the value of NumWeightsL0.

[0588] —For each reference picture index RefPicList[0][i], for i in the range 0 to NumRefIdxActive[0]-1 (inclusive), the luma weight, Cb weight, and Cr weight applied to the reference picture index are LumaWeightL0[i], ChromaWeightL0[0][i], and ChromaWeightL0[1][i], respectively.

[0589] When wp_info_in_ph_flag is equal to 1, pps_weighted_bipred_flag is equal to 1, and slice_type is equal to B, the following applies:

[0590] —The value of NumRefIdxActive[1] shall be less than or equal to the value of NumWeightsL1.

[0591] —For each reference picture index RefPicList[1][i], i in the range 0 to NumRefIdxActive[1]-1 (inclusive), the luma weight, Cb weight, and Cr weight applied to the reference picture index are LumaWeightL1[i], ChromaWeightL1[0][i], and ChromaWeightL1[1][i], respectively.

[0592] slice_cb_qp_offset indicates the time to determine Qp' Cb The value of the quantization parameter is the difference to be added to the value of pps_cb_qp_offset. The value of slice_cb_qp_offset shall be in the range -12 to +12, inclusive. When slice_cb_qp_offset is not present, it is inferred to be equal to 0. The value of pps_cb_qp_offset+slice_cb_qp_offset shall be in the range -12 to +12, inclusive.

[0593] slice_cr_qp_offset indicates the time to determine Qp' Cr The value of the quantization parameter is the difference to be added to the value of pps_cr_qp_offset. The value of slice_cr_qp_offset shall be in the range of -12 to +12, inclusive. When slice_cr_qp_offset is not present, it is inferred to be equal to 0. The value of pps_cr_qp_offset+slice_cr_qp_offset shall be in the range of -12 to +12, inclusive.

[0594] slice_join_cbcr_qp_offset indicates that when determining Qp' CbCr The value of slice_joint_cbcr_qp_offset_value is the difference to be added to the value of pps_joint_cbcr_qp_offset_value. The value of slice_joint_cbcr_qp_offset shall be in the range of -12 to +12, inclusive. When slice_joint_cbcr_qp_offset is not present, it is inferred to be equal to 0. The value of pps_joint_cbcr_qp_offset_value+slice_joint_cbcr_qp_offset shall be in the range of -12 to +12, inclusive.

[0595] cu_chroma_qp_offset_enabled_flag equal to 1 indicates that cu_chroma_qp_offset_flag may be present in transform unit and palette codec syntax. cu_chroma_qp_offset_enabled_flag equal to 0 indicates that cu_chroma_qp_offset_flag is not present in transform unit or palette codec syntax. If not present, the value of cu_chroma_qp_offset_enabled_flag is inferred to be equal to 0.

[0596] slice_sao_luma_flag equal to 1 indicates that SAO is enabled for the luma components in the current slice; slice_sao_luma_flag equal to 0 indicates that SAO is disabled for the luma components in the current slice. When slice_sao_luma_flag is not present, it is inferred to be equal to ph_sao_luma_enabled_flag.

[0597] slice_sao_chroma_flag equal to 1 indicates that SAO is enabled for the chroma components in the current slice; slice_sao_chroma_flag equal to 0 indicates that SAO is disabled for the chroma components in the current slice. When slice_sao_chroma_flag is not present, it is inferred to be equal to ph_sao_chroma_enabled_flag.

[0598] slice_deblocking_filter_override_flag equal to 1 indicates that the deblocking parameters are present in the slice header. slice_deblocking_filter_override_flag equal to 0 indicates that the deblocking parameters are not present in the slice header. When not present, the value of slice_deblocking_filter_override_flag is inferred to be equal to ph_deblocking_filter_override_flag.

[0599] slice_deblocking_filter_disabled_flag equal to 1 indicates that the operation of the deblocking filter is not applied to the current slice. slice_deblocking_filter_disabled_flag equal to 0 indicates that the operation of the deblocking filter is applied to the current slice. When slice_deblocking_filter_disabled_flag is not present, it is inferred to be equal to ph_deblocking_filter_disabled_flag.

[0600] slice_beta_offset_div2 and slice_tc_offset_div2 represent the deblocking parameter offsets for beta and tc (divided by 2) applied to the luma components of the current slice. The values ​​of slice_beta_offset_div2 and slice_tc_offset_div2 should both be in the range -12 to 12, inclusive. When not present, the values ​​of slice_beta_offset_div2 and slice_tc_offset_div2 are inferred to be equal to ph_beta_offset_div2 and ph_tc_offset_div2, respectively.

[0601] slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 represent the deblocking parameter offsets for beta and tc (divided by 2) applied to the Cb component of the current slice. The values ​​of slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 should both be in the range of -12 to 12, inclusive. When not present, the values ​​of slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 are inferred to be equal to ph_cb_beta_offset_div2 and ph_cb_tc_offset_div2, respectively.

[0602] slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 represent the deblocking parameter offsets for beta and tc (divided by 2) applied to the Cr components of the current slice. The values ​​of slice_cr_beta_offset_div2 and slice_cr_tc_offset_div2 should both be in the range -12 to 12, inclusive. When not present, the values ​​of slice_cr_beta_offset_div2 and slice_cr_tc_offset_div2 are inferred to be equal to ph_cr_beta_offset_div2 and ph_cr_tc_offset_div2, respectively.

[0603] slice_ts_residual_coding_disabled_flag equal to 1 indicates that the residual_coding() syntax structure is used to parse the residual samples of the transform skipped blocks of the current slice. slice_ts_residual_coding_disabled_flag equal to 0 indicates that the residual_ts_coding() syntax structure is used to parse the residual samples of the transform skipped blocks of the current slice. When slice_ts_residual_coding_disabled_flag is not present, it is inferred to be equal to 0.

[0604] slice_lmcs_enabled_flag equal to 1 indicates that luma mapping and chroma scaling are enabled for the current slice. slice_lmcs_enabled_flag equal to 0 indicates that luma mapping and chroma scaling are not enabled for the current slice. When slice_lmcs_enabled_flag is not present, it is inferred to be equal to 0.

[0605] slice_scaling_list_present_flag equal to 1 indicates that the scaling list data for the current slice is derived based on the scaling list data contained in the reference scaling list APS with aps_params_type equal to SCALING_APS and adaptation_parameter_set_id equal to ph_scaling_list_aps_id. slice_scaling_list_present_flag equal to 0 indicates that the scaling list data for the current picture is the default scaling list data specified in clause 7.4.3.21. When not present, the value of slice_scaling_list_present_flag is inferred to be equal to 0.

[0606] The variable NumEntryPoints represents the number of entry points in the current strip, and is derived as follows:

[0607]

[0608]

[0609] offset_len_minus1 plus 1 represents the length (in bits) of the entry_point_offset_minus1[i] syntax element. The value of offset_len_minus1 shall be in the range of 0 to 31, inclusive.

[0610] entry_point_offset_minus1[i] plus 1 represents the i-th entry point offset (in bytes), represented by offset_len_minus1 plus 1 bit. The slice data following the slice header consists of NumEntryPoints+1 subsets, where the subset index values ​​range from 0 to NumEntryPoints, inclusive. The first byte of the slice data is considered to be byte 0. When present, the anti-contention byte appearing in the slice data portion of the codec slice NAL unit is counted as part of the slice data for subset identification. Subset 0 consists of bytes 0 to entry_point_offset_minus1[0] (inclusive) of the codec slice data, and subset k (where k is in the range of 1 to NumEntryPoints-1, inclusive) consists of firstByte[k] to lastByte[k] (inclusive) of the codec slice data with firstByte[k] and lastByte[k], defined as:

[0611]

[0612] lastByte[k]=firstByte[k]+entry_point_offset_minus1[k] (147)

[0613] The last subset (where the subset index is equal to NumEntryPoints) consists of the remaining bytes of the encoded and decoded slice data.

[0614] When sps_entropy_coding_sync_enabled_flag is equal to 0 and a slice contains one or more complete slices, each subset shall consist of all codec bits of all CTUs in the slice within the same slice, and the number of subsets (ie, the value of NumEntryPoints+1) shall be equal to the number of slices in the slice.

[0615] When sps_entropy_coding_sync_enabled_flag is equal to 0 and a slice contains a subset of CTU rows from a single slice, NumEntryPoints shall be 0 and the number of subsets shall be 1. The subset shall consist of all codec bits of all CTUs in the slice.

[0616] When sps_entropy_coding_sync_enabled_flag is equal to 1, each subset k in the range 0 to NumEntryPoints (inclusive) shall consist of all codec bits of all CTUs in the CTU row in the slice, and the number of subsets (i.e., the value of NumEntryPoints+1) shall be equal to the total number of CTU rows for the particular slice in the slice.

[0617] slice_header_extension_length represents the length of the slice header extension data in bytes, excluding the bits used to signal the slice_header_extension_length itself. The value of slice_header_extension_length shall be in the range of 0 to 256, inclusive. If not present, the value of slice_header_extension_length is inferred to be equal to 0.

[0618] slice_header_extension_data_byte[i] can have any value. Decoders conforming to this version of this specification shall ignore the value of all slice_header_extension_data_byte[i] syntax elements. Its value does not affect the conformance of a decoder to the profiles represented in this version of this specification.

[0619] 3.5. Chroma QP Mapping Table

[0620] In JVET-Q2001-vC clause 7.3.2.3, the SPS includes a structure called the Chroma QP Table, which is shown below:

[0621]

[0622]

[0623] They have the following semantics and QP table derivation:

[0624] sps_joint_cbcr_enabled_flag equal to 0 disables joint coding of chroma residual. sps_joint_cbcr_enabled_flag equal to 1 enables joint coding of chroma residual. When not present, the value of sps_joint_cbcr_enabled_flag is inferred to be equal to 0.

[0625] same_qp_table_for_chroma equal to 1 indicates that when sps_joint_cbcr_enabled_flag is equal to 1, only one chroma QP mapping table is signaled, and that table applies to both Cb and Cr residuals, and in addition to the joint Cb-Cr residual. When sps_joint_cbcr_enabled_flag is equal to 1, same_q_table_for_cchroma equal to 0 indicates that chroma QP mapping tables are signaled in the SPS, two for Cb and Cr, and one for the joint Cb-Cr. When same_qp_table_for_chroma is not present in the bitstream, the value of same_qp_table_for_chrom is inferred to be equal to 1.

[0626] qp_table_start_minus26[i] plus 26 indicates the starting luma and chroma QPs used to describe the i-th chroma QP map. The value of qp_table_start_minus26[i] shall be in the range -26 - QpBdOffset to 36 (inclusive). When qp_table_start_minus26[i] is not present in the bitstream, the value of qp_tale_start_min26[i] is inferred to be equal to 0.

[0627] num_points_in_qp_table_minus1[i] plus 1 indicates the number of points used to describe the i-th chroma QP map table. The value of num_points_in_qp_table_minus1[i] shall be in the range of 0 to 63+QpBdOffset (inclusive). When num_points_in_qp_table_minus1[0] is not present in the bitstream, the value of num_points_in_qp_table_minws1[0] is inferred to be equal to 0.

[0628] delta_qp_in_val_minus1[i][j] represents the incremental value used to derive the input coordinates of the jth pivot point of the i-th chroma QP map. When delta_qp_in_val_minus1[0][j] is not present in the bitstream, the value of delta_qp_in_val_min is inferred to be equal to 0.

[0629] delta_qp_diff_val[i][j] represents the delta value used to derive the output coordinates of the j-th pivot point of the i-th chroma QP map.

[0630] The i-th chroma QP mapping table ChromaQpTable[i]-1 with i=0..numQpTables is derived as follows:

[0631]

[0632] When same_qp_table_for_chroma is equal to 1, ChromaQpTable[1][k] and ChromaQpTable[2][k] are set equal to ChromaQpTable[0][k], with k in the range from -QpBdOffset to 63, inclusive.

[0633] Bitstream conformance requires that the values ​​of qpInVal[i][j] and qpOutVal[i][j] shall be in the range -QpBdOffset to 63, where i is in the range 0 to numQpTables-1 (inclusive) and j is in the range 0 to num_points_in_qp_table_minus1[i]+1 (inclusive).

[0634] In the above description, QpBdOffset is derived as:

[0635] bit_depth_minus8 represents the bit depth BitDepth of the samples of the luminance and chrominance arrays, and the value of the luminance and chrominance quantization parameter range offset QpBdOffset, as shown below:

[0636] BitDepth=8+bit_depth_minus8

[0637] QpBdOffset=6*bit_depth_minus8

[0638] bit_depth_minus8 should be in the range of 0 to 8 (inclusive).

[0639] 4. Technical problems solved by the disclosed technical solutions

[0640] The existing designs of APS, deblocking, sub-pictures, and QP increment in the latest VVC draft specification have the following problems:

[0641] 1) Currently, based on the SPS syntax elements chroma_format_idc and

[0642] The ChromaArrayType derived from separate_colour_plane_flag is used to constrain the value of the APS syntax element scaling_list_chroma_present_flag, which is expressed as follows:

[0643] When ChromaArrayType is equal to 0, scaling_list_chroma_present_flag should be equal to

[0644] 0; scaling_list_chroma_present_flag shall be equal to 1 when ChromaArraytype is not equal to 0.

[0645] This constraint in the semantics of the APS syntax element introduces a semantic dependency of APS on SPS, which should not happen because there is no PPS ID or SPS ID in the APS syntax and the APS may apply to pictures (or slices of pictures) that reference different SPSs, which may be associated with different values ​​of ChromaArrayType.

[0646] a. In addition, similar APS-SPS semantic dependencies exist in the semantics of some ALF / CC-ALF APS syntax elements, as follows: when ChromaArrayType is equal to 0, alf_chroma_filter_signal_flag, alf_CC_cb_filter_signal_flog, and alf_CC_cr_filter_signal_flag shall be equal to 0.

[0647] b. Currently, when signaling LMCS APS, syntax elements related to chroma residual scaling are always signaled in the LMCS APS syntax structure, regardless of whether ChromaArrayType is equal to 0 (i.e., there is no chroma component in CLVS). This results in unnecessary signaling of syntax elements related to chroma.

[0648] 2) It is said that the deblocking control mechanism in the latest VVC text is quite complex, non-intuitive, not easy to understand, and therefore prone to errors. Here are some example issues we observed:

[0649] a. According to the current text, even if the deblocking filter is disabled in the PPS, it can be enabled in the PH or SH. For example, if PPS_deblocking_filter_disabled_flag is first signaled equal to 1, and deblocking_filter_override_enabled_flag is also signaled equal to 1, indicating that the deblocking filter is disabled in the PPS, and the deblocking filter enable / disable control is also allowed to be overridden in the PH or SH. Then, dbf_info_in_PH_flag is subsequently signaled, and the PH syntax element Ph_deblocking_filter_disabled_flag may be signaled as equal to 0, which will ultimately enable the deblocking filter for the slices associated with the PH. In this case, deblocking is ultimately enabled at the PH, regardless of whether it is disabled at a higher level (such as the PPS). This design logic is unique in VVC context, which is very different from the design logic of other codec tools (such as ALF, SAO, LMCS, TMVP, WP, etc.). Usually, when a codec tool is disabled at a higher level (such as SPS, PPS), it is completely disabled at a lower level (such as PH, SH).

[0650] b. In addition, the current definition of pps_deblocking_filter_disabled_flag is similar to "pps_doblocking_filter_disabled_flag equal to 1 indicates that for slices referencing a PPS in which slice_deblocking_filter_disabled_flag is not present, the operation of the deblocking filter is not applied...". However, according to the current syntax table, even if pps_deblocking_filter_disabled_flag is equal to 1 and slice_deblocking_filter_disabled_flag is not present, the operation of the deblocking filter will still apply if ph_deblocging_filler_disabled_flag is present and signaling ph_deblocging_filler_disabled_flag is equal to 0. Therefore, the current definition of pps_deblocking_filter_disabled_flag is incorrect.

[0651] c. In addition, according to the current text, if the PPS syntax elements deblocking_filter_override_enabled_flag and pps_deblocking_filter_disabled_flag are both equal to 1, it means that deblocking is disabled in PPS and the control of the deblocking filter is intended to be overridden in PH or SH. However, the subsequent PH syntax elements ph_deblocking_filter_override_flag and ph_debrocking_filter_disabled_flag may still be signaled as equal to 1, indicating that the resulting override process does not change anything (e.g., deblocking remains disabled in PH / SH), but just uses unnecessary bits for meaningless signaling.

[0652] d. Furthermore, according to the current text, when the SH syntax element slice_deblocking_filter_override_flag is not present, it is inferred to be equal to ph_deblocging_filler_overrid_flag. However, in addition to implicit or explicit signaling in the PPS, according to dbf_info_in_PH_flag, deblocking parameters can only be signaled in the PH or SH, but not both. Therefore, when dbf_info_in_ph_flag is true, the purpose is to allow signaling of override deblocking filter parameters in the PH. In this case, if the PH override flag is true, and the SH override flag is not signaled but is inferred to be equal to the PH override flag, additional deblocking filter parameters will still be signaled in the SH, which conflicts with the purpose.

[0653] 3) Currently, when the PPS syntax element single_slice_per_subpic_flag is not present, it is inferred to be equal to 0. single_slice_per_subbic_flag is not present in the following two cases: i) no_pic_partition_flag is equal to 1, ii) no_pic_partition_flag is equal to 0 and rect_slice_flag is equal to 0.

[0654] For case i), no_pic_partition_flag equal to 1 indicates that picture partitioning is not applied to each picture that references the PPS, so there is only one slice in each picture, and thus only one sub-picture in each picture, and only one slice in each sub-picture. Therefore, in this case, single_slice_per_subpic_flag should be inferred to be equal to 1.

[0655] For case ii), since rect_slice_flag is equal to 0, no inferred single_slice_per_subpic_flag value is needed.

[0656] 4) Currently, there is no mandatory signaling of luma QP increments at either picture or slice level in either PH or SH. However, slice level chroma QP offsets are selectively signaled in SH. This design is somewhat inconsistent.

[0657] a. In addition, the current semantics of the PPS syntax element cu_qp_delta_enabled_flag is as follows: cu_qp_delta_enabled_flag equal to 1 indicates that the ph_cu_qp_delta_subdiv_intra_slice and ph_cu_qp_della_subdiv_inter_slice syntax elements are present in the PH referencing the PPS, and cu_qp_delta_abs may be present in the transform unit syntax... However, cu_qp_delta_abs may also appear in the palette codec syntax, which should also be indicated by cu_qp_delta_enabled_flag. In other words, the current semantics of cu_qp_delta_enabled_flag is not clear enough and is a bit confusing.

[0658] 5) The current design of the chroma Qp mapping table does not directly represent the case where chroma Qp is equal to luma Qp.

[0659] 5. List of solutions and implementation examples

[0660] In order to solve the above problems and other unmentioned problems, the following summarized methods are disclosed. The items listed below should be regarded as examples to explain the general concept and should not be interpreted narrowly. In addition, these items can be used alone or in combination in any way.

[0661] In the following discussion, SH may be associated with PH, i.e., SH is associated with a slice in a picture associated with PH. SH may be associated with PPS, i.e., SH is associated with a slice in a picture associated with PPS. PH may be associated with PPS, i.e., PH is associated with a picture associated with PPS.

[0662] In the following discussion, an SPS may be associated with a PPS, ie, a PPS may reference an SPS.

[0663] In the following discussion, the changed text is based on the latest VVC text in JVET-Q2001-vE. Most relevant parts that have been added or modified are highlighted in bold italics, and some deleted parts are enclosed in double brackets (e.g., [[a]] indicates the deletion of the character "a").

[0664] 1. Regarding constraints on APS syntax elements to solve the first problem, one or more of the following methods are disclosed:

[0665] a. In one example, the value of scaling_list_chroma_present_flag is constrained according to the ChromaArrayType derived from the PH syntax element.

[0666] i. For example, whether the value of scaling_list_chroma_present_flag is constrained may depend on whether ph_scaling_list_aps_id exists, for example, as shown in the first set of embodiments.

[0667] 1) In one example, it is required that when ph_scaling_list_aps_id is present, the value of scaling_list_chroma_present_flag for APSNAL units with aps_params_type equal to SCALING_APS and adaptation_parameter_set_id equal to ph_scaling_list_aps_id shall be equal to ChromaArrayType==0?0:1.

[0668] ii. Alternatively, scaling_list_chroma_present_flag is constrained based on the ChromaArrayType derived from the PH syntax element, but is independent of the presence of ph_scaling_list_aps_id, for example, as shown in the first set of embodiments.

[0669] 1) In one example, it is required that the scaling_list_chroma_present_flag value of an APS NAL unit with aps_params_type equal to SCALING_APS should be equal to ChromaArrayType == 0?0:1.

[0670] b. In one example, the value of lmcs_delta_abs_crs is constrained according to the ChromaArrayType derived from the PH syntax element.

[0671] i. For example, whether the value of lmcs_delta_abs_crs is constrained may depend on whether ph_lmcs_aps_id exists, for example, as shown in the first set of embodiments.

[0672] 1) For example, it is required that when ph_lmcs_aps_id is present, if ChromaArrayType is equal to 0, the lmcs_delta_abs_crs value of the APSNAL unit with aps_params_type equal to LMCS_APS and adaptation_parameter_set_id equal to ph_lmcs_aps_id shall be equal to 0, otherwise it shall be greater than 0.

[0673] 2) Alternatively, it is required that when ph_lmcs_aps_id is present, if ChromaArrayType is equal to 0, then the value of lmcs_delta_abs_crs for APSNAL units with aps_params_type equal to LMCS_APS and adaptation_parameter_set_id equal to ph_lmcs_aps_id shall be equal to 0.

[0674] ii. Alternatively, lmcs_delta_abs_crs is constrained based on the ChromaArrayType derived from the PH syntax element, but is independent of the presence of ph_lmcs_aps_id, for example, as shown in the first set of embodiments.

[0675] 1) For example, it is required that if ChromaArrayType is equal to 0, the lmcs_delta_abs_crs value of the APSNAL unit is equal to ph_lmcs_aps_id, otherwise it should be greater than 0.

[0676] 2) For example, it is required that if ChromaArrayType is equal to 0, the value of lmcs_delta_abs_crs of the APS NAL unit equal to ph_lmcs_aps_id should be equal to 0.

[0677] c. In one example, the values ​​of the ALF APS syntax elements (eg, alf_chroma_filter_signal_flag, alf_cc_cb_filter_signal_flag, alf_cc_cr_filter_signal_flag, etc.) are constrained according to the ChromaArrayType derived from the PH syntax element and / or the SH syntax element.

[0678] i. For example, whether the values ​​of alf_chroma_filter_signal_flag and / or alf_cc_cb_filter_signal_flag and / or alf_cc_cr_filter_signal_flag are constrained may depend on whether ph_alf_aps_id_luma[i] or slice_alps_id_luma[i] exists and / or whether ChromaArrayType is equal to 0, for example, as shown in the first set of embodiments.

[0679] 1) For example, it is required that when ph_alf_aps_id_luma[i] is present and ChromaArrayType is equal to 0, the values ​​of alf_chroma_filter_signal_flag, alf_cc_cb_filter_signal_flag and alf_cc_cr_filter_signal_flag of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_alf_aps_id_luma[i] should all be equal to 0.

[0680] 2) In addition, it is required that when slice_alf_aps_id_luma[i] is present and ChromaArrayType is equal to 0, the values ​​of alf_cchroma_filter_signal_flag, alf_cc_cb_filter_signal_flag and alf_cc_cr_filter_signal_flag of the APS NAL units with aps_params_type equal to APSNAL and adaptation_parameter_set_id equal to slice_alps_ips_id_ulma[i] shall all be equal to 0.

[0681] ii. Alternatively, alf_chroma_filter_signal_flag and / or alf_cc_cb_filter_signal_flag and / or alf_cc_cr_filter_signal_flag are constrained based on the ChromaArrayType derived from the PH syntax element or the SH syntax element, but are independent of the presence of ph_alf_aps_id_luma[i] and / or slice_alps_id_luma[i]. For example, as shown in the first set of embodiments.

[0682] 1) For example, it is required that when ChromaArrayType is equal to 0, the values ​​of alf_chroma_filter_signal_flag, alf_cc_cb_filter_signal_flag, and alf_cc_cr_filter_signal_flag of the APS NAL unit with aps_params_type equal to ALF_APS should all be equal to 0.

[0683] 2) In addition, it is required that when ChromaArrayType is equal to 0, the values ​​of alf_chroma_filter_signal_flag, alf_cc_cb_filter_signal_flag and alf_cc_cr_filter_signal_flag of the APS NAL units with aps_params_type equal to ALF_APS shall all be equal to 0. iii. In addition, alf_chroma_filter_signal_flag and / or alf_cc_cb_filter_signal_flag and / or alf_cc_cr_filter_signal_flag are constrained based on the ChromaArrayType derived from the PH or SH syntax element associated with the chroma APS ID, for example, as shown in the first set of embodiments.

[0684] 1) For example, alf_chroma_filter_signal_flag is constrained according to the ChromaArrayType derived from the PH syntax element ph_alf_aps_id_chroma and / or the SH syntax element slice_alf_aps_id_chroma.

[0685] 2) For example, alf_cc_cb_filter_signal_flag is constrained according to the ChromaArrayType derived from the PH syntax element ph_cc_alf_cb_aps_id and / or the SH syntax element slice_cc_alp_cb_apps_id.

[0686] 3) For example, alf_cc_cr_filter_signal_flag is constrained according to the ChromaArrayType derived from the PH syntax element ph_cr_alf_cb_aps_id and / or the SH syntax element slice_cr_alp_cb_apps_id.

[0687] d. In one example, the semantics of the APS syntax elements in the ALF and / or SCALING LIST and / or LMCS data syntax structures may not depend on whether it is a 4:0:0 video codec or a separate color plane codec.

[0688] i. For example, the semantics of the APS syntax elements in the ALF data syntax structure (e.g., alf_chroma_filter_signal_flag, alf_cc_cb_filter_signal_flag, alf_cc_cr_filter_signal_flag, etc.) may not depend on variables / syntax derived from SPS / PH / SH syntax elements (e.g., ChromaArrayType), for example, as shown in the first set of embodiments.

[0689] ii. In addition, or, the semantics of the APS syntax elements in the SCALING LIST data syntax structure (e.g., scaling_list_chroma_present_flag, etc.) may not depend on variables / syntax derived from SPS / PH / SH syntax elements (e.g., ChromaArrayType), for example, as shown in the first set of embodiments.

[0690] e. In addition, whether the temporalId of the ALF / SCALING / LMCS APS NAL unit is constrained may depend on whether the corresponding APS ID exists, for example, as shown in the first set of embodiments.

[0691] i. For example, whether the temporalId of the ALF APS NAL unit is constrained may depend on whether ph_alf_aps_id_luma[i] and / or ph_alf_aps_id_chroma and / or ph_cc_alf_cb_aps_id and / or ph_cc_alp_cr_aps_id exist.

[0692] ii. For example, whether the temporalId of the LMCS APS NAL unit is constrained may depend on whether ph_lmcs_aps_id exists.

[0693] iii. For example, whether the temporalId of the SCALING APS NAL unit is constrained may depend on whether ph_scaling_list_aps_id exists.

[0694] f. In addition, whether the value of alf_luma_filter_signal_flag, alf_chroma_filter_signal_flag and / or alf_cc_cb_filter_signal_flag and / or alf_cc_cr_filter_signal_flag should be equal to 1 may depend on whether the corresponding APS ID exists, for example, as shown in the first group of embodiments.

[0695] i. For example, whether alf_luma_filter_signal_flag is equal to 1 may depend on whether ph_alf_aps_id_luma[i] and / or slice_alp_aps_id_luma[i] are present.

[0696] ii. For example, whether alf_chroma_filter_signal_flag is equal to 1 may depend on whether ph_alf_aps_id_chroma and / or slice_alp_aps_id_chroma exists.

[0697] iii. For example, whether alf_cc_cb_filter_signal_flag is equal to 1 may depend on whether ph_cc_alf_cb_aps_id and / or slice_cc_alp_cb_aps_id exists.

[0698] iv. For example, whether alf_cc_cr_filter_signal_flag is equal to 1 may depend on whether ph_cc_alf_cr_aps_id and / or slice_cc_alp_cr_aps_id exists.

[0699] g. In addition, or, whether the chroma ALF APS ID syntax elements in the SH (e.g., slice_alf_aps_id_chroma, slice_cc_alf_cb_aps_id, slice_cr_alf_cb_apa_id, etc.) can be inferred may depend on the value of ChromaArrayType, for example, as shown in the first set of embodiments.

[0700] i. For example, when ChromaArrayType is not equal to 0, the value of the chroma ALF APS ID syntax element in SH can be inferred (e.g., slice_alf_aps_id_chroma, slice_cc_alf_cb_aps_ID, slice_cr_alf_cb_aps_id, etc.).

[0701] 2. Regarding the signaling notification of deblocking control to solve the second problem, one or more of the following methods are disclosed, for example, as shown in the second group of embodiments:

[0702] a. In one example, an N-bit (eg, N=2) deblocking mode indicator (eg, named deblocking_filter_mode_idc) is signaled.

[0703] i. In one example, the syntax element deblocking_filter_mode_idc is u(2) coded.

[0704] a) Alternatively, the parsing process of deblocking_filter_mode_idc is an N-bit (eg, N=2) unsigned integer.

[0705] ii. In one example, the syntax element deblocking_filter_mode_idc is signaled in the PPS.

[0706] iii. In one example, the syntax element deblocking_filter_mode_idc is used to indicate the following four modes: a) deblocking is completely disabled and is not used for all slices;

[0707] b) deblocking is used for all slices using β and tC offsets of zero value; c) deblocking is used for all slices using β and tC offsets explicitly signaled in the PPS; and

[0708] d) Further control of deblocking at picture or stripe level.

[0709] b. The syntax flag ph / slice_deblocking_filter_used_flag is signaled in PH or SH to indicate whether deblocking is used for the current picture / slice.

[0710] c. The syntax flag ph / slice_deblocking_parameters_override_flag is signaled in PH or SH and indicates whether the β and tC offsets are overridden by the values ​​signaled in PH / SH.

[0711] i. Additionally, if slice_deblocking_parameters_override_flag is not present, its value is inferred to be equal to 0.

[0712] 3. Regarding the inference of the PPS syntax element single_slice_per_subpic_flag to solve the third problem, one or more of the following methods are disclosed:

[0713] a. In one example, when no_pic_partition_flag is equal to 1, single_slice_per_subpic_flags is inferred to be equal to 1, for example, the semantics of single_slice_per_subpic_flag is changed as follows:

[0714] When single_slice_per_subpic_flag is equal to 1, it means that each sub-picture consists of one and only one rectangular slice. When single_slice_per_subpic_flag is equal to 0, it means that each sub-picture can consist of one or more rectangular slices. When [[absent]], the value of single_slice_per_subpic_flags is inferred to be equal to [[0]]

[0715] 4. Regarding the picture or slice QP increment signaling notification to solve the fourth problem, one or more of the following methods are disclosed:

[0716] a. In one example, either in PH or SH, the picture level or slice level chroma QP offset is signaled.

[0717] i. For example, if there are chroma components in the video content (e.g., ChromaArrayType is not equal to 0), the chroma QP offset at the picture or slice level can always be signaled without being restricted by the current flag signaled in the PPS (e.g., pps_slice_chroma_qp_offsets_present_flag).

[0718] ii. Alternatively, if chroma components are present in the video content (eg, ChromaArrayType is not equal to 0), the slice_cb_qp_offset and slice_cr_qp_offset syntax elements may always be present in the associated slice header regardless of the PPS present flag (eg, pps_slice_chroma_qp_offsets_present_flag).

[0719] iii. In addition, the present flag indicating the presence of slice_cb_qp_offset and slice_cr_qp_offset syntax elements (eg, pps_slice_chroma_qp_offsets_present_flag) may not be signaled.

[0720] b. In one example, pps_cu_qp_delta_enabled_flag may be used to indicate the presence of cu_qp_delta_abs and cu_qp_delta_sign_flag in both transform unit syntax and palette codec syntax, and the semantics of pps_cu_qp_delta_eneabled_flag is changed as follows:

[0721] Equal to 1 indicates that the ph_cu_qp_delta_subdiv_intra_slice and ph_cu_qp_delta_subdiv_inter_slice syntax elements are present in the PH that references the PPS, and cu_qp_delta_abs Can exist in the transformation unit syntax pps_cu_qp_delta_enabled_flag is equal to 0, indicating that the ph_cu_qp_delta_subdiv_intra_slice and ph_cu_qp_delta_subdiv_inter_slice syntax elements are not present in the PH that references the PPS, and cu_qp_delta_abs Does not exist in the transformation unit syntax middle.

[0722] 5. Regarding the chroma Qp mapping table, one or more of the following methods are disclosed:

[0723] a. In one example, during the derivation of the chroma QP table, an XOR operator should be performed between (delta_qp_in_val_minus1[i][j]+1) and delta_qp_diff_val[i][j], as shown in the third set of embodiments.

[0724] 6. Examples

[0725] The following are some example embodiments of some of the inventive aspects summarized in Section 5 above, which can be applied to the VVC specification. The modified text is based on the latest VVC text in JVET-Q2001-vE. Most relevant parts that have been added or modified are highlighted in bold italics, and some deleted parts are marked with double brackets (e.g., [[a]] means deleting the "a" character).

[0726] 6.1. The first set of examples

[0727] This is a set of embodiments of Item 1 summarized in Section 5 above.

[0728] 6.1.1.1.ai Examples

[0729] Indicates the adaptation_parameter_set_id of the scaling list APS.

[0730] The TemporalId of the APS NAL unit with aps_params_type equal to SCALING_APS and adaptation_parameter_set_id equal to ph_scaling_list_aps_id shall be less than or equal to the Temporalid of the picture associated with the PH.

[0731]

[0732] …

[0733] Equal to 1 indicates that the chroma scaling list is present in scaling_list_data(). scaling_list_chroma_present_flag equal to 0 indicates that the chroma scaling list is not present in scaling_list_data(). [[Bitstream conformance requires that when ChromaArrayType is equal to 0, scaling_list_chroma_present_flag shall be equal to 0, and when ChormaArrayType is not equal to 0, scaling_list_chroma_present_flag shall be equal to 1. ]] Embodiment of 6.1.2.1.a.ii

[0734] Indicates the adaptation_parameter_set_id of the scaling list APS.

[0735] The TemporalId of the APS NAL unit with aps_params_type equal to SCALING_APS and adaptation_parameter_set_id equal to ph_scaling_list_aps_id shall be less than or equal to the Temporalid of the picture associated with the PH.

[0736]

[0737] …

[0738] Equal to 1 indicates that the chroma scaling list is present in scaling_list_data(). scaling_list_chroma_present_flag equal to 0 indicates that the chroma scaling list is not present in scaling_list_data(). [[Bitstream conformance requires that when ChromaArrayType is equal to 0, scaling_list_chroma_present_flag shall be equal to 0, and when ChormaArrayType is not equal to 0, scaling_list_chroma_present_flag shall be equal to 1. ]] Embodiments of 6.1.3.1.bi

[0739] Indicates the adaptation_parameter_set_id of the LMCS APS referenced by the slice associated with the PH.

[0740] The TemporalId of the APS NAL unit with aps_params_type equal to LMCS_APS and adaptation_parameter_set_id equal to ph_lmcs_aps_id shall be less than or equal to the Temporalid of the picture associated with the PH.

[0741]

[0742] 6.1.4.1.b.ii Example

[0743] Indicates the adaptation_parameter_set_id of the LMCS APS referenced by the slice associated with the PH.

[0744] The TemporalId of the APS NAL unit with aps_params_type equal to LMCS_APS and adaptation_parameter_set_id equal to ph_lmcs_aps_id shall be less than or equal to the Temporalid of the picture associated with the PH.

[0745]

[0746] 6.1.5.1.ci Example

[0747] The semantic changes of PH syntax elements are as follows:

[0748] Indicates the adaptation_parameter_set_id of the i-th ALF APS referenced by the luma component of the slice associated with the PH.

[0749] The value of alf_luma_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_alf_aps_id_luma[i].

[0750] The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_alf_aps_id_luma[i] shall be less than or equal to the Temporalid of the picture associated with the PH.

[0751]

[0752] …

[0753] The semantics of SH syntax elements change as follows:

[0754] …

[0755] Indicates the adaptation_parameter_set_id of the i-th ALF APS referenced by the luma component of the slice. When slice_alp_enabled_flag is equal to 1 and slice_als_aps_id_luma[i] is not present, the value of slice_alf_aps_id_luma[i] is inferred to be equal to ph_alf_aps_id_uma[i].

[0756] The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_alf_aps_id_luma[i] shall be less than or equal to the TemporalId of the codec slice NAL unit.

[0757] The value of alf_luma_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_alf_aps_id_luma[i].

[0758]

[0759] …

[0760] The semantic changes of APS syntax elements in the ALF data syntax structure are as follows:

[0761] …

[0762] alf_chroma_filter_signal_flag shall be equal to 0 when ChromaArrayType is equal to 0. ]]

[0763] …

[0764] Equal to 1 indicates that the cross-component filter of the Cb color component is signaled. alf_cc_cb_filter_signal_flag equal to 0 indicates that the cross-component filter of the Cb color component is not signaled. [[When ChromaArrayType is equal to 0, alf_cc_cb_filter_signal_flag shall be equal to 0. ]]

[0765] Equal to 1 indicates that cross-component filters for Cr color components are signaled. alf_cc_cr_filter_signal_flag equal to 0 indicates that cross-component filters for Cr color components are not signaled. [[When ChromaArrayType is equal to 0, alf_cc_cr_filter_signal_flag shall be equal to 0. ]]

[0766] 6.1.6.1.c.ii Example

[0767] The semantic changes of PH syntax elements are as follows:

[0768] Indicates the adaptation_parameter_set_id of the i-th ALF APS referenced by the luma component of the slice associated with the PH.

[0769] The value of alf_luma_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_alf_aps_id_luma[i].

[0770] The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_alf_aps_id_luma[i] shall be less than or equal to the Temporalid of the picture associated with the PH.

[0771]

[0772] =0 indicates that the adaptive loop filter is not applied to the Cb and Cr color components. ph_alf_chroma_idc equal to 1 indicates that the adaptive loop filter is applied to the Cb color component. ph_alf_chroma_idc equal to 2 indicates that the adaptive loop filter is applied to the Cr color component. ph_alf_chroma_idc equal to 3 indicates that the adaptive loop filter is applied to the Cb and Cr color components. When ph_alf_chroma_idc is not present, it is inferred to be equal to 0.

[0773] …

[0774] The semantics of SH syntax elements change as follows:

[0775] …

[0776] Indicates the adaptation_parameter_set_id of the i-th ALF APS referenced by the luma component of the slice. When slice_alf_enabled_flag is equal to 1 and slice_alf_aps_id_luma[i] is not present, the value of slice_alf_aps_id_luma[i] is inferred to be equal to the value of ph_alf_aps_id_luma[i].

[0777] The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_alf_aps_id_luma[i] shall be less than or equal to the TemporalId of the codec slice NAL unit.

[0778] The value of alf_luma_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_alf_aps_id_luma[i].

[0779]

[0780] …

[0781] The semantic changes of APS syntax elements in the ALF data syntax structure are as follows:

[0782] …

[0783] alf_chroma_filter_signal_flag shall be equal to 0 when ChromaArrayType is equal to 0. ]]

[0784] …

[0785] Equal to 1 indicates that the cross-component filter of the Cb color component is signaled. alf_cc_cb_filter_signal_flag equal to 0 indicates that the cross-component filter of the Cb color component is not signaled. [[When ChromaArrayType is equal to 0, alf_cc_cb_filter_signal_flag shall be equal to 0. ]]

[0786] Equal to 1 indicates that cross-component filters for Cr color components are signaled. alf_cc_cr_filter_signal_flag equal to 0 indicates that cross-component filters for Cr color components are not signaled. [[When ChromaArrayType is equal to 0, alf_cc_cr_filter_signal_flag shall be equal to 0. ]]

[0787] 6.1.7.1.c.iii Example

[0788] The semantic changes of PH syntax elements are as follows:

[0789] …

[0790] Indicates the adaptation_parameter_set_id of the ALF APS referenced by the chroma components of the slice associated with the PH.

[0791] The value of alf_chroma_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_alf_aps_id_chroma.

[0792]

[0793] …

[0794] Indicates the adaptation_parameter_set_id of the ALF APS referenced by the Cb color component of the slice associated with the PH.

[0795] The value of alf_cc_cb_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_cc_alf_cb_aps_id.

[0796]

[0797] …

[0798] Indicates the adaptation_parameter_set_id of the ALF APS referenced by the Cr color component of the slice associated with the PH.

[0799] The value of alf_cc_cr_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_cc_alf_cr_aps_id.

[0800]

[0801] …

[0802] The semantics of SH syntax elements change as follows:

[0803] …

[0804] Indicates the adaptation_parameter_set_id of the ALF APS referenced by the chroma components of the slice. The TemporalId of the APS NAL unit with aps_paramers_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_alf_aps_id_chroma shall be less than or equal to the TemporalId of the codec slice NAL unit. When slice_alf_enabled_flag is equal to 1 and slice_alf_aps_id_chroma is not present, the value of slice_alf_aps_id_chroma is inferred to be equal to the value of ph_alf_aps_id_chroma.

[0805] The value of alf_chroma_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_alf_aps_id_chroma.

[0806]

[0807] …

[0808] Indicates the adaptation_parameter_set_id referenced by the Cb color component of the slice.

[0809] The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_cc_alf_cb_aps_id shall be less than or equal to the TemporalId of the codec slice NAL unit. When slice_cc_alf_cb_enabled_flag is equal to 1 and slice_cc_alf_cb_aps_id is not present, the value of slice_cc_alf_cb_aps_id is inferred to be equal to the value of ph_cc_alf_cb_aps_id.

[0810] The value of alf_cc_cb_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_cc_alf_cb_aps_id.

[0811]

[0812] …

[0813] Indicates the adaptation_parameter_set_id referenced by the Cr color components of the slice. The TemporalId of the APS NAL unit with aps_paramers_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_cc_alf_cr_aps_id shall be less than or equal to the TemporalId of the codec slice NAL unit. When slice_cc_alf_cr_enabled_flag is equal to 1 and slice_cc_alf_cr_aps_id is not present, the value of slice_cc_alf_cr_aps_id is inferred to be equal to the value of ph_cc_alf_cr_aps_id.

[0814] The value of alf_cc_cr_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_cc_alf_cr_aps_id.

[0815]

[0816] …

[0817] The semantic changes of APS syntax elements are as follows:

[0818] …

[0819] alf_chroma_filter_signal_flag shall be equal to 0 when ChromaArrayType is equal to 0. ]]

[0820] …

[0821] Equal to 1 indicates that the cross-component filter of the Cb color component is signaled. alf_cc_cb_filter_signal_flag equal to 0 indicates that the cross-component filter of the Cb color component is not signaled. [[When ChromaArrayType is equal to 0, alf_cc_cb_filter_signal_flag shall be equal to 0. ]]

[0822] Equal to 1 indicates that cross-component filters for Cr color components are signaled. alf_cc_cr_filter_signal_flag equal to 0 indicates that cross-component filters for Cr color components are not signaled. [[When ChromaArrayType is equal to 0, alf_cc_cr_filter_signal_flag shall be equal to 0. ]]

[0823] …

[0824] 6.1.8.1.di Example

[0825] The semantic changes of APS syntax elements in the ALF data syntax structure are as follows:

[0826] …

[0827] alf_chroma_filter_signal_flag shall be equal to 0 when ChromaArrayType is equal to 0. ]]

[0828] …

[0829] Equal to 1 indicates that the cross-component filter of the Cb color component is signaled. alf_cc_cb_filter_signal_flag equal to 0 indicates that the cross-component filter of the Cb color component is not signaled. [[When ChromaArrayType is equal to 0, alf_cc_cb_filter_signal_flag shall be equal to 0. ]]

[0830] Equal to 1 indicates that cross-component filters for Cr color components are signaled. alf_cc_cr_filter_signal_flag equal to 0 indicates that cross-component filters for Cr color components are not signaled. [[When ChromaArrayType is equal to 0, alf_cc_cr_filter_signal_flag shall be equal to 0. ]]

[0831] …

[0832] Implementation of 6.1.9.1.d.ii

[0833] The semantic changes of APS syntax elements in the SCALING LIST data syntax structure are as follows:

[0834] …

[0835] Equal to 1 indicates that the chroma scaling list is present in scaling_list_data(). scaling_list_chroma_present_flag equal to 0 indicates that the chroma scaling list is not present in scaling_list_data(). [[Bitstream conformance requires that when ChromaArrayType is equal to 0, scaling_list_chroma_present_flag shall be equal to 0, and when ChormaArrayType is not equal to 0, scaling_list_chroma_present_flag shall be equal to 1.

[0836] …]]

[0837] 6.1.10.1.e and 1.f Examples

[0838] Indicates the adaptation_parameter_set_id of the scaling list APS.

[0839]

[0840] - The TemporalId of the APS NAL unit with aps_params_type equal to SCALING_APS and adaptation_parameter_set_id equal to ph_scaling_list_aps_id shall be less than or equal to the Temporalid of the picture associated with the PH.

[0841] …

[0842] Indicates the adaptation_parameter_set_id of the LMCS APS referenced by the slice associated with the PH.

[0843]

[0844] - The TemporalId of the APS NAL unit with aps_params_type equal to LMCS_APS and adaptation_parameter_set_id equal to ph_lmcs_aps_id shall be less than or equal to the Temporalid of the picture associated with the PH.

[0845] …

[0846] Indicates the adaptation_parameter_set_id of the i-th ALF APS referenced by the luma component of the slice associated with the PH.

[0847]

[0848] - The value of alf_luma_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_alf_aps_id_luma[i].

[0849] - The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_alf_aps_id_luma[i] shall be less than or equal to the Temporalid of the picture associated with the PH.

[0850] =0 indicates that the adaptive loop filter is not applied to the Cb and Cr color components. ph_alf_chroma_idc equal to 1 indicates that the adaptive loop filter is applied to the Cb color component. ph_alf_chroma_idc equal to 2 indicates that the adaptive loop filter is applied to the Cr color component. ph_alf_chroma_idc equal to 3 indicates that the adaptive loop filter is applied to the Cb and Cr color components. When ph_alf_chroma_idc is not present, it is inferred to be equal to 0.

[0851] Indicates the adaptation_parameter_set_id of the ALF APS referenced by the chroma components of the slice associated with the PH.

[0852]

[0853] - The value of alf_chroma_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_alf_aps_id_chroma.

[0854] - The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_alf_aps_id_chroma shall be less than or equal to the Temporalid of the picture associated with the PH.

[0855] …

[0856] Indicates the adaptation_parameter_set_id of the ALF APS referenced by the Cb color component of the slice associated with the PH.

[0857]

[0858] - The value of alf_cc_cb_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_cc_alf_cb_aps_id.

[0859] - The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_cc_alf_cb_aps_id shall be less than or equal to the Temporalid of the picture associated with the PH.

[0860] …

[0861] Indicates the adaptation_parameter_set_id of the ALF APS referenced by the Cr color component of the slice associated with the PH.

[0862]

[0863] - The value of alf_cc_cr_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_cc_alf_cr_aps_id.

[0864] - The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_cc_alf_cr_aps_id shall be less than or equal to the TemporalId of the picture associated with the PH.

[0865] …

[0866] Indicates the adaptation_parameter_set_id of the i-th ALF APS referenced by the luma component of the slice. When slice_alp_enabled_flag is equal to 1 and slice_als_aps_id_luma[i] is not present, the value of slice_alf_aps_id_luma[i] is inferred to be equal to the value of ph_alf_aps_id_luma[i].

[0867]

[0868] - The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_alf_aps_id_luma[i] shall be less than or equal to the TemporalId of the codec slice NAL unit.

[0869] - The value of alf_luma_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_alf_aps_id_luma[i].

[0870] …

[0871] Indicates the adaptation_parameter_set_id of the ALF APS referenced by the chroma components of the slice. When slice_alp_enabled_flag is equal to 1 and slice_alf_aps_id=chroma is not present, the value of slice_alf_aps_id is inferred to be equal to the value of ph_alf_aps_id_chroma.

[0872]

[0873] - The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_alf_aps_id_chroma shall be less than or equal to the TemporalId of the codec slice NAL unit.

[0874] - The value of alf_chroma_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_alf_aps_id_chroma.

[0875] …

[0876] Indicates the adaptation_parameter_set_id referenced by the Cb color component of the slice.

[0877] When slice_cc_alf_cb_enabled_flag is equal to 1 and slice_cd_alf_cb_aps_id is not present, the value of slice_cc_alf_cb_aps_id is inferred to be equal to the value of ph_cc_alf_cb_aps_id.

[0878]

[0879] - The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_cc_alf_cb_aps_id shall be less than or equal to the TemporalId of the codec slice NAL unit.

[0880] - The value of alf_cc_cb_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_cc_alf_cb_aps_id.

[0881] …

[0882] Indicates the adaptation_parameter_set_id referenced by the Cr color component of the slice. When slice_cd_alf_cr_enabled_flag is equal to 1 and slice_cc_alf_cr_aps_id is not present, the value of slice_cc_alf_cr_aps_id is inferred to be equal to the value of ph_cc_alf_cr_aps.

[0883]

[0884] - The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_cc_alf_cr_aps_id shall be less than or equal to the TemporalId of the codec slice NAL unit.

[0885] - The value of alf_cc_cr_filter_signal_flag shall be equal to 1 for APS NAL units with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_cc_alf_cr_aps_id.

[0886] …

[0887] 6.1.11.1.g Example

[0888] The semantics of SH syntax elements change as follows:

[0889] Indicates the adaptation_parameter_set_id of the ALF APS referenced by the chroma components of the slice. The TemporalId of the APS NAL unit with aps_paramers_type equal to ALF_APSadaptation_parameter_set_id equal to slice_alf_aps_id_chroma shall be less than or equal to the TemporalId of the codec slice NAL unit. When slice_alf_enabled_flag is equal to 1 and slice_alf_aps_id_chroma is not present When slice_alf_aps_id_chroma is inferred to be equal to the value of ph_alf_aps_id_chroma.

[0890] …

[0891] Indicates the adaptation_parameter_set_id referenced by the Cb color component of the slice.

[0892] The TemporalId of the APS NAL unit with aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_cc_alf_cb_aps_id shall be less than or equal to the TemporalId of the codec slice NAL unit. When slice_cc_alf_cb_aps_id is inferred to be equal to the value of ph_cc_alf_cb_aps_id.

[0893] …

[0894] Indicates the adaptation_parameter_set_id referenced by the Cr color component of the slice. The TemporalId of the APS NAL unit with aps_paramers_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_cc_alf_cr_aps_id shall be less than or equal to the TemporalId of the codec slice NAL unit. When slice_cc_alf_cr_enabled_flag is equal to 1 and slice_cc_alf_cr_aps_id does not exist When slice_cc_alf_cr_aps_id is inferred to be equal to the value of ph_cc_alf_cr_aps_id.

[0895] …

[0896] 6.2. Second set of examples

[0897] This is a set of embodiments of Item 2 (from 2.a to 2.c) summarized in Section 5 above.

[0898] The syntax of pic_parameter_set_rbsp() is changed as follows:

[0899] ...

[0901]

[0902] =1 indicates the presence of the deblocking filter control syntax element in the PPS. deblocking_filter_control_present_flag equal to 0 indicates the presence of the deblocking filter control syntax element in the PPS.

[0903] Equal to 1 indicates that ph_deblocking_filter_overrid_flag is present in the PH referencing the PPS or slice_deblocking_filter_override_flag is present in the slice header referencing the PPS. deblocking_filter_override_enabled_flag equal to 0 indicates that ph_deblocking_filter_override_flag is not present in the PH referencing the PPS or slice_deblocking_filter_override_flag is not present in the slice header referencing the PP. When not present, the value of deblocking_filter_override_enabled_flag is inferred to be equal to 0.

[0904] Equal to 1 indicates that the operation of the deblocking filter is not applied to slices that reference the PPS where slice_deblocking_filter_disabled_flag is not present. pps_deblocking_filter_disabled_flag equal to 0 indicates that the operation of the deblocking filter is applied to slices that reference the PPS where slice_deblocking_filter_disabled_flag is not present. [[When not present, the value of pps_deblocking_filter_disabled_flag is inferred to be equal to 0. ]]

[0905] dbf_info_in_ph_flag equal to 0 indicates that the deblocking filter information is not present in the PH syntax structure, and may be present in the slice headers that reference a PPS that does not contain a PH syntax structure. [[When not present, the value of dbf_info_in_ph_flag is inferred to be equal to 0. ]] ...

[0907] The syntax structure of picture_header_structure() is changed as follows:

[0908]

[0909] ...

[0911] ph_deblocking_filter_used_flag equal to 1 indicates that a deblocking filter is applied to the slices in the current picture. ph_deblocking_filter_used_flag equal to 0 indicates that a deblocking filter is not applied to the slices in the current picture. When not present, the value of ph_deblocking_filter_used_flag is inferred to be equal to (deblocking_filter_node_idc>0).

[0912] Equal to 1 means the deblocking parameter is present in PH. Equal to 0 indicates that the deblocking parameters are not present in PH. If not present, the value of ph_debocking_filter_override_flag is inferred to be equal to 0.

[0913] ph_deblocking_filter_disabled_flag is equal to 1 to indicate that the deblocking filter operation is not applied to the slices associated with the PH. ph_deblocking_filter_disabled_flag is equal to 0 to indicate that the deblocking filter operation is applied to the slices associated with the PH. When ph_deblocking_filter_disabled_flag is not present, it is inferred to be equal to pps_deblocking_filter_disabled_flag. ]] ...

[0915] The syntax of slice_header() has been changed as follows:

[0916]

[0917] ...

[0919]

[0920] Equal to 1 indicates the presence of deblocking parameters in the slice header. Equal to 0 indicates that no deblocking parameters are present in the slice header. When not present, the value of slice_deblocking_filter_override_flag is inferred to be equal to [[ph_deblocging_filter_override_flag]]

[0921] When slice_detblocking_filter_disabled_flag is equal to 1, it indicates that the deblocking filter operation is not applied to the current slice. When slice_detblocking_filter_disabled_flag is equal to 0, it indicates that the deblocking filter operation is applied to the current slice. When slice_detblocking_filter_disabled_flag is not present, it is inferred to be equal to ph_deblocking_filterd_disabled_flag. ]] ...

[0923] The decoding process for deblocking filter processing is changed as follows:

[0924] 8.8.3 Deblocking Filter Processing

[0925] 8.8.3.1 Overview

[0926] The deblocking filter applies to all codec sub-block edges and transform block edges of a picture, except for the following types of edges:

[0927] — the edge of the image border,

[0928] - an edge that coincides with the boundary of the sub-picture with sub-picture index subpicIdx and for which loop_filter_across_subpic_enabled_flag[subpicIdx] is equal to 0,

[0929] —When VirtualBoundariesPresentFlag is equal to 1, the edges that coincide with the virtual boundaries of the image,

[0930] - when loop_filter_across_tiles_enabled_flag is equal to 0, edges that coincide with tile boundaries,

[0931] - When loop_filter_across_slices_enabled_flag is equal to 0, the edges that coincide with the slice boundaries,

[0932] —With is equal to [[1] The upper or left border of the strip coincides with the edge,

[0933] -in is equal to [[1] The edge of the strip,

[0934] — edges that do not correspond to the boundaries of the 4×4 sample grid of the luma component,

[0935] — edges that do not correspond to the boundaries of the 8×8 sample grid of the chrominance components,

[0936] - an edge in the luma component with intra_bdpcm_luma_flag equal to 1 on both sides,

[0937] - an edge in a chroma component with intra_bdpcm_chroma_flag equal to 1 on both sides of the edge,

[0938] - an edge of a chroma sub-block that is not an edge of a related transform unit.

[0939] The vertical or horizontal edge type is indicated by the variable edgeType as specified in Table 42.

[0940] Table 42 - edgeType associated names

[0941] edgeType edgeType name 0 (vertical edge) EDGE_VER 1(horizontal edge) EDGE_HOR

[0942] When the current strip Equals [[0]] The following applies:

[0943] —The variable treeType is set equal to DUAL_TREE_LUMA.

[0944] - Filter vertical edges by invoking the one-directional deblocking filter process specified in clause 8.8.3.2, where the variable treeType, the reconstructed picture before deblocking, the array recPicture L and the variable edgeType set equal to EDGE_VER as input, the modified reconstructed picture after removing the blocks, that is, the array recPiture L as output.

[0945] - Filter the horizontal edges by invoking the one-directional deblocking filter process specified in clause 8.8.3.2, where the variable treeType, the modified reconstructed picture after deblocking, the array recPicture L and the variable edgeType set equal to EDGE_HOR as input, the modified reconstructed picture after removing the blocks, that is, the array recPiture L as output.

[0946] — When ChromaArrayType is not equal to 0, the following applies:

[0947] —The variable treeType is set equal to DUAL_TREE_CHROMA.

[0948] - Filter vertical edges by invoking the one-directional deblocking filter process specified in clause 8.8.3.2, where the variable treeType, the reconstructed picture before deblocking, the array recPicture Cb and recPicture Cr , and the variable edgeType set equal to EDGE_VER as input, the modified reconstructed picture after removing the blocks, that is, the array recPicture Cb and recPicture Cr as output.

[0949] - Filter the horizontal edges by invoking the one-directional deblocking filter process specified in clause 8.8.3.2, where the variable treeType, the modified reconstructed picture after deblocking, the array recPicture Cb and recPicture Cr , and the variable edgeType set equal to edge_HOR as input, the modified reconstructed picture after removing the block, that is, the array recPicture Cb and recPictureCr as output.

[0950] 6.3. The third set of examples

[0951] These changes based on JVET-Q2001-vE are marked in bold italics.

[0952] The i-th chroma QP mapping table ChromaQpTable[i]-1 with i=0..numQpTables is derived as follows:

[0953]

[0954]

[0955] When same_qp_table_for_chroma is equal to 1, ChromaQpTable[1][k] and ChromaQpTable[2][k] are set to ChromaQTable[0][k], with k in the range of -QpBdOffset to 63, inclusive.

[0956] Bitstream conformance requires that the values ​​of qpInVal[i][j] and qpOutVal[i][j] shall be in the range -QpBdOffset to 63, inclusive, i in the range 0 to numQpTables-1, inclusive, and j in the range 0 to num_points_in_qp_table_minus1[i]+1, inclusive.

[0957] Figure 1 A block diagram of an example video processing system 1900 in which various techniques of the present disclosure may be implemented is shown. Various implementations may include some or all of the components of system 1900. System 1900 may include an input 1902 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 received in a compressed or encoded format. Input 1902 may represent a network interface, a peripheral bus interface, or a storage interface. Examples of network interfaces include wired interfaces such as Ethernet, a passive optical network (PON), and wireless interfaces such as Wi-Fi or a cellular interface.

[0958] System 1900 may include a codec component 1904, which may implement various codec or encoding methods described in the present disclosure. Codec component 1904 may reduce the average bit rate of the video from input 1902 to the output of codec component 1904 to generate a codec representation of the video. Therefore, codec technology is sometimes referred to as video compression or video transcoding technology. The output of codec component 1904 may be stored or transmitted via a communication connection as represented by component 1906. The bitstream (or codec) representation of the storage or communication of the video received at input 1902 may be used by component 1908, which is used to generate pixel values ​​or displayable video sent to display interface 1910. The process of generating a user-viewable video from a bitstream representation is sometimes referred to as video decompression. In addition, although some video processing operations are referred to as "codec" operations or tools, it should be understood that the codec tool or operation is used at the encoder, and the corresponding decoding tool or operation of the inverse encoding result will be performed by the decoder.

[0959] Examples of peripheral bus interfaces or display interfaces may include universal serial bus (USB) or high definition multimedia interface (HDMI) or display port, etc. Examples of storage interfaces include SATA (Serial Advanced Technology Attachment), PCI, IDE interface, etc. The technology described in the present disclosure may be implemented in various electronic devices, such as mobile phones, laptops, smart phones, or other devices capable of performing digital data processing and / or video display.

[0960] Figure 2 3600 is a block diagram of a video processing device 3600. Device 3600 may be used to implement one or more methods described in the present disclosure. Device 3600 may be located in a smartphone, a tablet computer, a computer, an Internet of Things (IoT) receiver, etc. Device 3600 may include one or more processors 3602, one or more memories 3604, and video processing hardware 3606. Processor 3602 may be configured to implement one or more methods described in the present disclosure. Memory 3604 may be used to store data and code for implementing the methods and techniques described in the present disclosure. Video processing hardware 3606 may be used in hardware circuits to implement some of the techniques described in the present disclosure.

[0961] Figure 4 is a block diagram illustrating an example video coding system 100 that may utilize the techniques of this disclosure.

[0962] like Figure 4As shown, the video coding system 100 may include a source device 110 and a target device 120. The source device 110 may generate encoded video data, and the source device 110 may be referred to as a video encoding device. The target device 120 may decode the encoded video data generated by the source device 110, and the target device 120 may be referred to as a video decoding device.

[0963] Source device 110 may include a video source 112 , a video encoder 114 , and an input / output (I / O) interface 116 .

[0964] The video source 112 may include, for example, a source of a video capture device, an interface for receiving video data from a video content provider, and / or a computer graphics system for generating video data, or a combination of these sources. The video data may include one or more pictures. The video encoder 114 encodes the video data from the video source 112 to generate a bit stream. The bit stream may include a bit sequence that forms a codec representation of the video data. The bit stream may include a codec picture and associated data. The codec picture is a codec representation of the picture. The associated data may include a sequence parameter set, a picture parameter set, and other grammatical structures. The I / O interface 116 may include a modulator / demodulator (modem) and / or a transmitter. The encoded video data may be directly sent to the target device 120 via the network 130a via the I / O interface 116. The encoded video data may also be stored on a storage medium / server 130b for access by the target device 120.

[0965] Target device 120 may include an I / O interface 126 , a video decoder 124 , and a display device 122 .

[0966] The I / O interface 126 may include a receiver and / or a modem. The I / O interface 126 may obtain encoded video data from the source device 110 or the storage medium / server 130b. The video decoder 124 may decode the encoded video data. The display device 122 may display the decoded video data to the user. The display device 122 may be integrated with the target device 120, or may be external to the target device 120, and the target device 120 may be configured to interface with an external display device.

[0967] The video encoder 114 and the video decoder 124 may operate according to a video compression standard, such as the High Efficiency Video Coding (HEVC) standard, the Versatile Video Coding (VVC) standard, and other current and / or other standards.

[0968] Figure 5 is a block diagram illustrating an example of a video encoder 200, which may be Figure 4 The video encoder 114 in the system 100 illustrated in FIG.

[0969] Video encoder 200 may be configured to perform any or all of the techniques of this disclosure. Figure 5 In the example shown, the video encoder 200 includes multiple functional components. The techniques described in this disclosure may be shared among the various components of the video encoder 200. In some examples, a processor may be configured to perform any or all of the techniques described in this disclosure.

[0970] The functional components of the video encoder 200 may include a segmentation unit 201, a prediction unit 202 which may include a mode selection unit 203, a motion estimation unit 204, a motion compensation unit 205 and an intra-frame prediction unit 206, a residual generation unit 207, a transform unit 208, a quantization unit 209, an inverse quantization unit 210, an inverse transform unit 211, a reconstruction unit 212, a buffer 213 and an entropy coding and decoding unit 214.

[0971] In other examples, the video encoder 200 may include more, fewer, or different functional components. In one example, the prediction unit 202 may include an intra-block copy (IBC) unit. The IBC unit may perform prediction in an IBC mode, where at least one reference picture is a picture where the current video block is located.

[0972] Furthermore, some components such as the motion estimation unit 204 and the motion compensation unit 205 may be highly integrated but are not shown in the figure for the purpose of description. Figure 5 are represented separately in the example.

[0973] The partitioning unit 201 may partition a picture into one or more video blocks. The video encoder 200 and the video decoder 300 may support various video block sizes.

[0974] The mode selection unit 203 may select one of the codec modes (intra or inter), for example, based on the error result, and provide the resulting intra or inter codec block to the residual generation unit 207 to generate residual block data and the reconstruction unit 212 to reconstruct the codec block for use as a reference picture. In some examples, the mode selection unit 203 may select a combination of intra and inter prediction (CIIP) modes, where the prediction is based on an inter prediction signal and an intra prediction signal. In the case of inter prediction, the mode selection unit 203 may also select a resolution of motion vectors for the block (e.g., sub-pixel or integer pixel precision).

[0975] In order to perform inter-frame prediction on the current video block, the motion estimation unit 204 may generate motion information of the current video block by comparing the current video block with one or more reference frames from the buffer 213. The motion compensation unit 205 may determine a predicted video block of the current video block based on the motion information of pictures other than the picture associated with the current video block from the buffer 213 and decoded samples.

[0976] Motion estimation unit 204 and motion compensation unit 205 may perform different operations on the current video block, eg, depending on whether the current video block is in an I slice, a P slice, or a B slice.

[0977] In some examples, the motion estimation unit 204 may perform unidirectional prediction on the current video block, and the motion estimation unit 204 may search the reference picture of list 0 or 1 for the reference video block of the current video block. The motion estimation unit 204 may then generate a reference index indicating the reference picture containing the reference video block in list 0 or list 1 and a motion vector indicating the spatial displacement between the current video block and the reference video block. The motion estimation unit 204 may output the reference index, the prediction direction indicator, and the motion vector as the motion information of the current video block. The motion compensation unit 205 may generate a predicted video block of the current block based on the reference video block indicated by the motion information of the current video block.

[0978] In other examples, the motion estimation unit 204 may perform bidirectional prediction on the current video block, the motion estimation unit 204 may search the reference picture in list 0 for the reference video block of the current video block, and may also search the reference picture in list 1 for the reference video block of the current video block. The motion estimation unit 204 may then generate reference indexes indicating the reference pictures in list 0 and list 1, which include reference video blocks and motion vectors indicating spatial displacements between the reference video blocks and the current video block. The motion estimation unit 204 may output the reference index and motion vector of the current video block as motion information of the current video block. The motion compensation unit 205 may generate a predicted video block of the current video block based on the reference video block indicated by the motion information of the current video block.

[0979] In some examples, motion estimation unit 204 may output a complete set of motion information for use in a decoding process by a decoder.

[0980] In some examples, motion estimation unit 204 may not output a complete set of motion information for the current video. Instead, motion estimation unit 204 may reference motion information of another video block to signal motion information for the current video block. For example, motion estimation unit 204 may determine that the motion information of the current video block is sufficiently similar to the motion information of a neighboring video block.

[0981] In one example, motion estimation unit 204 may indicate in a syntax structure associated with the current video block a value that indicates to video decoder 300 that the current video block has the same motion information as another video block.

[0982] In another example, motion estimation unit 204 may identify another video block and a motion vector difference (MVD) in a syntax structure associated with the current video block. The motion vector difference represents the difference between the motion vector of the current video block and the motion vector of the indicated video block. Video decoder 300 may use the motion vector of the indicated video block and the motion vector difference to determine the motion vector of the current video block.

[0983] As described above, the video encoder 200 may predictively signal motion vectors. Two examples of predictive signaling techniques that may be implemented by the video encoder 200 include advanced motion vector prediction (AMVP) and merge mode signaling.

[0984] The intra prediction unit 206 may perform intra prediction on the current video block. When the intra prediction unit 206 performs intra prediction on the current video block, the intra prediction unit 206 may generate prediction data for the current video block based on decoded samples of other video blocks in the same picture. The prediction data for the current video block may include a prediction video block and various syntax elements.

[0985] The residual generation unit 207 may generate residual data for the current video block by subtracting (eg, indicated by a minus sign) the predicted video block of the current video block from the current video block. The residual data for the current video block may include residual video blocks corresponding to different sample components of samples in the current video block.

[0986] In other examples, for the current video block, such as in skip mode, there may be no residual data for the current video block, and the residual generation unit 207 may not perform a subtraction operation.

[0987] Transform processing unit 208 may generate one or more transform coefficient video blocks for the current video block by applying one or more transforms to the residual video block associated with the current video block.

[0988] After transform processing unit 208 generates a transform coefficient video block associated with the current video block, quantization unit 209 may quantize the transform coefficient video block associated with the current video block based on one or more quantization parameter (QP) values ​​associated with the current video block.

[0989] The inverse quantization unit 210 and the inverse transform unit 211 may apply inverse quantization and inverse transform to the transform coefficient video block, respectively, to reconstruct a residual video block from the transform coefficient video block. The reconstruction unit 212 may add the reconstructed residual video block to corresponding samples of one or more predicted video blocks generated by the prediction unit 202 to generate a reconstructed video block associated with the current block stored in the buffer 213.

[0990] After the reconstruction unit 212 reconstructs the video block, a loop filtering operation may be performed to reduce video block artifacts in the video block.

[0991] The entropy coding unit 214 may receive data from other functional components of the video encoder 200. When the entropy coding unit 214 receives the data, the entropy coding unit 214 may perform one or more entropy coding operations to generate entropy coded data and output a bitstream including the entropy coded data.

[0992] Figure 6 is a block diagram illustrating an example of a video decoder 300, which may be Figure 4 The video decoder 114 in the system 100 is shown.

[0993] Video decoder 300 may be configured to perform any or all of the techniques of this disclosure. Figure 6 In the example shown, video decoder 300 includes multiple functional components. The techniques described in this disclosure may be shared among various components of video decoder 300. In some examples, a processor may be configured to perform any or all of the techniques described in this disclosure.

[0994] In such Figure 6 In the example shown, the video decoder 300 includes an entropy decoding unit 301, a motion compensation unit 302, an intra-frame prediction unit 303, an inverse quantization unit 304, an inverse transform unit 305, and a reconstruction unit 306 and a buffer 307. In some examples, the video decoder 300 can perform operations generally related to the video encoder 200 ( Figure 5 ) is the decoding channel that is the opposite of the encoding channel described by .

[0995] The entropy decoding unit 301 may obtain a coded bitstream. The coded bitstream may include entropy coded video data (e.g., coded video data blocks). The entropy decoding unit 301 may decode the entropy coded video data, and based on the entropy decoded video data, the motion compensation unit 302 may determine motion information including motion vectors, motion vector precision, reference picture list index, and other motion information. For example, the motion compensation unit 302 may determine such information by performing AMVP and merge modes.

[0996] The motion compensation unit 302 may generate a motion compensated block, possibly performing interpolation based on an interpolation filter. An identifier for the interpolation filter at sub-pixel precision may be included in the syntax element.

[0997] Motion compensation unit 302 may calculate interpolated values ​​for sub-integer pixels of a reference block using interpolation filters used by video encoder 20 during encoding of the video block. Motion compensation unit 302 may determine the interpolation filters used by video encoder 200 according to received syntax information and use the interpolation filters to produce a prediction block.

[0998] The motion compensation unit 302 may use some syntax information to determine the size of blocks used to encode frames and / or slices of the encoded video sequence, partitioning information describing how each macroblock of a picture of the encoded video sequence is partitioned, a mode indicating how to encode each partition, one or more reference frames (and a list of reference frames) for each inter-frame codec block, and other information for decoding the encoded video sequence.

[0999] The intra prediction unit 303 may form a prediction block from spatially neighboring blocks using, for example, an intra prediction mode received in the bitstream. The inverse quantization unit 303 inversely quantizes, i.e., dequantizes, the quantized video block coefficients provided in the bitstream and decoded by the entropy decoding unit 301. The inverse transform unit 303 applies an inverse transform.

[1000] The reconstruction unit 306 may add the residual block to the corresponding prediction block generated by the motion compensation unit 202 or the intra prediction unit 303 to form a decoded block. If necessary, a deblocking filter may also be applied to filter the decoded block to remove blocky artifacts. The decoded video block is then stored in a buffer 307, which provides reference blocks for subsequent motion compensation / intra prediction and also produces decoded video for presentation on a display device.

[1001] A list of preferred solution examples for some embodiments is provided below.

[1002] The first set of clauses illustrates example implementations of the techniques discussed in the previous section.The following clauses illustrate example implementations of the techniques discussed in the previous section (eg, Item 1).

[1003] 1. A video processing method (eg, Figure 3 ), comprising: performing (3002) a conversion between a video comprising one or more chroma components and a codec representation of the video, the video comprising one or more video pictures comprising one or more slices, wherein the codec representation complies with a format rule, wherein the format rule specifies that a chroma array type field controls constraints on conversion characteristics of chroma used during the conversion.

[1004] 2. The method of clause 1, wherein the conversion characteristic comprises a constraint on a field indicating the presence of one or more scaling lists for one or more chroma components.

[1005] 3. The method of clause 1, wherein the conversion characteristic comprises a constraint on a value of a field indicating a codeword used for signaling luma mapping and chroma scaling.

[1006] 4. The method of clause 1, wherein the conversion characteristics comprise constraints on values ​​of syntax elements describing a set of adaptation parameters of an adaptive loop filter used during the conversion.

[1007] 5. The method of clause 1, wherein the format rule specifies using the same semantics for one or more entries of an adaptation parameter set that signals a chroma array type field of a 4:0:0 format or a separate color codec format.

[1008] 6. The method of clause 5, wherein the one or more entries include adaptive loop filter parameters, scaling list parameters, or luma mapping and chroma scaling parameters.

[1009] 7. The method of clauses 5-6, wherein the format rule further specifies that the constraints on the one or more entries of the adaptation parameter set depend on whether an identifier of the adaptation parameter set is included in the bitstream.

[1010] The following items illustrate example embodiments of the techniques discussed in the previous section (eg, item 2).

[1011] 8. A video processing method, comprising: performing a conversion between a video including one or more video pictures containing one or more video regions and a codec representation of the video, wherein the codec representation complies with a format rule, wherein the format rule specifies a deblocking mode indicator including a video region, wherein the deblocking mode indicator indicates the applicability of a deblocking filter to the video region during the conversion.

[1012] 9. The method of clause 8, wherein the deblocking mode indicator is an N-bit field, where N is an integer greater than 1.

[1013] 10. The method of any of clauses 8-9, wherein the deblocking mode indicator for the video region is included in a picture parameter set.

[1014] 11. The method of clause 8, wherein the deblocking mode indicator corresponds to a flag included in a header of the video region, the flag indicating applicability of a deblocking filter to the video region.

[1015] 12. The method of any of clauses 8-11, wherein the format rule specifies that a flag signaling whether deblocking filter parameters signaled in the deblocking mode indicator overrides default parameters.

[1016] 13. The method of any of clauses 8-12, wherein the video region corresponds to a video picture or a video slice.

[1017] The following items illustrate example embodiments of the techniques discussed in the previous section (eg, item 3).

[1018] 14. A video processing method, comprising: performing conversion between a video including one or more video pictures comprising one or more video strips and / or one or more video sub-pictures and a codec representation of the video, wherein the codec representation complies with a format rule, the format rule specifying a flag indicating whether a single stripe per sub-picture mode is enabled for the video picture when picture segmentation is disabled for the video picture.

[1019] The following items illustrate example embodiments of the techniques discussed in the previous section (eg, item 4).

[1020] 15. A video processing method, comprising: performing conversion between a video including one or more video pictures containing one or more video slices and a codec representation of the video, wherein the codec representation complies with a format rule, and the format rule stipulates that a picture or slice level chroma quantization parameter offset is signaled in a picture header or a slice header.

[1021] 16. The method of clause 15, wherein the format rule provides for including slice level chrominance quantization parameter offsets in a slice header.

[1022] The following items illustrate example embodiments of the techniques discussed in the previous section (eg, item 5).

[1023] 17. A video processing method, comprising: performing conversion between a video including one or more video pictures including one or more video slices and a codec representation of the video, wherein the codec representation conforms to a format rule, wherein the format rule specifies that a converted chroma quantization parameter (QP) table applicable to a video block of the video is derived as an XOR operation between (delta_qp_in_val_minus1[i][j]+1) and delta_qp_diff_val[i][j], wherein delta_qp_in_val_minus1[i][j] specifies an incremental value for deriving input coordinates of a j-th pivot point of an i-th chroma mapping table, and delta_qp_diff_val[i][j] specifies an incremental value for deriving output coordinates of a j-th pivot point of an i-th chroma QP mapping table, wherein i and j are integers.

[1024] 18. The method of any one of clauses 1 to 17, wherein the converting comprises encoding the video into a codec representation.

[1025] 19. The method of any one of clauses 1 to 17, wherein the converting comprises decoding the codec representation to generate pixel values ​​of the video.

[1026] 20. A video decoding apparatus comprising a processor configured to implement the method of one or more of clauses 1 to 19.

[1027] 21. A video encoding apparatus comprising a processor configured to implement the method of one or more of clauses 1 to 19.

[1028] 22. A computer program product having computer code stored thereon, which, when executed by a processor, causes the processor to implement the method of any one of clauses 1 to 19.

[1029] 23. The method, apparatus or system described in this document.

[1030] The second set of items illustrates example implementations of the techniques discussed in the previous section (eg, item 1).

[1031] 1. A video processing method (eg, Fig. 7A The method 700 shown in FIG. 7 comprises: performing conversion between a video and a bit stream of the video according to a format rule (method 702), and wherein the format rule stipulates that a first field at a sequence level, a picture level, or a slice level controls a value of a second field in an adaptive parameter set.

[1032] 2. The method of clause 1, wherein the first field indicates a chroma format identifier of the video.

[1033] 3. The method of clause 2, wherein the first field indicates chrominance samples relative to luma samples.

[1034] 4. The method of clause 1, wherein the first field indicates the presence of a chrominance component in the video.

[1035] 5. The method of clause 1, wherein the second field indicates the presence of one or more scaling lists for one or more chroma components.

[1036] 6. The method of clause 5, wherein the format rule provides that the second field depends on the presence of a syntax element indicating an identifier of a scaling adaptation parameter set, the scaling adaptation parameter set being referenced by a slice associated with a picture header or a slice header.

[1037] 7. The method of clause 6, wherein the format rule specifies that, in the presence of the syntax element, based on the value of the first field, a requirement is set for the value of the second field of an adaptation parameter set APS network abstraction layer NAL unit having an APS parameter type equal to SCALING_APS and an APS identifier equal to the syntax element.

[1038] 8. The method of clause 5, wherein the format rule specifies that the value of the second field is independent of the presence of a syntax element indicating an identifier of a SCALING adaptation parameter set, the SCALING adaptation parameter set being referenced by a slice associated with a picture header or a slice header.

[1039] 9. The method of clause 8, wherein the format rule specifies that, based on the value of the first field, a requirement is set for the value of the second field of an adaptation parameter set APS network abstraction layer NAL unit having an APS parameter type equal to SCALING_APS.

[1040] 10. The method of clause 7 or 9, wherein the format rule provides that the value of the second field is set based on whether the value of the first field is equal to 0.

[1041] 11. The method of clause 10, wherein the first field being equal to 0 indicates that the video is in monochrome format.

[1042] 12. The method of clause 1, wherein the second field indicates a codeword used for signaling luma mapping and chroma scaling.

[1043] 13. The method of clause 12, wherein the format rule provides that the second field depends on the presence of a syntax element indicating an identifier of a luminance mapping and chrominance scaling (LMCS) adaptation parameter set of luminance mapping and chrominance scaling used during the conversion.

[1044] 14. The method of clause 13, wherein the format rule specifies that, in the presence of the syntax element, based on the value of the first field, a requirement is set for the value of the second field of an adaptation parameter set APS network abstraction layer NAL unit having an APS parameter type equal to luma mapping and chroma scaling LMCS_APS and an APS identifier equal to the syntax element.

[1045] 15. The method of clause 12, wherein the format rule specifies that the value of the second field is independent of the presence of a syntax element indicating an identifier of a luma mapping and chroma scaling adaptation parameter set for luma mapping and chroma scaling used during the conversion.

[1046] 16. The method of clause 14, wherein the format rule provides that the requirement on the value of the second field is set based on whether the value of the first field is equal to zero.

[1047] 17. The method of clause 16, wherein the first field being equal to 0 indicates that the video is in monochrome format.

[1048] 18. The method of clause 1, wherein the second field describes an adaptive loop filter (ALF) adaptation parameter set of an adaptive loop filter used in the converting.

[1049] 19. The method of clause 18, wherein the format rule specifies that the value of the second field depends on i) the presence of another syntax element indicating an identifier of the ALF adaptation parameter set and ii) the value of the first field, wherein the ALF adaptation parameter set is referenced by a luma component of a slice associated with a picture header or a slice header.

[1050] 20. The method of clause 19, wherein the format rule specifies that, in the presence of another syntax element and the value of the first field is equal to 0, the value of the second field of the adaptation parameter set APS network abstraction layer NAL unit is equal to 0, and the adaptation parameter set APS network abstraction layer NAL unit has an APS parameter type equal to ALF_APS and an APS identifier equal to another syntax element.

[1051] 21. The method of clause 19 or 20, wherein the further syntax element in the picture header or in the slice header indicates an identifier of an adaptation parameter set of an i-th ALF APS or slice, the i-th ALF APS being referenced by the luma component of a slice in a picture.

[1052] 22. The method of clause 19 or 20, wherein the further syntax element corresponds to ph_alf_aps_id_luma[i] or slice_alf_aps_id_luma[i].

[1053] 23. The method of clause 18, wherein the format rule specifies that the value of the second field is independent of the presence of another syntax element, the other syntax element indicating an identifier of an ALF adaptation parameter set APS, the ALF adaptation parameter set APS being referenced by a luminance component of a slice associated with a picture header or a slice header.

[1054] 24. The method of clause 23, wherein the format rule specifies that, in the case where the value of the first field is equal to 0, the value of the second field of an APS network abstraction layer NAL unit having an APS parameter type equal to ALF_APS and an APS identifier equal to another syntax element is equal to 0.

[1055] 25. The method of clause 18, wherein the first field is derived from a chroma APS identifier associated with the syntax element in a picture header and / or a slice header.

[1056] 26. The method of clause 1, wherein the format rule specifies that the semantics of one or more entries of the adaptation parameter set are independent of whether the first field signals a 4:0:0 format or a separate color coding format.

[1057] 27. The method of clause 26, wherein the one or more entries comprise adaptive loop filter parameters or scaling list parameters or luma mapping and chroma scaling parameters.

[1058] 28. The method of clause 26 or 27, wherein the format rule further provides that the constraints on the one or more entries of the adaptive parameter set do not depend on variables and / or syntax elements derived from another syntax element at the sequence parameter set SPS level, the picture header PH level or the slice header SH level.

[1059] 29. The method of any one of clauses 1-28, wherein the format rule further specifies that the presence of a syntax element indicates that the identifier of the adaptive parameter set corresponding to the adaptive loop filter, scaling, and / or luma mapping and chroma scaling LMCS controls a constraint on a time domain identifier of an APS network abstraction layer NAL unit, wherein the time domain identifier corresponds to the adaptive loop filter, the scaling and / or the luma mapping and chroma scaling.

[1060] 30. The method of clause 29, wherein the format rule further specifies that whether the temporal identifier of the adaptation parameter set APS network abstraction layer NAL unit corresponding to the adaptive loop filter is constrained depends on the presence of the syntax element indicating the identifier of the APS referenced by the luma component, chroma component, Cb color component or Cr color component of the slice.

[1061] 31. The method of clause 29, wherein the format rule further stipulates that whether the time domain identifier of the adaptive parameter set APS network abstraction layer NAL unit corresponding to the LMCS is constrained depends on the presence of the syntax element indicating the identifier of the APS corresponding to the LMCS.

[1062] 32. The method of clause 23, wherein the format rule further stipulates that whether the time domain identifier of the adaptive parameter set APS network abstraction layer NAL unit corresponding to the scaling is constrained depends on the presence of the syntax element indicating the identifier of the APS corresponding to the scaling.

[1063] 33. A video processing method (e.g., Figure 7B The method 710 shown in FIG. 7 comprises: performing conversion between a video and a bitstream of the video according to a format rule (method 712), and wherein the format rule stipulates that the value of a syntax element associated with an adaptive loop filter ALF used in the conversion depends on the presence of another syntax element, and the other syntax element indicates an identifier of an adaptive parameter set APS corresponding to the adaptive loop filter.

[1064] 34. The method of clause 33, wherein the syntax element corresponds to a syntax element indicating whether a luminance filter set is signaled, a syntax element indicating whether a chrominance filter is signaled, a syntax element indicating whether a cross-component filter of a Cb color component is signaled, or a syntax element indicating whether a cross-component filter of a Cr color component is signaled.

[1065] 35. The method of clause 33, wherein the further syntax element indicates the identifier of the adaptation parameter set APS referenced by a luma component, a chroma component, a Cb color component or a Cr color component of a slice.

[1066] 36. A video processing method (e.g., Figure 7C The method 720 shown in FIG. 7 includes: performing conversion between a video and a bitstream of the video according to a format rule (method 722), and wherein the format rule specifies that a value of a field associated with a chroma component of the video controls whether a syntax element is inferred for the chroma component in a slice header associated with an adaptive loop filter.

[1067] 37. The method of clause 36, wherein the format rule further provides that, in the case where the value of the first field is not equal to 0, the value of the syntax element is inferred.

[1068] 38. The method of clause 36, wherein the syntax element indicates an identifier of an adaptation parameter set referenced by a chroma component, a Cb color component, or a Cr color component of the slice.

[1069] 39. The method of any of clauses 1-38, wherein the converting comprises encoding the video into the bitstream.

[1070] 40. The method of any of clauses 1-38, wherein the converting comprises decoding the video from the bitstream.

[1071] 41. The method of any of clauses 1-38, wherein the converting comprises generating the bitstream from the video, and the method further comprises storing the bitstream in a non-transitory computer-readable recording medium.

[1072] 42. A video processing apparatus comprising a processor configured to implement the method of any one or more of clauses 1-41.

[1073] 43. A method of storing a bitstream of a video, comprising the method as described in any one of clauses 1-41, further comprising storing the bitstream in a non-transitory computer-readable recording medium.

[1074] 44. A computer readable medium having program code stored thereon, wherein the program code, when executed, causes a processor to implement the method of any of clauses 1-41.

[1075] 45. A computer-readable medium storing a bit stream generated by the method described above.

[1076] 46. ​​A video processing device storing a bitstream representation, wherein the video processing device is configured to implement the method as described in any of clauses 1-41.

[1077] The third group of items illustrates example embodiments of the techniques discussed in the previous section (eg, items 2-5).

[1078] 1. A video processing method (eg, Fig. 8A The method 800 shown in FIG. 8 comprises: performing conversion between a video including one or more pictures including one or more slices and a bitstream of the video according to a format rule (method 802), and wherein the format rule stipulates that a field is included in a picture parameter set, the field indicating the presence of a syntax element related to a difference between a luminance quantization parameter of a codec unit and a prediction.

[1079] 2. The method of clause 1, wherein the syntax elements include: i) cu_qp_delta_abs, specifying the absolute value of the difference between the luma quantization parameter of the codec unit and the prediction, and ii) cu_qp_delta_sign_flag, specifying the sign of the difference.

[1080] 3. The method of clause 2, wherein the format rule specifies that the field being equal to 1 indicates that i) cu_qp_delta_abs and ii) cu_qp_delta_sign_flag are allowed to be present in transform unit syntax and palette codec syntax.

[1081] 4. The method of clause 2, wherein the format rule specifies that the field being equal to 0 indicates that i) cu_qp_delta_abs and ii) cu_qp_delta_sign_flag are not present in transform unit syntax or palette codec syntax.

[1082] 5. The method of clause 2 or 3, wherein the format rule specifies that the field being equal to 1 further indicates that ph_cu_qp_delta_subdiv_intra_slice and ph_cu_qp_delta_subdiv_inter_slice syntax elements are present in a picture header that references the picture parameter set.

[1083] 6. The method of clause 2 or 4, wherein the format rule specifies that the field being equal to 0 further indicates that ph_cu_qp_delta_subdiv_intra_slice and ph_cu_qp_delta_subdiv_inter_slice syntax elements are not present in a picture header that references the picture parameter set.

[1084] 7. A video processing method (e.g., Figure 8B 810), comprising:

[1085] Conversion between a video including one or more pictures including one or more sub-pictures and a bitstream of the video is performed according to a format rule (method 812), and wherein the format rule provides that in response to disabling picture segmentation for the picture, a first flag is enabled for the picture, the first flag indicating whether each sub-picture of the picture includes exactly one rectangular strip.

[1086] 8. The method of clause 7, wherein the format rule specifies that the first flag is equal to 1 if the picture segmentation is disabled for the picture.

[1087] 9. The method of clause 7, wherein the format rule provides that the first flag is equal to 1 in the case where the second flag is equal to 1 indicating that the picture segmentation is disabled for the picture.

[1088] 10. The method of clause 7, wherein the format rule provides that the first flag being equal to 0 indicates that each sub-picture of the picture is allowed to include one or more rectangular strips.

[1089] 11. A video processing method (eg, Figure 8C 820), comprising:

[1090] A conversion between a video comprising one or more video regions and a bitstream of the video is performed according to a format rule (method 822), and wherein the format rule provides that the bitstream includes a deblocking mode indicator for the video region, the deblocking mode indicator indicating applicability of a deblocking filter to the video region during the conversion.

[1091] 12. The method of clause 11, wherein the deblocking mode indicator is an N-bit field, where N is an integer greater than 1.

[1092] 13. The method of clause 11 or 12, wherein the deblocking mode indicator of the video region is u(2) coded.

[1093] 14. The method of clause 11, wherein the parsing process of the deblocking mode indicator for the video region is an N-bit unsigned integer, where N is an integer greater than 1.

[1094] 15. The method of any of clauses 11-14, wherein the deblocking mode indicator for the video region is included in a picture parameter set.

[1095] 16. The method of clause 1, wherein the deblocking mode indicator corresponds to a flag included in a header of the video region, the flag indicating applicability of the deblocking filter to the video region.

[1096] 17. The method of clause 16, wherein the video region corresponds to a picture or a slice.

[1097] 18. The method of any of clauses 11-17, wherein the format rule provides that a flag signaling whether signaling deblocking filter parameters in the deblocking mode indicator will override default parameters.

[1098] 19. The method of clause 18, wherein the format rule provides that, in the absence of the flag, the value of the flag is inferred to be equal to 0.

[1099] 20. A video processing method (eg, Fig.8D The method 830 shown in FIG. 8 includes: performing conversion between a video including one or more pictures including one or more slices and a bitstream of the video according to a format rule (method 832), and wherein the format rule stipulates that a picture level or slice level chroma quantization parameter offset is always signaled in a picture header or a slice header.

[1100] 21. The method of clause 20, wherein the format rule provides that the picture level or the slice level chroma quantization parameter offset is always signaled when the video has a chroma component, regardless of whether a current flag at the picture parameter set level is signaled in the picture parameter set, the current flag indicating the presence of a syntax element for determining the value of the chroma quantization parameter offset.

[1101] 22. The method of clause 20, wherein the format rule provides that a syntax element for determining the value of a chrominance quantization parameter offset is always present in the associated slice header, regardless of whether a current flag at the picture parameter set level is signaled in the picture parameter set, the current flag indicating the presence of the syntax element.

[1102] 23. The method of any of clauses 20-22, wherein the format rule provides for omitting a current flag at picture parameter set level, the current flag indicating the presence of a syntax element for determining a value of a chrominance quantization parameter offset.

[1103] 24. A video processing method (eg, Fig. 8EThe method 840 shown in ), comprises: performing conversion between a video including one or more pictures including one or more slices and a bitstream of the video according to a format rule, and wherein the format rule stipulates that a chroma quantization parameter QP table of the conversion applied to a video block of the video is derived as an XOR operation between two syntax elements.

[1104] 25. The method of clause 24, wherein the two syntax elements include i) delta_qp_in_val_minus1[i][j]+1 and ii) delta_qp_diff_val[i][j], wherein delta_qp_in_val_minus1[i][j] specifies an incremental value for deriving input coordinates of the jth pivot point of the i-th chroma mapping table, and delta_qp_diff_val[i][j] specifies an incremental value for deriving output coordinates of the jth pivot point of the i-th chroma QP mapping table, wherein i and j are integers.

[1105] 26. The method of any of clauses 1-25, wherein the converting comprises encoding the video into the bitstream.

[1106] 27. The method of any of clauses 1-25, wherein the converting comprises decoding the video from the bitstream.

[1107] 28. The method of any one of clauses 1-25, wherein the converting comprises generating the bitstream from the video, and the method further comprises: storing the bitstream in a non-transitory computer-readable recording medium.

[1108] 29. A video processing apparatus comprising a processor configured to implement the method of any one or more of clauses 1-28.

[1109] 30. A method of storing a bitstream of a video, comprising the method of any one of clauses 1-28, further comprising storing the bitstream in a non-transitory computer-readable recording medium.

[1110] 31. A computer readable medium having program code stored thereon, wherein the program code, when executed, causes a processor to implement the method of any one of clauses 1-28.

[1111] 32. A computer-readable medium storing a bit stream generated by the method described above.

[1112] 33. A video processing device storing a bitstream representation, wherein the video processing device is configured to implement the method as described in any of clauses 1-28.

[1113] As used herein, the term "video processing" may refer to video encoding, video decoding, video compression, or video decompression. For example, a video compression algorithm may be applied during conversion from a pixel representation of a video to a corresponding bitstream representation, or vice versa. For example, as defined by the syntax, the bitstream representation of the current video block may correspond to bits that are co-located or distributed at different locations within the bitstream. For example, a macroblock may be encoded based on error residual values ​​from a transform and codec, and bits may also be used in headers and other fields in the bitstream. In addition, as described in the above solution, during the conversion process, the decoder may parse the bitstream based on the determination knowing that certain fields may or may not be present. Similarly, the encoder may determine whether to include or not include certain syntax fields, and generate the codec representation accordingly by including or excluding syntax fields from the codec representation.

[1114] The disclosure and other solutions, examples, embodiments, modules and functional operations described in this document can be implemented in digital electronic circuits, or computer software, firmware or hardware, including the structures disclosed in this document and their structural equivalents, or a combination of one or more thereof. The disclosure and other embodiments 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-volatile computer-readable medium for execution by a data processing device or to control the operation of the data processing device. The computer-readable medium can be a machine-readable storage device, a machine-readable storage substrate, a storage device, a material composition that affects a machine-readable propagation signal, or a combination of one or more thereof. The term "data processing unit" or "data processing device" includes all devices, equipment and machines for processing data, including, for example, a programmable processor, a computer or a multiprocessor or a computer group. In addition to hardware, the device may also include code that creates an execution environment for a computer program, for example, code constituting processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more thereof. A propagated signal is an artificially generated signal, for example, a machine-generated electrical, optical or electromagnetic signal, which is generated to encode information for transmission to a suitable receiver device.

[1115] A computer program (also referred to as a program, software, software application, script, or code) may be written in any form of programming language (including compiled or interpreted languages) and may 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 may 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, or in multiple coordinated files (e.g., files that store one or more modules, subroutines, or portions of code). A computer program may be deployed for execution on one or more computers that are located at one site or distributed across multiple sites and interconnected by a communications network.

[1116] The processes and logic flows described in this document 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 the apparatus may also be implemented as, special purpose logic circuits, such as an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit).

[1117] For example, processors suitable for executing computer programs include general and special purpose microprocessors, and any one or more of any type of digital computer. Typically, the processor will receive instructions and data from a read-only memory or a random access memory or both. The basic components of a computer are a processor that executes instructions and one or more storage devices that store instructions and data. Typically, a computer will also include one or more mass storage devices for storing data, such as magnetic disks, magneto-optical disks, or optical disks, or be operatively coupled to one or more mass storage devices to receive data from them or transfer data to one or more mass storage devices, or both. However, a computer does not necessarily have such a device. Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, including, for example, semiconductor memory devices, such as EPROM, EEPROM, and flash memory devices; magnetic disks, such as internal hard disks or removable hard disks; magneto-optical disks; and CDROM and DVDROM disks. The processor and memory may be supplemented by, or incorporated into, dedicated logic circuits.

[1118] Although this patent document contains many specifics, they should not be construed as limitations on the scope of any invention or the claims, but rather as descriptions of features of particular embodiments of particular inventions. Certain features described in this patent document in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various functions described in the context of a single embodiment may also be implemented separately in multiple embodiments, or in any suitable subcombination. In addition, although the above-mentioned features may be described as working in certain combinations, or even initially claimed to be so, in some cases, one or more features in the claim combination may be removed from the combination, and the claim combination may be directed to subcombinations or variations of subcombinations.

[1119] Likewise, although operations are described in a particular order in the drawings, this should not be understood as requiring that such operations be performed in the particular order or order shown, or that all illustrated operations be performed, in order to achieve the desired results. In addition, the separation of various system components in the embodiments of this patent document should not be understood as requiring such separation in all embodiments.

[1120] Only a few implementations and examples are described, and other implementations, enhancements, and variations can be made based on what is described and illustrated in this patent document.

Claims

1. A video processing method, comprising: performing conversion between a video and a bitstream of said video according to format rules, The format rule specifies whether to constrain the values ​​of one or more first syntax elements related to the adaptive loop filter for the chrominance component included in the APS based on whether a second syntax element indicating an adaptive parameter set APS identifier referenced by the luma component at a picture level or a slice level exists, and whether an index based on the color format is equal to 0; The one or more first syntax elements include at least one of the following syntax elements: a syntax element indicating whether to signal a chroma filter and equal to 0 indicating that the chroma filter is not signaled, a syntax element indicating whether to signal a cross-component filter of the Cr color component and equal to 0 indicating that the cross-component filter of the Cr color component is not signaled, or a syntax element indicating whether to signal a cross-component filter of the Cb color component and equal to 0 indicating that the cross-component filter of the Cb color component is not signaled.

2. The method according to claim 1, wherein: When the second syntax element is present and the index of the color format is equal to 0, the value of the one or more first syntax elements of the constrained APS network abstraction layer NAL unit is equal to 0, the APS NAL unit has an APS parameter type equal to adaptive loop filter (ALF)_APS and the APS identifier equal to the second syntax element.

3. The method according to claim 1, wherein: The second syntax element at the picture level corresponds to alf_aps_id_luma in a picture header, or the second syntax element at the slice level corresponds to alf_aps_id_luma in a slice header.

4. The method according to claim 1, wherein: The format rule specifies whether to constrain the value of the third syntax element based on whether a fourth syntax element indicating the APS identifier referenced by the picture at the picture level exists, and based on whether the index of the color format is equal to 0, the third syntax element indicating whether the scaling list APS network abstraction layer NAL unit is allowed to include chroma-related syntax elements contained in the APS.

5. The method according to claim 4, wherein: When the fourth syntax element is present and the index of the color format is equal to 0, the value of the third syntax element constraining the scaling list APS NAL unit is equal to 0, and the scaling list APS NAL unit has the APS identifier equal to the fourth syntax element, wherein the third syntax element equal to 0 indicates that the scaling list APS NAL unit is not allowed to include syntax elements related to the chroma.

6. The method according to claim 1, wherein: The format rule stipulates that when the index of the color format is equal to 0, the value of the fifth syntax element of the luma mapping and chroma scaling LMCS APS NAL unit is inferred to be equal to 0, and the luma mapping and chroma scaling LMCS APS NAL unit has the APS identifier equal to the sixth syntax element at the picture level, and the sixth syntax element indicates the APS identifier referenced by the picture.

7. The method according to claim 1, wherein: The format rule stipulates that when the value of the seventh syntax element is equal to 1, indicating that picture partitioning is not applied to the picture, it is inferred that the value of the eighth syntax element included in the picture parameter set is equal to 1, and the value of the eighth syntax element is equal to 1, indicating that each sub-picture of the picture consists of one and only one rectangular slice.

8. The method according to claim 1, wherein: The format rules specify the inclusion of flags at the picture parameter set level indicating the presence of i) cu_qp_delta_abs, specifying the absolute value of a variable indicating the difference between the luma quantization parameter of a codec unit and the prediction, and ii) cu_qp_della_sign_flag, specifying the sign of the absolute value of the variable in transform unit syntax and palette codec syntax.

9. The method according to claim 1, wherein: The converting includes encoding the video into the bitstream.

10. The method according to claim 1, wherein: The converting includes decoding the video from the bitstream.

11. An apparatus for processing video data, comprising a processor and a non-transitory memory having instructions thereon, wherein: The instructions, when executed by the processor, cause the processor to: performing conversion between a video and a bitstream of said video according to format rules, The format rule specifies whether to constrain the values ​​of one or more first syntax elements related to the adaptive loop filter for the chrominance component included in the APS based on whether a second syntax element indicating an adaptive parameter set APS identifier referenced by the luma component at a picture level or a slice level exists, and whether an index based on the color format is equal to 0; The one or more first syntax elements include at least one of the following syntax elements: a syntax element indicating whether to signal a chroma filter and equal to 0 indicating that the chroma filter is not signaled, a syntax element indicating whether to signal a cross-component filter of the Cr color component and equal to 0 indicating that the cross-component filter of the Cr color component is not signaled, or a syntax element indicating whether to signal a cross-component filter of the Cb color component and equal to 0 indicating that the cross-component filter of the Cb color component is not signaled.

12. The device according to claim 11, wherein when the second syntax element is present and the index of the color format is equal to 0, the value of the one or more first syntax elements of the constrained APS network abstraction layer NAL unit is equal to 0, the APS NAL unit has an APS parameter type equal to adaptive loop filter ALF_APS and an APS identifier equal to the second syntax element, The second syntax element at the picture level corresponds to alf_aps_id_luma in a picture header, or the second syntax element at the slice level corresponds to alf_aps_id_luma in a slice header.

13. The device according to claim 11, wherein: The format rule specifies whether to constrain the value of a third syntax element based on whether a fourth syntax element indicating the APS identifier referenced by the picture at the picture level exists, and based on whether the index of the color format is equal to 0, the third syntax element indicating whether a scaling list APS network abstraction layer NAL unit is allowed to include a syntax element related to chrominance contained in the APS, wherein, when the fourth syntax element is present and the index of the color format is equal to 0, the value of the third syntax element constraining the scaling list APS NAL unit is equal to 0, the scaling list APS NAL unit having the APS identifier equal to the fourth syntax element, wherein the third syntax element equal to 0 indicates that the scaling list APS NAL unit is not allowed to include syntax elements related to the chroma, wherein the format rule specifies that, when the index of the color format is equal to 0, the value of the fifth syntax element of the luma mapping and chroma scaling LMCS APS NAL unit is inferred to be equal to 0, the luma mapping and chroma scaling LMCS APS NAL unit having the APS identifier equal to the sixth syntax element at the picture level, the sixth syntax element indicating the APS identifier referenced by the picture, The format rule specifies that when the value of the seventh syntax element is equal to 1, indicating that picture segmentation is not applied to the picture, it is inferred that the value of the eighth syntax element included in the picture parameter set is equal to 1, and the value of the eighth syntax element is equal to 1, indicating that each sub-picture of the picture consists of one and only one rectangular slice, and Therein, the format rules specify the inclusion of a flag at the picture parameter set level indicating the presence of i) cu_qp_delta_abs, specifying the absolute value of a variable indicating the difference between the luminance quantization parameter of a coding unit and a prediction, and ii) cu_qp_della_sign_flag, specifying the sign of the absolute value of the variable in the transform unit syntax and the palette coding syntax.

14. A non-transitory computer-readable storage medium storing instructions that cause a processor to: performing conversion between a video and a bitstream of said video according to format rules, in, The format rule specifies whether to constrain the values ​​of one or more first syntax elements related to the adaptive loop filter for the chrominance component included in the APS based on whether a second syntax element indicating an adaptation parameter set APS identifier referenced by the luma component at a picture level or a slice level exists, and whether an index based on the color format is equal to 0; The one or more first syntax elements include at least one of the following syntax elements: a syntax element indicating whether to signal a chroma filter and equal to 0 indicating that the chroma filter is not signaled, a syntax element indicating whether to signal a cross-component filter of the Cr color component and equal to 0 indicating that the cross-component filter of the Cr color component is not signaled, or a syntax element indicating whether to signal a cross-component filter of the Cb color component and equal to 0 indicating that the cross-component filter of the Cb color component is not signaled.

15. The non-transitory computer-readable storage medium of claim 14, wherein: when the second syntax element is present and the index of the color format is equal to 0, the value of the one or more first syntax elements of the constrained APS network abstraction layer NAL unit is equal to 0, the APS NAL unit has an APS parameter type equal to adaptive loop filter ALF_APS and an APS identifier equal to the second syntax element, The second syntax element at the picture level corresponds to alf_aps_id_luma in a picture header, or the second syntax element at the slice level corresponds to alf_aps_id_luma in a slice header.

16. The non-transitory computer-readable storage medium of claim 14, wherein: The format rule specifies whether to constrain the value of a third syntax element based on whether a fourth syntax element indicating the APS identifier referenced by the picture at the picture level exists, and based on whether the index of the color format is equal to 0, the third syntax element indicating whether a scaling list APS network abstraction layer NAL unit is allowed to include a syntax element related to chrominance contained in the APS, wherein, when the fourth syntax element is present and the index of the color format is equal to 0, the value of the third syntax element constraining the scaling list APS NAL unit is equal to 0, the scaling list APS NAL unit having the APS identifier equal to the fourth syntax element, wherein the third syntax element equal to 0 indicates that the scaling list APS NAL unit is not allowed to include syntax elements related to the chroma, wherein the format rule specifies that, when the index of the color format is equal to 0, the value of the fifth syntax element of the luma mapping and chroma scaling LMCS APS NAL unit is inferred to be equal to 0, the luma mapping and chroma scaling LMCS APS NAL unit having the APS identifier equal to the sixth syntax element at the picture level, the sixth syntax element indicating the APS identifier referenced by the picture, The format rule specifies that when the value of the seventh syntax element is equal to 1, indicating that picture segmentation is not applied to the picture, it is inferred that the value of the eighth syntax element included in the picture parameter set is equal to 1, and the value of the eighth syntax element is equal to 1, indicating that each sub-picture of the picture consists of one and only one rectangular slice, and Therein, the format rules specify the inclusion of a flag at the picture parameter set level indicating the presence of i) cu_qp_delta_abs, specifying the absolute value of a variable indicating the difference between the luminance quantization parameter of a coding unit and a prediction, and ii) cu_qp_della_sign_flag, specifying the sign of the absolute value of the variable in the transform unit syntax and the palette coding syntax.

17. A non-transitory computer-readable recording medium storing a bit stream of a video generated by a method executed by a video processing device, wherein: The method comprises: generating the bitstream of the video according to a format rule, The format rule specifies whether to constrain the values ​​of one or more first syntax elements related to the adaptive loop filter for the chrominance component included in the APS based on whether a second syntax element indicating an adaptive parameter set APS identifier referenced by the luma component at a picture level or a slice level exists, and whether an index based on the color format is equal to 0; The one or more first syntax elements include at least one of the following syntax elements: a syntax element indicating whether to signal a chroma filter and equal to 0 indicating that the chroma filter is not signaled, a syntax element indicating whether to signal a cross-component filter of the Cr color component and equal to 0 indicating that the cross-component filter of the Cr color component is not signaled, or a syntax element indicating whether to signal a cross-component filter of the Cb color component and equal to 0 indicating that the cross-component filter of the Cb color component is not signaled.

18. The non-transitory computer-readable recording medium according to claim 17, wherein: when the second syntax element is present and the index of the color format is equal to 0, the value of the one or more first syntax elements of the constrained APS network abstraction layer NAL unit is equal to 0, the APS NAL unit has an APS parameter type equal to adaptive loop filter ALF_APS and an APS identifier equal to the second syntax element, The second syntax element at the picture level corresponds to alf_aps_id_luma in a picture header, or the second syntax element at the slice level corresponds to alf_aps_id_luma in a slice header.

19. The non-transitory computer-readable recording medium according to claim 17, wherein: The format rule specifies whether to constrain the value of a third syntax element based on whether a fourth syntax element indicating the APS identifier referenced by the picture at the picture level exists, and based on whether the index of the color format is equal to 0, the third syntax element indicating whether a scaling list APS network abstraction layer NAL unit is allowed to include a syntax element related to chrominance contained in the APS, wherein, when the fourth syntax element is present and the index of the color format is equal to 0, the value of the third syntax element constraining the scaling list APS NAL unit is equal to 0, the scaling list APS NAL unit having the APS identifier equal to the fourth syntax element, wherein the third syntax element equal to 0 indicates that the scaling list APS NAL unit is not allowed to include syntax elements related to the chroma, wherein the format rule specifies that, when the index of the color format is equal to 0, the value of the fifth syntax element of the luma mapping and chroma scaling LMCS APS NAL unit is inferred to be equal to 0, the luma mapping and chroma scaling LMCS APS NAL unit having the APS identifier equal to the sixth syntax element at the picture level, the sixth syntax element indicating the APS identifier referenced by the picture, The format rule specifies that when the value of the seventh syntax element is equal to 1, indicating that picture segmentation is not applied to the picture, it is inferred that the value of the eighth syntax element included in the picture parameter set is equal to 1, and the value of the eighth syntax element is equal to 1, indicating that each sub-picture of the picture consists of one and only one rectangular slice, and Therein, the format rules specify the inclusion of a flag at the picture parameter set level indicating the presence of i) cu_qp_delta_abs, specifying the absolute value of a variable indicating the difference between the luminance quantization parameter of a coding unit and a prediction, and ii) cu_qp_della_sign_flag, specifying the sign of the absolute value of the variable in the transform unit syntax and the palette coding syntax.

20. A method for storing a bitstream of a video, comprising: Generate the bitstream of the video according to a format rule; as well as storing the bitstream in a non-transitory computer-readable recording medium, The format rule specifies whether to constrain the values ​​of one or more first syntax elements related to the adaptive loop filter for the chrominance component included in the APS based on whether a second syntax element indicating an adaptive parameter set APS identifier referenced by the luma component at a picture level or a slice level exists, and whether an index based on the color format is equal to 0; The one or more first syntax elements include at least one of the following syntax elements: A syntax element indicating whether a chroma filter is signaled and equal to 0 indicates that the chroma filter is not signaled, a syntax element indicating whether a cross-component filter of a Cr color component is signaled and equal to 0 indicates that the cross-component filter of the Cr color component is not signaled, or a syntax element indicating whether a cross-component filter of a Cb color component is signaled and equal to 0 indicates that the cross-component filter of the Cb color component is not signaled.

Images