Signaling of prediction weights in general constraint information of the bitstream

Abstract

Systems, methods, and apparatus for video processing are described that include weighted prediction for video blocks. An example method includes: performing conversion between a current slice of a current picture of a video and a bitstream of the video, wherein the bitstream conforms to a format rule, and wherein the format rule specifies the presence of a general constraint information syntax structure that includes one or more constraint flags indicating that constraints on explicit weighted prediction are enabled for slices of a set of pictures.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is an application entering the Chinese national phase of International Patent Application No. PCT / US2021 / 015017 filed on January 26, 2021, which claims priority to U.S. Provisional Patent Application No. US 62 / 978,740 filed on February 19, 2020. The entire disclosure of the above application is incorporated by reference as part of the disclosure of this application. Technical Field

[0003] This patent 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 demand for digital video usage is expected to continue to grow. Summary of the invention

[0005] This document discloses techniques that can be used by video encoders and decoders to process a bitstream of video to perform video encoding and decoding, including weighted prediction.

[0006] In one example aspect, a video processing method is disclosed. The method includes: performing conversion between a current slice of a current picture of a video and a bitstream of the video according to a rule, wherein the rule specifies that a value of a first syntax element of a picture parameter set (PPS) and a value of a second syntax element of the PPS control whether a third syntax element is included in the bitstream, and wherein the first syntax element indicates whether weighted prediction is enabled for a bidirectional slice (B slice) of a codec picture in the bitstream that references the PPS, the second syntax element indicates whether information related to weighted prediction is present in a picture header or a slice header of a codec picture that references the PPS, and the third syntax element indicates the number of weights associated with a reference picture list 1 of the current slice.

[0007] In another example aspect, another video processing method is disclosed. The method includes: performing conversion between a current slice of a current picture of a video and a bitstream of the video, wherein the bitstream conforms to a format rule, and wherein the format rule specifies that values ​​of a plurality of syntax elements indicating whether prediction weights are included in a slice header of the current slice are inferred based on a slice type of the current slice and a value of a first flag included in a picture parameter set (PPS) referenced by the current picture.

[0008] In yet another example aspect, another video processing method is disclosed. The method includes performing conversion between a current slice of a current picture of a video and a bitstream of the video, wherein the bitstream conforms to a format rule, and wherein the format rule specifies the presence of a general constraint information syntax structure, the general constraint information syntax structure including one or more constraint flags indicating that constraints on explicit weighted prediction are enabled for slices of a set of pictures.

[0009] In yet another example aspect, another video processing method is disclosed. The method includes: performing conversion between a current slice of a current picture of a video and a bitstream of the video according to a rule, wherein the rule specifies that one or more constraint flags indicating that constraints on explicit weighted prediction are enabled for slices of a set of pictures are included in a parameter set or header associated with the current slice.

[0010] In yet another example aspect, another video processing method is disclosed. The method includes performing conversion between a video including a current picture and a bitstream of the video, wherein the bitstream complies with a format rule, and wherein the format rule specifies that an indication of whether the current picture excludes a bidirectional slice (B slice) is included in a picture header syntax structure associated with the current picture.

[0011] In yet another example aspect, a video encoder apparatus is disclosed. The video encoder includes a processor configured to implement the above method.

[0012] In yet another example aspect, a video decoder apparatus is disclosed. The video decoder includes a processor configured to implement the above method.

[0013] In yet another example aspect, a computer readable medium having code stored thereon is disclosed. The code is in the form of processor executable code embodying one of the methods described herein.

[0014] These and other features are described throughout this document. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a block diagram illustrating an example video processing system in which the various techniques disclosed herein may be implemented.

[0016] Figure 2 is a block diagram of an example hardware platform for video processing.

[0017] Figure 3 is a block diagram illustrating an example video codec system in which some embodiments of the present disclosure may be implemented.

[0018] Figure 4 is a block diagram illustrating an example of an encoder in which some embodiments of the present disclosure may be implemented.

[0019] Figure 5is a block diagram illustrating an example of a decoder in which some embodiments of the present disclosure may be implemented.

[0020] Figures 6 to 10 A flow chart illustrating an example method of video processing is shown. DETAILED DESCRIPTION

[0021] Section headings are used in this document for ease of understanding and do not limit the applicability of the techniques and embodiments disclosed in each section to that section. In addition, H.266 technical terms are used in some descriptions only for ease of understanding and not to limit the scope of the disclosed techniques. Therefore, the techniques described herein are also applicable to other video codec protocols and designs.

[0022] 1. Introduction

[0023] This document relates to video codec technology. Specifically, it is about the design of PH and SH syntax in video codec. The concept can be applied alone or in various combinations to any video codec standard or non-standard video codec supporting multi-layer video codec, such as the Versatile Video Codec (VVC) under development.

[0024] 2. Abbreviations

[0025] APS Adaptive Parameter Set

[0026] AU Access Unit

[0027] AUD Access Unit Delimiter

[0028] AVC Advanced Video Codec

[0029] CLVS Codec Layer Video Sequence

[0030] CPB codec picture buffer

[0031] CRA Completely Random Access

[0032] CTU Codec Tree Unit

[0033] CVS codec video sequence

[0034] DPB decoded picture buffer

[0035] DPS Decoding Parameter Set

[0036] EOB End of bitstream

[0037] EOS sequence end

[0038] GDR Gradual Decode Refresh

[0039] HEVC High Efficiency Video Codec

[0040] HRD Hypothesized Reference Decoder

[0041] IDR Instant Decode Refresh

[0042] JEM Joint Exploration Model

[0043] MCTS Motion Constraints Episode Set

[0044] NAL Network Abstraction Layer

[0045] OLS output layer set

[0046] PH Image Header

[0047] PPS Picture Parameter Set

[0048] PTL grades, tiers and levels

[0049] PU Picture Unit

[0050] RBSP Raw Byte Sequence Payload

[0051] SEI Supplemental Enhancement Information

[0052] SH Strip Header

[0053] SPS Sequence Parameter Set

[0054] SVC Scalable Video Codec

[0055] VCL video codec layer

[0056] VPS Video Parameter Set

[0057] VTM VVC test model

[0058] VUI Video Availability Information

[0059] VVC Multi-functional Video Codec

[0060] 3. Preliminary Discussion

[0061] Video codec standards have evolved primarily through the well-known ITU-T and ISO / IEC standards. ITU-T developed H.261 and H.263, ISO / IEC developed MPEG-1 and MPEG-4 Vision, and the two organizations jointly developed the H.262 / MPEG-2 Video standard, the H.264 / MPEG-4 Advanced Video Codec (AVC) standard, and the H.265 / HEVC standard. Starting with H.262, video codec standards are 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 put them into 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, and the first version of the VVC Test Model (VTM) was released at that time. Due to the continuous efforts on VVC standardization, new codec technologies are adopted into the VVC standard at each JVET meeting. The working draft of VVC and the test model VTM are updated after each meeting. The VVC project now aims to be technically completed (FDIS) at the July 2020 meeting.

[0062] PH Syntax and Semantics

[0063] In the latest VVC draft text, the PH syntax and semantics are as follows:

[0064]

[0065] The PH RBSP contains the PH syntax structure, namely picture_header_structure().

[0066]

[0067]

[0068]

[0069]

[0070]

[0071] The PH syntax structure contains information common to all slices of the coded picture associated with the PH syntax structure.

[0072] gdr_or_irap_pic_flag equal to 1 specifies that the current picture is a GDR or IRAP picture. gdr_or_irap_pic_flag equal to 0 specifies that the current picture may or may not be a GDR or IRAP picture.

[0073] gdr_pic_flag equal to 1 specifies that the picture associated with the PH is a GDR picture. gdr_pic_flag equal to 0 specifies 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.

[0074] ph_inter_slice_allowed_flag equal to 0 specifies that all codec slices of the picture have slice_type equal to 2. ph_inter_slice_allowed_flag equal to 1 specifies that one or more codec slices with slice_type equal to 0 or 1 may or may not be present in the picture.

[0075] ph_intra_slice_allowed_flag equal to 0 specifies that all codec slices of the picture have slice_type equal to 0 or 1. ph_intra_slice_allowed_flag equal to 1 specifies that there may or may not be one or more codec slices with slice_type equal to 2 in the picture. When not present, the value of ph_intra_slice_allowed_flag is inferred to be equal to 1.

[0076] NOTE 1 – For bitstreams that should undergo sub-picture based bitstream merging without changing the PH NAL units, the encoder is expected to set the values ​​of ph_inter_slice_allowed_flag and ph_intra_slice_allowed_flag equal to 1.

[0077] non_reference_picture_flag equal to 1 specifies that the picture associated with the PH is never used as a reference picture. non_reference_picture_flag equal to 0 specifies that the picture associated with the PH may or may not be used as a reference picture.

[0078] ph_pic_parameter_set_id specifies the value of pps_pic_parameter_set_id of the PPS being used. The value of ph_pic_parameter_set_id should be in the range of 0 to 63, inclusive.

[0079] A bitstream conformance requirement is that the value of TemporalId of the PH shall be greater than or equal to the value of TemporalId of the PPS with pps_pic_parameter_set_id equal to ph_pic_parameter_set_id.

[0080] ph_pic_order_cnt_lsb specifies the picture order count of the current picture modulo MaxPicOrderCntLsb. 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.

[0081] no_output_of_prior_pics_flag affects the output of previously decoded pictures in the DPB after decoding a CLVSS picture that is not the first picture in the bitstream as specified in Annex C.

[0082] recovery_poc_cnt specifies the recovery point of the decoded picture in output order. If the current picture is a GDR picture associated with PH, and there is a picture picA that follows the current GDR picture in decoding order in the CLVS with PicOrderCntVal equal to the value of PicOrderCntVal of the current GDR picture plus recovery_poc_cnt, then picture picA is called the recovery point picture. Otherwise, the first picture in output order with a PicOrderCntVal greater than the value of PicOrderCntVal of the current picture plus recovery_poc_cnt is called the recovery point picture. In decoding order, the recovery point picture should not be before the current GDR picture. The value of recovery_poc_cnt should be in the range of 0 to MaxPicOrderCntLsb-1 (including 0 and MaxPicOrderCntLsb-1).

[0083] When the current picture is a GDR picture, the variable RpPicOrderCntVal is derived as follows:

[0084] RpPicOrderCntVal=PicOrderCntVal+recovery_poc_cnt (82)

[0085] 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 of the associated GDR picture, the current decoded picture and subsequent decoded pictures in output order exactly match the corresponding pictures produced by starting the decoding process from the previous IRAP picture (when present) that precedes the associated GDR picture in decoding order.

[0086] ph_extra_bit[i] may be equal to 1 or 0. A decoder conforming to this version of this specification shall ignore the value of ph_extra_bit[i]. Its value does not affect the conformance of a decoder to the profile specified in this version of the specification.

[0087] ph_poc_msb_present_flag equal to 1 specifies that the syntax element poc_msb_val is present in ph. ph_poc_msb_present_flag equal to 0 specifies that the syntax element poc_msb_val is not present in 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.

[0088] poc_msb_val specifies the POC MSB value of the current picture. The length of the syntax element poc_msb_val is poc_msb_len_minus1+1 bits.

[0089] ph_alf_enabled_flag equal to 1 specifies 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 specifies that the adaptive loop filter may be disabled for one, multiple, or all slices associated with the PH. When not present, ph_alf_enabled_flag is inferred to be equal to 0.

[0090] ph_num_alf_aps_ids_luma specifies the number of ALF APSs referenced by the slice associated with the PH.

[0091] ph_alf_aps_id_luma[i] specifies the adaptation_parameter_set_id of the i-th ALF APS referenced by the luma component of the slice associated with the PH.

[0092] 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].

[0093] 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.

[0094] ph_alf_chroma_idc equal to 0 specifies that the adaptive loop filter is not applied to the Cb and Cr color components. ph_alf_chroma_idc equal to 1 specifies that the adaptive loop filter is applied to the Cb color component. ph_alf_chroma_idc equal to 2 specifies that the adaptive loop filter is applied to the Cr color component. ph_alf_chroma_idc equal to 3 specifies 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.

[0095] ph_alf_aps_id_chroma specifies the adaptation_parameter_set_id of the ALF APS referenced by the chroma components of the slice associated with the PH.

[0096] 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.

[0097] 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.

[0098] ph_cc_alf_cb_enabled_flag equal to 1 specifies that cross-component filters for Cb color components are enabled for all slices associated with the PH and may be applied to Cb color components in a slice. ph_cc_alf_cb_enabled_flag equal to 0 specifies that cross-component filters for Cb color components may be disabled for one, multiple, or all slices associated with the PH. When not present, ph_cc_alf_cb_enabled_flag is inferred to be equal to 0.

[0099] ph_cc_alf_cb_aps_id specifies the adaptation_parameter_set_id of the ALF APS referenced by the Cb color component of the slice associated with the PH.

[0100] 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.

[0101] 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.

[0102] ph_cc_alf_cr_enabled_flag equal to 1 specifies 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 a slice. ph_cc_alf_cr_enabled_flag equal to 0 specifies that cross-component filters for Cr color components may be disabled for one, multiple, or all slices associated with the PH. When not present, ph_cc_alf_cr_enabled_flag is inferred to be equal to 0.

[0103] ph_cc_alf_cr_aps_id specifies the adaptation_parameter_set_id of the ALF APS referenced by the Cr color component of the slice associated with the PH.

[0104] 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.

[0105] 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.

[0106] ph_lmcs_enabled_flag equal to 1 specifies that luma mapping and chroma scaling are enabled for all slices associated with the PH. ph_lmcs_enabled_flag equal to 0 specifies that luma mapping and chroma scaling are disabled for one, more than one, or all slices associated with the PH. When not present, the value of ph_lmcs_enabled_flag is inferred to be equal to 0.

[0107] ph_lmcs_aps_id specifies 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.

[0108] ph_chroma_residual_scale_flag equal to 1 specifies that chroma residual scaling is enabled for all slices associated with the PH. ph_chroma_residual_scale_flag equal to 0 specifies that chroma residual scaling may be disabled for one, multiple, or all slices associated with the PH. When ph_chroma_residual_scale_flag is not present, it is inferred to be equal to 0.

[0109] ph_scaling_list_present_flag equal to 1 specifies that the scaling list data for the slices associated with the PH is derived based on the scaling list data contained in the referenced scaling list APS. ph_scaling_list_present_flag equal to 0 specifies 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.

[0110] ph_scaling_list_aps_id specifies the adaptation_parameter_set_id of the scaling list APS.The TemporalId of the APS NAL units 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.

[0111] ph_virtual_boundaries_present_flag equal to 1 specifies that information about virtual boundaries is signaled in the PH. ph_virtual_boundaries_present_flag equal to 0 specifies 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.

[0112] A bitstream conformance requirement is that when subpic_info_present_flag is equal to 1, the value of ph_virtual_boundaries_present_flag shall be equal to 0.

[0113] The variable VirtualBoundariesPresentFlag is derived as follows:

[0114]

[0115] ph_num_ver_virtual_boundaries specifies the number of ph_virtual_boundaries_pos_x[i] syntax elements present in the PH. When ph_num_ver_virtual_boundaries is not present, it is inferred to be equal to 0.

[0116] The variable NumVerVirtualBoundaries is derived as follows:

[0117]

[0118] ph_virtual_boundaries_pos_x[i] specifies 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.

[0119] The list VirtualBoundariesPosX[i] (i ranges from 0 to NumVerVirtualBoundaries-1 (including 0 and NumVerVirtualBoundaries-1)) that specifies the positions of vertical virtual boundaries, in units of luma samples, is derived as follows:

[0120]

[0121]

[0122] The distance between any two vertical virtual boundaries shall be greater than or equal to CtbSizeY luma samples.

[0123] ph_num_hor_virtual_boundaries specifies the number of ph_virtual_boundaries_pos_y[i] syntax elements present in the PH. When ph_num_hor_virtual_boundaries is not present, it is inferred to be equal to 0.

[0124] The parameter NumHorVirtualBoundaries is derived as follows:

[0125]

[0126] 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.

[0127] ph_virtual_boundaries_pos_y[i] specifies 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.

[0128] The list VirtualBoundariesPosY[i] (i ranges from 0 to NumHorVirtualBoundaries-1 (including 0 and NumHorVirtualBoundaries-1)) that specifies the positions of horizontal virtual boundaries, in units of luma samples, is derived as follows:

[0129]

[0130] The distance between any two horizontal virtual boundaries shall be greater than or equal to CtbSizeY luma samples.

[0131] pic_output_flag affects the decoded picture output and removal process as specified in Annex C. When pic_output_flag is not present, it is inferred to be equal to 1.

[0132] partition_constraints_override_flag equal to 1 specifies that the partition constraints parameters are present in the PH. partition_constraints_override_flag equal to 0 specifies that the partition constraints parameters are not present in the PH. When not present, the value of partition_constraints_override_flag is inferred to be equal to 0.

[0133] ph_log2_diff_min_qt_min_cb_intra_slice_luma specifies the difference between the base-2 logarithm of the minimum size in the luma samples of the luma leaf blocks resulting from the quadtree partitioning of the CTU and the base-2 logarithm of the minimum decoded block size in the luma samples of the luma CU in the slice with slice_type equal to 2(I) associated with the PH. The value of ph_log2_diff_min_qt_min_cb_intra_slice_luma should 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.

[0134] ph_max_mtt_hierarchy_depth_intra_slice_luma specifies the maximum hierarchical depth of codec units resulting from 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 should 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.

[0135] ph_log2_diff_max_bt_min_qt_intra_slice_luma specifies 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 luma leaf blocks resulting from a quadtree partitioning of CTUs in slices 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.

[0136] ph_log2_diff_max_tt_min_qt_intra_slice_luma specifies 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 luma leaf blocks resulting from a quadtree partitioning of CTUs in slices 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.

[0137] ph_log2_diff_min_qt_min_cb_intra_slice_chroma specifies the difference between the base-2 logarithm of the minimum size in 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 in the luma samples of the chroma CU with treeType equal to DUAL_TREE_CHROMA in the slice with slice_type equal to 2(I) associated with the PH. The value of ph_log2_diff_min_qt_min_cb_intra_slice_chroma should 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.

[0138] ph_max_mtt_hierarchy_depth_intra_slice_chroma specifies the maximum hierarchical depth of chroma codec units resulting from multi-type tree partitioning of chroma quadtree leaves 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.

[0139] ph_log2_diff_max_bt_min_qt_intra_slice_chroma specifies 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 binary partitioning and the minimum dimension (width or height) in the luma samples of chroma leaf blocks resulting from quadtree partitioning of chroma CTUs with treeType equal to DUAL_TREE_CHROMA in slices 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.

[0140] ph_log2_diff_max_tt_min_qt_intra_slice_chroma specifies 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 chroma leaf blocks 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.

[0141] ph_cu_qp_delta_subdiv_intra_slice specifies the maximum cbSubdiv value for codec units in intra slices that convey 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.

[0142] When not present, the value of ph_cu_qp_delta_subdiv_intra_slice is inferred to be equal to 0.

[0143] ph_cu_chroma_qp_offset_subdiv_intra_slice specifies the maximum cbSubdiv value of the codec unit in the intra slice 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.

[0144] When not present, the value of ph_cu_chroma_qp_offset_subdiv_intra_slice is inferred to be equal to 0.

[0145] ph_log2_diff_min_qt_min_cb_inter_slice specifies the difference between the base 2 logarithm of the minimum size in the luma samples of the luma leaf blocks resulting from the quadtree partitioning of the CTU and the base 2 logarithm of the minimum luma codec block size in the luma samples of the luma CU in the 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. 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_inter_slice.

[0146] ph_max_mtt_hierarchy_depth_inter_slice specifies the maximum hierarchical depth of codec units resulting from multi-type tree partitioning of quadtree leaves in slices with slice_type associated with PH equal to 0 (B) or 1 (P). 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.

[0147] ph_log2_diff_max_bt_min_qt_inter_slice specifies 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 luma leaf blocks resulting from a quadtree partitioning of a CTU in a slice with slice_type equal to 0 (B) or 1 (P) associated with the PH. 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.

[0148] ph_log2_diff_max_tt_min_qt_inter_slice specifies 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 luma leaf blocks resulting from a quadtree partitioning of a CTU in a slice with slice_type equal to 0 (B) or 1 (P) associated with the PH. The value of ph_log2_diff_max_tt_min_qt_inter_slice should 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.

[0149] ph_cu_qp_delta_subdiv_inter_slice specifies the maximum cbSubdiv value for codec units in inter slices that convey 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.

[0150] When not present, the value of ph_cu_qp_delta_subdiv_inter_slice is inferred to be equal to 0.

[0151] ph_cu_chroma_qp_offset_subdiv_inter_slice specifies the maximum cbSubdiv value of the codec unit in the inter slices that transmit 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.

[0152] When not present, the value of ph_cu_chroma_qp_offset_subdiv_inter_slice is inferred to be equal to 0.

[0153] ph_temporal_mvp_enabled_flag specifies whether the temporal motion vector predictor can be used for inter prediction of the slice associated with the PH. If ph_temporal_mvp_enabled_flag is equal to 0, the syntax elements of the slice associated with the PH shall be constrained so that no temporal motion vector predictor is used in the decoding of the slice. Otherwise (ph_temporal_mvp_enabled_flag is equal to 1), the temporal motion vector predictor can be used in the decoding of the slice 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.

[0154] The maximum number of sub-block-based merge MVP candidates, MaxNumSubblockMergeCand, is derived as follows:

[0155]

[0156]

[0157] The value of MaxNumSubblockMergeCand should be in the range of 0 to 5 (inclusive).

[0158] ph_collocated_from_l0_flag equal to 1 specifies that the collocated picture used for temporal motion vector prediction is derived from reference picture list 0. ph_collocated_from_l0_flag equal to 0 specifies that the collocated picture used for temporal motion vector prediction is derived from reference picture list 1.

[0159] ph_collocated_ref_idx specifies the reference index of the collocated picture used for temporal motion vector prediction.

[0160] 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 (including 0 and num_ref_entries[0][RplsIdx[0]]-1).

[0161] 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 (including 0 and num_ref_entries[1][RplsIdx[1]]-1).

[0162] When not present, the value of ph_collocated_ref_idx is inferred to be equal to 0.

[0163] mvd_l1_zero_flag equal to 1 indicates that the mvd_coding(x0,y0,1) syntax structure is not parsed and for compIdx=0..1 and cpIdx=0..2, MvdL1[x0][y0][compIdx] and MvdCpL1[x0][y0][cpIdx][compIdx] are set equal to 0. mvd_l1_zero_flag equal to 0 indicates that the mvd_coding(x0,y0,1) syntax structure is parsed.

[0164] ph_fpel_mmvd_enabled_flag equal to 1 specifies 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 specifies 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.

[0165] ph_disable_bdof_flag equal to 1 specifies that inter bi-prediction based on bi-directional optical flow inter prediction is disabled in slices associated with the PH. ph_disable_bdof_flag equal to 0 specifies that inter bi-prediction based on bi-directional optical flow inter prediction may or may not be enabled in slices associated with the PH.

[0166] When ph_disable_bdof_flag is not present, the following applies:

[0167] – If sps_bdof_enabled_flag is equal to 1, the value of ph_disable_bdof_flag is inferred to be equal to 0.

[0168] – Otherwise (sps_bdof_enabled_flag is equal to 0), the value of ph_disable_bdof_flag is inferred to be equal to 1.

[0169] ph_disable_dmvr_flag equal to 1 specifies 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 specifies that inter bi-prediction based on decoder motion vector refinement may or may not be enabled in slices associated with the PH.

[0170] When ph_disable_dmvr_flag is not present, the following applies:

[0171] – If sps_dmvr_enabled_flag is equal to 1, the value of ph_disable_dmvr_flag is inferred to be equal to 0.

[0172] – Otherwise (sps_dmvr_enabled_flag is equal to 0), the value of ph_disable_dmvr_flag is inferred to be equal to 1.

[0173] ph_disable_prof_flag equal to 1 specifies that prediction refinement with optical flow is disabled in slices associated with the PH. ph_disable_prof_flag equal to 0 specifies that prediction refinement with optical flow may or may not be enabled in slices associated with the PH.

[0174] When ph_disable_prof_flag is not present, the following applies:

[0175] – If sps_affine_prof_enabled_flag is equal to 1, the value of ph_disable_prof_flag is inferred to be equal to 0.

[0176] – Otherwise (sps_affine_prof_enabled_flag is equal to 0), the value of ph_disable_prof_flag is inferred to be equal to 1.

[0177] ph_qp_delta specifies the Qp to be used for codec blocks in the picture until modified by the value of CuQpDeltaVal in the codec unit layer. Y The initial value of .

[0178] When qp_delta_info_in_ph_flag is equal to 1, the Qp of all slices of the picture YThe initial value of the quantization parameter SliceQp Y is derived as follows:

[0179] SliceQp Y =26+init_qp_minus26+ph_qp_delta (89)

[0180] SliceQp Y The value of should be in the range of -QpBdOffset to +63 (including -QpBdOffset and +63).

[0181] ph_joint_cbcr_sign_flag specifies whether the co-located residual samples of the two chroma components have inverted signs in a transform unit where 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 equal to 0 specifies that the sign of each residual sample of the Cr (or Cb) component is the same as the sign of the co-located Cb (or Cr) residual sample, and ph_joint_cbcr_sign_flag equal to 1 specifies that the sign of each residual sample of the Cr (or Cb) component is given by the inverted sign of the co-located Cb (or Cr) residual sample.

[0182] ph_sao_luma_enabled_flag equal to 1 specifies that SAO is enabled for luma components in all slices associated with the PH; ph_sao_luma_enabled_flag equal to 0 specifies that SAO for luma components may be disabled for one, multiple, or all slices associated with the PH. When ph_sao_luma_enabled_flag is not present, it is inferred to be equal to 0.

[0183] ph_sao_chroma_enabled_flag equal to 1 specifies that SAO is enabled for chroma components in all slices associated with the PH; ph_sao_chroma_enabled_flag equal to 0 specifies that SAO for chroma components may be disabled for one, multiple, or all slices associated with the PH. When ph_sao_chroma_enabled_flag is not present, it is inferred to be equal to 0.

[0184] ph_dep_quant_enabled_flag equal to 0 specifies that dependent quantization is disabled for the current picture. ph_dep_quant_enabled_flag equal to 1 specifies 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.

[0185] pic_sign_data_hiding_enabled_flag equal to 0 specifies that sign bit hiding is disabled for the current picture. pic_sign_data_hiding_enabled_flag equal to 1 specifies 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.

[0186] ph_deblocking_filter_override_flag equal to 1 specifies that deblocking parameters are present in PH. ph_deblocking_filter_override_flag equal to 0 specifies that deblocking parameters are not present in PH. When not present, the value of ph_deblocking_filter_override_flag is inferred to be equal to 0.

[0187] ph_deblocking_filter_disabled_flag equal to 1 specifies 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 specifies 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.

[0188] ph_beta_offset_div2 and ph_tc_offset_div2 specify the deblocking parameter offsets (divided by 2) of beta and tc 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 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.

[0189] ph_cb_beta_offset_div2 and ph_cb_tc_offset_div2 specify the deblocking parameter offsets (divided by 2) applied to the beta and tc of 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 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.

[0190] ph_cr_beta_offset_div2 and ph_cr_tc_offset_div2 specify the deblocking parameter offsets (divided by 2) applied to the β and tC of 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.

[0191] ph_extension_length specifies 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. When not present, the value of ph_extension_length is inferred to be equal to 0.

[0192] ph_extension_data_byte may have any value. A decoder conforming to this version of this specification shall ignore the value of ph_extension_data_byte. Its value does not affect the profile specified in this version of the specification for decoders conforming to it.

[0193] SH Syntax and Semantics

[0194] In the latest VVC draft text, the SH syntax and semantics are as follows:

[0195]

[0196]

[0197]

[0198]

[0199] The variable CuQpDeltaVal, which specifies the difference between the luma quantization parameter and its prediction for the codec unit containing cu_qp_delta_abs, is set equal to 0. The variable CuQpDeltaVal specifies the difference between the luma quantization parameter and its prediction for the codec unit containing cu_chroma_qp_offset_flag. Cb , Qp′ Cr and Qp′ CbCr The corresponding value of the quantization parameter is used when the value of the variable CuQpOffset Cb 、CuQpOffset Cr and CuQpOffset CbCr are all set equal to 0.

[0200] picture_header_in_slice_header_flag equal to 1 specifies that the PH syntax structure is present in the slice header. picture_header_in_slice_header_flag equal to 0 specifies that the PH syntax structure is not present in the slice header.

[0201] A bitstream conformance requirement is that the value of picture_header_in_slice_header_flag shall be the same in all codec slices in a CLVS.

[0202] When picture_header_in_slice_header_flag is equal to 1 for a codec slice, a bitstream conformance requirement is that no VCL NAL units with nal_unit_type equal to PH_NUT shall be present in the CLVS.

[0203] When picture_header_in_slice_header_flag is equal to 0, all codec slices in the current picture shall have picture_header_in_slice_header_flag equal to 0, and the current PU shall have a PH NAL unit.

[0204] slice_subpic_id specifies the sub-picture ID of the sub-picture containing the slice. If slice_subpic_id exists, the value of the variable CurrSubpicIdx is derived such 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.

[0205] slice_address specifies 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.

[0206] If rect_slice_flag is equal to 0, the following applies:

[0207] -The strip address is the raster scan slice index.

[0208] - The length of slice_address is Ceil(Log2(NumTilesInPic)) bits.

[0209] -slice_address values ​​should be in the range of 0 to NumTilesInPic-1 (including 0 and NumTilesInPic-1).

[0210] Otherwise (rect_slice_flag is equal to 1), the following applies:

[0211] - The slice address is the sub-picture level slice index of the slice.

[0212] - The length of slice_address is Ceil(Log2(NumSlicesInSubpic[CurrSubpicIdx])) bits.

[0213] - The value of slice_address should be in the range of 0 to NumSlicesInSubpic[CurrSubpicIdx]-1 (including 0 and NumSlicesInSubpic[CurrSubpicIdx]-1).

[0214] The requirement for bitstream conformance is that the following constraints apply:

[0215] - 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.

[0216] Otherwise, a pair of slice_subpic_id and slice_address values ​​shall not be equal to a pair of slice_subpic_id and slice_address values ​​of any other codec slice NAL unit of the same codec picture.

[0217] - The shape of the slices of a picture shall be such that each CTU, when decoded, shall have its entire left and entire top borders consisting of the picture boundary or consisting of the boundaries of the previously decoded CTU(s).

[0218] 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 decoders conforming to the profile specified in this version of the specification.

[0219] num_tiles_in_slice_minus1 plus 1 (when present) specifies the number of tiles in a slice. The value of num_tiles_in_slice_minus1 should be in the range of 0 to NumTilesInPic-1, inclusive.

[0220] The variable NumCtusInCurrSlice specifying the number of CTUs in the current slice and the list CtbAddrInCurrSlice[i] specifying the picture raster scan address of the i-th CTB in the slice (i ranges from 0 to NumCtusInCurrSlice-1 (including 0 and NumCtusInCurrSlice-1)) are derived as follows:

[0221]

[0222]

[0223] The variables SubpicLeftBoundaryPos, SubpicTopBoundaryPos, SubpicRightBoundaryPos, and SubpicBotBoundaryPos are derived as follows:

[0224]

[0225] slice_type specifies the codec type of the slice according to Table 9.

[0226] Table 9 – Name associations with slice_type

[0227] slice_type The name of slice_type 0 B (B band) 1 P(P stripe) 2 I(I strip)

[0228] When not present, the value of slice_type is inferred to be equal to 2.

[0229] 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 (including IDR_W_RADL and CRA_NUT) and vps_independent_layer_flag[GeneralLayerIdx[nuh_layer_id]] is equal to 1, slice_type shall be equal to 2.

[0230] The variables MinQtLog2SizeY, MinQtLog2SizeC, MinQtSizeY, MinQtSizeC, MaxBtSizeY, MaxBtSizeC, MinBtSizeY, MaxTtSizeY, MaxTtSizeC, MinTtSizeY, MaxMttDepthY, and MaxMttDepthC are derived as follows:

[0231] - If slice_type is equal to 2 (I), the following applies:

[0232] MinQtLog2SizeY=

[0233] MinCbLog2SizeY+ph_log2_diff_min_qt_min_cb_intra_slice_luma (119)

[0234] MinQtLog2SizeC=MinCbLog2SizeY+ph_log2_diff_min_qt_min_cb_intra_slice_chroma (120)

[0236] MaxBtSizeY=1<<(MinQtLog2SizeY+ph_log2_diff_max_bt_min_qt_intra_slice_luma) (121)

[0238] MaxBtSizeC = 1 << (MinQtLog2SizeC + ph_log2_diff_max_bt_min_qt_intra_slice_chroma) (122)

[0240] MaxTtSizeY = 1 << (MinQtLog2SizeY + ph_log2_diff_max_tt_min_qt_intra_slice_luma) (123)

[0242] MaxTtSizeC = 1 << (MinQtLog2SizeC + ph_log2_diff_max_tt_min_qt_intra_slice_chroma) (124)

[0244] MaxMttDepthY = ph_max_mtt_hierarchy_depth_intra_slice_luma (125)

[0245] MaxMttDepthC = ph_max_mtt_hierarchy_depth_intra_slice_chroma (126)

[0246] CuQpDeltaSubdiv = ph_cu_qp_delta_subdiv_intra_slice (127)

[0247] CuChromaQpOffsetSubdiv = ph_cu_chroma_qp_offset_subdiv_intra_slice (128)

[0249] - Otherwise (slice_type equals 0 (B) or 1 (P)), the following applies:

[0250] MinQtLog2SizeY = MinCbLog2SizeY + ph_log2_diff_min_qt_min_cb_inter_slice(129)

[0251] MinQtLog2SizeC = MinCbLog2SizeY + ph_log2_diff_min_qt_min_cb_inter_slice(130)

[0252] MaxBtSizeY = 1 << (MinQtLog2SizeY + ph_log2_diff_max_bt_min_qt_inter_slice) (131)

[0253] MaxBtSizeC = 1 << (MinQtLog2SizeC + ph_log2_diff_max_bt_min_qt_inter_slice) (132)

[0254] MaxTtSizeY = 1 << (MinQtLog2SizeY + ph_log2_diff_max_tt_min_qt_inter_slice) (133)

[0255] MaxTtSizeC = 1 << (MinQtLog2SizeC + ph_log2_diff_max_tt_min_qt_inter_slice) (134)

[0256] MaxMttDepthY = ph_max_mtt_hierarchy_depth_inter_slice (135)

[0257] MaxMttDepthC = ph_max_mtt_hierarchy_depth_inter_slice (136)

[0258] CuQpDeltaSubdiv = ph_cu_qp_delta_subdiv_inter_slice (137)

[0259] CuChromaQpOffsetSubdiv = ph_cu_chroma_qp_offset_subdiv_inter_slice (138)

[0261] - The following applies:

[0262] MinQtSizeY = 1 << MinQtLog2SizeY (139)

[0263] MinQtSizeC = 1 << MinQtLog2SizeC (140)

[0264] MinBtSizeY = 1 << MinCbLog2SizeY (141)

[0265] MinTtSizeY=1< <MinCbLog2SizeY (142)

[0266] slice_alf_enabled_flag equal to 1 specifies that the adaptive loop filter is enabled and may be applied to the Y, Cb, or Cr color components in the slice. slice_alf_enabled_flag equal to 0 specifies 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.

[0267] slice_num_alf_aps_ids_luma specifies the number of ALF APS 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.

[0268] slice_alf_aps_id_luma[i] specifies the adaptation_parameter_set_id of the i-th ALF APS referenced by the luma component 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_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].

[0269] 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].

[0270] slice_alf_chroma_idc equal to 0 specifies 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.

[0271] slice_alf_aps_id_chroma specifies 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.

[0272] 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.

[0273] slice_cc_alf_cb_enabled_flag equal to 0 specifies 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.

[0274] slice_cc_alf_cb_aps_id specifies the adaptation_parameter_set_id of the Cb color component reference of the slice.

[0275] The TemporalId of APS NAL units 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.

[0276] 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.

[0277] slice_cc_alf_cr_enabled_flag equal to 0 specifies 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.

[0278] slice_cc_alf_cr_aps_id specifies the adaptation_parameter_set_id of the Cr color component reference 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_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.

[0279] 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.

[0280] When separate_colour_plane_flag is equal to 1, colour_plane_id identifies the colour plane associated with the current slice. The value of colour_plane_id shall be in the range of 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.

[0281] NOTE 1 – There is no dependency between the decoding processes of different colour planes of a picture.

[0282] num_ref_idx_active_override_flag equal to 1 specifies that the syntax element num_ref_idx_active_minus1[0] is present for P slices and B slices, and the syntax element num_ref_idx_active_minus1[1] is present for B slices. num_ref_idx_active_override_flag equal to 0 specifies that the syntax elements num_ref_idx_active_minus1[0] and num_ref_idx_active_minus1[1] are not present. When not present, the value of num_ref_idx_active_override_flag is inferred to be equal to 1.

[0283] num_ref_idx_active_minus1[i] is used to derive the variable NumRefIdxActive[i], as specified in equation 143. The value of num_ref_idx_active_minus1[i] shall be in the range of 0 to 14, inclusive.

[0284] For i equal to 0 or 1, num_ref_idx_active_override_flag is equal to 1, and num_ref_idx_active_minus1[i] is inferred to be equal to 0 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.

[0285] 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] is not present, num_ref_idx_active_minus1[0] is inferred to be equal to 0.

[0286] The variable NumRefIdxActive[i] is derived as follows:

[0287]

[0288] The value of NumRefIdxActive[i]-1 specifies the maximum reference index of reference picture list i that can be used for decoding the slice. When the value of NumRefIdxActive[i] is equal to 0, no reference index of reference picture list i can be used for decoding the slice.

[0289] When the current slice is a P slice, the value of NumRefIdxActive[0] should be greater than 0.

[0290] When the current slice is a B slice, both NumRefIdxActive[0] and NumRefIdxActive[1] should be greater than 0.

[0291] cabac_init_flag specifies the method used to determine the initialization table used during the initialization of context variables. When cabac_init_flag is not present, it is inferred to be equal to 0.

[0292] slice_collocated_from_l0_flag equal to 1 specifies that the collocated picture used for temporal motion vector prediction is derived from reference picture list 0. slice_collocated_from_l0_flag equal to 0 specifies that the collocated picture used for temporal motion vector prediction is derived from reference picture list 1.

[0293] 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:

[0294] - 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.

[0295] Otherwise (rpl_info_in_ph_flag is equal to 0 and slice_type is equal to P), the value of slice_collocated_from_l0_flag is inferred to be equal to 1.

[0296] slice_collocated_ref_idx specifies the reference index of the collocated picture used for temporal motion vector prediction.

[0297] When slice_type is equal to P or when 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 should be in the range of 0 to NumRefIdxActive[0]-1 (including 0 and NumRefIdxActive[0]-1).

[0298] 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.

[0299] When slice_collocated_ref_idx is not present, the following applies:

[0300] - 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.

[0301] Otherwise (rpl_info_in_ph_flag is equal to 0), the value of slice_collocated_ref_idx is inferred to be equal to 0.

[0302] A requirement for bitstream conformance is that the picture referenced by slice_collocated_ref_idx shall be the same for all slices of a coded picture.

[0303] The bitstream conformance requirement is that the values ​​of pic_width_in_luma_samples and pic_height_in_luma_samples of the reference picture referred to 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_10_flag? 0:1][slice_collocated_ref_idx] shall be equal to 0.

[0304] slice_qp_delta specifies the Qp to be used for codec blocks in the slice until it is modified by the value of CuQpDeltaVal in the codec unit layer. Y The initial value of .

[0305] When qp_delta_info_in_ph_flag is equal to 0, the Qp Y The initial value of the quantization parameter SliceQp Y is derived as follows:

[0306] SliceQp Y =26+init_qp_minus26+slice_qp_delta (144)

[0307] SliceQp Y The value of should be in the range of -QpBdOffset to +63 (including -QpBdOffset and +63).

[0308] When any of the following conditions is true:

[0309] - 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.

[0310] - 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.

[0311] The following applies:

[0312] - The value of NumRefIdxActive[0] shall be less than or equal to the value of NumWeightsL0.

[0313] - For each reference picture index RefPicList[0][i] (i is in the range of 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.

[0314] 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:

[0315] -The value of NumRefIdxActive[1] shall be less than or equal to the value of NumWeightsL1.

[0316] - For each reference picture index RefPicList[1][i] (i is in the range of 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.

[0317] slice_cb_qp_offset specifies the offset in determining Qp′ Cb The difference to be added to the value of pps_cb_qp_offset when quantizing the parameter value. The value of slice_cb_qp_offset shall be in the range of -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 of -12 to +12, inclusive.

[0318] slice_cr_qp_offset specifies the offset in determining Qp′ Cr The difference to be added to the value of pps_cr_qp_offset when quantizing the parameter value. 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.

[0319] slice_join_cbcr_qp_offset specifies the offset in 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.

[0320] cu_chroma_qp_offset_enabled_flag equal to 1 specifies 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 specifies that cu_chroma_qp_offset_flag is not present in transform unit or palette codec syntax. When not present, the value of cu_chroma_qp_offset_enabled_flag is inferred to be equal to 0.

[0321] slice_sao_luma_flag equal to 1 specifies that SAO is enabled for luma components in the current slice; slice_sao_luma_flag equal to 0 specifies that SAO is disabled for 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.

[0322] slice_sao_chroma_flag equal to 1 specifies that SAO is enabled for the chroma components in the current slice; slice_sao_chroma_flag equal to 0 specifies 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.

[0323] slice_deblocking_filter_override_flag equal to 1 specifies that the deblocking parameters are present in the slice header. slice_deblocking_filter_override_flag equal to 0 specifies 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.

[0324] slice_deblocking_filter_disabled_flag equal to 1 specifies that the operation of the deblocking filter is not applied to the current slice. slice_deblocking_filter_disabled_flag equal to 0 specifies 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.

[0325] slice_beta_offset_div2 and slice_tc_offset_div2 specify the deblocking parameter offsets (divided by 2) of beta and tc 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 of -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.

[0326] slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 specify the deblocking parameter offsets (divided by 2) for beta and tc 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.

[0327] slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 specify the deblocking parameter offsets (divided by 2) applied to the β and tC of 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 of -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.

[0328] slice_ts_residual_coding_disabled_flag equal to 1 specifies that the residual_coding() syntax structure is used to parse the residual samples of the transform skip blocks of the current slice. slice_ts_residual_coding_disabled_flag equal to 0 specifies that the residual_ts_coding() syntax structure is used to parse the residual samples of the transform skip blocks of the current slice. When slice_ts_residual_coding_disabled_flag is not present, it is inferred to be equal to 0.

[0329] slice_lmcs_enabled_flag equal to 1 specifies that luma mapping and chroma scaling are enabled for the current slice. slice_lmcs_enabled_flag equal to 0 specifies 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.

[0330] slice_scaling_list_present_flag equal to 1 specifies 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 specifies that the scaling list data for the current picture is the default scaling list data derived as 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.

[0331] The variable NumEntryPoints, which specifies the number of entry points in the current strip, is derived as follows:

[0332]

[0333]

[0334] offset_len_minus1 plus 1 specifies the length of the entry_point_offset_minus1[i] syntax element in bits. The value of offset_len_minus1 shall be in the range of 0 to 31, inclusive.

[0335] entry_point_offset_minus1[i] plus 1 specifies the i-th entry point offset in bytes and is represented by offset_len_minus1 plus 1 bit. The slice data following the slice header consists of NumEntryPoints+1 subsets, where the subset index value ranges from 0 to NumEntryPoints (including 0 and NumEntryPoints). The first byte of the slice data is treated as byte 0. When present, the contention prevention byte present in the slice data portion of a coded slice NAL unit is counted as part of the slice data for subset identification purposes. Subset 0 consists of bytes 0 to entry_point_offset_minus1[0] (including 0 and entry_point_offset_minus1[0]) of the codec stripe data, and subset k (k is in the range of 1 to NumEntryPoints-1 (including 1 and NumEntryPoints-1)) consists of bytes firstByte[k] to lastByte[k] (including firstByte[k] and lastByte[k]) of the codec stripe data, where firstByte[k] and lastByte[k] are defined as:

[0336]

[0337] lastByte[k]=firstByte[k]+entry_point_offset_minus1[k] (147)

[0338] The last subset (with subset index equal to NumEntryPoints) consists of the remaining bytes of the encoded and decoded stripe data.

[0339] 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 same slice in the slice, and the number of subsets (ie, the value of NumEntryPoints+1) shall be equal to the number of slices in the slice.

[0340] 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.

[0341] When sps_entropy_coding_sync_enabled_flag is equal to 1, each subset k (k is in the range of 0 to NumEntryPoints, inclusive) shall consist of all codec bits of all CTUs in the CTU rows in the slice, and the number of subsets (i.e., the value of NumEntryPoints+1) shall be equal to the total number of slice-specific CTU rows in the slice.

[0342] slice_header_extension_length specifies 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. When not present, the value of slice_header_extension_length is inferred to be equal to 0.

[0343] slice_header_extension_data_byte[i] can have any value. A decoder 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 profile specified in this version of the specification for decoders conforming to the specification.

[0344] 3.3. Weighted Prediction Syntax and Semantics

[0345] In the latest VVC draft text, the weighted prediction syntax and semantics are as follows:

[0346]

[0347]

[0348] luma_log2_weight_denom is the base-2 logarithm of the denominator of all luma weighting factors. The value of luma_log2_weight_denom should be in the range of 0 to 7, inclusive.

[0349] delta_chroma_log2_weight_denom is the difference in base 2 logarithms of the denominators of all chroma weighting factors. When delta_chroma_log2_weight_denom is not present, it is inferred to be equal to 0.

[0350] The variable ChromaLog2WeightDenom is derived to be equal to luma_log2_weight_denom + delta_chroma_log2_weight_denom and this value should be in the range of 0 to 7 (inclusive).

[0351] num_l0_weights specifies the number of weights signaled for the entries in reference picture list 0 when wp_info_in_ph_flag is equal to 1. The value of num_l0_weights shall be in the range of 0 to num_ref_entries[0][RplsIdx[0]], inclusive.

[0352] If wp_info_in_ph_flag is equal to 1, the variable NumWeightsL0 is set equal to num_l0_weights. Otherwise (wp_info_in_ph_flag is equal to 0), NumWeightsL0 is set equal to NumRefIdxActive[0].

[0353] luma_weight_l0_flag[i] equal to 1 specifies that weighting factors for luma components predicted using list 0 of RefPicList[0][i] are present. luma_weight_l0_flag[i] equal to 0 specifies that these weighting factors are not present.

[0354] chroma_weight_l0_flag[i] equal to 1 specifies that weighting factors for chroma prediction values ​​using list 0 prediction of RefPicList[0][i] are present. chroma_weight_l0_flag[i] equal to 0 specifies that these weighting factors are not present. When chroma_weight_l0_flag[i] is not present, it is inferred to be equal to 0.

[0355] delta_luma_weight_l0[i] is the difference in weighting factors applied to the luma prediction values ​​of list 0 prediction using RefPicList[0][i].

[0356] LumaWeightL0[i] is derived to be equal to (1 << luma_log2_weight_denom) + delta_luma_weight_l0[i]. When luma_weight_l0_flag[i] is equal to 1, the value of delta_luma_weight_l0[i] shall be in the range of -128 to 127 (including -128 and 127). When luma_weight_l0_flag[i] is equal to 0, LumaWeightL0[i] is inferred to be equal to 2 luma_log2_weight_denom 。

[0357] luma_offset_l0[i] is the added offset applied to the luma prediction value predicted using RefPicList[0][i] in list 0. The value of luma_offset_l0[i] shall be in the range of -128 to 127 (including -128 and 127). When luma_weight_l0_flag[i] is equal to 0, luma_offset_l0[i] is inferred to be equal to 0.

[0358] delta_chroma_weight_l0[i][j] is the difference of the weighting factors applied to the chroma prediction values predicted using RefPicList[0][i] in list 0, where j is equal to 0 for Cb and j is equal to 1 for Cr.

[0359] The variable ChromaWeightL0[i][j] is derived to be equal to (1 << ChromaLog2WeightDenom) + delta_chroma_weight_l0[i][j]. When chroma_weight_l0_flag[i] is equal to 1, the value of delta_chroma_weight_l0[i][j] shall be in the range of -128 to 127 (including -128 and 127). When chroma_weight_l0_flag[i] is equal to 0, ChromaWeightL0[i][j] is inferred to be equal to 2 ChromaLog2WeightDenom 。

[0360] delta_chroma_offset_l0[i][j] is the difference of the added offsets applied to the chroma prediction values predicted using RefPicList[0][i] in list 0, where j is equal to 0 for Cb and j is equal to 1 for Cr.

[0361] The variable ChromaOffsetL0[i][j] is derived as follows:

[0362]

[0363] The value of delta_chroma_offset_l0[i][j] shall be in the range of -4*128 to 4*127 (inclusive). When chroma_weight_l0_flag[i] is equal to 0, ChromaOffsetL0[i][j] is inferred to be equal to 0.

[0364] num_l1_weights specifies the number of weights signaled for the entries in reference picture list 1 when wp_info_in_ph_flag is equal to 1. The value of num_l1_weights shall be in the range of 0 to num_ref_entries[1][RplsIdx[1]], inclusive.

[0365] If wp_info_in_ph_flag is equal to 1, the variable NumWeightsL1 is set equal to num_l1_weights. Otherwise (wp_info_in_ph_flag is equal to 0), NumWeightsL1 is set equal to NumRefIdxActive[1].

[0366] luma_weight_l1_flag[i], chroma_weight_l1_flag[i], delta_luma_weight_l1[i], luma_offset_l1[i], delta_chroma_weight_l1[i][j], and delta_chroma_offset_l1[i][j] have the same semantics as luma_weight_l0_flag[i], chroma_weight_l0_flag[i], delta_luma_weight_l0[i], luma_offset_l0[i], delta_chroma_weight_l0[i][j], and delta_chroma_offset_l0[i][j], respectively, with l0, L0, List0, and List0 replaced by l1, L1, List1, and List1, respectively.

[0367] The variable sumWeightL0Flags is derived to be equal to the sum of luma_weight_l0_flag[i]+2*chroma_weight_l0_flag[i], where i=0..NumRefIdxActive[0]-1.

[0368] When slice_type is equal to B, the variable sumWeightL1Flags is derived to be equal to the sum of luma_weight_l1_flag[i]+2*chroma_weight_l1_flag[i], where i=0..NumRefIdxActive[1]-1.

[0369] The bitstream conformance requirement is that when slice_type is equal to P, sumWeightL0Flags shall be less than or equal to 24, and when slice_type is equal to B, the sum of sumWeightL0Flags and sumWeightL1Flags shall be less than or equal to 24.

[0370] 4. Examples of technical problems solved by the disclosed technical solutions

[0371] The existing designs of PPS, PH and SH grammars have the following problems:

[0372] 1) In the pred_weight_table() syntax in the latest VVC draft text, the syntax element num_l1_weights is signaled when wp_info_in_ph_flag is equal to 1, even when pps_weighted_pred_flag is equal to 1 but pps_weighted_bipred_flag is equal to 0. Therefore, under the same conditions, the list of syntax elements uma_weight_l1_flag[i] is also signaled, and the lists of syntax elements luma_weight_l1_flag[i], chroma_weight_l1_flag[i], delta_luma_weight_l1[i], luma_offset_l1[i], delta_chroma_weight_l1[i][j] and delta_chroma_offset_l1[i][j] may also be signaled. However, when pps_weighted_bipred_flag is equal to 0, weighted prediction is not applied to B slices, so all these signaled syntax elements are useless.

[0373] 2) When wp_info_in_ph_flag is equal to 1 (in this case, at least one of pps_weighted_pred_flag and pps_weighted_bipred_flag is equal to 1), the pred_weight_table() syntax structure is present in the PH syntax structure of the picture that references the PPS. In this case, when pps_weighted_pred_flag is equal to 0 (in this case, pps_weighted_bipred_flag is equal to 1), although the list of luma_weight_l0_flag[i] syntax elements is signaled in the PH syntax structure, weighted prediction is not applied for P slices, so the value of the list of luma_weight_l0_flag[i] syntax elements for P slices should be inferred to be equal to 0. Similarly, when pps_weighted_bipred_flag is equal to 0 (in this case, pps_weighted_pred_flag is equal to 1), since weighted prediction is not applied to B slices, the list of luma_weight_l0_flag[i] syntax elements and the list of luma_weight_l1_flag[i] syntax elements for B slices should be inferred to be equal to 0.

[0374] 3) When wp_info_in_ph_flag is equal to 1 (in this case, at least one of pps_weighted_pred_flag and pps_weighted_bipred_flag is equal to 1), the pred_weight_table() syntax structure is present in the PH syntax structure of the picture that references the PPS. In this case, if the picture does not have a B slice and pps_weighted_bipred_flag is equal to 1, all syntax elements in the pred_weight_table() syntax structure of the reference picture list 1 will be useless.

[0375] 5. Examples of Techniques and Embodiments

[0376] In order to solve the above problems, the following summarized methods are disclosed. The present invention should be considered as an example to explain the general concept and should not be interpreted in a narrow way. In addition, these inventions can be applied alone or combined in any way. In the following techniques and embodiments, the most relevant parts that have been added or modified are as follows: are shown, and the most relevant removals are highlighted in bold double brackets, e.g. Indicates that "a" has been removed.

[0377] 1. Signaling notification of weighted prediction related syntax elements:

[0378] 1) To address the first issue, whether to signal the number of weights of entries in reference picture list 1 and / or the luma / chroma weights of entries in reference picture list 1 may depend on the enabling of explicit weighted prediction for B slices.

[0379] a. In one example, in the pred_weight_table() syntax, the following syntax:

[0380]

[0381] is changed as follows:

[0382]

[0383] And the following semantics:

[0384] Specifies the number of weights signaled for entries in reference picture list 1 when wp_info_in_ph_flag is equal to 1. The value of num_l1_weights shall be in the range of 0 to num_ref_entries[1][RplsIdx[1]], inclusive.

[0385] If wp_info_in_ph_flag is equal to 1, the variable NumWeightsL1 is set equal to num_l1_weights. Otherwise (wp_info_in_ph_flag is equal to 0), NumWeightsL1 is set equal to NumRefIdxActive[1].

[0386] is changed as follows:

[0387] Specify The number of weights signaled for the entries in reference picture list 1. The value of num_l1_weights shall be in the range of 0 to num_ref_entries[1][RplsIdx[1]], inclusive.

[0388]

[0389] 2) To solve the second problem, in the slice header semantics, add the following inferences for luma_weight_l0_flag[i], chroma_weight_l0_flag[i], luma_weight_l1_flag[i], and chroma_weight_l1_flag[i]:

[0390] a. When pps_weighted_pred_flag is equal to 0 and slice_type is equal to P, for each value of i in the range of 0 to NumRefIdxActive[0]-1 (including 0 and NumRefIdxActive[0]-1), the value of luma_weight_l0_flag[i] is inferred to be equal to 0, and the value of chroma_weight_l0_flag[i] is inferred to be equal to 0.

[0391] b. When pps_weighted_bipred_flag is equal to 0 and slice_type is equal to B, for each value of i in the range of 0 to NumRefIdxActive[0]-1 (including 0 and NumRefIdxActive[0]-1), the value of luma_weight_l0_flag[i] is inferred to be equal to 0, and the value of chroma_weight_l0_flag[i] is inferred to be equal to 0.

[0392] c. Additionally, alternatively, when pps_weighted_bipred_flag is equal to 0 and slice_type is equal to B, for each value of i in the range of 0 to NumRefIdxActive[1]-1 (including 0 and NumRefIdxActive[1]-1), the value of luma_weight_l1_flag[i] is inferred to be equal to 0, and the value of chroma_weight_10_flag[i] is inferred to be equal to 0.

[0393] 3) To solve the third problem, the following alternative approach can be applied:

[0394] a. Bullet 2.1 above applies, and for pictures without B slices, the encoder forces them to reference a PPS with pps_weighted_bipred_flag equal to 0. The latter part can be achieved by adding the following constraint: Pictures containing no B slices shall only reference a PPS with pps_weighted_bipred_flag equal to 0.

[0395] b. For pictures without B slices, the encoder forces them to reference a PPS with wp_info_in_ph_flag equal to 0. This can be achieved by adding the following constraint: Pictures containing no B slices shall only reference a PPS with wp_info_in_ph_flag equal to 0.

[0396] c. For pictures without B slices, the encoder forces the value of the syntax element num_l1_weights in the pred_weight_table() syntax structure to be equal to 0. This can be achieved by adding the following constraint as part of the semantics of num_l1_weights: When wp_info_in_ph_flag is equal to 1 and the current picture does not contain B slices, the value of num_l1_weights shall be equal to 0.

[0397] 4) A flag may be used to signal in the SPS that explicit weighted prediction is enabled.

[0398] a. Furthermore, alternatively, this one flag SPS indication may be used to be conditional on the signaling of an indication of explicit weighted prediction for P and B slices in the SPS (ie, sps_weighted_pred_flag and sps_weighted_bipred_flag).

[0399] b. Alternatively, one or more constraint flags may be added to the generic constraint information syntax to indicate constraints on explicit weighted prediction.

[0400] i. In one example, a constraint flag (e.g., named no_explicit_weighted_prediction_constraint_flag) is added, and when the constraint flag indicates that explicit weighted prediction for P slices and B slices (or only for P slices or only for B slices) is not applied, the corresponding SPS flag(s) should be equal to 0.

[0401] 5) A flag may be used to signal in the PPS that explicit weighted prediction is enabled.

[0402] a. Furthermore, alternatively, this one flag PPS indication may be used to be conditional on the signaling of an indication of explicit weighted prediction for P and B slices in the PPS (ie, pps_weighted_pred_flag and pps_weighted_bipred_flag).

[0403] b. Alternatively, one or more constraint flags may be added to the generic constraint information syntax to indicate constraints on explicit weighted prediction.

[0404] i. In one example, a constraint flag (e.g., named no_explicit_weighted_prediction_constraint_flag) is added, and when the constraint flag indicates that explicit weighted prediction for P slices and B slices (or only for P slices or only for B slices) is not applied, the corresponding PPS flag(s) should be equal to 0.

[0405] 6) The indication of explicit weighted prediction applied to P slices or B slices may be signaled in the picture header or slice header instead of being signaled in the SPS and PPS.

[0406] a. In one example, whether such an indication is signaled in a picture header or a slice header may follow where the RPL exists, ie, may depend on whether the RPL information exists in a PH syntax structure or a SH syntax structure (eg, according to the value of rpl_info_in_ph_flag).

[0407] b. Furthermore, alternatively, whether such an indication is signaled may depend on the slice type.

[0408] c. Furthermore, alternatively, whether such an indication is signaled may depend on whether the current picture may include an inter slice or a P slice or a B slice.

[0409] 2. Indication of whether a picture does not contain a B slice and signaling of using the indication to skip some syntax elements:

[0410] 1) An indication of whether the current picture does not contain a B slice may be added to the PH syntax structure.

[0411] a. In one example, the indication is a flag, for example, named ph_b_slices_allowed_flag, ph_b_slices_allowed_flag equal to 1 specifies that the picture may contain one or more B slices, and ph_b_slices_allowed_flag equal to 0 specifies that the picture does not contain B slices.

[0412] i. Furthermore, alternatively, ph_b_slices_allowed_flag may be signaled in the PH syntax structure only when ph_inter_slice_allowed_flag is equal to 1.

[0413] ii. Furthermore, alternatively, when ph_inter_slice_allowed_flag is equal to 0, the value of ph_b_slices_allowed_flag may be inferred to be equal to 0.

[0414] b. In one example, when ph_b_slices_allowed_flag is equal to 0, the syntax elements of reference picture list 1 in the ref_pic_lists() syntax and the ref_pic_list_struct() syntax may be skipped.

[0415] c. In one example, when ph_b_slices_allowed_flag is equal to 0, the syntax element mvd_l1_zero_flag in the PH syntax structure may be skipped.

[0416] i. Furthermore, alternatively, when ph_b_slices_allowed_flag is equal to 0, the value of mvd_l1_zero_flag may be inferred to be equal to 1.

[0417] d. In one example, when ph_b_slices_allowed_flag is equal to 0, the syntax element num_l1_weights and other parameters in the pred_weight_table() syntax for reference picture list 1 may be skipped.

[0418] i. Furthermore, alternatively, when ph_b_slices_allowed_flag is equal to 0, the value of num_l1_weights may be inferred to be equal to 0.

[0419] e. In one example, when ph_b_slices_allowed_flag is equal to 0, the syntax element num_ref_idx_active_minus1[1] in the SH syntax may be skipped.

[0420] i. Additionally, alternatively, when ph_b_slices_allowed_flag is equal to 0, the value of NumRefIdxActive[1] may be inferred to be equal to 0.

[0421] f. In one example, when ph_b_slices_allowed_flag is equal to 0, the syntax element slice_collocated_from_l0_flag in the SH syntax may be skipped.

[0422] i. Furthermore, alternatively, when ph_b_slices_allowed_flag is equal to 0, the value of slice_collocated_from_l0_flag may be inferred to be equal to 1.

[0423] 6. Examples

[0424]

[0425] 6.1. First embodiment

[0426] This is an embodiment of items 1.1, 1.1.a, 1.2.a and 1.2.b summarized in Section 5 above.

[0427] 7.3.7.2 Weighted Prediction Parameter Syntax

[0428]

[0429]

[0430] 7.4.8.2 Weighted Prediction Parameter Semantics

[0431] It is the base 2 logarithm of the denominator of all luma weighting factors. The value of luma_log2_weight_denom should be in the range of 0 to 7 (inclusive).

[0432] It is the difference of the base 2 logarithms of the denominators of all chroma weighting factors. When delta_chroma_log2_weight_denom is not present, it is inferred to be equal to 0.

[0433] The variable ChromaLog2WeightDenom is derived to be equal to luma_log2_weight_denom + delta_chroma_log2_weight_denom and this value should be in the range of 0 to 7 (inclusive).

[0434] Specifies the number of weights signaled for entries in reference picture list 0 when wp_info_in_ph_flag is equal to 1. The value of num_l0_weights shall be in the range of 0 to num_ref_entries[0][RplsIdx[0]], inclusive.

[0435] If wp_info_in_ph_flag is equal to 1, the variable NumWeightsL0 is set equal to num_l0_weights. Otherwise (wp_info_in_ph_flag is equal to 0), NumWeightsL0 is set equal to NumRefIdxActive[0].

[0436] equal to 1 specifies that weighting factors for luma components predicted using list 0 of RefPicList[0][i] are present. luma_weight_l0_flag[i] equal to 0 specifies that these weighting factors are not present.

[0437] equal to 1 specifies the presence of weighting factors for the chroma prediction values ​​using list 0 prediction of RefPicList[0][i]. chroma_weight_l0_flag[i] equal to 0 specifies the absence of these weighting factors. When chroma_weight_l0_flag[i] is not present, it is inferred to be equal to 0.

[0438] is the difference in weighting factors applied to the luma prediction value of List 0 prediction using RefPicList[0][i]. ...

[0439] Specify when wp_info_in_ph_flag When equal to 1, the number of weights to signal for the entries in reference picture list 1. The value of num_l1_weights shall be in the range of 0 to num_ref_entries[1][RplsIdx[1]], inclusive.

[0440] [[If wp_info_in_ph_flag is equal to 1, then the variable NumWeightsL1 is set equal to num_l1_weights. Otherwise (wp_info_in_ph_flag is equal to 0), NumWeightsL1 is set equal to NumRefIdxActive[1]. ]]

[0441]

[0442] ...

[0443] 7.4.8.1 Generic Strip Header Semantics ...

[0444] Specifies the Qp to be used for codec blocks in the slice until modified by the value of CuQpDeltaVal in the codec unit layer. Y The initial value of .

[0445] When qp_delta_info_in_ph_flag is equal to 0, the Qp Y The initial value of the quantization parameter SliceQp Y is derived as follows:

[0446] SliceQp Y =26+init_qp_minus26+slice_qp_delta (144)

[0447] SliceQp Y The value of should be in the range of -QpBdOffset to +63 (including -QpBdOffset and +63).

[0448] When any of the following conditions is true:

[0449] - 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.

[0450] - 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.

[0451] The following applies:

[0452] - The value of NumRefIdxActive[0] shall be less than or equal to the value of NumWeightsL0.

[0453] - For each reference picture index RefPicList[0][i] (i is in the range of 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.

[0454] 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:

[0455] -The value of NumRefIdxActive[1] shall be less than or equal to the value of NumWeightsL1.

[0456] - For each reference picture index RefPicList[1][i] (i is in the range of 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.

[0457]

[0458] ...[keep the remaining text from the standard document]

[0459] Figure 1 1 is a block diagram illustrating an example video processing system 1000 in which various techniques disclosed herein may be implemented. Various implementations may include some or all of the components of system 1000. System 1000 may include an input 1002 for receiving video content. The video content may be received in a raw or uncompressed format, such as 8 or 10 bit multi-component pixel values, or may be in a compressed or encoded format. Input 1002 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.

[0460] System 1000 may include a codec component 1004 that can implement various codecs or encoding methods described in this document. Codec component 1004 can reduce the average bit rate of the video from input 1002 to the output of codec component 1004 to generate a codec representation of the video. Codec technology is therefore sometimes referred to as video compression or video transcoding technology. The output of codec component 1004 can be stored or sent via a communication connection such as represented by component 1006. The bitstream (or codec) representation of the storage or communication transmission of the video received at input 1002 can be used by component 1008 to generate pixel values ​​or transmit to a displayable video of display interface 1010. The process of generating user-visible video from the 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 will be understood that the codec tool or operation is used at the encoder, and the corresponding decoding tool or operation of the inverse codec result will be performed by the decoder.

[0461] Examples of peripheral bus interfaces or display interfaces may include Universal Serial Bus (USB), High Definition Multimedia Interface (HDMI), or DisplayPort, etc. Examples of storage interfaces include SATA (Serial Advanced Technology Attachment), PCI, IDE interfaces, etc. The technology described in this document may be embodied in various electronic devices, such as mobile phones, laptops, smart phones, or other devices capable of performing digital data processing and / or video display.

[0462] Figure 2 2000 is a block diagram of a video processing apparatus 2000. The apparatus 2000 may be used to implement one or more methods described herein. The apparatus 2000 may be embodied in a smartphone, a tablet computer, a computer, an Internet of Things (IoT) receiver, etc. The apparatus 2000 may include one or more processors 2002, one or more memories 2004, and video processing hardware 2006. The processor(s) 2002 may be configured to implement the methods described herein (e.g., Figure 6-Figure 10 2004 can be used to store data and code for implementing the methods and techniques described herein. Video processing hardware 2006 can be used to implement some of the techniques described in this document in hardware circuitry. In some embodiments, hardware 2006 can be partially or entirely in processor 2002 (e.g., a graphics processor).

[0463] Figure 3 is a block diagram illustrating an example video encoding and decoding system 100 that may utilize the techniques of the present disclosure. Figure 3 As shown, the video codec system 100 may include a source device 110 and a target device 120. The source device 110 generates encoded video data, wherein 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, wherein the target device 120 may be referred to as a video decoding device. The source device 110 may include a video source 112, a video encoder 114, and an input / output (I / O) interface 116.

[0464] The video source 112 may include a source, such as 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 related data. The codec picture is a codec representation of the picture. Related 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 coded video data may be directly sent to the target device 120 via the network 130a via the I / O interface 116. The coded video data may also be stored on a storage medium / server 130b for access by the target device 120.

[0465] Target device 120 may include an I / O interface 126 , a video decoder 124 , and a display device 122 .

[0466] The I / O interface 126 may include a receiver and / or a modem. The I / O interface 126 may obtain coded video data from the source device 110 or the storage medium / server 130b. The video decoder 124 may decode the coded 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 outside the target device 120 configured to interface with an external display device.

[0467] The video encoder 114 and the video decoder 124 may operate in accordance with a video compression standard, such as the High Efficiency Video Codec (HEVC) standard, the Versatile Video Codec (VVM) standard, and other current and / or additional standards.

[0468] Figure 4 is a block diagram showing an example of a video encoder 200, which may be Figure 3 The video encoder 114 in the system 100 is shown.

[0469] Video encoder 200 may be configured to perform any or all of the techniques of this disclosure. Figure 4 In the example of , video encoder 200 includes multiple functional components. The techniques described in this disclosure can be shared between various components of video encoder 200. In some examples, a processor can be configured to perform any or all of the techniques described in this disclosure.

[0470] 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 unit 214.

[0471] In other examples, the video encoder 200 may include more, fewer, or different functional components. In an example, the prediction unit 202 may include an intra block copy (IBC) unit. The IBC unit may perform prediction in IBC mode, where at least one reference picture is a picture in which the current video block is located.

[0472] Furthermore, some components such as the motion estimation unit 204 and the motion compensation unit 205 may be highly integrated, but for the purpose of explanation, they are described in detail in the following sections. Figure 4 In the example, they are shown separately.

[0473] 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.

[0474] The mode selection unit 203 may select one of the coding modes (e.g., intra or inter) based on the error result, and provide the resulting intra-coded block or inter-coded block to the residual generation unit 207 to generate residual block data, and to the reconstruction unit 212 to reconstruct the coded block for use as a reference picture. In some examples, the mode selection unit 203 may select a combination of intra and inter prediction modes (CIIP), 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 the motion vector of the block (e.g., sub-pixel or integer pixel precision).

[0475] 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 and decoded samples of pictures from the buffer 213 other than the picture associated with the current video block.

[0476] 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.

[0477] 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 list 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 in list 0 or list 1, the reference index including the reference video block and a motion vector indicating a 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.

[0478] In other examples, the motion estimation unit 204 may perform bidirectional prediction on the current video block, and the motion estimation unit 204 may search for a reference video block of the current video block in the reference pictures in list 0, and may also search for another reference video block of the current video block in list 1. The motion estimation unit 204 may then generate a reference index indicating the reference pictures in list 0 and list 1 containing the reference video block and a motion vector indicating a spatial displacement between the reference video block and the current video block. The motion estimation unit 204 may output the reference index and the motion vector of the current video block as the 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.

[0479] In some examples, motion estimation unit 204 may output a complete set of motion information for use in a decoding process of a decoder.

[0480] 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 signal the motion information of the current video block with reference to the motion information of another 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.

[0481] In one example, motion estimation unit 204 may indicate a value in a syntax structure associated with the current video block that indicates to video decoder 300 that the current video block has the same motion information as another video block.

[0482] In another example, the 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 indicates the difference between the motion vector of the current video block and the motion vector of the indicated video block. The 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.

[0483] As discussed 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.

[0484] 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.

[0485] The residual generation unit 207 can generate residual data for the current video block by subtracting (e.g., indicated by a minus sign) the predicted video block(s) 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 the samples in the current video block.

[0486] In other examples, 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.

[0487] Transform processing unit 208 may generate one or more transform coefficient video blocks for a current video block by applying one or more transforms to a residual video block associated with the current video block.

[0488] 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.

[0489] 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 the residual video block from the transform coefficient video block. The reconstruction unit 212 may add the reconstructed residual video block to the 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 for storage in the buffer 213.

[0490] After the reconstruction unit 212 reconstructs the video block, a loop filtering operation may be performed to reduce video blocking artifacts in the video block.

[0491] 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.

[0492] Figure 5 is a block diagram showing an example of a video decoder 300, which may be Figure 3 The video decoder 114 in the system 100 is shown.

[0493] Video decoder 300 may be configured to perform any or all of the techniques of this disclosure. Figure 5 In the example of , video decoder 300 includes multiple functional components. The techniques described in this disclosure can be shared between various components of video decoder 300. In some examples, a processor can be configured to perform any or all of the techniques described in this disclosure.

[0494] exist Figure 5 In the example of FIG. 3 , 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, a reconstruction unit 306, and a buffer 307. In some examples, the video decoder 300 can perform the same operations as those generally performed for the video encoder 200 ( Figure 4 ) is the reverse of the encoding process described in .

[0495] The entropy decoding unit 301 may retrieve a codec bitstream. The codec bitstream may include entropy-coded video data (e.g., coded blocks of video data). 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 indexes, and other motion information. The motion compensation unit 302 may determine such information, for example, by performing AMVP and Merge modes.

[0496] The motion compensation unit 302 may generate a motion compensated block, and interpolation may be performed based on an interpolation filter. An identifier of an interpolation filter to be used with sub-pixel precision may be included in a syntax element.

[0497] The motion compensation unit 302 may calculate interpolation of sub-integer pixels of the reference block using an interpolation filter as used by the video encoder 200 during encoding of the video block. The motion compensation unit 302 may determine the interpolation filter used by the video encoder 200 based on received syntax information and use the interpolation filter to generate a prediction block.

[0498] The motion compensation unit 302 may use some syntax information to determine the size of blocks used to encode (multiple) frames and / or (multiple) 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 each partition is encoded, one or more reference frames (and reference frame lists) for each inter-frame coded block, and other information used to decode the encoded video sequence.

[0499] The intra prediction unit 303 may form a prediction block from spatially adjacent 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.

[0500] 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 block artifacts. The decoded video block is then stored in a buffer 307 to provide a reference block for subsequent motion compensation / intra prediction and also to generate a decoded video for presentation on a display device.

[0501] Figures 6 to 10 It is shown that in e.g. Figures 1 to 5 An exemplary method for implementing the above technical solution in the embodiment shown in FIG.

[0502] Figure 6 A flowchart of an example method 600 of video processing is shown. The method 600 includes, at operation 610, performing conversion between a current slice of a current picture of a video and a bitstream of the video according to a rule, the rule stipulating that a value of a first syntax element of a picture parameter set (PPS) and a value of a second syntax element of the PPS control whether a third syntax element is included in the bitstream, the first syntax element indicating whether weighted prediction is enabled for a bidirectional slice (B slice) of a codec picture in a bitstream that references the PPS, the second syntax element indicating whether information related to weighted prediction is present in a picture header or a slice header of a codec picture that references the PPS, and the third syntax element indicating the number of weights associated with reference picture list 1 of the current slice.

[0503] Figure 7 A flowchart of an example method 700 of video processing is shown. The method 700 includes, at operation 710, performing conversion between a current slice of a current picture of a video and a bitstream of the video, the bitstream conforming to a format rule, wherein the format rule stipulates that values ​​of a plurality of syntax elements indicating whether prediction weights are included in a slice header of the current slice are inferred based on a slice type of the current slice and a value of a first flag included in a PPS referenced by the current picture.

[0504] Figure 8 A flow chart of an example method 800 of video processing is shown. The method 800 includes, at operation 810, performing conversion between a current slice of a current picture of a video and a bitstream of the video, the bitstream conforming to a format rule, wherein the format rule specifies the presence of a general constraint information syntax structure, the general constraint information syntax structure including one or more constraint flags indicating that constraints on explicit weighted prediction are enabled for slices of a set of pictures.

[0505] Fig. 9 A flow chart of an example method 900 for video processing is shown. The method 900 includes, at operation 910, performing conversion between a current slice of a current picture of a video and a bitstream of the video according to a rule that specifies that one or more constraint flags indicating that constraints on explicit weighted prediction are enabled for slices of a set of pictures are included in a parameter set or header associated with the current slice.

[0506] Fig.10 A flow chart of an example method 1000 of video processing is shown. The method 1000 includes, at operation 1010, performing conversion between a video including a current picture and a bitstream of the video, the bitstream conforming to a format rule, wherein the format rule specifies that an indication of whether the current picture does not include a bidirectional slice (B slice) is included in a picture header syntax structure associated with the current picture.

[0507] Next, a list of preferred solutions for some embodiments is provided.

[0508] A1. A video processing method, comprising: performing conversion between a current slice of a current picture of a video and a bitstream of the video according to a rule, wherein the rule stipulates that a value of a first syntax element of a picture parameter set (PPS) and a value of a second syntax element of the PPS control whether a third syntax element is included in the bitstream, and wherein the first syntax element indicates whether weighted prediction is enabled for a bidirectional slice (B slice) of a codec picture in a bitstream that references the PPS, the second syntax element indicates whether information related to weighted prediction is present in a picture header or a slice header of a codec picture that references the PPS, and the third syntax element indicates the number of weights associated with a reference picture list 1 of the current slice.

[0509] A2. The method of solution A1, wherein the first syntax element is pps_weighted_bipred_flag, the second syntax element is wp_info_in_ph_flag, and the third syntax element is num_l1_weights.

[0510] A3. The method according to solution A1 or A2, wherein the first syntax element equal to 0 indicates that weighted prediction is disabled for B slices of the coded picture of the reference PPS.

[0511] A4. The method according to solution A1 or A2, wherein the first syntax element equal to 1 indicates that weighted prediction is enabled for B slices of the coded picture of the reference PPS.

[0512] A5. A method according to solution A1 or A2, wherein when the fourth syntax element included in the sequence parameter set (SPS) is equal to 0, the first syntax element is equal to 0.

[0513] A6. The method of solution A5, wherein the fourth syntax element is sps_weighted_bipred_flag.

[0514] A7. A method according to solution A1 or A2, wherein the first syntax element equal to 0 indicates that the number of weights associated with reference picture list 1 is not included in the slice header of the current slice.

[0515] A8. The method of solution A1 or A2, wherein the first syntax element equal to 1 and the second syntax element equal to 1 indicate that the number of weights associated with reference picture list 1 is included in the slice header of the current slice.

[0516] A9. A method according to any one of solutions A1 to A8, wherein the conversion comprises decoding the video from a bitstream.

[0517] A10. A method according to any one of solutions A1 to A8, wherein the conversion includes encoding the video into a bitstream.

[0518] A11. A method for storing a bitstream representing a video to a computer-readable recording medium, comprising: generating a bitstream from a video according to the method described in any one or more of Solutions A1 to A8; and storing the bitstream in a computer-readable recording medium.

[0519] A12. A video processing device comprising a processor configured to implement the method according to any one or more of solutions A1 to A11.

[0520] A13. A computer-readable medium having instructions stored thereon, which when executed cause a processor to implement the method according to one or more of solutions A1 to A11.

[0521] A14. A computer-readable medium storing a bitstream, wherein the bitstream is generated according to any one or more of solutions A1 to A11.

[0522] A15. A video processing device storing a bitstream, wherein the video processing device is configured to implement the method according to any one or more of solutions A1 to A11.

[0523] Next, a list of alternative solutions preferred by some embodiments is provided.

[0524] B1. A video processing method, comprising: performing conversion between a current slice of a current picture of a video and a bitstream of the video, wherein the bitstream complies with a format rule, and wherein the format rule stipulates that values ​​of multiple syntax elements indicating whether prediction weights are included in a slice header of the current slice are inferred based on a slice type of the current slice and a value of a first flag included in a picture parameter set (PPS) referenced by the current picture.

[0525] B2. A method according to solution B1, wherein the multiple syntax elements include a first syntax element indicating the number of luma weights associated with reference picture list 0 of the current slice, a second syntax element indicating the number of chroma weights associated with reference picture list 0 of the current slice, a third syntax element indicating the number of luma weights associated with reference picture list 1 of the current slice, and a fourth syntax element indicating the number of chroma weights associated with reference picture list 1 of the current slice.

[0526] B3. The method of solution B2, wherein the first syntax element is luma_weight_l0_flag[i], the second syntax element is chroma_weight_l0_flag[i], the third syntax element is luma_weight_l1_flag[i], and the fourth syntax element is chroma_weight_l1_flag[i], and wherein i is a non-negative integer.

[0527] B4. A method according to solution B2 or B3, wherein the first flag indicates whether weighted prediction is enabled for a picture referring to a PPS, and wherein the first syntax element and the second syntax element are inferred to be 0 because the first flag is equal to 0 and the slice type is a uni-directional prediction slice (P slice).

[0528] B5. A method according to solution B4, wherein the first flag is pps_weighted_pred_flag.

[0529] B6. A method according to solution B2 or B3, wherein the first flag indicates whether weighted bidirectional prediction is enabled for a picture of a reference PPS, and wherein the first syntax element and the second syntax element are inferred to be 0 because the first flag is equal to 0 and the slice type is a bidirectional slice (B slice).

[0530] B7. A method according to solution B2 or B3, wherein the first flag indicates whether weighted bidirectional prediction is enabled for a picture of a reference PPS, and wherein since the first flag is equal to 0 and the slice type is a bidirectional slice (B slice), the third syntax element and the second syntax element are inferred to be 0.

[0531] B8. A method according to solution B6 or B7, wherein the first flag is pps_weighted_bipred_flag.

[0532] B9. A method according to any one of solutions B6 to B8, wherein, since the current picture does not include a B slice, the current picture refers to a PPS with a first flag equal to 0.

[0533] B10. A method according to any one of solutions B6 to B8, wherein, since the current picture does not include a B slice, the current picture refers to a PPS with a second flag equal to 0.

[0534] B11. A method according to any one of solutions B6 to B8, wherein, since the second flag is equal to 0 and the current picture does not include a B slice, the value of the syntax element indicating the number of weights associated with reference picture list 1 of the current slice is 0.

[0535] B12. The method according to solution B10 or B11, wherein the second flag indicates whether information related to weighted prediction exists in a picture header or a slice header of a picture referring to the PPS.

[0536] B13. A method according to any one of solutions B10 to B12, wherein the second flag is wp_info_in_ph_flag.

[0537] B14. A method according to any one of solutions B1 to B13, wherein the conversion comprises decoding the video from a bitstream.

[0538] B15. A method according to any one of solutions B1 to B13, wherein the conversion comprises encoding the video into a bitstream.

[0539] B16. A method for storing a bitstream representing a video to a computer-readable recording medium, comprising: generating a bitstream from a video according to the method described in any one or more of solutions B1 to B13; and storing the bitstream in a computer-readable recording medium.

[0540] B17. A video processing device comprising a processor configured to implement the method according to any one or more of solutions B1 to B16.

[0541] B18. A computer-readable medium having instructions stored thereon, which, when executed, cause a processor to implement the method according to one or more of solutions B1 to B16.

[0542] B19. A computer-readable medium storing a bitstream, wherein the bitstream is generated according to any one or more of solutions B1 to B16.

[0543] B20. A video processing device storing a bitstream, wherein the video processing device is configured to implement the method according to any one or more of solutions B1 to B16.

[0544] A further list of solutions preferred for some embodiments is provided next.

[0545] C1. A video processing method, comprising: performing conversion between a current slice of a current picture of a video and a bitstream of the video, wherein the bitstream conforms to a format rule, and wherein the format rule specifies the presence of a general constraint information syntax structure, the general constraint information syntax structure including one or more constraint flags indicating that constraints on explicit weighted prediction are enabled for slices of a picture set.

[0546] C2. A method according to solution C1, wherein one or more constraint flags are included in the bitstream.

[0547] C3. The method of solution C1, wherein one or more constraint flags are included in a parameter set associated with the current slice.

[0548] C4. A method according to solution C1, wherein one or more constraint flags are included in a decoder capability information network abstraction layer (NAL) unit.

[0549] C5. A method according to solution C1, wherein the one or more constraint flags include a first constraint flag indicating whether explicit weighted prediction is applied to one or both of a unidirectional prediction slice (P slice) and a bidirectional prediction slice (B slice) of a picture set, and wherein the value of the first constraint flag conforms to the value of a second flag included in a sequence parameter set (SPS) associated with the current slice.

[0550] C6. A method according to solution C5, wherein the first constraint flag is gci_no_explicit_weighted_prediction_constraint_flag.

[0551] C7. A method according to solution C5, wherein since the second flag is equal to 1, the first constraint flag is equal to 0.

[0552] C8. The method of solution C7, wherein the second flag is sps_weighted_pred_flag or sps_weighted_bipred_flag.

[0553] C9. A video processing method, comprising: performing conversion between a current slice of a current picture of a video and a bitstream of the video according to a rule, wherein the rule stipulates that one or more constraint flags indicating that constraints on explicit weighted prediction are enabled for slices of a picture set are included in a parameter set or header associated with the current slice.

[0554] C10. A method according to solution C9, wherein the one or more constraint flags consist of a first flag indicating whether an indication of explicit weighted prediction for a unidirectional prediction slice (P slice) or a bidirectional prediction slice (B slice) is included in a sequence parameter set (SPS) associated with the current slice.

[0555] C11. The method according to solution C10, wherein the first flag is sps_weighted_pred_flag or sps_weighted_bipred_flag.

[0556] C12. A method according to solution C9, wherein the one or more constraint flags consist of a first flag indicating whether an indication of explicit weighted prediction for a unidirectionally predicted slice (P slice) or a bidirectionally predicted slice (B slice) is included in a picture parameter set (PPS) associated with the current slice.

[0557] C13. The method of solution C12, wherein the first flag is pps_weighted_pred_flag or pps_weighted_bipred_flag.

[0558] C14. A method according to solution C9, wherein the one or more constraint flags include a first constraint flag indicating whether explicit weighted prediction is applied to one or both of a unidirectional prediction slice (P slice) and a bidirectional prediction slice (B slice), and wherein the value of the first constraint flag conforms to the value of a second constraint flag included in a picture parameter set (PPS) associated with the current slice.

[0559] C15. A method according to solution C9, wherein the one or more constraint flags consist of a first flag indicating whether an indication of explicit weighted prediction for a unidirectionally predicted slice (P slice) or a bidirectionally predicted slice (B slice) is included in a picture header or a slice header associated with the current slice.

[0560] C16. A method according to solution C15, wherein the indication is included in the picture header or the slice header because the information related to the reference picture list is included in the picture header syntax structure or the slice header syntax structure, respectively.

[0561] C17. The method of solution C15, wherein the indication is based on a slice type of a slice associated with the current video block.

[0562] C18. The method according to solution C15, wherein the indication is based on the current picture including an inter slice, a P slice or a B slice.

[0563] C19. A video processing method, comprising: performing conversion between a video including a current picture and a bitstream of the video, wherein the bitstream complies with a format rule, and wherein the format rule specifies that an indication of whether the current picture does not include a bidirectional slice (B slice) is included in a picture header syntax structure associated with the current picture.

[0564] C20. A method according to solution C19, wherein the indication equal to 1 specifies that the current picture includes one or more B slices.

[0565] C21. A method according to solution C19, wherein the indication equal to 0 specifies that the current picture does not include a B slice.

[0566] C22. A method according to solution C20 or C21, wherein the indication is ph_b_slices_allowed_flag.

[0567] C23. A method according to solution C19, wherein the indication equal to 0 specifies that syntax elements in the syntax structure related to reference picture list 1 are excluded from the bitstream.

[0568] C24. The method of solution C23, wherein the indication is ph_b_slices_allowed_flag, and wherein the syntax structure is ref_pic_lists() or ref_pic_list_struct().

[0569] C25. A method according to solution C19, wherein the indication equal to 0 specifies that syntax elements related to parsing syntax structures for motion vector difference codec tools are excluded from the picture header syntax structure.

[0570] C26. A method according to solution C19, wherein the indication equal to 0 specifies that the value of a syntax element related to parsing a syntax structure for a motion vector difference codec is inferred to be equal to 1.

[0571] C27. The method of solution C25 or C26, wherein the indication is ph_b_slices_allowed_flag, and wherein the syntax element is mvd_l1_zero_flag.

[0572] C28. A method according to solution C19, wherein the indication equal to 0 specifies that syntax elements related to weighted prediction of the current video block in the current picture are excluded from the bitstream.

[0573] C29. The method of solution C28, wherein the indication is ph_b_slices_allowed_flag, and wherein the syntax element is num_l1_weights.

[0574] C30. A method according to solution C19, wherein the indication equal to 0 specifies that syntax elements related to the maximum reference index of the reference picture list associated with the current picture are excluded from the slice header syntax structure.

[0575] C31. The method of solution C30, wherein the indication is ph_b_slices_allowed_flag, and wherein the syntax element is num_ref_idx_active_minus1.

[0576] C32. A method according to solution C19, wherein the indication equal to 0 specifies that syntax elements related to a co-located slice used for temporal motion vector prediction of a current video block in a current picture derived from reference picture list 0 associated with the current picture are excluded from the slice header syntax structure.

[0577] C33. The method of solution C32, wherein the indication is ph_b_slices_allowed_flag, and wherein the syntax element is slice_collocated_from_l0_flag.

[0578] C34. A method according to any one of solutions C1 to C33, wherein the conversion comprises decoding the video from a bitstream.

[0579] C35. A method according to any one of solutions C1 to C33, wherein the conversion includes encoding the video into a bitstream.

[0580] C36. A method for storing a bitstream representing a video to a computer-readable recording medium, comprising: generating a bitstream from a video according to the method described in any one or more of solutions C1 to C33; and storing the bitstream in a computer-readable recording medium.

[0581] C37. A video processing device comprising a processor configured to implement the method according to any one or more of solutions C1 to C36.

[0582] C38. A computer-readable medium having instructions stored thereon, which, when executed, cause a processor to implement a method according to one or more of solutions C1 to C36.

[0583] C39. A computer-readable medium storing a bitstream, wherein the bitstream is generated according to any one or more of solutions C1 to C36.

[0584] C40. A video processing device storing a bitstream, wherein the video processing device is configured to implement the method according to any one or more of solutions C1 to C36.

[0585] Next, a further solution list is provided which is preferred for some embodiments.

[0586] P1. A video processing method, comprising: performing conversion between a video region of a video and a codec representation of the video, wherein the codec representation complies with a format rule, wherein the format rule stipulates that the value of a first field indicating that weighted prediction is enabled for the video region controls a second field indicating the number of weights associated with a reference picture list associated with the conversion of the video region.

[0587] P2. A method according to solution P1, wherein, in case the first field indicates that weighted prediction is disabled, the format rules provide that the second field is excluded from the codec representation.

[0588] P3. A method according to solution P1 or P2, wherein the second field indicating the number of weights associated with the reference picture list indicates a luma weight.

[0589] P4. A method according to any one of solutions P1 to P3, wherein the second field indicating the number of weights associated with the reference picture list indicates a chroma weight.

[0590] P5. A method according to any one of solutions P1 to P4, wherein the reference picture list corresponds to reference picture list 1.

[0591] P6. A method according to any one of solutions P1 to P5, wherein the video area corresponds to a bidirectional slice (B slice).

[0592] P7. A method according to any one of solutions P1 to P5, wherein the video region corresponds to a uni-directional prediction slice (P slice).

[0593] P8. A video processing method, comprising: performing conversion between a video comprising one or more video pictures and a codec representation of the video, wherein the codec representation complies with a format rule, wherein the format rule specifies that a syntax element in a picture header of the video picture indicates whether the video picture includes a slice that is a bidirectional prediction slice or a bidirectional prediction (B slice).

[0594] P9. A method according to solution P8, wherein the syntax element is a single-bit flag.

[0595] P10. A method according to solution P8 or P9, wherein, when the first field indicates that the video picture includes 0 B slices, the format rule also excludes syntax elements related to the second reference picture list (reference picture list 1).

[0596] P11. A method according to solution P10, wherein the syntax elements related to the second reference picture list come from a picture header.

[0597] P12. A method according to solution P10, wherein the syntax elements include syntax elements related to weight parameters for using the second reference picture list.

[0598] P13. A method according to any of the preceding claims, wherein the video area comprises a video codec unit.

[0599] P14. A method according to any of the preceding claims, wherein the video area comprises a video picture.

[0600] P15. A method according to any one of solutions P1 to P14, wherein the conversion comprises encoding the video into a codec representation.

[0601] P16. A method according to any one of solutions P1 to P14, wherein the conversion comprises decoding the codec representation to generate pixel values ​​of the video.

[0602] P17. A video decoding device comprising a processor configured to implement the method according to one or more of solutions P1 to P16.

[0603] P18. A video encoding device comprising a processor configured to implement the method according to one or more of solutions P1 to P16.

[0604] P19. A computer program product having computer code stored thereon, which, when executed by a processor, causes the processor to implement a method according to any one of solutions P1 to P16.

[0605] P20. A method, device or system described in this document.

[0606] In this document, the term "video processing" may refer to video encoding, video decoding, video compression, or video decompression. For example, during the conversion from a pixel representation of a video to a corresponding bitstream representation, a video compression algorithm may be applied, or vice versa. As defined by the grammar, a bitstream representation (or simply bitstream) of a current video block may correspond, for example, to bits that are co-located or dispersed in different places within the bitstream. For example, a macroblock may be encoded according to the error residual values ​​of the transform and the codec and also using bits in the header and other fields in the bitstream.

[0607] The disclosed and other solutions, examples, embodiments, modules and functional operations described in this document can be implemented in digital electronic circuits, or in computer software, firmware or hardware (including the structures disclosed in this document and their structural equivalents), or in a combination of one or more of them. The disclosed and other embodiments can be implemented as one or more computer program products, i.e., one or more modules of computer program instructions encoded on a computer-readable medium, which are used to be run by a data processing device or 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 memory device, a combination of substances that affect machine-readable propagation signals, or a combination of one or more of them. The term "data processing device" includes all devices, equipment and machines for processing data, including, for example, a programmable processor, a computer, or multiple processors or computers. In addition to hardware, the device may also include code that creates an operating environment for the computer program in question, for example, code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them. A propagation signal is an artificially generated signal generated to encode information for transmission to a suitable receiver device, such as a machine-generated electrical signal, an optical signal, or an electromagnetic signal.

[0608] A computer program (also known as a program, software, software application, script, or code) can be written in any form of programming language (including compiled or interpreted languages), and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program does not necessarily correspond to a file in a file system. A program 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 in question, or in multiple coordinated files (e.g., files storing one or more modules, subroutines, or code portions). A computer program may be deployed to run on one computer or on multiple computers located at one site or distributed across multiple sites and interconnected by a communication network.

[0609] The processes and logic flows described in this document can be performed by one or more programmable processors running one or more computer programs to perform functions by operating on input data and generating output. The processes and logic flows can also be performed by special purpose logic circuits, and the apparatus can also be implemented as special purpose logic circuits, such as FPGAs (field programmable gate arrays) or ASICs (application specific integrated circuits).

[0610] Processors suitable for running computer programs include, for example, general-purpose and special-purpose microprocessors, and any one or more processors 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 elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Typically, a computer will also include one or more mass storage devices (e.g., magnetic disks, magneto-optical disks, or optical disks) for storing data, or operably coupled to receive data from or transfer data to or from the one or more mass storage devices. However, a computer does not require 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 disks; magneto-optical disks; and CD ROM and DVD-ROM disks. The processor and memory can be supplemented by or incorporated into a dedicated logic circuit.

[0611] Although this patent document contains many details, these details should not be interpreted as limitations on any subject matter or the scope of possible protection, but as descriptions of features of specific embodiments specified for specific technologies. Certain features described in the context of separate embodiments in this patent document may also be implemented in combination in a single embodiment. On the contrary, the various features described in the context of a single embodiment may also be implemented in multiple embodiments or in any suitable sub-combination, respectively. In addition, although features may be described above as working in certain combinations and even initially claimed as such, one or more features from the claimed combination may be excluded from the combination in some cases, and the claimed combination may be directed to a sub-combination or a variation of the sub-combination.

[0612] Similarly, although operations are depicted in a particular order in the drawings, this should not be understood as requiring that such operations be performed in the particular order shown or in a sequential order, or that all of the operations shown be performed, to achieve the desired results. In addition, the separation of various system components in the embodiments described in this patent document should not be understood as requiring such separation in all embodiments.

[0613] Only a few implementations and examples are described, and other implementations, enhancements, and variations may be made based on what is described and shown in this patent document.

Claims

1. A video processing method, comprising: performing conversion between a current slice of a current picture of a video and a bitstream of said video, wherein the bitstream complies with a format rule, and wherein the format rule specifies that there is a general constraint information syntax structure, and the general constraint information syntax structure is at a higher level than a sequence parameter set SPS; the general constraint information syntax structure comprises a first constraint flag, and the first constraint flag indicates that a constraint on explicit weighted prediction is enabled for both a unidirectionally predicted P slice and a bidirectionally predicted B slice of a picture set; In which, when the value of the first constraint flag indicates that the explicit weighted prediction is not applied to both the P slice and the B slice, the value of the second flag included in the sequence parameter set SPS indicates that the explicit weighted prediction is not applied to the P slice referenced by the SPS, and the value of the third flag included in the SPS indicates that the explicit weighted prediction is not applied to the B slice referenced by the SPS.

2. The method according to claim 1, wherein: The first constraint flag is included in the bitstream.

3. The method according to claim 1, wherein: The first restriction flag is included in a parameter set associated with the current slice.

4. The method according to claim 1, wherein: The first constraint flag is included in a decoder capability information network abstraction layer NAL unit.

5. The method according to claim 1, wherein: The first constraint flag is gci_no_explicit_weighted_prediction_constraint_flag.

6. The method according to claim 1, wherein: Since the second flag is equal to 1, the first constraint flag is equal to 0.

7. The method according to claim 1, wherein: The second flag is sps_weighted_pred_flag, and the third flag is sps_weighted_bipred_flag.

8. The method according to claim 1, wherein: The converting includes decoding the video from the bitstream.

9. The method according to claim 1, wherein: The converting includes encoding the video into the bitstream.

10. A video data processing apparatus 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 current slice of a current picture of a video and a bitstream of said video, wherein the bitstream complies with a format rule, and wherein the format rule specifies that there is a general constraint information syntax structure, and the general constraint information syntax structure is at a higher level than a sequence parameter set SPS; the general constraint information syntax structure comprises a first constraint flag, and the first constraint flag indicates that a constraint on explicit weighted prediction is enabled for both a unidirectionally predicted P slice and a bidirectionally predicted B slice of a picture set; In which, when the value of the first constraint flag indicates that the explicit weighted prediction is not applied to both the P slice and the B slice, the value of the second flag included in the sequence parameter set SPS indicates that the explicit weighted prediction is not applied to the P slice referenced by the SPS, and the value of the third flag included in the SPS indicates that the explicit weighted prediction is not applied to the B slice referenced by the SPS.

11. The device according to claim 10, wherein: The first constraint flag is gci_no_explicit_weighted_prediction_constraint_flag.

12. The device according to claim 10, wherein: The second flag is sps_weighted_pred_flag, and the third flag is sps_weighted_bipred_flag.

13. A non-transitory computer-readable storage medium having stored therein instructions that cause a processor to: performing conversion between a current slice of a current picture of a video and a bitstream of said video, in, The bitstream complies with a format rule, wherein the format rule specifies that a general constraint information syntax structure exists, and the general constraint information syntax structure is at a higher level than a sequence parameter set SPS; the general constraint information syntax structure includes a first constraint flag, wherein the first constraint flag indicates that a constraint on explicit weighted prediction is enabled for both unidirectionally predicted P slices and bidirectionally predicted B slices of a picture set; In which, when the value of the first constraint flag indicates that the explicit weighted prediction is not applied to both the P slice and the B slice, the value of the second flag included in the sequence parameter set SPS indicates that the explicit weighted prediction is not applied to the P slice referenced by the SPS, and the value of the third flag included in the SPS indicates that the explicit weighted prediction is not applied to the B slice referenced by the SPS.

14. The non-transitory computer-readable storage medium of claim 13, wherein: The first constraint flag is gci_no_explicit_weighted_prediction_constraint_flag.

15. The non-transitory computer-readable storage medium of claim 13, wherein: The second flag is sps_weighted_pred_flag, and the third flag is sps_weighted_bipred_flag.

16. 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, the video comprising a current picture, the current picture comprising a current slice, wherein the bitstream complies with a format rule, and wherein the format rule specifies that there is a general constraint information syntax structure, and the general constraint information syntax structure is at a higher level than a sequence parameter set SPS; the general constraint information syntax structure comprises a first constraint flag, and the first constraint flag indicates that a constraint on explicit weighted prediction is enabled for both a unidirectionally predicted P slice and a bidirectionally predicted B slice of a picture set; In which, when the value of the first constraint flag indicates that the explicit weighted prediction is not applied to both the P slice and the B slice, the value of the second flag included in the sequence parameter set SPS indicates that the explicit weighted prediction is not applied to the P slice referenced by the SPS, and the value of the third flag included in the SPS indicates that the explicit weighted prediction is not applied to the B slice referenced by the SPS.

17. The non-transitory computer-readable recording medium according to claim 16, wherein: The second flag is sps_weighted_pred_flag, and the third flag is sps_weighted_bipred_flag.

18. The non-transitory computer-readable recording medium according to claim 16, wherein: The first constraint flag is gci_no_explicit_weighted_prediction_constraint_flag.

19. A method for storing a bit stream of a video, comprising: generating the bitstream of the video, the video comprising a current picture, the current picture comprising a current slice, and storing the bitstream in a non-transitory computer-readable recording medium, wherein the bitstream complies with a format rule, and wherein the format rule specifies that there is a general constraint information syntax structure, and the general constraint information syntax structure is at a higher level than a sequence parameter set SPS; the general constraint information syntax structure comprises a first constraint flag, and the first constraint flag indicates that a constraint on explicit weighted prediction is enabled for both a unidirectionally predicted P slice and a bidirectionally predicted B slice of a picture set; In which, when the value of the first constraint flag indicates that the explicit weighted prediction is not applied to both the P slice and the B slice, the value of the second flag included in the sequence parameter set SPS indicates that the explicit weighted prediction is not applied to the P slice referenced by the SPS, and the value of the third flag included in the SPS indicates that the explicit weighted prediction is not applied to the B slice referenced by the SPS.

Images