PALLET MODE WITH LOCAL DOUBLE TREE MODE DEFINITION

Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on International Patent Application No. PCT / CN2021 / 096707, filed on May 28, 2021, which claims the priority to and benefits of International Patent Application No. PCT / CN2020 / 093641, filed on May 31, 2020.TECHNICAL FIELD

[0002] This patent document relates to image and video coding and decoding.BACKGROUND

[0003] Digital video accounts for the largest bandwidth use on the internet and other digital communication networks. As the number of connected user devices capable of receiving and displaying video increases, it is expected that the bandwidth demand for digital video usage will continue to grow.

[0004] BROSS B ET AL: "Versatile Video Coding (Draft 7)" (16. JVET MEETING; 20191001 - 20191011; GENEVA; (THE JOINT VIDEO EXPLORATION TEAM OF ISO / IEC JTC1 / SC29 / WG11 AND ITU-T SG.16 ),no. JVET-P2001 ; m51515 17 October 2019) describes a framework where luma and chroma can be processed separately within a node, and where the set of usable prediction tools depends on that split and on the node's context.

[0005] HE (QUALCOMM) Y ET AL: "AHG9: A summary of proposals on general constraints information" (131. MPEG MEETING; 20200629 - 20200703; ONLINE; (MOTION PICTURE EXPERT GROUP OR ISO / IEC JTC1 / SC29 / WG11),no. m54124 ; JVET-S0138 26 May 2020) aggregates proposals for a global constraint framework that lets profiles switch entire tool classes or features on / off for conformance and implementation simplicity.SUMMARY

[0006] The present document discloses techniques that can be used by video encoders and decoders for processing coded representation of video using control information useful for decoding of the coded representation.

[0007] The present invention is defined in the independent claims. Enabling disclosure for the protected invention is provided with the embodiments described in relation to problem 11 and the respective solution in embodiments 11.e and 11.e.i. The other embodiments, figures, and aspects are provided for illustrative purposes and do not represent embodiments of the invention unless when combined with all of the features respectively defined in the independent claims.BRIEF DESCRIPTION OF DRAWINGS

[0008] FIG. 1 is a block diagram of an example video processing system. FIG. 2 is a block diagram of a video processing apparatus. FIG. 3 is a flowchart for an example method of video processing. FIG. 4 is a block diagram that illustrates a video coding system in accordance with some embodiments of the present disclosure. FIG. 5 is a block diagram that illustrates an encoder in accordance with some embodiments of the present disclosure. FIG. 6 is a block diagram that illustrates a decoder in accordance with some embodiments of the present disclosure. FIGS. 7 to 9 are flowcharts for example methods of video processing. DETAILED DESCRIPTION

[0009] Section headings are used in the present document for ease of understanding and do not limit the applicability of techniques and embodiments disclosed in each section only to that section. Furthermore, H.266 terminology is used in some description only for ease of understanding and not for limiting scope of the disclosed techniques. As such, the techniques described herein are applicable to other video codec protocols and designs also.1. Introduction

[0010] This document is related to video coding technologies. Specifically, it is about the design of SH, PPS, APS, and GCI syntax elements in video coding. The ideas may be applied individually or in various combination, to any video coding standard or non-standard video codec that supports multi-layer video coding, e.g., the being-developed Versatile Video Coding (VVC).2. Abbreviations

[0011] APSAdaptation Parameter Set AUAccess Unit AUDAccess Unit Delimiter AVCAdvanced Video Coding CLVSCoded Layer Video Sequence CPBCoded Picture Buffer CRAClean Random Access CTUCoding Tree Unit CVSCoded Video Sequence DPBDecoded Picture Buffer DPSDecoding Parameter Set EOBEnd Of Bitstream EOSEnd Of Sequence GCIGeneral Constraint Information GDRGradual Decoding Refresh HEVCHigh Efficiency Video Coding HRDHypothetical Reference Decoder IDRInstantaneous Decoding Refresh JEMJoint Exploration Model MCTSMotion-Constrained Tile Sets NALNetwork Abstraction Layer OLSOutput Layer Set PHPicture Header PPSPicture Parameter Set PTLProfile, Tier and Level PUPicture Unit RBSPRaw Byte Sequence Payload SEISupplemental Enhancement Information SHSlice Header SPSSequence Parameter Set SVCScalable Video Coding VCLVideo Coding Layer VPSVideo Parameter Set VTMVVC Test Model VUIVideo Usability Information VVCVersatile Video Coding 3. Initial discussion

[0012] Video coding standards have evolved primarily through the development of the well-known ITU-T and ISO / IEC standards. The ITU-T produced H.261 and H.263, ISO / IEC produced MPEG-1 and MPEG-4 Visual, and the two organizations jointly produced the H.262 / MPEG-2 Video and H.264 / MPEG-4 Advanced Video Coding (AVC) and H.265 / HEVC standards. Since H.262, the video coding standards are based on the hybrid video coding structure wherein temporal prediction plus transform coding are utilized. To explore the future video coding technologies beyond HEVC, the Joint Video Exploration Team (JVET) was founded by VCEG and MPEG jointly in 2015. Since then, many new methods have been adopted by JVET and put into the reference software named Joint Exploration Model (JEM). The JVET meeting is concurrently held once every quarter, and the new coding standard is targeting at 50% bitrate reduction as compared to HEVC. The new video coding standard was officially named as Versatile Video Coding (VVC) in the April 2018 JVET meeting, and the first version of VVC test model (VTM) was released at that time. As there are continuous effort contributing to VVC standardization, new coding techniques are being adopted to the VVC standard in every JVET meeting. The VVC working draft and test model VTM are then updated after every meeting. The VVC project is now aiming for technical completion (FDIS) at the July 2020 meeting.3.1. GCI syntax and semantics

[0013] In the latest VVC draft text, the GCI syntax and semantics are as follows: general_constraint_info( ) {Descriptor  general_progressive_source_flag u(1) general_interlaced_source_flag u(1) general_non_packed_constraint_flag u(1) general_frame_only_constraint_flag u(1) general_non_projected_constraint_flag u(1) intra_only_constraint_flag u(1) max_bitdepth_constraint_idc u(4) max_chroma_format_constraint_idc u(2) no_res_change_in_clvs_constraint_flag u(1) one_tile_per_pic_constraint_flag u(1) one_slice_per_pic_constraint_flag u(1) one_subpic_per_pic_constraint_flag u(1) no_qtbtt_dual_tree_intra_constraint_flag u(1) no_partition_constraints_override_constraint_flag u(1) no_sao_constraint_flag u(1) no_alf_constraint_flag u(1) no_ccalf_constraint_flag u(1) no_joint_cbcr_constraint_flag u(1) no_ref_wraparound_constraint_flag u(1) no_temporal_mvp_constraint_flag u(1) no_sbtmvp_constraint_flag u(1) no_amvr_constraint_flag u(1) no_bdof_constraint_flag u(1) no_dmvr_constraint_flag u(1) no_cclm_constraint_flag u(1) no_mts_constraint_flag u(1) no_sbt_constraint_flag u(1) no_affine_motion_constraint_flag u(1) no_bcw_constraint_flag u(1) no_ibc_constraint_flag u(1) no_ciip_constraint_flag u(1) no_fpel_mmvd_constraint_flag u(1) no_gpm_constraint flag u(1) no_ladf_constraint_flag u(1) no_transform_skip_constraint_flag u(1) no_bdpcm_constraint_flag u(1) no_qp_delta_constraint_flag u(1) no_dep_quant_constraint_flag u(1) no_sign_data_hiding_constraint_flag u(1) no_mixed_nalu_types_in_pic_constraint_flag u(1) no_trail_constraint_flag u(1) no_stsa_constraint_flag u(1) no_rasl_constraint_flag u(1) no_radl_constraint_flag u(1) no_idr_constraint_flag u(1) no_cra_constraint_flag u(1) no_gdr_constraint_flag u(1) no_aps_constraint_flag u(1)  while( !byte_aligned( ) )  gci_alignment_zero_bit f(1) num_reserved_constraint_bytes u(8)  for( i = 0; i < num_reserved_constraint_bytes; i++ )  gci_reserved_constraint_byte [ i ]u(8)} general_progressive_source_flag and general_interlaced_source_flag are interpreted as follows: If general_progressive_source_flag is equal to 1 and general_interlaced_source_flag is equal to 0, the source scan type of the pictures in OlsInScope should be interpreted as progressive only. Otherwise, if general_progressive_source_flag is equal to 0 and general_interlaced_source_flag is equal to 1, the source scan type of the pictures in OlsInScope should be interpreted as interlaced only. Otherwise, if general_progressive_source_flag is equal to 0 and general_interlaced_source_flag is equal to 0, the source scan type of the pictures in OlsInScope should be interpreted as unknown or unspecified. Otherwise (general_progressive_source_flag is equal to 1 and general_interlaced_source_flag is equal to 1), the source scan type of each picture in OlsInScope is indicated at the picture level using the syntax element source_scan_type in a frame-field information SEI message. It is a requirement of bitstream conformance that when general_progressive_source_flag is equal to 1 and general_interlaced_source_flag is equal to 1, a frame-field information SEI message shall be present in each AU. NOTE 1 - Decoders may ignore the values of general_progressive_source_flag and general_interlaced_source_flag. Moreover, the actual source scan type of the pictures is outside the scope of this Specification and the method by which the encoder selects the values of general_progressive_source_flag and general_interlaced_source_flag is unspecified. general_non_packed_constraint_flag equal to 1 specifies that there shall not be any frame packing arrangement SEI messages present in the bitstream of the OlsInScope. general_non_packed_constraint_flag equal to 0 does not impose such a constraint. NOTE 2 - Decoders may ignore the value of general_non_packed_constraint_flag, as there are no decoding process requirements associated with the presence or interpretation of frame packing arrangement SEI messages. general_frame_only_constraint_flag equal to 1 specifies that OlsInScope conveys pictures that represent frames. general_frame_only_constraint_flag equal to 0 specifies that OlsInScope conveys pictures that may or may not represent frames. NOTE 3 - Decoders may ignore the value of general_frame_only_constraint_flag, as there are no decoding process requirements associated with it. general_non_projected_constraint_flag equal to 1 specifies that there shall not be any equirectangular projection SEI messages or generalized cubemap projection SEI messages present in the bitstream of the OlsInScope. general_non_projected_constraint_flag equal to 0 does not impose such a constraint. NOTE 4 - Decoders may ignore the value of general _non_projected_constraint_flag, as there are no decoding process requirements associated with the presence or interpretation of equirectangular projection SEI messages and generalized cubemap projection SEI messages. intra_only_constraint_flag equal to 1 specifies that slice_type shall be equal to I. intra_only_constraint_flag equal to 0 does not impose such a constraint. max_bitdepth_constraint_idc specifies that bit_depth_minus8 shall be in the range of 0 to max_bitdepth_constraint_idc, inclusive. max_chroma_format_constraint_idc specifies that chroma_format_idc shall be in the range of 0 to max_chroma_format_constraint idc, inclusive. no_res_change_in_clvs_constraint_flag equal to 1 specifies that res_change_in_clvs_allowed_flag shall be equal to 0. no_res_change_in_clvs_constraint_flag equal to 0 does not impose such a constraint. one_tile_per_pic_constraint_flag equal to 1 specifies that each picture shall contain only one tile. one_tile_per_pic_constraint_flag equal to 0 does not impose such a constraint. one_slice_per_pic_constraint_flag equal to 1 specifies that each picture shall contain only one slice. one_slice_per_pic_constraint_flag equal to 0 does not impose such a constraint. one_subpic_per_pic_constraint_flag equal to 1 specifies that each picture shall contain only one subpicture. one_subpic_per_pic_constraint_flag equal to 0 does not impose such a constraint. When one_slice_per_pic_constraint_flag is equal to 1, the value of one_subpic_per_pic_constraint_flag shall be equal to 1. no_qtbtt_dual_tree_intra_constraint_flag equal to 1 specifies that qtbtt_dual_tree_intra_flag shall be equal to 0. no_qtbtt_dual_tree_intra_constraint_flag equal to 0 does not impose such a constraint. no_partition_constraints_override_constraint_flag equal to 1 specifies that partition_constraints_override_enabled_flag shall be equal to 0. no_partition_constraints_override_constraint _flag equal to 0 does not impose such a constraint. no_sao_constraint_flag equal to 1 specifies that sps_sao_enabled_flag shall be equal to 0. no_sao_constraint_flag equal to 0 does not impose such a constraint. no_alf_constraint_flag equal to 1 specifies that sps_alf_enabled_flag shall be equal to 0. no_alf_constraint_flag equal to 0 does not impose such a constraint. no_ccalf_constraint_flag equal to 1 specifies that sps_ccalf_enabled_flag shall be equal to 0. no_ccalf_constraint_flag equal to 0 does not impose such a constraint. no_joint_cber_constraint_flag equal to 1 specifies that sps_joint_cbcr_enabled_flag shall be equal to 0. no_joint_cbcr_constraint_flag equal to 0 does not impose such a constraint. no_ref_wraparound_constraint_flag equal to 1 specifies that sps_ref_wraparound_enabled_flag shall be equal to 0. no_ref_wraparound_constraint_flag equal to 0 does not impose such a constraint. no_temporal_mvp_constraint_flag equal to 1 specifies that sps_temporal_mvp_enabled_flag shall be equal to 0. no_temporal_mvp_constraint_flag equal to 0 does not impose such a constraint. no_sbtmvp_constraint_flag equal to 1 specifies that sps_sbtmvp_enabled_flag shall be equal to 0. no_sbtmvp_constraint_flag equal to 0 does not impose such a constraint. no_amvr_constraint_flag equal to 1 specifies that sps_amvr_enabled_flag shall be equal to 0. no_amvr_constraint_flag equal to 0 does not impose such a constraint. no_bdof_constraint_flag equal to 1 specifies that sps_bdof_enabled_flag shall be equal to 0. no_bdof_constraint_flag equal to 0 does not impose such a constraint. no_dmvr_constraint_flag equal to 1 specifies that sps_dmvr_enabled_flag shall be equal to 0. no_dmvr_constraint_flag equal to 0 does not impose such a constraint. no_cclm_constraint_flag equal to 1 specifies that sps_cclm_enabled_flag shall be equal to 0. no_cclm_constraint_flag equal to 0 does not impose such a constraint. no_mts_constraint_flag equal to 1 specifies that sps_mts_enabled_flag shall be equal to 0. no_mts_constraint_flag equal to 0 does not impose such a constraint. no_sbt_constraint_flag equal to 1 specifies that sps_sbt_enabled_flag shall be equal to 0. no_sbt_constraint_flag equal to 0 does not impose such a constraint. no_affine_motion_constraint_flag equal to 1 specifies that sps_affine_enabled_flag shall be equal to 0. no_affine_motion_constraint_flag equal to 0 does not impose such a constraint. no_bcw_constraint_flag equal to 1 specifies that sps_bcw_enabled_flag shall be equal to 0. no_bcw_constraint_flag equal to 0 does not impose such a constraint. no_ibc_constraint_flag equal to 1 specifies that sps_ibc_enabled_flag shall be equal to 0. no_ibc_constraint_flag equal to 0 does not impose such a constraint. no_ciip_constraint_flag equal to 1 specifies that sps_ciip_enabled_flag shall be equal to 0. no_cipp_constraint_flag equal to 0 does not impose such a constraint. no_fpel_mmvd_constraint_flag equal to 1 specifies that sps_fpel mmvd enabled flag shall be equal to 0. no_fpel_mmvd_constraint_flag equal to 0 does not impose such a constraint. no_gpm_constraint_flag equal to 1 specifies that sps_gpm_enabled_flag shall be equal to 0. no_gpm_constraint_flag equal to 0 does not impose such a constraint. no_ladf_constraint_flag equal to 1 specifies that sps_ladf_enabled_flag shall be equal to 0. no_ladf_constraint_flag equal to 0 does not impose such a constraint. no_transform_skip_constraint_flag equal to 1 specifies that sps_transfrom_skip_enabled_flag shall be equal to 0. no_transform_skip_constraint_flag equal to 0 does not impose such a constraint. no_bdpcm_constraint_flag equal to 1 specifies that spsbdpcm_enabled_flag shall be equal to 0. no_bdpcm_constraint_flag equal to 0 does not impose such a constraint. no_qp_delta_constraint_flag equal to 1 specifies that it is a requirement of bitstream conformance that cu_qp_delta_enabled_flag shall be equal to 0. no_qp_delta_constraint_flag equal to 0 does not impose such a constraint. no_dep_quant_constraint_flag equal to 1 specifies that it is a requirement of bitstream conformance that sps_dep_quant_enabled_flag shall be equal to 0. no_dep_quant_constraint_flag equal to 0 does not impose such a constraint. no_sign_data_hiding_constraint_flag equal to 1 specifies that it is a requirement of bitstream conformance that sps_sign_data_hiding_enabled_flag shall be equal to 0. no_sign_data_hiding_constraint_flag equal to 0 does not impose such a constraint. no_mixed_nalu_types_in_pic_constraint_flag equal to 1 specifies that it is a requirement of bitstream conformance that mixed_nalu_types_in_pic_flag shall be equal to 0. no_mixed_nalu types_in_pic_constraint _flag equal to 0 does not impose such a constraint. no_trail_constraint_flag equal to 1 specifies that there shall be no NAL unit with nuh_unit_type equal to TRAIL_NUT present in OlsInScope. no_trail_constraint_flag equal to 0 does not impose such a constraint. no_stsa_constraint_flag equal to 1 specifies that there shall be no NAL unit with nuh_unit_type equal to STSA_NUT present in OlsInScope. no_stsa_constraint_flag equal to 0 does not impose such a constraint. no_rasl_constraint_flag equal to 1 specifies that there shall be no NAL unit with nuh_unit_type equal to RASL_NUT present in OlsInScope. no_rasl_constraint_flag equal to 0 does not impose such a constraint. no_radl_constraint_flag equal to 1 specifies that there shall be no NAL unit with nuh_unit_type equal to RADL_NUT present in OlsInScope. no_radl_constraint_flag equal to 0 does not impose such a constraint. no_idr_constraint_flag equal to 1 specifies that there shall be no NAL unit with nuh_unit_type equal to IDR_W_RADL or IDR_N_LP present in OlsInScope. no_idr_constraint_flag equal to 0 does not impose such a constraint. no_cra_constraint_flag equal to 1 specifies that there shall be no NAL unit with nuh_unit_type equal to CRA_NUT present in OlsInScope. no_cra_constraint_flag equal to 0 does not impose such a constraint. no_gdr_constraint_flag equal to 1 specifies that there shall be no NAL unit with nuh_unit_type equal to GDR_NUT present in OlsInScope. no_gdr_constraint_flag equal to 0 does not impose such a constraint. no_aps_constraint_flag equal to 1 specifies that there shall be no NAL unit with nuh_unit_type equal to PREFIX_APS_NUT or SUFFIX_APS_NUT present in OlsInScope. no_aps_constraint_flag equal to 0 does not impose such a constraint. gci_alignment_zero_bits shall be equal to 0. num_reserved_constraint_bytes specifies the number of the reserved constraint bytes. The value of num_reserved_constraint_bytes shall be 0. Other values of num_reserved_constraint_bytes are reserved for future use by ITU-T | ISO / IEC and shall not be present in bitstreams conforming to this version of this Specification. gci_reserved_constraint_byte [ i ] may have any value. Its presence and value do not affect decoder conformance to profiles specified in this version of this Specification. Decoders conforming to this version of this Specification shall ignore the values of all the gci_reserved_constraint_byte[ i ] syntax elements. 3.2. SPS syntax and semantics

[0014] In the latest VVC draft text, the SPS syntax and semantics are as follows: seq_parameter_set_rbsp( ) {Descript or  sps_seq_parameter_set_id u(4) sps_video_parameter_set_id u(4) sps_max_sublayers_minus1 u(3) sps_reserved_zero_4bits u(4) sps_ptl_dpb_hrd_params_present_flag u(1)  if( sps_ptl_dpb_hrd_params_present_flag )   profile_tier_level( 1, sps_max_sublayers_minus1 ) gdr_enabled_flag u(1) chroma_format_idc u(2)  if( chroma_format_idc = = 3)  separate_colour_plane_flag u(1) res_change_in_clvs_allowed_flag u(1) pic_width_max_in_luma_samples ue(v) pic_height_max_in_luma_samples ue(v) sps_conformance_window_flag u(1)  if( sps_conformance_window_flag ) {  sps_conf_win_left offset ue(v)  sps_conf_win_right_offset ue(v)  sps_conf_win_top_offset ue(v)  sps_conf_win_bottom_offset ue(v)  } sps_log2_ctu_size_minus5 u(2) subpic_info_present_flag u(1)  if( subpic_info_present_flag ) {  sps_num_subpics_minus1 ue(v)  sps_independent_subpics_flag u(1)   for( i = 0; sps_num_subpics_minus1 > 0 && i <= sps_num_subpics_minus1; i++ ) {    if( i > 0 && pic_width_max_in_luma_samples > CtbSizeY )    subpic_ctu_top_left_x [ i ]u(v)    if( i > 0 && pic_height_max_in_luma_samples > CtbSizeY ) {    subpic_ctu_top_left_y [ i ]u(v)    if( i < sps_num_subpics_minus1 &&      pic_width_max_in_luma_samples > CtbSizeY )   subpic_width_minus1 [ i ]u(v)   if( i < sps_num_subpics_minus1 && pic_height_max_in_luma_samples > CtbSizeY )   subpic_height_minus1 [ i ]u(v)   if( !sps_independent_subpics_flag) {    subpic_treated_as_pic_flag [ i ]u(1)    loop_filter_across_subpic_enabled_flag [ i ]u(1)    }   }  sps_subpic_id_len_minus1 ue(v)  subpic_id_mapping_explicitly_signalled_flag u(1)   if( subpic_id_mapping_explicitly_signalled_flag ) {   subpic_id_mapping_in_sps_flag u(1)    if( subpic_id_mapping_in_sps_flag )     for( i = 0; i <= sps_num_subpics_minus1; i++)     sps_subpic_id [ i ]u(v)   }  } bit_depth_minus8 ue(v) sps_entropy_coding_sync_enabled_flag u(1)  if( sps_entropy_coding_sync_enabled_flag )  sps_wpp_entry_ point offsets present flag u(1) sps_weighted_pred_flag u(1) sps_weighted_bipred_flag u(1) log2_max_pic_order_cnt_lsb_minus4 u(4) sps_poc_msb_flag u(1)  if( sps_poc_msb_flag )  poc_msb_len_minus1 ue(v) num_extra_ph_bits_bytes u(2)   extra_ph_bits_struct( num_extra_ph_bits_bytes ) num_extra_sh_bits_bytes u(2)   extra_sh_bits_struct( num_extra_sh_bits_bytes )  if( sps_max_sublayers_minus1 > 0 )  sps_sublayer_dpb_params_flag u(1)  if( sps_ptl_dpb_hrd_params_present_flag )   dpb_parameters( sps_max_sublayers_minus1, sps_sublayer_dpb_params_flag ) long_term_ref_pics_flag u(1) inter_layer_ref_pics_present_flag u(1) sps_idr_rpl_present_flag u(1) rpl1_same_as_rpl0_flag u(1)  for( i = 0; i < !rpl1_same_as_rpl0_flag ? 2 : 1; i++ ) {  num_ref_pic_lists_in_sps [ i ] ue(v)   for( j = 0; j < num_ref_pic_lists_in_sps[ i ]; j++)    ref_pic_list_struct( i, j )  }  if( ChromaArrayType != 0 )  qtbtt_dual_tree_intra_flag u(1) log2_min_luma_coding_block_size_minus2 ue(v) partition_constraints_override_enabled_flag u(1) sps_log2_diff_min_qt_min_cb_intra_slice_luma ue(v) sps_max_mtt_hierarchy_depth_intra_slice_luma ue(v)  if( sps_max_mtt_hierarchy_depth_intra_slice_luma != 0 ) {  sps_log2_diff_max_bt_min_qt_intra_slice_luma ue(v)  sps_log2_diff_max_tt_min_qt_intra_slice_luma ue(v)  } sps_log2_diff_min_qt_min_cb_inter_slice ue(v) sps_max_mtt_hierarchy_depth_inter_slice ue(v)  if( sps_max_mtt_hierarchy_depth_inter_slice != 0) {  sps_log2_diff_max_bt_min_qt_inter_slice ue(v)  sps_log2_diff_max_tt_min_qt_inter_slice ue(v)  }  if( qtbtt_dual_tree_intra_flag ) {  sps_log2_diff_min_qt_min_cb_intra_slice_chroma ue(v)  sps_max_mtt_hierarchy_depth_intra_slice_chroma ue(v)   if( sps_max_mtt_hierarchy_depth_intra_slice_chroma != 0) {   sps_log2_diff_max_bt_min_qt_intra_slice_chroma ue(v)   sps_log2_diff_max_tt_min_qt_intra_slice_chroma ue(v)   }  } sps_max_luma_transform_size_64_flag u(1)  if( ChromaArrayType != 0 ) {  sps_joint_cbcr_enabled_flag u(1)  same_qp_table_for_chroma u(1)   numQpTables = same_qp_table_for_chroma ? 1 : ( sps_joint_cbcr enabled _flag ? 3 : 2 )   for( i = 0; i < numQpTables; i++ ) {   qp_table_start_minus26 [ i ]se(v)   num_points_in_qp_table_minus1 [ i ]ue(v)    for( j = 0; j <= num_points_in_qp_table_minus1[ i ]; j++) {    delta_qp_in_val_minus1 [ i ][ j ]ue(v)    delta_qp_diff_val [ i ][ j ]ue(v)    }   }  } sps_sao_enabled_flag u(1) sps_alf_enabled_flag u(1)  if( sps_alf_enabled_flag && ChromaArrayType != 0 )  sps_ccalf_enabled_flag u(1) sps_transform_skip_enabled_flag u(1)  if( sps_transform_skip_enabled_flag ) {  log2_transform_skip_max_size_minus2 ue(v)  sps_bdpcm_enabled_flag u(1)  } sps_ref_wraparound_enabled_flag u(1) sps_temporal_mvp_enabled_flag u(1)  if( sps_temporal_mvp_enabled_flag )  sps_sbtmvp_enabled_flag u(1) sps_amvr_enabled flag u(1) sps_bdof_enabled_flag u(1)  if( sps_bdof_enabled_flag )  sps_bdof_pic_present_flag u(1) sps_smvd_enabled_flag u(1) sps_dmvr_enabled_flag u(1)  if( sps_dmvr_enabled_flag)  sps_dmvr_pic_present_flag u(1) sps_mmvd_enabled_flag u(1) sps_isp_enabled_flag u(1) sps_mrl_enabled_flag u(1) sps_mip_enabled_flag u(1)  if( ChromaArrayType != 0)  sps_cclm_enabled_flag u(1)  if( chroma_format_idc = = 1 ) {  sps_chroma_horizontal_collocated_flag u(1)  sps_chroma_vertical_collocated_flag u(1)  } sps_mts_enabled_flag u(1)  if( sps_mts_enabled_flag ) {  sps_explicit_mts_intra_enabled_flag u(1)  sps_explicit_mts_inter_enabled_flag u(1)  } six_minus_max_num_merge_cand ue(v) sps_sbt_enabled_flag u(1) sps_affine_enabled_flag u(1)  if( sps_affine_enabled_flag ) {  five_minus_max_num_subblock_merge_cand ue(v)  sps_affine type flag u(1)   if( sps_amvr_enabled_flag )   sps_affine_amvr_enabled_flag u(1)  sps_affine_prof_enabled_flag u(1)   if( sps_affine_prof_enabled_flag )   sps_prof_pic_present_flag u(1)  } sps_palette_enabled_flag u(1)  if( ChromaArrayType = = 3 && !sps_max_luma_transform_size_64_flag )  sps_act_enabled_flag u(1)  if( sps_transform_skip_enabled_flag || sps_palette_enabled_flag )  min_qp_prime_ts_minus4 ue(v) sps_bcw_enabled_flag u(1) sps_ibc_enabled_flag u(1)  if( sps_ibc_enabled_flag )  six_minus_max_num_ibc_merge_cand ue(v) sps_ciip_enabled_flag u(1)  if( sps_mmvd_enabled_flag )  sps_fpel_mmvd_enabled_flag u(1)  if( MaxNumMergeCand >= 2) {  sps_gpm_enabled_flag u(1)   if( sps_gpm_enabled_flag && MaxNumMergeCand >= 3 )   max_num_merge_cand_minus_max_num_gpm_cand ue(v)  } sps_lmcs_enabled_flag u(1) sps_lfnst_enabled_flag u(1) sps_ladf_enabled_flag u(1)  if( sps_ladf_enabled_flag ) {  sps_num_ladf_intervals_minus2 u(2)  sps_ladf_lowest_interval_qp_offset se(v)   for( i = 0; i < sps_num_ladf_intervals_minus2 + 1; i++ ) {   sps_ladf_qp_offset [ i ]se(v)   sps_ladf_delta_threshold_minus1 [ i ]ue(v)   }  } log2_parallel_merge_level_minus2 ue(v) sps_scaling_list_enabled_flag u(1) sps_dep_quant_enabled_flag u(1)  if( !sps_dep_quant_enabled_flag )  sps_sign_data_hiding_enabled_flag u(1) sps_virtual_boundaries_enabled_flag u(1)  if( sps_virtual_boundaries_enabled_flag ) {  sps_virtual_boundaries_present_flag u(1)   if( sps_virtual_boundaries_present_flag ) {   sps_num_ver_virtual_boundaries u(2)    for( i = 0; i < sps_num_ver_virtual_boundaries; i++ )    sps_virtual_boundaries_pos_x [ i ]u(13)   sps_num_hor_virtual_boundaries u(2)    for( i = 0; i < sps_num_hor_virtual_boundaries; i++ )    sps_virtual_boundaries_pos_y [ i ]u(13)   }  }  if( sps_ptl_dpb_hrd_params_present_flag ) {  sps_general_hrd_params_present_flag u(1)   if( sps_general_hrd_params_present_flag ) {    general_hrd_parameters( )    if( sps_max_sublayers_minus1 > 0 )    sps_sublayer_cpb_params_present_flag u(1)    firstSubLayer = sps_sublayer_cpb_params_present_flag ? 0 :     sps_max_sublayers_minus1    ols_hrd_parameters( firstSubLayer, sps_max_sublayers_minus1 )   }  } field_seq_flag u(1) vui_parameters_ present flag u(1)  if( vui_parameters_present_flag )   vui_parameters( ) / * Specified in ITU-T H.SEI | ISO / IEC 23002-7 * /  sps_extension_flag u(1)  if( sps_extension_flag )   while( more_rbsp_data( ) )   sps_extension_data_flag u(1)  rbsp_trailing_bits( )}

[0015] An SPS RBSP shall be available to the decoding process prior to it being referenced, included in at least one AU with TemporalId equal to 0 or provided through external means.

[0016] All SPS NAL units with a particular value of sps_seq_parameter_set_id in a CVS shall have the same content.

[0017] sps_seq_parameter_set_id provides an identifier for the SPS for reference by other syntax elements.

[0018] SPS NAL units, regardless of the nuh_layer_id values, share the same value space of sps_seq_parameter_set_id.

[0019] Let spsLayerId be the value of the nuh_layer_id of a particular SPS NAL unit, and vclLayerId be the value of the nuh_layer_id of a particular VCL NAL unit. The particular VCL NAL unit shall not refer to the particular SPS NAL unit unless spsLayerId is less than or equal to vclLayerId and the layer with nuh_layer_id equal to spsLayerId is included in at least one OLS that includes the layer with nuh_layer_id equal to vclLayerId. sps_video_parameter_set_id, when greater than 0, specifies the value of vps_video_parameter_set_id for the VPS referred to by the SPS.

[0020] When sps_video_parameter_set_id is equal to 0, the following applies: The SPS does not refer to a VPS. No VPS is referred to when decoding each CLVS referring to the SPS. The value of vps_max_layers_minus1 is inferred to be equal to 0. The CVS shall contain only one layer (i.e., all VCL NAL unit in the CVS shall have the same value of nuh_layer_id). The value of GeneralLayerIdx[ nuh_layer_id ] is inferred to be equal to 0. The value of vps_independent_layer_flag[ GeneralLayerIdx[ nuh_layer_id ] ] is inferred to be equal to 1.

[0021] When vps_independent_layer_flag[ GeneralLayerIdx[ nuh_layer_id ] ] is equal to 1, the SPS referred to by a CLVS with a particluar nuh_layer_id value nuhLayerId shall have nuh_layer_id equal to nuhLayerId.

[0022] The value of sps_video_parameter_set _id shall be the same in all SPSs that are referred to by CLVSs in a CVS. sps_max_sublayers_minus1 plus 1 specifies the maximum number of temporal sublayers that may be present in each CLVS referring to the SPS. The value of sps_max_sublayers_minus1 shall be in the range of 0 to vps_max_sublayers_minus1, inclusive. sps_reserved_zero_4bits shall be equal to 0 in bitstreams conforming to this version of this Specification. Other values for sps_reserved_zero_4bits are reserved for future use by ITU-T | ISO / IEC. sps_ptl_dpb_hrd_params_present_flag equal to 1 specifies that a profile_tier_level( ) syntax structure and a dpb_parameters( ) syntax structure are present in the SPS, and a general_hrd_parameters( ) syntax structure and an ols_hrd_parameters( ) syntax structure may also be present in the SPS. sps_ptl_dpb_hrd_params_present_flag equal to 0 specifies that none of these four syntax structures is present in the SPS. The value of sps_ptl_dpb_hrd_params_present_flag shall be equal to vps_independent_layer_flag[ GeneralLayerIdx[ nuh_layer_id ] ]. gdr_enabled_flag equal to 1 specifies that GDR pictures may be present in CLVSs referring to the SPS. gdr_enabled_flag equal to 0 specifies that GDR pictures are not present in CLVSs referring to the SPS. chroma_format_idc specifies the chroma sampling relative to the luma sampling as specified in clause 6.2. separate_colour_plane_flag equal to 1 specifies that the three colour components of the 4:4:4 chroma format are coded separately. separate_colour_plane_flag equal to 0 specifies that the colour components are not coded separately. When separate_colour_plane_flag is not present, it is inferred to be equal to 0. When separate_colour_plane_flag is equal to 1, the coded picture consists of three separate components, each of which consists of coded samples of one colour plane (Y, Cb, or Cr) and uses the monochrome coding syntax. In this case, each colour plane is associated with a specific colour_plane_id value. NOTE 1 - There is no dependency in decoding processes between the colour planes having different colour_plane_id values. For example, the decoding process of a monochrome picture with one value of colour_plane_id does not use any data from monochrome pictures having different values of colour_plane _id for inter prediction.

[0023] Depending on the value of separate_colour_plane_flag, the value of the variable ChromaArrayType is assigned as follows: If separate_colour_plane_flag is equal to 0, ChromaArrayType is set equal to chroma_format_idc. Otherwise (separate_colour_plane_flag is equal to 1), ChromaArrayType is set equal to 0. res_change_in_clvs_allowed_flag equal to 1 specifies that the picture spatial resolution may change within a CLVS referring to the SPS. res_change_in_clvs_allowed_flag equal to 0 specifies that the picture spatial resolution does not change within any CLVS referring to the SPS. pic_width_max_in_luma_samples specifies the maximum width, in units of luma samples, of each decoded picture referring to the SPS. pic_width_max_in_luma_samples shall not be equal to 0 and shall be an integer multiple of Max( 8, MinCbSizeY ).

[0024] It is a requirement of bitstream conformance that, for any OLS with OLS index i that contains one or more layers that refers to the SPS, the value of pic_width_max_in_luma_samples shall be less than or equal to the value of ols_dpb_pic_width[ i ]. pic_height_max_in_luma_samples specifies the maximum height, in units of luma samples, of each decoded picture referring to the SPS. pic_height_max_in_luma_samples shall not be equal to 0 and shall be an integer multiple of Max( 8, MinCbSizeY ).

[0025] It is a requirement of bitstream conformance that, for any OLS with OLS index i that contains one or more layers that refers to the SPS, the value of pic_height_max_in_luma_samples shall be less than or equal to the value of ols_dpb_pic_height[ i ]. sps_conformance_window_flag equal to 1 indicates that the conformance cropping window offset parameters follow next in the SPS. sps_conformance_window_flag equal to 0 indicates that the conformance cropping window offset parameters are not present in the SPS. sps_conf_win_left_offset, sps_conf_win_right_offset, sps_conf_win_top_offset, and sps_conf_win_bottom_offset specify the cropping window that is applied to pictures with pic_width_in_luma_samples equal to pic_width_max_in_luma_samples and pic_height_in_luma_samples equal to pic_height_max_in_luma_samples. When sps_conformance_window_flag is equal to 0, the values of sps_conf_win_left_offset, sps_conf_win_right_offset, sps_conf_win_top_offset, and sps_conf_win_bottom_offset are inferred to be equal to 0.

[0026] The conformance cropping window contains the luma samples with horizontal picture coordinates from SubWidthC * sps_conf_win_left_offset to pic_width_max_in_luma_samples - ( SubWidthC * sps_conf_win_right_offset + 1 ) and vertical picture coordinates from SubHeightC * sps_conf_win_top_offset to pic_height_max_in_luma_samples - ( SubHeightC * sps_conf_win_bottom_offset + 1 ), inclusive.

[0027] The value of SubWidthC * ( sps_conf_win_left_offset + sps_conf_win_right_offset ) shall be less than pic_width_max_in_luma_samples, and the value of SubHeightC * ( sps_conf_win_top_offset + sps_conf_win_bottom_offset ) shall be less than pic_height_max_in_luma_samples.

[0028] When ChromaArrayType is not equal to 0, the corresponding specified samples of the two chroma arrays are the samples having picture coordinates ( x / SubWidthC, y / SubHeightC ), where ( x, y ) are the picture coordinates of the specified luma samples. NOTE 2 - The conformance cropping window offset parameters are only applied at the output. All internal decoding processes are applied to the uncropped picture size. sps_log2_ctu_size_minus5 plus 5 specifies the luma coding tree block size of each CTU. The value of sps_log2_ctu_size_minus5 shall be in the range of 0 to 2, inclusive. The value 3 for sps_log2_ctu_size_minus5 is reserved for future use by ITU-T | ISO / IEC.

[0029] The variables CtbLog2SizeY and CtbSizeY are derived as follows: CtbLog 2 SizeY = sps _ log 2 _ ctu _ size _ minus 5 + 5 CtbSizeY = 1 ≪ CtbLog 2 SizeY subpic_info_present_flag equal to 1 specifies that subpicture information is present for the CLVS and there may be one or more than one subpicture in each picture of the CLVS. subpic_info_present_flag equal to 0 specifies that subpicture information is not present for the CLVS and there is only one subpicture in each picture of the CLVS.

[0030] When res_change_in_clvs_allowed_flag is equal to 1, the value of subpic_info_present_flag shall be equal to 0. NOTE 3 - When a bitstream is the result of a sub-bitstream extraction process and contains only a subset of the subpictures of the input bitstream to the sub-bitstream extraction process, it might be required to set the value of subpic_info_present_ flag equal to 1 in the RBSP of the SPSs. sps_num_subpics_minus1 plus 1 specifies the number of subpictures in each picture in the CLVS. The value of sps_num_subpics_minus1 shall be in the range of 0 to Ceil( pic_width_max_in_luma_samples ÷ CtbSizeY ) * Ceil( pic_height_max_in_luma_samples ÷ CtbSizeY ) - 1, inclusive. When not present, the value of sps_num_subpics_minus1 is inferred to be equal to 0. sps_independent_subpics_flag equal to 1 specifies that no intra prediction, no inter prediction and no in-loop filtering operations may be performed across any subpicture boundary in the CLVS. sps_independent_subpics_flag equal to 0 specifies that inter prediction or in-loop filtering operations across the subpicture boundaries in the CLVS may be allowed. When not present, the value of sps_independent_subpics_flag is inferred to be equal to 0. subpic_ctu_top_left_x [ i ] specifies horizontal position of top left CTU of i-th subpicture in unit of CtbSizeY. The length of the syntax element is Ceil( Log2( ( pic_width_max_in_luma_samples + CtbSizeY - 1 ) >> CtbLog2SizeY ) ) bits. When not present, the value of subpic_ctu_top_left_x[ i ] is inferred to be equal to 0. subpic_ctu_top_left_y [ i ] specifies vertical position of top left CTU of i-th subpicture in unit of CtbSizeY. The length of the syntax element is Ceil( Log2( ( pic_height_max_in_luma_samples + CtbSizeY - 1 ) >> CtbLog2SizeY ) ) bits. When not present, the value of subpic_ctu_top_left_y[ i ] is inferred to be equal to 0. subpic_width_minus1 [ i ] plus 1 specifies the width of the i-th subpicture in units of CtbSizeY. The length of the syntax element is Ceil( Log2( ( pic_width_max_in_luma_samples + CtbSizeY - 1 ) >> CtbLog2SizeY ) ) bits.

[0031] When not present, the value of subpic_width_minus1[ i ] is inferred to be equal to ( ( pic_width_max_in_luma_samples + CtbSizeY- 1 ) >> CtbLog2SizeY ) - subpic_ctu_top_le ft_x[ i ] - 1. subpic_height_minus1 [ i ] plus 1 specifies the height of the i-th subpicture in units of CtbSizeY. The length of the syntax element is

[0032] Ceil( Log2( ( pic_height_max_in_luma_samples + CtbSizeY - 1 ) >> CtbLog2SizeY ) ) bits. When not present, the value of subpic_height_minus1[ i ] is inferred to be equal to ( ( pic_height_max_in_luma_samples + CtbSizeY- 1 ) >> CtbLog2SizeY ) - subpic_ctu_top_l eft_y[ i ] - 1. subpic_treated_as_pic_flag [ i ] equal to 1 specifies that the i-th subpicture of each coded picture in the CLVS is treated as a picture in the decoding process excluding in-loop filtering operations. subpic_treated_as_pic_flag[ i ] equal to 0 specifies that the i-th subpicture of each coded picture in the CLVS is not treated as a picture in the decoding process excluding in-loop filtering operations. When not present, the value of subpic_treated_as_pic_flag[ i ] is inferred to be equal to sps_independent_subpics_flag.

[0033] When subpic_treated_as_pic_flag[ i ] is equal to 1, it is a requirement of bitstream conformance that all of the following conditions are true for each output layer and its reference layers in an OLS that includes the layer containing the i-th subpicture as an output layer: All pictures in the output layer and its reference layers shall have the same value of pic_width_in_luma_samples and the same value of pic_height_in_luma_samples. All the SPSs referred to by the output layer and its reference layers shall have the same value of sps_num_subpics_minus1 and shall have the same values of subpic_ctu_top_left_x[ j ], subpic_ctu_top_left_y[ j ], subpic_width_minus1[ j ], subpic_height_minus1[ j ], and loop_filter_across_subpic_enabled_flag[ j ], respectively, for each value of j in the range of 0 to sps _num_subpics_minus1, inclusive. All pictures in each access unit in the output layer and its reference layers shall have the same value of SubpicIdVal[ j ] for each value of j in the range of 0 to sps_num_subpics_minus1, inclusive. loop_filter_across_subpic_enabled_flag[ i ] equal to 1 specifies that in-loop filtering operations may be performed across the boundaries of the i-th subpicture in each coded picture in the CLVS. loop_filter_across_subpic_enabled_flag[ i ] equal to 0 specifies that in-loop filtering operations are not performed across the boundaries of the i-th subpicture in each coded picture in the CLVS. When not present, the value of loop_filter_across_subpic_enabled_pic_flag[ i ] is inferred to be equal to 1 - sps_independent_subpics_flag.

[0034] It is a requirement of bitstream conformance that the shapes of the subpictures shall be such that each subpicture, when decoded, shall have its entire left boundary and entire top boundary consisting of picture boundaries or consisting of boundaries of previously decoded subpictures. sps_subpic_id_len_minus1 plus 1 specifies the number of bits used to represent the syntax element sps_subpic_id[ i ], the syntax elements pps_subpic_id[ i ], when present, and the syntax element slice_subpic_id, when present. The value of sps_subpic_id_len_minus1 shall be in the range of 0 to 15, inclusive. The value of 1 << ( sps_subpic_id_len_minus1 + 1 ) shall be greater than or equal to sps_num_subpics_minus1 + 1. subpic_id_mapping_explicitly_signalled_flag equal to 1 specifies that the subpicture ID mapping is explicitly signalled, either in the SPS or in the PPSs referred to by coded pictures of the CLVS. subpic_id_mapping_explicitly_signalled_flag equal to 0 specifies that the subpicture ID mapping is not explicitly signalled for the CLVS. When not present, the value of subpic_id_mapping_explicitly_signalled_flag is inferred to be equal to 0. subpic_id_mapping_in_sps_flag equal to 1 specifies that the subpicture ID mapping is signalled in the SPS when subpic_id_mapping_explicitly_signalled_flag is equal to 1. subpic_id_mapping_in_sps_flag equal to 0 specifies that subpicture ID mapping is signalled in the PPSs referred to by coded pictures of the CLVS when subpic_id_mapping_explicitly_signalled_flag is equal to 1. sps_subpic_id [ i ] specifies the subpicture ID of the i-th subpicture. The length of the sps_subpic_id[ i ] syntax element is sps_subpic_id_len_minus1 + 1 bits. bit_depth_minus8 specifies the bit depth of the samples of the luma and chroma arrays, BitDepth, and the value of the luma and chroma quantization parameter range offset, QpBdOffset, as follows: BitDepth = 8 + bit _ depth _ minus 8 QpBdOffset = 6 * bit _ depth _ minus 8 bit_depth_minus8 shall be in the range of 0 to 8, inclusive. sps_entropy_coding_sync_enabled_flag equal to 1 specifies that a specific synchronization process for context variables is invoked before decoding the CTU that includes the first CTB of a row of CTBs in each tile in each picture referring to the SPS, and a specific storage process for context variables is invoked after decoding the CTU that includes the first CTB of a row of CTBs in each tile in each picture referring to the SPS. sps_entropy_coding_sync_enabled_flag equal to 0 specifies that no specific synchronization process for context variables is required to be invoked before decoding the CTU that includes the first CTB of a row of CTBs in each tile in each picture referring to the SPS, and no specific storage process for context variables is required to be invoked after decoding the CTU that includes the first CTB of a row of CTBs in each tile in each picture referring to the SPS. sps_wpp_entry_point_offsets_present_flag equal to 1 specifies that signalling for entry point offsets for CTU rows may be present in the slice headers of pictures referring to the SPS when sps_entropy_coding_sync_enabled_flag is equal to 1. sps_wpp_entry_point_offsets_present_flag equal to 0 specifies that signalling for entry point offsets for CTU rows are not present in the slice headers of pictures referring to the SPS. When not present, the value of sps_wpp_entry_point_offsets_present_flag is inferred to be equal to 0. sps_weighted_pred_flag equal to 1 specifies that weighted prediction may be applied to P slices referring to the SPS. sps_weighted_pred_flag equal to 0 specifies that weighted prediction is not applied to P slices referring to the SPS. sps_weighted_bipred_flag equal to 1 specifies that explicit weighted prediction may be applied to B slices referring to the SPS. sps_weighted_bipred_flag equal to 0 specifies that explicit weighted prediction is not applied to B slices referring to the SPS. log2_max_pic_order_cnt_lsb_minus4 specifies the value of the variable MaxPicOrderCntLsb that is used in the decoding process for picture order count as follows: MaxPicOrderCntLsb = 2 log 2 _ max _ pic _ order _ cnt _ lsb _ minus 4 + 4

[0035] The value of log2_max_pic_order_cnt_lsb_minus4 shall be in the range of 0 to 12, inclusive. sps_poc_msb_flag equal to 1 specifies that the ph_poc_msb_present_flag syntax element is present in PHs referring to the SPS. sps_poc_msb_flag equal to 0 specifies that the ph_poc_msb_present_ flag syntax element is not present in PHs referring to the SPS. poc_msb_len_minus1 plus 1 specifies the length, in bits, of the poc_msb_val syntax elements, when present in the PHs referring to the SPS. The value of poc_msb_len_minus1 shall be in the range of 0 to 32 - log2 _max_pic_order_cnt_lsb_minus4 - 5, inclusive. num_extra_ph_bits_bytes specifies the number of bytes of extra bits in the PH syntax structure for coded pictures referring to the SPS. The value of num_extra_ph_bits_bytes shall be equal to 0 in bitstreams conforming to this version of this Specification. Although the value of num_extra_ph_bits_bytes is required to be equal to 0 in this version of this Specification, decoder conforming to this version of this Specification shall allow the value of num_extra_ph_bits_bytes equal to 1 or 2 to appear in the syntax. num_extra_sh_bits_bytes specifies the number of bytes of extra bits in the slice headers for coded pictures referring to the SPS. The value of num_extra_sh_bits_bytes shall be equal to 0 in bitstreams conforming to this version of this Specification. Although the value of num_extra_sh_bits_bytes is required to be equal to 0 in this version of this Specification, decoder conforming to this version of this Specification shall allow the value of num_extra_sh_bits_bytes equal to 1 or 2 to appear in the syntax. sps_sublayer_dpb_params_flag is used to control the presence of max_dec_pic_buffering_minus1[ i ], max_num_reorder_pics[ i ], and max_latency_increase_plus1[ i ] syntax elements in the dpb_parameters( ) syntax strucure in the SPS. When not present, the value of sps_sub_dpb_params_info_present_flag is inferred to be equal to 0. long_term_ref_pics_flag equal to 0 specifies that no LTRP is used for inter prediction of any coded picture in the CLVS. long_term_ref_pics_flag equal to 1 specifies that LTRPs may be used for inter prediction of one or more coded pictures in the CLVS. inter_layer_ref_pics_present_flag equal to 0 specifies that no ILRP is used for inter prediction of any coded picture in the CLVS. inter_layer_ref_pic_flag equal to 1 specifies that ILRPs may be used for inter prediction of one or more coded pictures in the CLVS. When sps_video_parameter_set_id is equal to 0, the value of inter_layer_ref_pics_present_flag is inferred to be equal to 0. When vps_independent_layer_flag[ GeneralLayerIdx[ nuh_layer_id ] ] is equal to 1, the value of inter_layer_ref_pics_present_flag shall be equal to 0. [Ed. (YK): Check whether there is a better name for this syntax element.] sps_idr_rpl_present_flag equal to 1 specifies that reference picture list syntax elements are present in slice headers of IDR pictures. sps_idr_rpl_present_flag equal to 0 specifies that reference picture list syntax elements are not present in slice headers of IDR pictures. rpl1_same_as_rpl0_flag equal to 1 specifies that the syntax element num_ref_pic_lists_in_sps[ 1 ] and the syntax structure ref_pic_list_struct( 1, rplsIdx ) are not present and the following applies: The value of num_ref_pic_lists_in_sps[ 1 ] is inferred to be equal to the value of num_ref_pic_lists_in_sps[ 0 ]. The value of each of syntax elements in ref_pic_list_struct( 1, rplsIdx ) is inferred to be equal to the value of corresponding syntax element in ref_pic_list_struct( 0, rplsIdx ) for rplsIdx ranging from 0 to num_ref_pic_lists_in_sps[ 0 ] - 1. num_ref_pic_lists_in_sps [ i ] specifies the number of the ref_pic_list_struct( listIdx, rplsIdx ) syntax structures with listIdx equal to i included in the SPS. The value of num_ref_pic_lists_in_sps[ i ] shall be in the range of 0 to 64, inclusive. NOTE 4 - For each value of listIdx (equal to 0 or 1), a decoder should allocate memory for a total number of num_ref_pic_lists_in_sps[ i ] + 1 ref_pic_list_struct( listIdx, rplsIdx ) syntax structures since there may be one ref_pic_list_struct( listIdx, rplsIdx ) syntax structure directly signalled in the slice headers of a current picture. qtbtt_dual_tree_intra_flag equal to 1 specifies that, for I slices, each CTU is split into coding units with 64×64 luma samples using an implicit quadtree split, and these coding units are the root of two separate coding_tree syntax structure for luma and chroma. qtbtt_dual_tree_intra_flag equal to 0 specifies separate coding_tree syntax structure is not used for I slices. When qtbtt_dual_tree_intra_flag is not present, it is inferred to be equal to 0. log2_min_luma_coding_block_size_minus2 plus 2 specifies the minimum luma coding block size. The value range of log2_min_luma_coding_block_size_minus2 shall be in the range of 0 to Min( 4, sps_log2_ctu_size_minus5 + 3 ), inclusive.

[0036] The variables MinCbLog2SizeY, MinCbSizeY, IbcBufWidthY, IbcBufWidthC and Vsize are derived as follows: MinCbLog 2 SizeY = log 2 _ min _ luma _ coding _ block _ size _ minus 2 + 2 MinCbSizeY = 1 ≪ MinCbLog 2 SizeY IbcBufWidthY = 256 * 128 / CtbSizeY IbcBufWidthC = IbcBufWidthY / SubWidthC VSize = Min 64 CtbSizeY

[0037] The value of MinCbSizeY shall less than or equal to VSize.

[0038] The variables CtbWidthC and CtbHeightC, which specify the width and height, respectively, of the array for each chroma CTB, are derived as follows: If chroma_format_idc is equal to 0 (monochrome) or separate_colour_plane_flag is equal to 1, CtbWidthC and CtbHeightC are both equal to 0. Otherwise, CtbWidthC and CtbHeightC are derived as follows: CtbWidthC = CtbSizeY / SubWidthC CtbHeightC = CtbSizeY / SubHeightC

[0039] For log2BlockWidth ranging from 0 to 4 and for log2BlockHeight ranging from 0 to 4, inclusive, the up-right diagonal scan order array initialization process as specified in clause 6.5.2 is invoked with 1 << log2BlockWidth and 1 << log2BlockHeight as inputs, and the output is assigned to DiagScanOrder[ log2BlockWidth ][ log2BlockHeight ].

[0040] For log2BlockWidth ranging from 0 to 6 and for log2BlockHeight ranging from 0 to 6, inclusive, the horizontal and vertical traverse scan order array initialization process as specified in clause 6.5.3 is invoked with 1 << log2BlockWidth and 1 << log2BlockHeight as inputs, and the output is assigned to HorTravScanOrder[ log2BlockWidth ][ log2BlockHeight ] and VerTravScanOrder[ log2BlockWidth ][ log2BlockHeight ]. partition_constraints_override_enabled_flag equal to 1 specifies the presence of partition_constraints_override_flag in PHs referring to the SPS. partition_constraints_override_enabled_flag equal to 0 specifies the absence of partition_constraints_override_flag in PHs referring to the SPS. sps_log2_diff_min_qt_min _cb_intra_slice_luma specifies the default difference between the base 2 logarithm of the minimum size in luma samples of a luma leaf block resulting from quadtree splitting of a CTU and the base 2 logarithm of the minimum coding block size in luma samples for luma CUs in slices with slice_type equal to 2 (I) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default difference can be overridden by ph_log2_diff_min_qt_min_cb_luma present in PHs referring to the SPS. The value of sps_log2_diff_min_qt_min_cb_intra_slice_luma shall be in the range of 0 to CtbLog2SizeY - MinCbLog2SizeY, inclusive. The base 2 logarithm of the minimum size in luma samples of a luma leaf block resulting from quadtree splitting of a CTU is derived as follows: MinQtLog 2 SizeIntraY = sps _ log 2 _ diff _ min _ qt _ min _ cb _ intra _ slice _ luma + MinCbLog 2 SizeY sps_max_mtt_hierarchy_depth_intra_slice_luma specifies the default maximum hierarchy depth for coding units resulting from multi-type tree splitting of a quadtree leaf in slices with slice_type equal to 2 (I) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default maximum hierarchy depth can be overridden by ph_max_mtt_hierarchy_depth_intra_slice_luma present in PHs referring to the SPS. The value of sps_max_mtt_hierarchy_depth_intra_slice_luma shall be in the range of 0 to 2*( CtbLog2SizeY - MinCbLog2SizeY ), inclusive. sps_log2_diff _max_bt_min_qt_intra _slice_luma specifies the default difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a luma coding block that can be split using a binary split and the minimum size (width or height) in luma samples of a luma leaf block resulting from quadtree splitting of a CTU in slices with slice_type equal to 2 (I) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default difference can be overridden by ph_log2_diff_max_bt_min_qt_luma present in PHs referring to the SPS. The value of sps_log2_diff_max_bt_min_qt_intra_slice_luma shall be in the range of 0 to CtbLog2SizeY - MinQtLog2SizeIntraY, inclusive. When sps_log2_diff_max_bt_min_qt_intra_slice_luma is not present, the value of sps_log2_diff_max_bt_min_qt_intra_slice_luma is inferred to be equal to 0. sps_log2_diff _max_tt _min_qt _intra_slice _luma specifies the default difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a luma coding block that can be split using a ternary split and the minimum size (width or height) in luma samples of a luma leaf block resulting from quadtree splitting of a CTU in slices with slice_type equal to 2 (I) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default difference can be overridden by ph_log2_diff_max_tt_min_qt_luma present in PHs referring to the SPS. The value of sps_log2_diff_max_tt_min_qt_intra_slice_luma shall be in the range of 0 to CtbLog2SizeY - MinQtLog2SizeIntraY, inclusive. When sps_log2_diff_max_tt_min_qt_intra_slice_luma is not present, the value of sps_log2_diff_max_tt_min_qt_intra_slice_luma is inferred to be equal to 0. sps_log2_diff_min_qt_min_cb_inter_slice specifies the default difference between the base 2 logarithm of the minimum size in luma samples of a luma leaf block resulting from quadtree splitting of a CTU and the base 2 logarithm of the minimum luma coding block size in luma samples for luma CUs in slices with slice_type equal to 0 (B) or 1 (P) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default difference can be overridden by ph_log2_diff_min_qt_min_cb_luma present in PHs referring to the SPS. The value of sps_log2_diff_min_qt_min_cb_inter_slice shall be in the range of 0 to CtbLog2SizeY - MinCbLog2SizeY, inclusive. The base 2 logarithm of the minimum size in luma samples of a luma leaf block resulting from quadtree splitting of a CTU is derived as follows: MinQtLog 2 SizeInterY = sps _ log 2 _ diff _ min _ qt _ min _ cb _ inter _ slice + MinCbLog 2 SizeY sps_max_mtt_hierarchy_depth_inter_slice specifies the default maximum hierarchy depth for coding units resulting from multi-type tree splitting of a quadtree leaf in slices with slice_type equal to 0 (B) or 1 (P) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default maximum hierarchy depth can be overridden by ph_max_mtt_hierarchy_depth_inter_slice present in PHs referring to the SPS. The value of sps_max_mtt_hierarchy_depth_inter_slice shall be in the range of 0 to 2*( CtbLog2SizeY - MinCbLog2SizeY ), inclusive. sps_log2_diff_max_bt_min_qt_inter_slice specifies the default difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a luma coding block that can be split using a binary split and the minimum size (width or height) in luma samples of a luma leaf block resulting from quadtree splitting of a CTU in slices with slice_type equal to 0 (B) or 1 (P) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default difference can be overridden by ph_log2_diff_max_bt_min_qt_luma present in PHs referring to the SPS. The value of sps_log2_diff_max_bt_min_qt_inter_slice shall be in the range of 0 to CtbLog2SizeY - MinQtLog2SizeInterY, inclusive. When sps_log2_diff_max_bt_min_qt_inter_slice is not present, the value of sps_log2_diff_max_bt_min_qt_inter_slice is inferred to be equal to 0. sps_log2_diff_max _tt _min_qt _inter _slice specifies the default difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a luma coding block that can be split using a ternary split and the minimum size (width or height) in luma samples of a luma leaf block resulting from quadtree splitting of a CTU in slices with slice_type equal to 0 (B) or 1 (P) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default difference can be overridden by ph_log2_diff_max_tt_min_qt_luma present in PHs referring to the SPS. The value of sps_log2_diff_max_tt_min_qt_inter_slice shall be in the range of 0 to CtbLog2SizeY - MinQtLog2SizeInterY, inclusive. When sps_log2_diff_max_tt_min_qt_inter_slice is not present, the value of sps_log2_diff_max_tt_min_qt_inter_slice is inferred to be equal to 0. sps_log2_diff_min_qt_min_cb_intra_slice_chroma specifies the default difference between the base 2 logarithm of the minimum size in luma samples of a chroma leaf block resulting from quadtree splitting of a chroma CTU with treeType equal to DUAL_TREE_CHROMA and the base 2 logarithm of the minimum coding block size in luma samples for chroma CUs with treeType equal to DUAL_TREE_CHROMA in slices with slice_type equal to 2 (I) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default difference can be overridden by ph_log2_diff_min_qt_min_cb_chroma present in PHs referring to the SPS. The value of sps_log2_diff_min_qt_min_cb_intra_slice_chroma shall be in the range of 0 to CtbLog2SizeY - MinCbLog2SizeY, inclusive. When not present, the value of sps_log2_diff_min_qt_min_cb_intra_slice_chroma is inferred to be equal to 0. The base 2 logarithm of the minimum size in luma samples of a chroma leaf block resulting from quadtree splitting of a CTU with treeType equal to DUAL_TREE_CHROMA is derived as follows: MinQtLog 2 SizeIntraC = sps _ log 2 _ diff _ min _ qt _ min _ cb _ intra _ slice _ chroma + MinCbLog 2 SizeY sps_max_mtt_hierarchy_depth_intra_slice_chroma specifies the default maximum hierarchy depth for chroma coding units resulting from multi-type tree splitting of a chroma quadtree leaf with treeType equal to DUAL_TREE_CHROMA in slices with slice_type equal to 2 (I) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default maximum hierarchy depth can be overridden by ph_max_mtt_hierarchy_depth_chroma present in PHs referring to the SPS. The value of sps_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 sps_max_mtt_hierarchy_depth_intra_slice_chroma is inferred to be equal to 0. sps_log2_diff_max_bt_min_qt_intra_slice_chroma specifies the default difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a chroma coding block that can be split using a binary split and the minimum size (width or height) in luma samples of a chroma leaf block resulting from quadtree splitting of a chroma CTU with treeType equal to DUAL_TREE_CHROMA in slices with slice_type equal to 2 (I) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default difference can be overridden by ph_log2_diff_max_bt_min_qt_chroma present in PHs referring to the SPS. The value of sps_log2_diff_max_bt_min_qt_intra_slice_chroma shall be in the range of 0 to CtbLog2SizeY - MinQtLog2SizeIntraC, inclusive. When sps_log2_diff_max_bt_min_qt_intra_slice_chroma is not present, the value of sps_log2_diff_max_bt_min_qt_intra_slice_chroma is inferred to be equal to 0. sps_log2_diff _max_tt _min_qt_intra_slice _chroma specifies the default difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a chroma coding block that can be split using a ternary split and the minimum size (width or height) in luma samples of a chroma leaf block resulting from quadtree splitting of a chroma CTU with treeType equal to DUAL_TREE_CHROMA in slices with slice_type equal to 2 (I) referring to the SPS. When partition_constraints_override_enabled_flag is equal to 1, the default difference can be overridden by ph_log2_ diff_max_tt_min_qt_chroma present in PHs referring to the SPS. The value of sps_log2_diff_max_tt_min_qt_intra _slice_chroma shall be in the range of 0 to CtbLog2SizeY - MinQtLog2SizeIntraC, inclusive. When sps_log2_diff_max_tt_min_qt_intra_slice_chroma is not present, the value of sps_log2_diff_max_tt_min_qt_intra_slice_chroma is inferred to be equal to 0. sps_max_luma_transform_size_64_flag equal to 1 specifies that the maximum transform size in luma samples is equal to 64. sps_max_luma_transform_size_64_flag equal to 0 specifies that the maximum transform size in luma samples is equal to 32.

[0041] When CtbSizeY is less than 64, the value of sps_max_luma_transform_size_64_flag shall be equal to 0.

[0042] The variables MinTbLog2SizeY, MaxTbLog2SizeY, MinTbSizeY, and MaxTbSizeY are derived as follows: MinTbLog 2 SizeY = 2 MaxTbLog 2 SizeY = sps _ max _ luma _ transform _ size _ 64 _ flag ? 6 : 5 MinTbSizeY = 1 ≪ MinTbLog 2 SizeY MaxTbSizeY = 1 ≪ MaxTbLog 2 SizeY sps_joint_cbcr_enabled_flag equal to 0 specifies that the joint coding of chroma residuals is disabled. sps_joint_cbcr_enabled_flag equal to 1 specifies that the j oint coding of chroma residuals is enabled. When not present, the value of sps_joint_cber_enabled_flag is inferred to be equal to 0. same_qp_table_for_chroma equal to 1 specifies that only one chroma QP mapping table is signalled and this table applies to Cb and Cr residuals and additionally to joint Cb-Cr residuals when sps_joint_cbcr_enabled_flag is equal to 1. same_qp_table_for_chroma equal to 0 specifies that chroma QP mapping tables, two for Cb and Cr, and one additional for joint Cb-Cr when sps_joint_cbcr_enabled_flag is equal to 1, are signalled in the SPS. When same_qp_table_for_chroma is not present in the bitstream, the value of same_qp_table_for_chroma is inferred to be equal to 1. qp_table_start_minus26 [ i ] plus 26 specifies the starting luma and chroma QP used to describe the i-th chroma QP mapping table. The value of qp_table_start_minus26[ i ] shall be in the range of -26 - QpBdOffset to 36 inclusive. When qp_table_start_minus26[ i ] is not present in the bitstream, the value of qp_table_start_minus26[ i ] is inferred to be equal to 0. num_points_in_qp_table_minus1 [ i ] plus 1 specifies the number of points used to describe the i-th chroma QP mapping table. The value of num_points_in_qp_table_minus1[ i ] shall be in the range of 0 to 63 + QpBdOffset, inclusive. When num_points_in_qp_table_minus1[ 0 ] is not present in the bitstream, the value of num_points_in_qp_table_minus1[ 0 ] is inferred to be equal to 0. delta_qp_in_val_minus1[ i ][ j ] specifies a delta value used to derive the input coordinate of the j-th pivot point of the i-th chroma QP mapping table. When delta_qp_in_val_minus1[ 0 ][ j ] is not present in the bitstream, the value of delta_qp_in_val_minus1[ 0 ][ j ] is inferred to be equal to 0. delta_qp_diff_val [ i ][ j ] specifies a delta value used to derive the output coordinate of the j-th pivot point of the i-th chroma QP mapping table.

[0043] The i-th chroma QP mapping table ChromaQpTable[ i ] for i = 0..numQpTables - 1 is derived as follows: qpInVal[ i ][ 0 ] = qp_table_start_minus26[ i ] + 26 qpOutVal[ i ][ 0 ] = qpInVal[ i ][ 0 ] for( j = 0; j <= num_points_in_qp_table_minus1[ i ]; j++ ) { qpInVal[ i ][ j + 1 ] = qpInVal[ i ][ j ] + delta_qp_in_val_minus1[ i ][ j ] + 1 qpOutVal[ i ][ j + 1 ] = qpOutVal[ i ][ j ] + ( delta_qp_in_val_minus1[ i ][ j ] ^ delta_qp_diff_val[ i ][ j ] ) } ChromaQpTable[ i ][ qpInVal[ i ][ 0] ] = qpOutVal[ i ][ 0 ] for( k = qpInVal[ i ][ 0 ] - 1; k >= -QpBdOffset; k - - ) ChromaQpTable[ i ][ k ] = Clip3( -QpBdOffset, 63, ChromaQpTable[ i ][ k + 1 ] - 1 ) (62) for( j = 0; j <= num_points_in_qp_table_minus1[ i ]; j++ ) { sh = ( delta_qp_in_val_minus1[ i ][j ] + 1 ) >> 1 for( k = qpInVal[ i ][ j ] + 1, m = 1; k <= qpInval[ i ][ j + 1 ]; k++, m++ ) ChromaQpTable[ i ][ k ] = ChromaQpTable[ i ][ qpInVal[ i ][ j ] ] + ( ( qpOutVal[ i ][j + 1] - qpOutVal[ i ][j ] ) * m + sh) / ( delta_qp_in_val_minus1[ i ][j] + 1 ) } for( k = qpInVal[ i ][ num_points_in_qp_table_minus1[ i ] + 1 ] + 1; k <= 63; k++ ) ChromaQpTable[ i ][ k ] = Clip3( -QpBdOffset, 63, ChromaQpTable[ i ][ k - 1 ] + 1 )

[0044] When same_qp_table_for_chroma is equal to 1, ChromaQpTable[ 1 ][ k ] and ChromaQpTable[ 2 ][ k ] are set equal to ChromaQpTable[ 0 ][ k ] for k in the range of -QpBdOffset to 63, inclusive.

[0045] It is a requirement of bitstream conformance that the values of qpInVal[ i ][ j ] and qpOutVal[ i ][ j ] shall be in the range of -QpBdOffset to 63, inclusive for i in the range of 0 to numQpTables - 1, inclusive, and j in the range of 0 to num_points_in_qp_table_minus1[ i ] + 1, inclusive. sps_sao_enabled_flag equal to 1 specifies that the sample adaptive offset process is applied to the reconstructed picture after the deblocking filter process. sps_sao_enabled_flag equal to 0 specifies that the sample adaptive offset process is not applied to the reconstructed picture after the deblocking filter process. sps_alf _enabled_flag equal to 0 specifies that the adaptive loop filter is disabled. sps_alf_enabled_flag equal to 1 specifies that the adaptive loop filter is enabled. sps_ccalf _enabled_flag equal to 0 specifies that the cross-component adaptive loop filter is disabled. sps_ccalf_enabled_flag equal to 1 specifies that the cross-component adaptive loop filter may be enabled. sps_transform_skip_enabled_flag equa to 1 specifies that transform_skip_flag may be present in the transform unit syntax. sps_transform_skip_enabled_flag equal to 0 specifies that transform_skip_flag is not present in the transform unit syntax. log2_transform_skip_max_size_minus2 specifies the maximum block size used for transform skip, and shall be in the range of 0 to 3, inclusive.

[0046] The variable MaxTsSize is set equal to 1 << ( log2_transform_skip_max_size_minus2 + 2 ). sps_bdpcm_enabled_flag equal to 1 specifies that intra_bdpcm_luma_flag and intra_bdpcm_chroma_flag may be present in the coding unit syntax for intra coding units. sps_bdpcm_enabled_flag equal to 0 specifies that intra_bdpcm_luma _flag and intra_bdpcm_chroma_flag are not present in the coding unit syntax for intra coding units. When not present, the value of sps_bdpcm_enabled_flag is inferred to be equal to 0. sps_ref_wraparound_enabled_flag equal to 1 specifies that horizontal wrap-around motion compensation is applied in inter prediction. sps_ref_wraparound_enabled_flag equal to 0 specifies that horizontal wrap-around motion compensation is not applied. When the value of ( CtbSizeY / MinCbSizeY + 1) is greater than ( pic_width_in_luma_samples / MinCbSizeY - 1 ), where pic_width_in_luma_samples is the value of pic_width_in_luma_samples in any PPS that refers to the SPS, the value of sps_ref_wraparound_enabled_flag shall be equal to 0. [Ed. (YK): The semantics here still depends on PPS syntax elements.] sps_temporal_mvp_enabled_flag equal to 1 specifies that temporal motion vector predictors may be used in the CLVS. sps_temporal_mvp_enabled_flag equal to 0 specifies that temporal motion vector predictors are not used in the CLVS. sps_sbtmvp_enabled_flag equal to 1 specifies that subblock-based temporal motion vector predictors may be used in decoding of pictures with all slices having slice_type not equal to I in the CLVS. sps_sbtmvp_enabled_flag equal to 0 specifies that subblock-based temporal motion vector predictors are not used in the CLVS. When sps_sbtmvp_enabled_flag is not present, it is inferred to be equal to 0. sps_amvr_enabled_flag equal to 1 specifies that adaptive motion vector difference resolution is used in motion vector coding. amvr_enabled_flag equal to 0 specifies that adaptive motion vector difference resolution is not used in motion vector coding. sps_bdof_enabled_flag equal to 0 specifies that the bi-directional optical flow inter prediction is disabled. sps_bdof_enabled_flag equal to 1 specifies that the bi-directional optical flow inter prediction is enabled. sps_bdof_pic_present_flag equal to 1 specifies that ph_disable_bdof_flag is present in PHs referring to the SPS. sps_bdof_pic_present_flag equal to 0 specifies that ph_disable_bdof_flag is not present in PHs referring to the SPS. When sps_bdof_pic_present_flag is not present, the value of sps_bdof_pic_present_flag is inferred to be equal to 0. sps_smvd_enabled_flag equal to 1 specifies that symmetric motion vector difference may be used in motion vector decoding. sps_smvd_enabled_flag equal to 0 specifies that symmetric motion vector difference is not used in motion vector coding. sps_dmvr_enabled_flag equal to 1 specifies that decoder motion vector refinement based inter bi-prediction is enabled. sps_dmvr_enabled_flag equal to 0 specifies that decoder motion vector refinement based inter bi-prediction is disabled. sps_dmvr_pic_present_flag equal to 1 specifies that ph_disable_dmvr_flag is present in PHs referring to the SPS. sps_dmvr_pic_present_flag equal to 0 specifies that ph_disable_dmvr_flag is not present in PHs referring to the SPS. When sps_dmvr_pic_present_flag is not present, the value of sps_dmvr_pic_present_ flag is inferred to be equal to 0. sps_mmvd_enabled_flag equal to 1 specifies that merge mode with motion vector difference is enabled. sps_mmvd_enabled_flag equal to 0 specifies that merge mode with motion vector difference is disabled. sps_isp_enabled_flag equal to 1 specifies that intra prediction with subpartitions is enabled. sps_isp_enabled_flag equal to 0 specifies that intra prediction with subpartitions is disabled. sps_mrl_enabled_flag equal to 1 specifies that intra prediction with multiple reference lines is enabled. sps_mrl_enabled_flag equal to 0 specifies that intra prediction with multiple reference lines is disabled. sps_mip_enabled_flag equal to 1 specifies that matrix-based intra prediction is enabled. sps_mip_enabled_flag equal to 0 specifies that matrix-based intra prediction is disabled. sps_cclm_enabled_flag equal to 0 specifies that the cross-component linear model intra prediction from luma component to chroma component is disabled. sps_cclm_enabled_flag equal to 1 specifies that the cross-component linear model intra prediction from luma component to chroma componenent is enabled. When sps_cclm_enabled_flag is not present, it is inferred to be equal to 0. sps_chroma_horizontal_collocated_flag equal to 1 specifies that prediction processes operate in a manner designed for chroma sample positions that are not horizontally shifted relative to corresponding luma sample positions. sps_chroma_horizontal_collocated_flag equal to 0 specifies that prediction processes operate in a manner designed for chroma sample positions that are shifted to the right by 0.5 in units of luma samples relative to corresponding luma sample positions. When sps_chroma_horizontal_collocated_flag is not present, it is inferred to be equal to 1. sps_chroma_vertical_collocated_flag equal to 1 specifies that prediction processes operate in a manner designed for chroma sample positions that are not vertically shifted relative to corresponding luma sample positions. sps_chroma_vertical_collocated_flag equal to 0 specifies that prediction processes operate in a manner designed for chroma sample positions that are shifted downward by 0.5 in units of luma samples relative to corresponding luma sample positions. When sps_chroma_vertical_collocated_flag is not present, it is inferred to be equal to 1. sps_mts_enabled_flag equal to 1 specifies that sps_explicit_mts_intra_enabled_flag is present in the sequence parameter set RBSP syntax and sps_explicit_mts_inter_enabled_flag is present in the sequence parameter set RBSP syntax. sps_mts_enabled_flag equal to 0 specifies that sps_explicit_mts_intra_enabled_flag is not present in the sequence parameter set RBSP syntax and sps_explicit_mts_inter_enabled_flag is not present in the sequence parameter set RBSP syntax. sps_explicit_mts_intra_enabled_flag equal to 1 specifies that mts_idx may be present in intra coding unit syntax. sps_explicit_mts_intra_enabled_flag equal to 0 specifies that mts_idx is not present in intra coding unit syntax. When not present, the value of sps_explicit_mts_intra_enabled_flag is inferred to be equal to 0. sps_explicit_mts_inter_enabled_flag equal to 1 specifies that mts_idx may be present in inter coding unit syntax. sps_explicit_mts_inter_enabled_flag equal to 0 specifies that mts_idx is not present in inter coding unit syntax. When not present, the value of sps_explicit_mts_inter_enabled_flag is inferred to be equal to 0. six_minus_max_num_merge_cand specifies the maximum number of merging motion vector prediction (MVP) candidates supported in the SPS subtracted from 6. The value of six_minus_max_num_merge_cand shall be in the range of 0 to 5, inclusive.

[0047] The maximum number of merging MVP candidates, MaxNumMergeCand, is derived as follows: MaxNumMergeCand = 6 − six _ minus _ max _ num _ merge _ cand sps_sbt_enabled_flag equal to 0 specifies that subblock transform for inter-predicted CUs is disabled. sps_sbt_enabled_flag equal to 1 specifies that subblock transform for inter-predicteds CU is enabled. sps_affine_enabled_flag specifies whether affine model based motion compensation can be used for inter prediction. If sps_affine_enabled_flag is equal to 0, the syntax shall be constrained such that no affine model based motion compensation is used in the CLVS, and inter_affine_flag and cu_affine_type_flag are not present in coding unit syntax of the CLVS. Otherwise (sps_affine_enabled_flag is equal to 1), affine model based motion compensation can be used in the CLVS. five_minus_max_num_subblock_merge_cand specifies the maximum number of subblock-based merging motion vector prediction candidates supported in the SPS subtracted from 5. sps_affine_type_flag specifies whether 6-parameter affine model based motion compensation can be used for inter prediction. If sps_affine_type_flag is equal to 0, the syntax shall be constrained such that no 6-parameter affine model based motion compensation is used in the CLVS, and cu_affine_type_flag is not present in coding unit syntax in the CLVS. Otherwise (sps_affine_type_flag is equal to 1), 6-parameter affine model based motion compensation can be used in the CLVS. When not present, the value of sps_affine_type_flag is inferred to be equal to 0. sps_affine_amvr_enabled_flag equal to 1 specifies that adaptive motion vector difference resolution is used in motion vector coding of affine inter mode. sps_affine_amvr_enabled_flag equal to 0 specifies that adaptive motion vector difference resolution is not used in motion vector coding of affine inter mode. When not present, the value of sps_affine_amvr_enabled_flag is inferred to be equal to 0. sps_affine_prof_enabled_flag specifies whether the prediction refinement with optical flow can be used for affine motion compensation. If sps_affine_prof_enabled_flag is equal to 0, the affine motion compensation shall not be refined with optical flow. Otherwise (sps_affine_prof_enabled_flag is equal to 1), the affine motion compensation can be refined with optical flow. When not present, the value of sps_affine_prof_enabled_flag is inferred to be equal to 0. sps_prof_pic_present_flag equal to 1 specifies that ph_disable_prof_flag is present in PHs referring to the SPS. sps_prof_pic_present_flag equal to 0 specifies that ph_disable_prof_ flag is not present in PHs referring to the SPS. When sps_prof_pic_present_flag is not present, the value of sps_prof_pic_present_flag is inferred to be equal to 0. sps_palette_enabled_flag equal to 1 specifies that pred_mode_plt_flag may be present in the coding unit syntax. sps_palette_enabled_flag equal to 0 specifies that pred_mode_plt_flag is not present in the coding unit syntax. When sps_palette_enabled_flag is not present, it is inferred to be equal to 0. sps_act_enabled_flag equal to 1 specifies that adaptive colour transform may be used and the cu_act_enabled_flag may be present in the coding unit syntax. sps_act_enabled_flag equal to 0 speifies that adaptive colour transform is not used and cu_act_enabled_flag is not present in the coding unit syntax. When sps_act_enabled_flag is not present, it is inferred to be equal to 0. min_qp_prime_ts_minus4 specifies the minimum allowed quantization parameter for transform skip mode as follows: QpPrimeTsMin = 4 + min _ qp _ prime _ ts _ minus 4

[0048] The value of min_qp_prime_ts_minus4 shall be in the range of 0 to 48, inclusive. sps_bcw_enabled_flag specifies whether bi-prediction with CU weights can be used for inter prediction. If sps_bcw_enabled_flag is equal to 0, the syntax shall be constrained such that no bi-prediction with CU weights is used in the CLVS, and bcw_idx is not present in coding unit syntax of the CLVS. Otherwise (sps_bcw_enabled_flag is equal to 1), bi-prediction with CU weights can be used in the CLVS. sps_ibc_enabled_flag equal to 1 specifies that the IBC prediction mode may be used in decoding of pictures in the CLVS. sps_ibc_enabled_flag equal to 0 specifies that the IBC prediction mode is not used in the CLVS. When sps_ibc_enabled_flag is not present, it is inferred to be equal to 0. six_minus_max_num_ibc_merge_cand specifies the maximum number of IBC merging block vector prediction (BVP) candidates supported in the SPS subtracted from 6. The value of six_minus_max_num_ibc_merge_cand shall be in the range of 0 to 5, inclusive.

[0049] The maximum number of IBC merging BVP candidates, MaxNumIbcMergeCand, is derived as follows: sps_ciip_enabled_flag specifies that ciip_flag may be present in the coding unit syntax for inter coding units. sps_ciip_enabled _flag equal to 0 specifies that ciip_flag is not present in the coding unit syntax for inter coding units. sps_fpel_mmvd_enabled_flag equal to 1 specifies that merge mode with motion vector difference is using integer sample precision. sps_fpel_mmvd_enabled_flag equal to 0 specifies that merge mode with motion vector difference can use fractional sample precision. sps_gpm_enabled_flag specifies whether geometric partition based motion compensation can be used for inter prediction. sps_gpm_enabled_flag equal to 0 specifies that the syntax shall be constrained such that no geometric partition based motion compensation is used in the CLVS, and merge_gpm_partition_idx, merge_gpm_idx0, and merge_gpm_idx1 are not present in coding unit syntax of the CLVS. sps_gpmenabled_flag equal to 1 specifies that geometric partition based motion compensation can be used in the CLVS. When not present, the value of sps_gpm_enabled_flag is inferred to be equal to 0. max_num_merge_cand_minus_max_num_gpm_cand specifies the maximum number of geometric partitioning merge mode candidates supported in the SPS subtracted from MaxNumMergeCand.

[0050] The maximum number of geometric partitioning merge mode candidates, MaxNumGpmMergeCand, is derived as follows:

[0051] The value of MaxNumGpmMergeCand shall be in the range of 2 to MaxNumMergeCand, inclusive. sps_lmcs_enabled_flag equal to 1 specifies that luma mapping with chroma scaling is used in the CLVS. sps_lmes_enabled_flag equal to 0 specifies that luma mapping with chroma scaling is not used in the CLVS. sps_lfnst_enabled_flag equal to 1 specifies that lfnst_idx may be present in intra coding unit syntax. sps_lfnst_enabled_flag equal to 0 specifies that lfnst_idx is not present in intra coding unit syntax. sps_ladf_enabled_flag equal to 1, specifies that sps_num_ladf_intervals_minus2, sps_ladf--_lowest_interval_qp_offset, sps_ladf_qp_offset[ i ], and sps_ladf_delta_threshold_minus1[ i ] are present in the SPS. sps_num_ladf_intervals_minus2 plus 1 specifies the number of sps_ladf_delta_threshold_minus1[ i ] and sps_ladf_qp_offset[ i ] syntax elements that are present in the SPS. The value of sps_num_ladf_intervals_minus2 shall be in the range of 0 to 3, inclusive. sps_ladf_lowest_interval_qp_offset specifies the offset used to derive the variable qP as specified in clause 8.8.3.6.1. The value of sps_ladf_lowest_interval_qp_offset shall be in the range of -63 to 63, inclusive. sps_ladf qp_offset[ i ] specifies the offset array used to derive the variable qP as specified in clause 8.8.3.6.1. The value of sps_ladf_qp_offset[ i ] shall be in the range of -63 to 63, inclusive. sps_ladf_delta_threshold_minus1[ i ] is used to compute the values of SpsLadfIntervalLowerBound[ i ], which specifies the lower bound of the i-th luma intensity level interval. The value of sps_ladf_delta_threshold_minus1[ i ] shall be in the range of 0 to 2 BitDepth< - 3, inclusive.

[0052] The value of SpsLadfIntervalLowerBound[ 0 ] is set equal to 0.

[0053] For each value of i in the range of 0 to sps_num_ladf_intervals_minus2, inclusive, the variable SpsLadfIntervalLowerBound[ i + 1 ] is derived as follows: SpsLadfIntervalLowerBound i + 1 = SpsLadfIntervalLowerBound i + sps_ladf_delta_threshold_minus 1 i + 1 log2_parallel_merge_level_minus2 plus 2 specifies the value of the variable Log2ParMrgLevel, which is used in the derivation process for spatial merging candidates as specified in clause 8.5.2.3, the derivation process for motion vectors and reference indices in subblock merge mode as specified in clause 8.5.5.2, and to control the invocation of the updating process for the history-based motion vector predictor list in clause 8.5.2.1. The value of log2_parallel_merge_level_minus2 shall be in the range of 0 to CtbLog2SizeY - 2, inclusive. The variable Log2ParMrgLevel is derived as follows: Log 2 ParMrgLevel = log 2 _parallel_merge_level_minus 2 + 2 sps_scaling_list_enabled_flag equal to 1 specifies that a scaling list is used for the scaling process for transform coefficients. sps_scaling_list_enabled_flag equal to 0 specifies that scaling list is not used for the scaling process for transform coefficients. sps_dep_quant_enabled_flag equal to 0 specifies that dependent quantization is disabled for pictures referring to the SPS. sps_dep_quant_enabled_flag equal to 1 specifies that dependent quantization may be enabled for pictures referring to the SPS. sps_sign_data_hiding_enabled_flag equal to 0 specifies that sign bit hiding is disabled for pictures referring to the SPS. sps_sign_data_hiding_enabled_flag equal to 1 specifies that sign bit hiding may be enabled for pictures referring to the SPS. When sps_sign_data_hidingenabled_flag is not present, it is inferred to be equal to 0. sps_virtual_boundaries_enabled_flag equal to 1 specifies that disabling in-loop filtering across virtual boundaries may be applied in the coded pictures in the CLVS. sps_virtual_boundaries_enabled_flag equal to 0 specifies that disabling in-loop filtering across virtual boundaries is not applied in the coded pictures in the CLVS. In-loop filtering operations include the deblocking filter, sample adaptive offset filter, and adaptive loop filter operations. sps_virtual_boundaries_present_flag equal to 1 specifies that information of virtual boundaries is signalled in the SPS. sps_virtual_boundaries_present_flag equal to 0 specifies that information of virtual boundaries is not signalled in the SPS. When there is one or more than one virtual boundaries signalled in the SPS, the in-loop filtering operations are disabled across the virtual boundaries in pictures referring to the SPS. In-loop filtering operations include the deblocking filter, sample adaptive offset filter, and adaptive loop filter operations.

[0054] It is a requirement of bitstream conformance that when the value of res_change_in_clvs_allowed _flag is equal to 1, the value of sps_virtual_boundaries_present_flag shall be equal to 0. sps_num_ver_virtual_boundaries specifies the number of sps_virtual_boundaries_pos_x[ i ] syntax elements that are present in the SPS. When sps_num_ver_virtual_boundaries is not present, it is inferred to be equal to 0. sps_virtual_boundaries_pos_x [ i ] specifies the location of the i-th vertical virtual boundary in units of luma samples divided by 8. The value of sps_virtual_boundaries_pos_x[ i ] shall be in the range of 1 to Ceil( pic_width_in_luma_samples ÷ 8) - 1, inclusive. [Ed. (VD): pic_width_in_luma_samples is in the PPS, not in the SPS.] sps_num_hor_virtual_boundaries specifies the number of sps_virtual_boundaries_pos_y[ i ] syntax elements that are present in the SPS. When sps_num_hor_virtual_boundaries is not present, it is inferred to be equal to 0.

[0055] When sps_virtual_boundaries_enabled_flag is equal to 1 and sps_virtual_boundaries_present_flag is equal to 1, the sum of sps_num _ver_virtual_boundaries and sps_num_hor_ virtual_boundaries shall be greater than 0. sps_virtual_boundaries_pos_y[ i ] specifies the location of the i-th horizontal virtual boundary in units of luma samples divided by 8. The value of sps_virtual_boundaries_pos_y[ i ] shall be in the range of 1 to Ceil( pic_height_in_luma_samples ÷ 8 ) - 1, inclusive. [Ed. (VD): pic_height_in_luma_samples is in the PPS, not in the SPS.] sps_general_hrd_params_present_flag equal to 1 specifies that the syntax structure general_hrd_parameters( ) is present in the SPS RBSP syntax structure. sps_general_hrd_params_present_flag equal to 0 specifies that the syntax structure general _hrd_parameters( ) is not present in the SPS RBSP syntax structure. sps_sublayer_cpb_params_present_flag equal to 1 specifies that the syntax structure old_hrd_parameters( ) in the SPS RBSP includes HRD parameters for sublayer representations with TemporalId in the range of 0 to sps_max_sublayers_minus1, inclusive. sps_sublayer_cpb_params_present_flag equal to 0 specifies that the syntax structure ols_hrd_parameters( ) in the SPS RBSP includes HRD parameters for the sublayer representation with TemporalId equal to sps_max_sublayers_minus1 only. When sps_max_sublayers_minus1 is equal to 0, the value of sps_sublayer_cpb_params_present_flag is inferred to be equal to 0.

[0056] When sps_sublayer_cpb_params_present_flag is equal to 0, the HRD parameters for the sublayer representations with TemporalId in the range of 0 to sps_max_sublayers _minus1 - 1, inclusive, are inferred to be the same as that for the sublayer representation with TemporalId equal to sps_max_sublayers_minus1. These include the HRD parameters starting from the fixed_pic_rate_general_flag[ i ] syntax element till the sublayer_hrd_parameters( i ) syntax structure immediately under the condition "if( general_vcl_hrd_params_present_flag )" in the ols_hrd_parameters syntax structure. field_seq_flag equal to 1 indicates that the CLVS conveys pictures that represent fields. field_seq_flag equal to 0 indicates that the CLVS conveys pictures that represent frames. When general_frame_only_constraint_flag is equal to 1, the value of field_seq_flag shall be equal to 0.

[0057] When field_seq_flag is equal to 1, a frame-field information SEI message shall be present for every coded picture in the CLVS. NOTE 5 - The specified decoding process does not treat pictures that represent fields or frames differently. A sequence of pictures that represent fields would therefore be coded with the picture dimensions of an individual field. For example, pictures that represent 1080i fields would commonly have cropped output dimensions of 1920x540, while the sequence picture rate would commonly express the rate of the source fields (typically between 50 and 60 Hz), instead of the source frame rate (typically between 25 and 30 Hz). vui_parameters_present_flag equal to 1 specifies that the syntax structure vui_parameters( ) is present in the SPS RBSP syntax structure. vui_parameters_present_flag equal to 0 specifies that the syntax structure vui_parameters( ) is not present in the SPS RBSP syntax structure. sps_extension_flag equal to 0 specifies that no sps_extension_data_flag syntax elements are present in the SPS RBSP syntax structure. sps_extension_flag equal to 1 specifies that there are sps_extension_data_flag syntax elements present in the SPS RBSP syntax structure. sps_extension_data_flag may have any value. Its presence and value do not affect decoder conformance to profiles specified in this version of this Specification. Decoders conforming to this version of this Specification shall ignore all sps_extension_data_flag syntax elements. 3.3. PPS syntax and semantics

[0058] In the latest VVC draft text, the PPS syntax and semantics are as follows: pic_parameter_set_rbsp( ) {Descript or  pps_pic_parameter_set_id ue(v) pps_seq_parameter_set_id u(4) mixed_nalu_types_in_pic_flag u(1) pic_width_in_luma_samples ue(v) pic_height_in_luma_samples ue(v) pps_conformance_window_flag u(1)  if( pps_conformance_window_flag ) {  pps_conf_win_left_offset ue(v)  pps_conf_win_right_offset ue(v)  pps_conf_win_top_offset ue(v)  pps_conf_win_bottom_offset ue(v)  } scaling_window_explicit_signalling_flag u(1)  if( scaling_window_explicit_signalling_flag ) {  scaling_win_left_offset ue(v)  scaling_win_right_offset ue(v)  scaling_win_top_offset ue(v)  scaling_win_bottom_offset ue(v)  } output_flag_present_flag u(1) subpic_id_mapping_in_pps_flag u(1)  if( subpic_id_mapping_in_pps_flag ) {  pps_num_subpics_minus1 ue(v)  pps_subpic_id_len_minus1 ue(v)   for( i = 0; i <= pps_num_subpic minus 1; i++)   pps_subpic_id[ i ]u(v)  } no_pic_partition_flag u(1)  if( !no_pic_partition_flag ) {  pps_log2_ctu_size_minus5 u(2)  num_exp_tile_columns_minus1 ue(v)  num_exp_tile_rows_minus1 ue(v)   for( i = 0; i <= num_exp_tile_columns_minus1; i++ )   tile_column_width_minus1[ i ]ue(v)   for( i = 0; i <= num_exp_tile_rows_minus1; i++ )   tile_row_height_minus1[ i ]ue(v)   if( NumTilesInPic > 1 )   rect_slice_flag u(1)   if( rect_slice_flag )   single_slice_per_subpic_flag u(1)   if( rect_slice_flag && !single_slice_per_subpic_flag ) {   num_slices_in_pic_minus1 ue(v)    if( num_slices_in_pic_minus1 > 0 )    tile_idx_delta_present_flag u(1)    for( i = 0; i < num_slices_in_pic_minus1; i++ ) {     if( NumTileColumns > 1 )     slice_width_in_tiles_minus1[ i ]ue(v)     if( NumTileRows > 1 &&      ( tile_idx_delta_present_flag ∥ tileIdx % NumTileColumns = = 0))     slice_height_in_tiles_minus1 [ i ]ue(v)     if( slice_width_in_tiles_minus1[ i ] = = 0 &&      slice_height_in_tiles_minus1[ i ] = = 0 &&      RowHeight[ SliceTopLeftTileIdx[ i ] / NumTileColumns ] > 1 ) {    num_exp_slices_in_tile [ i ]ue(v)     for( j = 0; j < num_exp_slices_in_tile[ i ]; j++ )     exp_slice_height_in_ctus_minus1 [ j ]ue(v)     i += NumSlicesInTile[ i ] - 1    }    if( tile _idx_delta_present_flag && i < num_slices_in_pic_minus1 )    tile_idx_delta [ i ]se(v)    }   }  loop_filter_across_tiles_enabled_flag u(1)  loop_filter_across_slices_enabled_flag u(1)  } cabac_init_present_flag u(1)  for( i = 0; i < 2; i++ )  num_ref_idx_default_active_minus1 [ i ]ue(v) rpl1_idx_present_flag u(1) init_qp_minus26 se(v) cu_qp_delta_enabled_flag u(1) pps_chroma_tool_offsets_present_flag u(1)  if( pps_chroma_tool_offsets_present_flag ) {  pps_cb_qp_offset se(v)  pps_cr_qp_offset se(v)  pps_joint_cber_qp_offset_present_flag u(1)   if( pps_joint_cber_qp_offset_present_flag )   pps_joint_cber_qp_offset_value se(v)  pps_slice_chroma_qp_offsets_present_flag u(1)  pps_cu_chroma_qp_offset_list_enabled_flag u(1)  }  if( pps_cu_chroma_qp_offset_list_enabled_flag ) {  chroma_qp_offset_list_len_minus1 ue(v)   for( i = 0; i <= chroma_qp_offset_list_len_minus1; i++ ) {   cb_qp_offset_list [ i ]se(v)   cr_qp_offset_list [ i ]se(v)    if( pps_joint_cbcr_qp_offset_present_flag )    joint_cbcr_qp_offset_list [ i ]se(v)   }  } pps_weighted_pred_flag u(1) pps_weighted_bipred_flag u(1) deblocking_filter_control_present_flag u(1)  if( deblocking_filter_control_present_flag) {  deblocking_filter_override_enabled_flag u(1)  pps_deblocking_filter_disabled_flag u(1)   if( !pps_deblocking_filter_disabled_flag ) {   pps_beta_offset_div2 se(v)   pps_tc_offset_div2 se(v)   pps_cb_beta_offset_div2 se(v)   pps_cb_tc_offset_div2 se(v)   pps_cr_beta_offset_div2 se(v)   pps_cr_tc_offset_div2 se(v)   }  } rpl_info_in_ph_flag u(1)  if( deblocking_filter_override_enabled_flag )  dbf_info_in_ph_flag u(1) sao_info_in_ph_flag u(1) alf _info_in_ph_flag u(1)  if( ( pps _weighted_pred_flag ∥ pps_weighted_bipred_flag ) && rpl_info_in_ph_flag )  wp_info_in_ph_flag u(1) qp_delta_info_in_ph_flag u(1) pps_ref_wraparound_enabled_flag u(1)  if( pps_ref_wraparound_enabled_flag )  pps_ref_wraparound_offset ue(v) picture_header_extension_present_flag u(1) slice_header_extension_present_flag u(1) pps_extension_flag u(1)  if( pps_extension_flag )   while( more_rbsp_data() )   pps_extension_data_flag u(1)  rbsp_trailing_bits( )}

[0059] A PPS RBSP shall be available to the decoding process prior to it being referenced, included in at least one AU with TemporalId less than or equal to the TemporalId of the PPS NAL unit or provided through external means.

[0060] All PPS NAL units with a particular value of pps_pic_parameter_set_id within a PU shall have the same content. pps_pic_parameter_set_id identifies the PPS for reference by other syntax elements. The value of pps_pic_parameter_set_id shall be in the range of 0 to 63, inclusive.

[0061] PPS NAL units, regardless of the nuh_layer_id values, share the same value space of pps_pic_parameter_set_id.

[0062] Let ppsLayerId be the value of the nuh_layer_id of a particular PPS NAL unit, and vclLayerId be the value of the nuh_layer_id of a particular VCL NAL unit. The particular VCL NAL unit shall not refer to the particular PPS NAL unit unless ppsLayerId is less than or equal to vclLayerId and the layer with nuh_layer_id equal to ppsLayerId is included in at least one OLS that includes the layer with nuh_layer_id equal to vclLayerId. pps_seq_parameter_set_id specifies the value of sps_seq_parameter_set_id for the SPS. The value of pps _seq_parameter_set _id shall be in the range of 0 to 15, inclusive. The value of pps_seq_parameter_set_id shall be the same in all PPSs that are referred to by coded pictures in a CLVS. mixed_nalu_types_in_pic_flag equal to 1 specifies that each picture referring to the PPS has more than one VCL NAL unit, the VCL NAL units do not have the same value of nal_unit_type, and the picture is not an IRAP picture. mixed_nalu_types_in_pic_flag equal to 0 specifies that each picture referring to the PPS has one or more VCL NAL units and the VCL NAL units of each picture refering to the PPS have the same value of nal_unit_type.

[0063] When no_mixed_nalu_types_in_pic_constraint_flag is equal to 1, the value of mixed_nalu_types_in_pic_flag shall be equal to 0.

[0064] For each slice with a nal_unit_type value nalUnitTypeA in the range of IDR_W_RADL to CRA_NUT, inclusive, in a picture picA that also contains one or more slices with another value of nal_unit_type (i.e., the value of mixed_nalu_types_in_pic_flag for the picture picA is equal to 1), the following applies: The slice shall belong to a subpicture subpicA for which the value of the corresponding subpic_treated_as_pic_flag[ i ] is equal to 1. The slice shall not belong to a subpicture of picA containing VCL NAL units with nal_unit_type not equal to nalUnitTypeA. If nalUnitTypeA is equal to CRA, for all the following PUs following the current picture in the CLVS in decoding order and in output order, neither RefPicList[ 0 ] nor RefPicList[ 1 ] of a slice in subpicA in those PUs shall include any picture preceding picA in decoding order in an active entry. Otherwise (i.e., nalUnitTypeA is equal to IDR_W_RADL or IDR_N_LP), for all the PUs in the CLVS following the current picture in decoding order, neither RefPicList[ 0] nor RefPicList[ 1 ] of a slice in subpicA in those PUs shall include any picture preceding picA in decoding order in an active entry. NOTE 1- mixed_nalu_types_in_pic_flag equal to 1 indicates that pictures referring to the PPS contain slices with different NAL unit types, e.g., coded pictures originating from a subpicture bitstream merging operation for which encoders have to ensure matching bitstream structure and further alignment of parameters of the original bitstreams. One example of such alignments is as follows: When the value of sps_idr_rpl_flag is equal to 0 and mixed_nalu_types_in_pic_flag is equal to 1, a picture referring to the PPS cannot have slices with nal_unit_type equal to IDR_W_RADL or IDR_N_LP. pic_width_in_luma_samples specifies the width of each decoded picture referring to the PPS in units of luma samples. pic_width_in_luma_samples shall not be equal to 0, shall be an integer multiple of Max( 8, MinCbSizeY ), and shall be less than or equal to pic_width_max_in_luma_samples.

[0065] When res_change_in_clvs_allowed_flag equal to 0, the value of pic_width_in_luma_samples shall be equal to pic_width_max_in_luma_samples. pic_height_in_luma_samples specifies the height of each decoded picture referring to the PPS in units of luma samples. pic_height_in_luma_samples shall not be equal to 0 and shall be an integer multiple of Max( 8, MinCbSizeY ), and shall be less than or equal to pic_height_max_in_luma_samples.

[0066] When res_change_in_clvs_allowed_flag equal to 0, the value of pic_height_in_luma_samples shall be equal to pic_height_max_in_luma_samples.

[0067] The variables PicWidthInCtbsY, PicHeightInCtbsY, PicSizeInCtbsY, PicWidthInMinCbsY, PicHeightInMinCbsY, PicSizeInMinCbsY, PicSizeInSamplesY, PicWidthInSamplesC and PicHeightInSamplesC are derived as follows: PicWidthInCtbsY = Ceil pic_width_in_luma_samples ÷ CtbSizeY PicHeightInCtbsY = Ceil pic_height_in_luma_samples ÷ CtbSizeY PicSizeInCtbsY = PicWidthInCtbsY * PicHeightInCtbsY PicWidthInMinCbsY = pic_width_in_luma_samples / MinCbSizeY PicHeightInMinCbsY = pic_height_in_luma_samples / MinCbSizeY PicSizeInMinCbsY = PicWidthInMinCbsY * PicHeightInMinCbsY PicSizeInSamplesY = pic_width_in_luma_samples * pic_height_in_luma_samples PicWidthInSamplesC = pic_width_in_luma_samples / SubWidthC PicHeightInSamplesC = pic_height_in_luma_samples / SubHeightC pps_conformance_window_flag equal to 1 indicates that the conformance cropping window offset parameters follow next in the PPS. pps_conformance_window_flag equal to 0 indicates that the conformance cropping window offset parameters are not present in the PPS. pps_conf_win_left_offset, pps_conf_win_right_offset , pps_conf_win_top_offset, and pps_conf_win_bottom_offset specify the samples of the pictures in the CLVS that are output from the decoding process, in terms of a rectangular region specified in picture coordinates for output. When pps_conformance_window_flag is equal to 0, the values of pps_conf_win_left_offset, pps_conf_win_right_offset, pps_conf_win_top _offset, and pps_conf_win_bottom_offset are inferred to be equal to 0.

[0068] The conformance cropping window contains the luma samples with horizontal picture coordinates from SubWidthC * pps_conf_win_left_offset to pic_width_in_luma_samples - ( SubWidthC * pps_conf_win_right_offset + 1 ) and vertical picture coordinates from SubHeightC * pps_conf_win_top_offset to pic_height in luma samples - ( SubHeightC * pps_conf_win_bottom_offset + 1 ), inclusive.

[0069] The value of SubWidthC * ( pps_conf_win_left_offset + pps_conf_win_right_offset ) shall be less than pic_width_in_luma_samples, and the value of SubHeightC * ( pps_conf_win_top_offset + pps_conf_win_bottom_offset ) shall be less than pic_height_in_luma_samples.

[0070] When ChromaArrayType is not equal to 0, the corresponding specified samples of the two chroma arrays are the samples having picture coordinates ( x / SubWidthC, y / SubHeightC ), where (x, y ) are the picture coordinates of the specified luma samples. NOTE 2 - The conformance cropping window offset parameters are only applied at the output. All internal decoding processes are applied to the uncropped picture size.

[0071] Let ppsA and ppsB be any two PPSs referring to the same SPS. It is a requirement of bitstream conformance that, when ppsA and ppsB have the same the values of pic_width_in_luma_samples and pic_height_in_luma_samples, respectively, ppsA and ppsB shall have the same values of pps_conf_win_left_offset, pps_conf_win_right_offset, pps_conf_win_top_offset, and pps_conf_win_bottom_offset, respectively.

[0072] When pic_width_in_luma_samples is equal to pic_width_max_in_luma_samples and pic_height_in_luma_samples is equal to pic_height_max_in_luma_samples, it is a requirement of bitstream conformance that pps_conf_win_left_offset, pps_conf_win_right_offset, pps_conf_win_top_offset, and pps_conf_win_bottom_offset, are equal to sps_conf_win_left_offset, sps_conf_win_right_offset, sps_conf_win_top_offset, and sps_conf_win_bottom_offset, respectively. scaling_window_explicit_signalling_flag equal to 1 specifies that the scaling window offset parameters are present in the PPS. scaling window_explicit_signalling _flag equal to 0 specifies that the scaling window offset parameters are not present in the PPS. When res_change_in_clvs_allowed_flag is equal to 0, the value of scaling_window_explicit_signalling_flag shall be equal to 0. scaling_win_left_offset , scaling_win_right_offset, scaling_win_top_offset, and scaling_win_bottom_offset specify the offsets that are applied to the picture size for scaling ratio calculation. When not present, the values of scaling_win_left_offset, scaling_win_right_offset, scaling_win_top_offset, and scaling_win_bottom_offset are inferred to be equal to pps_conf_win_left_offset, pps_conf_win_right_offset, pps_conf_win_top_offset, and pps_conf_win_bottom_offset, respectively.

[0073] The value of SubWidthC * ( scaling_win_left_offset + scaling_win_right_offset ) shall be less than pic_width_in_luma_samples, and the value of SubHeightC * ( scaling_win_top_offset + scaling_win_bottom_offset ) shall be less than pic_height_in_luma_samples.

[0074] The variables PicOutputWidthL and PicOutputHeightL are derived as follows: PicOutputWidthL = pic_width_in_luma_samples − SubWidthC ∗ scaling_win_right_offset + scaling_win_left_offset PicOutputHeightL = pic_height_in_luma_samples − SubWidthC ∗ scaling_win_bottom_offset + scaling_win_top_offset

[0075] Let refPicOutputWidthL and refPicOutputHeightL be the PicOutputWidthL and PicOutputHeightL, respectively, of a reference picture of a current picture referring to this PPS. Is a requirement of bitstream conformance that all of the following conditions are satisfied: PicOutputWidthL * 2 shall be greater than or equal to refPicWidthInLumaSamples. PicOutputHeightL * 2 shall be greater than or equal to refPicHeightInLumaSamples. PicOutputWidthL shall be less than or equal to refPicWidthInLumaSamples * 8. PicOutputHeightL shall be less than or equal to refPicHeightInLumaSamples * 8. PicOutputWidthL * pic_width_max_in_luma_samples shall be greater than or equal to refPicOutputWidthL * (pic_width_in_luma_samples - Max( 8, MinCbSizeY )). PicOutputHeightL * pic_height_max_in_luma_samples shall be greater than or equal to refPicOutputHeightL * (pic_height_in_luma_samples - Max( 8, MinCbSizeY )). output_flag_present_flag equal to 1 indicates that the pic_output_flag syntax element is present in slice headers referring to the PPS. output_flag_present_flag equal to 0 indicates that the pic_output_flag syntax element is not present in slice headers referring to the PPS. subpic_id_mapping_in_pps_flag equal to 1 specifies that the subpicture ID mapping is signalled in the PPS. subpic_id_mapping_in_pps_flag equal to 0 specifies that the subpicture ID mapping is not signalled in the PPS. If subpic_id_mapping_explicitly_signalled_flag is 0 or subpic_id_mapping_in_sps_flag is equal to 1, the value of subpic_id_mapping_in_pps_flag shall be equal to 0. Otherwise (subpic_id_mapping_explicitly_signalled_flag is equal to 1 and subpic_id_mapping_in_sps_flag is equal to 0), the value of subpic_id_mapping_in_pps_flag shall be equal to 1. pps_num_subpics_minus1 shall be equal to sps_num_subpics_minus1. pps_subpic_id_len_minus1 shall be equal to sps_subpic_id_len_minus1. pps_subpic_id[ i ] specifies the subpicture ID of the i-th subpicture. The length of the pps_subpic_id[ i ] syntax element is pps_subpic_id_len_minus1 + 1 bits.

[0076] The variable SubpicIdVal[ i ], for each value of i in the range of 0 to sps_num_subpics_minus1, inclusive, is derived as follows:

[0077] It is a requirement of bitstream conformance that both of the following constraints apply: For any two differenty values of i and j in the range of 0 to sps_num_subpics_minus1, inclusive, SubpicIdVal[ i ] shall not be equal to SubpicIdVal[ j ]. When the current picture is not the first picture of the CLVS, for each value of i in the range of 0 to sps_num_subpics_minus1, inclusive, if the value of SubpicIdVal[ i ] is not equal to the value of SubpicIdVal[ i ] of the previous picture in decoding order in the same layer, the nal_unit_type for all coded slice NAL units of the subpicture in the current picture with subpicture index i shall be equal to a particular value in the range of IDR_W_RADL to CRA_NUT, inclusive. no_pic_partition_flag equal to 1 specifies that no picture partitioning is applied to each picture referring to the PPS. no_pic_partition_flag equal to 0 specifies each picture referring to the PPS may be partitioned into more than one tile or slice.

[0078] It is a requirement of bitstream conformance that the value of no_pic_partition _flag shall be the same for all PPSs that are referred to by coded pictures within a CLVS.

[0079] It is a requirement of bitstream conformance that the value of no_pic_partition_flag shall not be equal to 1 when the value of sps_num_subpics_minus1 + 1 is greater than 1. pps_log2_ctu_size_minus5 plus 5 specifies the luma coding tree block size of each CTU. pps_log2_ctu_size_minus5 shall be equal to sps_log2_ctu_size_minus5. num_exp_tile_columns_minus1 plus 1 specifies the number of explicitly provided tile column widths. The value of num_exp_tile_columns_minus1 shall be in the range of 0 to PicWidthInCtbsY - 1, inclusive. When no_pic_partition _flag is equal to 1, the value of num_exp_tile_columns_minus1 is inferred to be equal to 0. num_exp_tile_rows_minus1 plus 1 specifies the number of explicitly provided tile row heights. The value of num_exp_tile_rows_minus1 shall be in the range of 0 to PicHeightInCtbsY - 1, inclusive. When no_pic_partition _flag is equal to 1, the value of num_tile_rows _minus1 is inferred to be equal to 0. tile_column_width_minus1[ i ] plus 1 specifies the width of the i-th tile column in units of CTBs for i in the range of 0 to num_exp_tile_columns_minus1 - 1, inclusive. tile_column_width_minus1[ num_exp_tile_columns_minus1 ] is used to derive the width of the tile columns with index greater than or equal to num_exp_tile_columns_minus1 as specified in clause 6.5.1. The value of tile_column_width_minus1[ i ] shall be in the range of 0 to PicWidthInCtbsY - 1, inclusive. When not present, the value of tile_column_width_minus1[ 0 ] is inferred to be equal to PicWidthInCtbsY - 1. tile_row_height_minus1 [ i ] plus 1 specifies the height of the i-th tile row in units of CTBs for i in the range of 0 to num_exp_tile_rows_minus1 - 1, inclusive. tile_row_height_minus1[ num_exp_tile_rows_minus1 ] is used to derive the height of the tile rows with index greater than or equal to num_exp_tile_rows_minus1 as specified in clause 6.5.1. The value of tile_row_height_minus1[ i ] shall be in the range of 0 to PicHeightInCtbsY - 1, inclusive. When not present, the value of tile_row_height_minus1[ 0 ] is inferred to be equal to PicHeightInCtbsY - 1. rect_slice_flag equal to 0 specifies that tiles within each slice are in raster scan order and the slice information is not signalled in PPS. rect_slice_flag equal to 1 specifies that tiles within each slice cover a rectangular region of the picture and the slice information is signalled in the PPS. When not present, rect_slice_flag is inferred to be equal to 1. When subpic_info_present_flag is equal to 1, the value of rect_slice_flag shall be equal to 1. single_slice_per_subpic_flag equal to 1 specifies that each subpicture consists of one and only one rectangular slice. single_slice_per_subpic_flag equal to 0 specifies that each subpicture may consist of one or more rectangular slices. When single_slice_per_subpic_flag is equal to 1, num_slices_in_pic_minus1 is inferred to be equal to sps_num_subpics_minus1. When not present, the value of single_slice_per_subpic_flag is inferred to be equal to 0. num_slices_in_pic_minus1 plus 1 specifies the number of rectangular slices in each picture referring to the PPS. The value of num_slices_in_pic_minus1 shall be in the range of 0 to MaxSlicesPerPicture - 1, inclusive, where MaxSlicesPerPicture is specified in Annex A. When no_pic_partition_flag is equal to 1, the value of num_slices_in_pic_minus1 is inferred to be equal to 0. tile_idx_delta_present_flag equal to 0 specifies that tile_idx_delta values are not present in the PPS and all rectangular slices in pictures referring to the PPS are specified in raster order according to the process defined in clause 6.5.1. tile_idx_delta_present_flag equal to 1 specifies that tile_idx_delta values may be present in the PPS and all rectangular slices in pictures referring to the PPS are specified in the order indicated by the values of tile_idx _delta. When not present, the value of tile_idx_delta_present_flag is inferred to be equal to 0. slice _width_in_tiles _minus1 [ i ] plus 1 specifies the width of the i-th rectangular slice in units of tile columns. The value of slice_width_in_tiles_minus1[ i ] shall be in the range of 0 to NumTileColumns - 1, inclusive.

[0080] When slice_width_in_tiles_minus1[ i ] is not present, the following applies: If NumTileColumns is equal to 1, the value of slice_width_in_tiles_minus1[ i ] is inferred to be equal to 0. Otherwise, the value of slice_width_in_tiles_minus1[ i ] is inferred as specified in clause 6.5.1. slice_height_in_tiles_minus1[ i ] plus 1 specifies the height of the i-th rectangular slice in units of tile rows. The value of slice_height_in_tiles_minus1[ i ] shall be in the range of 0 to NumTileRows - 1, inclusive.

[0081] When slice_height_in_tiles_minus1[ i ] is not present, the following applies: If NumTileRows is equal to 1, or tile_idx_delta_present_flag is equal to 0 and tileIdx % NumTileColumns is greater than 0), the value of slice_height_in_tiles_minus1[ i ] is inferred to be equal to 0. Otherwise (NumTileRows is not equal to 1, and tile_idx_delta_present_flag is equal to 1 or tileIdx % NumTileColumns is equal to 0), when tile_idx_delta_present_flag is equal to 1 or tileIdx % NumTileColumns is equal to 0, the value of slice_height_in_tiles_minus1[ i ] is inferred to be equal to slice_height_in_tiles_minus1[ i - 1 ]. num_exp_slices_in_tile [ i ] specifies the number of explicitly provided slice heights in the current tile that contains more than one rectangular slices. The value of num_exp_slices_in_tile[ i ] shall be in the range of 0 to RowHeight[ tileY ] - 1, inclusive, where tileY is the tile row index containing the i-th slice. When not present, the value of num_exp_slices_in_tile[ i ] is inferred to be equal to 0. When num_exp_slices_in_tile[ i ] is equal to 0, the value of the variable NumSlicesInTile[ i ] is derived to be equal to 1. exp_slice_height_in_ctus_minus1 [ j ] plus 1 specifies the height of the j-th rectangular slice in the current tile in units of CTU rows. The value of exp_slice_height_in_ctus_minus1[ j ] shall be in the range of 0 to RowHeight[ tileY ] - 1, inclusive, where tileY is the tile row index of the current tile.

[0082] When num_exp_slices_in_tile[ i ] is greater than 0, the variable NumSlicesInTile[ i ] and SliceHeightInCtusMinus1[ i + k ] for k in the range of 0 to NumSlicesInTile[ i ] - 1 are derived as follows: remainingHeightInCtbsY = RowHeight[ SliceTopLeftTileIdx[ i ] / NumTileColumns ] numExpSliceInTile = num_exp_slices_in_tile[ i ] for( j = 0; j < numExpSliceInTile - 1; j++ ) { SliceHeightInCtusMinus1[ i++ ] = exp_slice_height_in_ctu_minus1[ j ] remainingHeightInCtbsY -= SliceHeightInCtusMinus1[ j ] } uniformSliceHeightMinus1 = SliceHeightInCtusMinus1[ i - 1 ] (81) while( remainingHeightInCtbsY >= (uniformSliceHeightMinus1 + 1) ) { SliceHeightInCtusMinus1[ i++ ] = uniformSliceHeightMinus1 remainingHeightInCtbsY -= (uniformSliceHeightMinus1 + 1) j++ } if( remainingHeightInCtbsY > 0 ) { SliceHeightInCtusMinus1[ i++ ] = remainingHeightInCtbsY j++ } NumSlicesInTile[ i ] = j tile_idx_delta [ i ] specifies the difference between the tile index of the first tile in the i-th rectangular slice and the tile index of the first tile in the ( i + 1 )-th rectangular slice. The value of tile_idx_delta[ i ] shall be in the range of -NumTilesInPic + 1 to NumTilesInPic - 1, inclusive. When not present, the value of tile_idx_delta[ i ] is inferred to be equal to 0. When present, the value of tile_idx_delta[ i ] shall not be equal to 0. loop_filter_across_tiles_enabled_flag equal to 1 specifies that in-loop filtering operations may be performed across tile boundaries in pictures referring to the PPS. loop_filter_across_tiles_enabled_flag equal to 0 specifies that in-loop filtering operations are not performed across tile boundaries in pictures referring to the PPS. The in-loop filtering operations include the deblocking filter, sample adaptive offset filter, and adaptive loop filter operations. When not present, the value of loop_filter_across_tiles_enabled_flag is inferred to be equal to 1. loop_filter_across_slices_enabled_flag equal to 1 specifies that in-loop filtering operations may be performed across slice boundaries in pictures referring to the PPS. loop_filter_across_slice_enabled_flag equal to 0 specifies that in-loop filtering operations are not performed across slice boundaries in pictures referring to the PPS. The in-loop filtering operations include the deblocking filter, sample adaptive offset filter, and adaptive loop filter operations. When not present, the value of loop_filter_across_slices_enabled_flag is inferred to be equal to 0. cabac_init_present_flag equal to 1 specifies that cabac_init_flag is present in slice headers referring to the PPS. cabac_init_present_flag equal to 0 specifies that cabac_init_flag is not present in slice headers referring to the PPS. num_ref_idx_default_active_minus1 [ i ] plus 1, when i is equal to 0, specifies the inferred value of the variable NumRefIdxActive[ 0 ] for P or B slices with num_ref_idx_active_override_flag equal to 0, and, when i is equal to 1, specifies the inferred value of NumRefIdxActive[ 1 ] for B slices with num_ref_idx_active_override_flag equal to 0. The value of num_ref_idx_default_active_minus1[ i ] shall be in the range of 0 to 14, inclusive. rpl1_idx_present_flag equal to 0 specifies that ref_pic_list_sps_flag[ 1 ] and ref_pic_list_idx[ 1 ] are not present in the PH syntax structures or the slice headers for pictures referring to the PPS. rpl1_idx_present_flag equal to 1 specifies that ref_pic_list_sps_flag[ 1 ] and ref_pic_list_idx[ 1 ] may be present in the PH syntax structures or the slice headers for pictures referring to the PPS. init_qp_minus26 plus 26 specifies the initial value of SliceQp Y for each slice referring to the PPS. The initial value of SliceQp Y is modified at the picture level when a non-zero value of ph_qp_delta is decoded or at the slice level when a non-zero value of slice_qp_delta is decoded. The value of init_qp_minus26 shall be in the range of -( 26 + QpBdOffset ) to +37, inclusive. cu_qp_delta_enabled_flag equal to 1 specifies that the ph_cu_qp_delta_subdiv_intra_slice and ph_cu_qp_delta_subdiv_inter_slice syntax elements are present in PHs referring to the PPS and cu_qp_delta_abs may be present in the transform unit syntax. cu_qp_delta_enabled_flag equal to 0 specifies that the ph_cu_qp_delta_subdiv_intra_slice and ph_cu_qp_delta_subdiv_inter_slice syntax elements are not present in PHs referring to the PPS and cu_qp_delta_abs is not present in the transform unit syntax. pps_chroma_tool _offsets_present_flag equal to 1 specifies that chroma tool offsets related syntax elements are present in the PPS RBSP syntax structure. pps_chroma_tool_offsets_present_flag equal to 0 specifies that chroma tool offsets related syntax elements are not present in in the PPS RBSP syntax structure. When ChromaArrayType is equal to 0, the value of pps_chroma_tool_offsets_present_flag shall be equal to 0. pps_cb_qp_offset and pps_cr_qp_offset specify the offsets to the luma quantization parameter Qp' Y used for deriving Qp' Cb and Qp' Cr , respectively. The values of pps_cb_qp_offset and pps_cr_qp_offset shall be in the range of -12 to +12, inclusive. When ChromaArrayType is equal to 0, pps_cb_qp_offset and pps_cr_qp_offset are not used in the decoding process and decoders shall ignore their value. When not present, the values of pps _cb_qp_offset and pps_cr_qp_offset are inferred to be equalt to 0. pps_joint_cber_qp_offset_present_flag equal to 1 specifies that pps_joint_cber_qp_offset_value and joint_cbcr_qp_offset_list[ i ] are present in the PPS RBSP syntax structure. pps_joint_cber_qp_offset_present_flag equal to 0 specifies that pps_joint_cber_qp_offset_value and joint_cbcr_qp_offset_list[ i ] are not present in the PPS RBSP syntax structure. When ChromaArrayType is equal to 0 or sps_joint_cber_enabled_flag is equal to 0, the value of pps_joint_cber_qp_offset_present_flag shall be equal to 0. When not present, the value of pps_joint_cber_qp_offset_present_flag is inferred to be equal to 0. pps_joint_cber_qp_offset_value specifies the offset to the luma quantization parameter Qp' Y used for deriving Qp' CbCr . The value of pps_joint_cbcr_qp_offset_value shall be in the range of -12 to +12, inclusive. When ChromaArrayType is equal to 0 or sps_joint_cbcr_enabled_flag is equal to 0, pps_joint_cbcr_qp offset value is not used in the decoding process and decoders shall ignore its value. When pps_joint_cbcr_qp_offset_present_flag is equal to 0, pps_joint_cbcr_qp_offset_value is not present and is inferred to be equal to 0. pps_slice_chroma_qp_offsets_present_flag equal to 1 specifies that the slice_cb_qp_offset and slice_cr_qp_offset syntax elements are present in the associated slice headers. pps_slice_chroma_qp_offsets_present_flag equal to 0 specifies that the slice _cb_qp_offset and slice_cr_qp_offset syntax elements are not present in the associated slice headers. When not present, the value of pps_slice_chroma_qp_offsets_present_flag is inferred to be equal to 0. pps_cu_chroma_qp_offset_list_enabled_flag equal to 1 specifies that the ph_cu_chroma_qp_offset_subdiv_intra_slice and ph_cu_chroma_qp_offset_subdiv_inter_slice syntax elements are present in PHs referring to the PPS and cu_chroma_qp_offset_flag may be present in the transform unit syntax and the palette coding syntax. pps_cu_chroma_qp_offset_list_enabled_flag equal to 0 specifies that the ph_cu_chroma_qp_offset_subdiv_intra_slice and ph_cu_chroma_qp_offset_subdiv_inter_slice syntax elements are not present in PHs referring to the PPS and the cu_chroma_qp_offset_flag is not present in the transform unit syntax and the palette coding syntax. When not present, the value of pps_cu_chroma_qp_offset_list_enabled_flag is inferred to be equal to 0. chroma_qp_offset_list_len_minus1 plus 1 specifies the number of cb_qp_offset_list[ i ], cr_qp_offset_list[ i ], and joint_cbcr_qp_offset_list[ i ], syntax elements that are present in the PPS RBSP syntax structure. The value of chroma_qp_offset_list_len_minus1 shall be in the range of 0 to 5, inclusive. cb_qp_offset_list [ i ], cr_qp_offset_list [ i ], and joint_cbcr_qp_offset_list [ i ], specify offsets used in the derivation of Qp' Cb , Qp' Cr , and Qp' CbCr , respectively. The values of cb_qp_offset_list[ i ], cr_qp_offset_list[ i ], and joint_cber_qp_offset_list[ i ] shall be in the range of -12 to +12, inclusive. When pps_joint_cber_qp_offset_present_flag is equal to 0, joint_cbcr_qp_offset_list[ i ] is not present and it is inferred to be equal to 0. pps_weighted_pred_flag equal to 0 specifies that weighted prediction is not applied to P slices referring to the PPS. pps_weighted_pred_flag equal to 1 specifies that weighted prediction is applied to P slices referring to the PPS. When sps_weighted_pred_flag is equal to 0, the value of pps _weighted_pred_flag shall be equal to 0. pps_weighted_bipred_flag equal to 0 specifies that explicit weighted prediction is not applied to B slices referring to the PPS. pps_weighted_bipred_flag equal to 1 specifies that explicit weighted prediction is applied to B slices referring to the PPS. When sps_weighted_bipred_flag is equal to 0, the value of pps_weighted_bipred_flag shall be equal to 0. deblocking_filter _control_present_flag equal to 1 specifies the presence of deblocking filter control syntax elements in the PPS. deblocking_filter_control_present_flag equal to 0 specifies the absence of deblocking filter control syntax elements in the PPS. deblocking_filter_override_enabled_flag equal to 1 specifies the presence of ph_deblocking_filter_override_flag in the PHs referring to the PPS or slice_deblocking_filter_override_flag in the slice headers referring to the PPS. deblocking_filter_override_enabled_flag equal to 0 specifies the absence of ph_deblocking_filter_override_flag in PHs referring to the PPS or slice_deblocking_filter_override_flag in slice headers referring to the PPS. When not present, the value of deblocking_filter_override_enabled_flag is inferred to be equal to 0. pps_deblocking_filter_disabled_flag equal to 1 specifies that the operation of deblocking filter is not applied for slices referring to the PPS in which slice_deblocking_filter_disabled_flag is not present. pps_deblocking_filter_disabled_flag equal to 0 specifies that the operation of the deblocking filter is applied for slices referring to the PPS in which slice_deblocking_filter_disabled_flag is not present. When not present, the value of pps_deblocking_filter_disabled_flag is inferred to be equal to 0. pps_beta_offset_div2 and pps_tc_offset_div2 specify the default deblocking parameter offsets for β and tC (divided by 2) that are applied to the luma component for slices referring to the PPS, unless the default deblocking parameter offsets are overridden by the deblocking parameter offsets present in the picture headers or the slice headers of the slices referring to the PPS. The values of pps_beta_offset_div2 and pps_tc_offset_div2 shall both be in the range of -12 to 12, inclusive. When not present, the values of pps_beta_offset_div2 and pps_tc_offset_div2 are both inferred to be equal to 0. pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2 specify the default deblocking parameter offsets for β and tC (divided by 2) that are applied to the Cb component for slices referring to the PPS, unless the default deblocking parameter offsets are overridden by the deblocking parameter offsets present in the picture headers or the slice headers of the slices referring to the PPS. The values of pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2 shall both be in the range of -12 to 12, inclusive. When not present, the values of pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2 are both inferred to be equal to 0. pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2 specify the default deblocking parameter offsets for β and tC (divided by 2) that are applied to the Cr component for slices referring to the PPS, unless the default deblocking parameter offsets are overridden by the deblocking parameter offsets present in the picture headers or the slice headers of the slices referring to the PPS. The values of pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2 shall both be in the range of -12 to 12, inclusive. When not present, the values of pps_cr_beta_offset_div2 and pps_cr_tc_offset_div2 are both inferred to be equal to 0. rpl_info_in_ph_flag equal to 1 specifies that reference picture list information is present in the PH syntax structure and not present in slice headers referring to the PPS that do not contain a PH syntax structure. rpl_info_in_ph_flag equal to 0 specifies that reference picture list information is not present in the PH syntax structure and may be present in slice headers referring to the PPS that do not contain a PH syntax structure. dbf_info_in_ph_flag equal to 1 specifies that deblocking filter information is present in the PH syntax structure and not present in slice headers referring to the PPS that do not contain a PH syntax structure. dbf_info_in_ph_flag equal to 0 specifies that deblocking filter information is not present in the PH syntax structure and may be present in slice headers referring to the PPS that do not contain a PH syntax structure. When not present, the value of dbf_info_in_ph_flag is inferred to be equal to 0. sao_info_in_ph_flag equal to 1 specifies that SAO filter information is present in the PH syntax structure and not present in slice headers referring to the PPS that do not contain a PH syntax structure. sao_info_in_ph_flag equal to 0 specifies that SAO filter information is not present in the PH syntax structure and may be present in slice headers referring to the PPS that do not contain a PH syntax structure. alf_info_in_ph_flag equal to 1 specifies that ALF information is present in the PH syntax structure and not present in slice headers referring to the PPS that do not contain a PH syntax structure. alf_info_in_ph_flag equal to 0 specifies that ALF information is not present in the PH syntax structure and may be present in slice headers referring to the PPS that do not contain a PH syntax structure. wp_info_in_ph_flag equal to 1 specifies that weighted prediction information may be present in the PH syntax structure and not present in slice headers referring to the PPS that do not contain a PH syntax structure. wp_info_in_ph_flag equal to 0 specifies that weighted prediction information is not present in the PH syntax structure and may be present in slice headers referring to the PPS that do not contain a PH syntax structure. When not present, the value of wp_info_in_ph_flag is inferred to be equal to 0. qp_delta_info_in_ph_flag equal to 1 specifies that QP delta information is present in the PH syntax structure and not present in slice headers referring to the PPS that do not contain a PH syntax structure. qp_delta_info_in_ph_flag equal to 0 specifies that QP delta information is not present in the PH syntax structure and may be present in slice headers referring to the PPS that do not contain a PH syntax structure. pps_ref_wraparound_enabled_flag equal to 1 specifies that horizontal wrap-around motion compensation is applied in inter prediction. pps_ref_wraparound_enabled_flag equal to 0 specifies that horizontal wrap-around motion compensation is not applied. When the value of CtbSizeY / MinCbSizeY + 1 is greater than pic_width_in_luma_samples / MinCbSizeY - 1, the value of pps_ref_wraparound_enabled_flag shall be equal to 0. When sps_ref_wraparound_enabled_flag is equal to 0, the value of pps_ref_wraparound_enabled_flag shall be equal to 0. pps_ref_wraparound_offset plus ( CtbSizeY / MinCbSizeY ) + 2 specifies the offset used for computing the horizontal wrap-around position in units of MinCbSizeY luma samples. The value of pps_ref_wraparound_offset shall be in the range of 0 to ( pic_width_in_luma_samples / MinCbSizeY ) - ( CtbSizeY / MinCbSizeY ) - 2, inclusive.

[0083] The variable PpsRefWraparoundOffset is set equal to pps_ref_wraparound_offset+( CtbSizeY / MinCbSizeY ) + 2. picture_header_extension_present_flag equal to 0 specifies that no PH extension syntax elements are present in PHs referring to the PPS. picture_header_extension_present_flag equal to 1 specifies that PH extension syntax elements are present in PHs referring to the PPS. picture_header_extension_present_flag shall be equal to 0 in bitstreams conforming to this version of this Specification. slice_header_extension_present_flag equal to 0 specifies that no slice header extension syntax elements are present in the slice headers for coded pictures referring to the PPS. slice_header_extension_present_flag equal to 1 specifies that slice header extension syntax elements are present in the slice headers for coded pictures referring to the PPS. slice_header_extension_present_flag shall be equal to 0 in bitstreams conforming to this version of this Specification. pps_extension_flag equal to 0 specifies that no pps_extension_data_flag syntax elements are present in the PPS RBSP syntax structure. pps_extension_flag equal to 1 specifies that there are pps_extension_data_flag syntax elements present in the PPS RBSP syntax structure. pps_extension_data_flag may have any value. Its presence and value do not affect decoder conformance to profiles specified in this version of this Specification. Decoders conforming to this version of this Specification shall ignore all pps_extension_data_flag syntax elements. 3.4. APS syntax and semantics

[0084] In the latest VVC draft text, the APS syntax and semantics are as follows: adaptation_parameter_set_rbsp( ) {Descript or  adaptation_parameter_set_id u(5) aps_params_type u(3)  if( aps_params_type = = ALF_APS )   alf_data()  else if( aps_params_type = = LMCS_APS )   lmcs_data( )  else if( aps_params_type = = SCALING_APS )   scaling_list_data() aps_extension_flag u(1)  if( aps_extension_flag )   while( more_rbsp_data( ) )   aps_extension_data flag u(1)  rbsp_trailing_bits( )}

[0085] The APS RBSP contains a ALF syntax structure, i.e., alf_data(). alf_data( ) {Descript or  alf_luma_filter_signal_flag u(1) alf_chroma_filter_signal_flag u(1) alf_cc_cb_filter_signal_flag u(1) alf_cc_cr_filter_signal_flag u(1)  if( alf_luma_filter_signal_flag ) {  alf_luma_clip_flag u(1)  alf_luma_num_filters_signalled_minus1 ue(v)   if( alf_luma_num_filters_signalled_minus1 > 0 )    for( filtIdx = 0; filtIdx < NumAlfFilters; filtIdx++ )    alf_luma_coeff_delta_idx [ filtIdx ]u(v)   for( sfIdx = 0; sfIdx <= alf_luma_num_filters_signalled_minus1; sfIdx++ )    for( j = 0; j < 12; j++ ) {    alf_luma_coeff_abs [ sfIdx ][ j ]ue(v)     if( alf_luma_coeff_abs[ sfIdx ][ j ] )     alf_luma_coeff_sign [ sfIdx ][ j ]u(1)    }   if( alf_luma_clip_flag )    for( sfIdx = 0; sfIdx <= alf_luma_num_filters_signalled_minus1; sfIdx++ )     for( j = 0; j < 12; j++ )     alf_luma_clip_idx [ sfIdx ][ j ]u(2)  }  if( alf_chroma_filter_signal_flag ) {  alf_chroma_clip_flag u(1)  alf_chroma_num_alt_filters_minus1 ue(v)   for( altIdx = 0; altIdx <= alf_chroma_num_alt_filters_minus1; altIdx++) {    for(j = 0; j < 6; j++ ) {    alf_chroma_coeff_abs [ altIdx ][ j ]ue(v)     if( alf_chroma_coeff_abs[ altIdx ][ j ] > 0 )     alf_chroma_coeff_sign [ altIdx ][ j ]u(1)    }    if( alf_chroma_clip_flag )     for( j = 0; j < 6; j++ )     alf_chroma_clip_idx [ altIdx ][ j ]u(2)   }  } if( alf_cc_cb_filter_signal_flag ) {  alf_cc_cb_filters_signalled_minus1 ue(v)  for( k = 0; k < alf_cc_cb_filters_signalled_minus1 + 1; k++ ) {   for(j = 0; j < 7; j++ ) {    alf_ce_cb_mapped_coeff_abs [ k ][ j ]u(3)    if( alf_cc_cb_mapped_coeff_abs[ k ][ j ] )     alf_cc_cb_coeff_sign [ k ][ j ]u(1)   }  } } if( alf_cc_cr_filter_signal_flag ) {  alf_cc _cr_filters _signalled _minus1 ue(v)  for( k = 0; k < alf_cc_cr_filters_signalled_minus1 + 1; k++ ) {   for(j = 0; j < 7; j++ ) {    alf_cc_cr_mapped_coeff_abs [ k ][ j ]u(3)    if( alf_cc_cr_mapped_coeff_abs[ k ][ j ] )     alf_cc_cr_coeff_sign [ k ][ j ]u(1)   }  } }}

[0086] The APS RBSP contains a LMCS syntax structure, i.e., lmcs_data( ). lmcs_data() {Descriptor  lmcs_min_bin_idx ue(v) lmcs_delta_max_bin_idx ue(v) lmcs_delta_cw_prec_minus1 ue(v)  for( i = lmcs_min_bin_idx; i <= LmcsMaxBinIdx; i++ ) {  lmcs_delta_abs_cw [ i ]u(v)   if( lmcs_delta_abs_cw[ i ] > 0 )   lmcs_delta_sign_cw_flag [ i ]u(1)  } lmcs_delta_abs_crs u(3)  if( lmcs_delta_abs_crs > 0 )  lmcs_delta_sign_crs_flag u(1)}

[0087] The APS RBSP contains a scaling list data syntax structure, i.e., scaling_list_data(). scaling_list_data( ) {Descriptor  scaling_matrix_for_lfnst_disabled_flag u(1) scaling_list_chroma_present_flag u(1)  for( id = 0; id < 28; id ++ )   matrixSize = (id < 2 ) ? 2 : ( ( id < 8 ) ? 4 : 8 )   if( scaling_list_chroma_present_flag ∥ ( id % 3 = = 2 ) || (id = = 27 ) ) {   scaling_list_copy_mode_flag [ id ]u(1)    if( !scaling_list_copy_mode_flag[ id ] )    scaling_list_pred_mode_flag [ id ]u(1)    if( ( scaling_list_copy_mode_flag[ id ] ∥scaling_list_pred_mode_flag[ id ] ) &&      id != 0 && id != 2 && id != 8)    scaling_list_pred_id_delta [ id ]ue(v)    if( !scaling_list_-copy_mode_flag[ id ] ) {     nextCoef = 0     if( id > 13 ) {     scaling_list_dc_coef [ id - 14 ]se(v)      nextCoef += scaling_list_dc_coef[ id - 14 ]     }     for( i = 0; i < matrixSize * matrixSize; i++ ) {      x = DiagScanOrder[ 3 ][ 3 ][ i ][ 0 ]      y = DiagScanOrder[ 3 ][ 3 ][ i ][ 1 ]      if( ! ( id > 25 && x >= 4 && y >= 4 ) ) {      scaling_list_delta_coef [ id ][ i ]se(v)      nextCoef += scaling_list_delta_coef[ id ][ i ]     }     ScalingList[ id ][ i ] = nextCoef    }   }  } }}

[0088] Each APS RBSP shall be available to the decoding process prior to it being referenced, included in at least one AU with TemporalId less than or equal to the TemporalId of the coded slice NAL unit that refers it or provided through external means.

[0089] All APS NAL units with a particular value of adaptation_parameter_set_id and a particular value of aps_params_type within a PU, regardless of whether they are prefix or suffix APS NAL units, shall have the same content. adaptation_parameter_set_id provides an identifier for the APS for reference by other syntax elements.

[0090] When aps_params_type is equal to ALF_APS or SCALING_APS, the value of adaptation_parameter_set_id shall be in the range of 0 to 7, inclusive.

[0091] When aps_params_type is equal to LMCS_APS, the value of adaptation_parameter_set_id shall be in the range of 0 to 3, inclusive.

[0092] Let apsLayerId be the value of the nuh_layer_id of a particular APS NAL unit, and vclLayerId be the value of the nuh_layer_id of a particular VCL NAL unit. The particular VCL NAL unit shall not refer to the particular APS NAL unit unless apsLayerId is less than or equal to vclLayerId and the layer with nuh_layer_id equal to apsLayerId is included in at least one OLS that includes the layer with nuh_layer_id equal to vclLayerId. aps_params_type specifies the type of APS parameters carried in the APS as specified in Table 6. Table 6 - APS parameters type codes and types of APS parametersaps_params_type Name of aps_params_type Type of APS parameters 0ALF_APSALF parameters1LMCS_APSLMCS parameters2SCALING_APSScaling list parameters3..7ReservedReserved

[0093] All APS NAL units with a particular value of aps_params_type, regardless of the nuh_layer_id values, share the same value space for adaptation_parameter_set_id. APS NAL units with different values of aps_params_type use separate values spaces for adaptation_parameter_set_id. NOTE 1 - An APS NAL unit (with a particular value of adaptation_parameter_set_id and a particular value of aps_params_type) can be shared across pictures, and different slices within a picture can refer to different ALF APSs. NOTE 2 - A suffix APS NAL unit associated with a particular VCL NAL unit (this VCL NAL unit precedes the suffix APS NAL unit in decoding order) is not for use by the particular VCL NAL unit, but for use by VCL NAL units following the suffix APS NAL unit in decoding order. aps_extension_flag equal to 0 specifies that no aps_extension_data_flag syntax elements are present in the APS RBSP syntax structure. aps_extension_flag equal to 1 specifies that there are aps_extension_data_flag syntax elements present in the APS RBSP syntax structure. aps_extension_data_flag may have any value. Its presence and value do not affect decoder conformance to profiles specified in this version of this Specification. Decoders conforming to this version of this Specification shall ignore all aps_extension_data_flag syntax elements. alf_luma_filter_signal_flag equal to 1 specifies that a luma filter set is signalled. alf_luma_filter_signal_flag equal to 0 specifies that a luma filter set is not signalled. alf_chroma_filter_signal_flag equal to 1 specifies that a chroma filter is signalled. alf_chroma_filter_signal_flag equal to 0 specifies that a chroma filter is not signalled. When ChromaArrayType is equal to 0, alf_chroma_filter_signal_flag shall be equal to 0.

[0094] At least one of the values of alf_luma_filter_signal_flag, alf_chroma_filter_signal_flag, alf_cc_cb_filter_signal_flag and alf_cc_cr_filter_signal_flag shall be equal to 1.

[0095] The variable NumAlfFilters specifying the number of different adaptive loop filters is set equal to 25. alf_luma_clip_flag equal to 0 specifies that linear adaptive loop filtering is applied on luma component. alf_luma_clip_flag equal to 1 specifies that non-linear adaptive loop filtering may be applied on luma component. alf_luma_num_filters_signalled_minus1 plus 1 specifies the number of adpative loop filter classes for which luma coefficients can be signalled. The value of alf_luma_num_filters_signalled_minus1 shall be in the range of 0 to NumAlfFilters - 1, inclusive. alf_luma_coeff_delta_idx [ filtIdx ] specifies the indices of the signalled adaptive loop filter luma coefficient deltas for the filter class indicated by filtIdx ranging from 0 to NumAlfFilters - 1. When alf_luma_coeff_delta_idx[ filtIdx ] is not present, it is inferred to be equal to 0. The length of alf_luma_coeff_delta_idx[ filtIdx ] is Ceil( Log2( alf_luma_num_filters_signalled_minus1 + 1 ) ) bits. The value of alf_luma_coeff_delta_idx[ filtIdx ] shall be in the range of 0 to alf_luma_num_filters_signalled_minus1, inclusive. alf_luma_coeff_abs [ sfIdx ][ j ] specifies the absolute value of the j-th coefficient of the signalled luma filter indicated by sfIdx. When alf_luma_coeff_abs[ sfIdx ][ j ] is not present, it is inferred to be equal 0. The value of alf_luma_coeff_abs[ sfIdx ][ j ] shall be in the range of 0 to 128, inclusive. alf_luma_coeff_sign [ sfIdx ][ j ] specifies the sign of the j-th luma coefficient of the filter indicated by sfIdx as follows: If alf_luma_coeff_sign[ sfIdx ][ j ] is equal to 0, the corresponding luma filter coefficient has a positive value. Otherwise (alf_luma_coeff_sign[ sfIdx ][ j ] is equal to 1), the corresponding luma filter coefficient has a negative value.

[0096] When alf_luma_coeff_sign[ sfIdx ][ j ] is not present, it is inferred to be equal to 0.

[0097] The variable filtCoeff[ sfIdx ][ j ] with sfIdx = 0..alf_luma_num_filters_signalled_minus1, j = 0..11 is initialized as follows: filtCoeff sfIdx j = alf_luma_coeff_abs sfIdx j * 1 − 2 * alf_luma_coeff_sign sfIdx j

[0098] The luma filter coefficients AlfCoeff L [ adaptation_parameter_set_id ] with elements AlfCoeff L [ adaptation_parameter_set_id ][ filtIdx ][ j ], with filtIdx = 0..NumAlfFilters - 1 and j = 0..11 are derived as follows:

[0099] The fixed filter coefficients AlfFixFiltCoeff[ i ][ j ] with i = 0..64, j = 0..11 and the class to filter mapping AlfClassToFiltMap[ m ][ n ] with m = 0..15 and n = 0..24 are derived as follows: AlfClassToFiltMap = { 8 , 2 , 2 , 2 , 3 , 4 , 53 , 9 , 9 , 52 , 4 , 4 , 5 , 9 , 2 , 8 , 10 , 9 , 1 , 3 , 39 , 39 , 10 , 9 , 52 11 , 12 , 13 , 14 , 15 , 30 , 11 , 17 , 18 , 19 , 16 20 , 20 , 4 , 53 , 21 , 22 , 23 , 14 , 25 , 26 , 26 , 27 , 28 , 10 16 , 12 , 31 , 32 , 14 , 16 , 30 , 33 , 53 , 34 , 35 , 16 , 20 , 4 , 7 , 16 , 21 , 36 , 18 , 19 , 21 , 26 , 37 , 38 , 39 35 , 11 , 13 , 14 , 43 , 35 , 16 , 4 , 34 , 62 , 35 , 35 , 30 , 56 , 7 , 35 , 21 , 38 , 24 , 40 , 16 , 21 , 48 , 57 , 39 11 , 31 , 32 , 43 , 44 , 16 , 4 , 17 , 34 , 45 , 30 , 20 , 20 , 7 , 5 , 21 , 22 , 46 , 40 , 47 , 26 , 48 , 63 , 58 , 10 12 , 13 , 50 , 51 , 52 , 11 , 17 , 53 , 45 , 9 , 30 , 4 , 53 , 19 , 0 , 22 , 23 , 25 , 43 , 44 , 37 , 27 , 28 , 10,55 30 , 33 , 62 , 51 , 44 , 20 , 41 , 56 , 34 , 45 , 20 , 41 , 41 , 56 , 5 , 30 , 56 , 38 , 40 , 47 , 11 , 37 , 42 , 57 , 8 35 , 11 , 23 , 32 , 14 , 35 , 20 , 4 , 17 , 18 , 21 , 20 , 20 , 20 , 4 , 16 , 21 , 36 , 46 , 25 , 41 , 26 , 48 , 49 , 58 12 , 31 , 59 , 59 , 3 , 33 , 33 , 59 , 59 , 52 , 4 , 33 , 17 , 59 , 55 , 22 , 36 , 59 , 59 , 60 , 22 , 36 , 59 , 25 , 55 31 , 25 , 15 , 60 , 60 , 22 , 17 , 19 , 55 , 55 , 20 , 20 , 53 , 19 , 55 , 22 , 46 , 25 , 43 , 60 , 37 , 28 , 10 , 55 , 52 12 , 31 , 32 , 50 , 51 , 11 , 33 , 53 , 19 , 45 , 16 , 4 , 4 , 53 , 5 , 22 , 36 , 18 , 25 , 43 , 26 , 27 , 27 , 28 , 10 5 , 2 , 44 , 52 , 3 , 4 , 53 , 45 , 9 , 3 , 4 , 56 , 5 , 0 , 2 , 5 , 10 , 47 , 52 , 3 , 63 , 39 , 10 , 9 , 52 12 , 34 , 44 , 44 , 3 , 56 , 56 , 62 , 45 , 9 , 56 , 56 , 7 , 5 , 0 , 22 , 38 , 40 , 47 , 52 , 48 , 57 , 39 , 10 , 9 35 , 11 , 23 , 14 , 51 , 35 , 20 , 41 , 56 , 62 , 16 , 20 , 41 , 56 , 7 , 16 , 21 , 38 , 24 , 40 , 26 , 26 , 42 , 57 , 39

[0100] It is a requirement of bitstream conformance that the values of AlfCoeff L [ adaptation_parameter_set_id ][ filtIdx ][ j ] with filtIdx = 0..NumAlfFilters - 1, j = 0..11 shall be in the range of -2 7< to 2 7< - 1, inclusive. alf_luma_clip_idx [ sfIdx ][ j ] specifies the clipping index of the clipping value to use before multiplying by the j-th coefficient of the signalled luma filter indicated by sfIdx. It is a requirement of bitstream conformance that the values of alf_luma_clip_idx[ sfIdx ][ j ] with sfIdx = 0..alf_luma_num_filters_signalled_minus1 and j = 0..11 shall be in the range of 0 to 3, inclusive.

[0101] The luma filter clipping values AlfClip L [ adaptation_parameter_set_id ] with elements AlfClip L [ adaptation_parameter_set_id ][ filtIdx ][ j ], with filtIdx = 0..NumAlfFilters - 1 and j = 0..11 are derived as specified in Table 8 depending on BitDepth and clipIdx set equal to alf_luma_clip_idx[ alf_luma_coeff_delta_idx[ filtIdx ] ][ j ]. alf_chroma_clip_flag equal to 0 specifies that linear adaptive loop filtering is applied on chroma components; alf_chroma_clip_flag equal to 1 specifies that non-linear adaptive loop filtering is applied on chroma components. When not present, alf_chroma_clip_flag is inferred to be equal to 0. alf_chroma _num _alt_filters _minus1 plus 1 specifies the number of alternative filters for chroma components. The value of alf_chroma_num_alt_filters_minus1 shall be in the range of 0 to 7, inclusive. alf_chroma_coeff_abs [ altIdx ][ j ] specifies the absolute value of the j -th chroma filter coefficient for the alternative chroma filter with index altIdx. When alf_chroma_coeff_abs[ altIdx ][ j ] is not present, it is inferred to be equal 0. The value of alf_chroma_coeff_abs[ sfIdx ][ j ] shall be in the range of 0 to 128, inclusive. alf_chroma_coeff_sign [ altIdx ][ j ] specifies the sign of the j -th chroma filter coefficient for the alternative chroma filter with index altIdx as follows: If alf_chroma_coeff_sign[ altIdx ][ j ] is equal to 0, the corresponding chroma filter coefficient has a positive value. Otherwise (alf_chroma_coeff_sign[ altIdx ][ j ] is equal to 1), the corresponding chroma filter coefficient has a negative value.

[0102] When alf_chroma_coeff_sign[ altIdx ][ j ] is not present, it is inferred to be equal to 0.

[0103] The chroma filter coefficients AlfCoeff C [ adaptation_parameter_set_id ][ altIdx ] with elements AlfCoeff C [ adaptation_parameter_set_id ][ altIdx ][ j ], with altIdx = 0..alf_chroma_num_alt_filters_minus1, j = 0..5 are derived as follows: AlfCoeff C adaptation_parameter_set_id altIdx j = alf_chroma_coeff_abs altIdx j * 1 − 2 * alf_chroma_coeff_sign altIdx j

[0104] It is a requirement of bitstream conformance that the values of AlfCoeff C [ adaptation_parameter_set_id ][ altIdx ][ j ] with altIdx = 0..alf_chroma_num_alt_filters_minus1, j = 0..5 shall be in the range of -2 7< to 2 7< - 1, inclusive. alf_cc_cb_filter_signal_flag equal to 1 specifies that cross-component filters for the Cb colour component are signalled. alf_cc_cb_filter_signal_flag equal to 0 specifies that cross-component filters for Cb colour component are not signalled. When ChromaArrayType is equal to 0, alf_cc_cb_filter_signal_flag shall be equal to 0. alf_cc_cb_filters_signalled_minus1 plus 1 specifies the number of cross-component filters for the Cb colour component signalled in the current ALF APS. The value of alf_cc_cb_filters_signalled_minus1 shall be in the range of 0 to 3, inclusive. alf_cc_cb_mapped_coeff _abs [ k ][ j ] specifies the absolute value of the j-th mapped coefficient of the signalled k-th cross-component filter for the Cb colour component. When alf_cc_cb_mapped_coeff_abs[ k ][ j ] is not present, it is inferred to be equal to 0. alf_cc_cb_coeff_sign [ k ][ j ] specifies the sign of the j-th coefficient of the signalled k-th cross-component filter for the Cb colour component as follows: If alf_cc_cb_coeff_sign[ k ][ j ] is equal to 0, the corresponding cross-component filter coefficient has a positive value. Otherwise (alf_cc_cb_sign[ k ][ j ] is equal to 1), the corresponding cross-component filter coefficient has a negative value.

[0105] When alf_cc_cb_coeff_sign[ k ][ j ] is not present, it is inferred to be equal to 0.

[0106] The signalled k-th cross-component filter coefficients for the Cb colour component CcAlfApsCoeff Cb [ adaptation_parameter_set_id ][ k ][ j ], with j = 0..6 are derived as follows: If alf_cc_cb_mapped_coeff_abs[ k ][ j ] is equal to 0, CcAlfApsCoeff Cb [ adaptation_parameter_set_id ][ k ][ j ] is set equal to 0. Otherwise, CcAlfApsCoeff Cb [ adaptation_parameter_set_id ][ k ][ j ] is set equal to ( 1 - 2 * alf_cc_cb_coeff_sign[ k ][ j ] ) * 2 alf_cc_cb_mapped_coeff_abs[ k ][ j ] - 1< . alf_cc_cr_filter_signal_flag equal to 1 specifies that cross-component filters for the Cr colour component are signalled. alf_cc_cr_filter_signal_flag equal to 0 specifies that cross-component filters for the Cr colour component are not signalled. When ChromaArrayType is equal to 0, alf_cc_cr_filter_signal_flag shall be equal to 0. alf_cc_cr_filters_signalled_minus1 plus 1 specifies the number of cross-component filters for the Cr colour component signalled in the current ALF APS. The value of alf_cc_cr_filters_signalled_minus1 shall be in the range of 0 to 3, inclusive. alf_cc_cr_mapped coeff_abs [ k ][ j ] specifies the absolute value of the j-th mapped coefficient of the signalled k-th cross-component filter for the Cr colour component. When alf_cc_cr_mapped_coeff_abs[ k ][ j ] is not present, it is inferred to be equal to 0. alf_cc_cr_coeff_sign [ k ][ j ] specifies the sign of the j -th coefficient of the signalled k-th cross-component filter for the Cr colour component as follows: If alf_ce_cr_coeff_sign[ k ][ j ] is equal to 0, the corresponding cross-component filter coefficient has a positive value. Otherwise (alf_cc_cr_sign[ k ][ j ] is equal to 1), the corresponding cross-component filter coefficient has a negative value.

[0107] When alf_cc_cr_coeff_sign[ k ][ j ] is not present, it is inferred to be equal to 0.

[0108] The signalled k-th cross-component filter coefficients for the Cr colour component CcAlfApsCoeff Cr [ adaptation_parameter_set_id ][ k ][ j ], with j = 0..6 are derived as follows: If alf_cc_cr_mapped_coeff_abs[ k ][ j ] is equal to 0, CcAlfApsCoeff Cr [ adaptation_parameter_set_id ][ k ][ j ] is set equal to 0. Otherwise, CcAlfApsCoeff Cr [ adaptation_parameter_set_id ][ k ][ j ] is set equal to ( 1 - 2 * alf_cc_cr_coeff_sign[ k ][ j ] ) * 2 alf_cc_cr_mapped_coeff_abs[ k ][ j ] - 1< . alf_chroma_clip_idx[ altIdx ][ j ] specifies the clipping index of the clipping value to use before multiplying by the j-th coefficient of the alternative chroma filter with index altIdx. It is a requirement of bitstream conformance that the values of alf_chroma_clip_idx[ altIdx ][ j ] with altIdx = 0..alf_chroma_num_alt_filters_minus1, j = 0..5 shall be in the range of 0 to 3, inclusive.

[0109] The chroma filter clipping values AlfClip C [ adaptation_parameter_set_id ][ altIdx ] with elements AlfClip C [ adaptation_parameter_set_id ][ altIdx ][ j ], with altIdx = 0..alf_chroma_num_alt_filters_minus1, j = 0..5 are derived as specified in Table 8 depending on BitDepth and clipIdx set equal to alf_chroma_clip_idx[ altIdx ][ j ]. Table 8 - Specification AlfClip depending on BitDepth and clipIdxBitDepth clipIdx 0 1 2 3 8 2 8< 2 5< 2 3< 2 1< 9 2 9< 2 6< 2 4< 2 2< 10 2 10< 2 7< 2 5< 2 3< 11 2 11< 2 8< 2 6< 2 4< 12 2 12< 2 9< 2 7< 2 5< 13 2 13< 2 10< 2 8< 2 6< 14 2 14< 2 11< 2 9< 2 7< 15 2 15< 2 12< 2 10< 2 8< 16 2 16< 2 13< 2 11< 2 9< lmcs_min_bin_idx specifies the minimum bin index used in the luma mapping with chroma scaling construction process. The value of lmcs_min_bin_idx shall be in the range of 0 to 15, inclusive. lmcs_delta_max_bin_idx specifies the delta value between 15 and the maximum bin index LmcsMaxBinIdx used in the luma mapping with chroma scaling construction process. The value of lmcs_delta_max_bin_idx shall be in the range of 0 to 15, inclusive. The value of LmcsMaxBinIdx is set equal to 15 - lmcs_delta_max_bin_idx. The value of LmcsMaxBinIdx shall be greater than or equal to lmcs_min_bin_idx. lmcs_delta_cw_prec_minus1 plus 1 specifies the number of bits used for the representation of the syntax lmcs_delta_abs_cw[ i ]. The value of lmcs_delta_cw_prec_minus1 shall be in the range of 0 to BitDepth - 2, inclusive. lmcs_delta_abs_cw [ i ] specifies the absolute delta codeword value for the ith bin. lmcs_delta_sign_cw_flag [ i ] specifies the sign of the variable lmcsDeltaCW[ i ] as follows: If lmcs_delta_sign_cw_flag[ i ] is equal to 0, lmcsDeltaCW[ i ] is a positive value. Otherwise ( lmcs_delta_sign_cw_flag[ i ] is not equal to 0 ), lmcsDeltaCW[ i ] is a negative value.

[0110] When lmcs_delta_sign_cw_flag[ i ] is not present, it is inferred to be equal to 0.

[0111] The variable OrgCW is derived as follows: OrgCW = 1 ≪ BitDepth / 16

[0112] The variable lmcsDeltaCW[ i ], with i = Imcs_min_bin_idx..LmcsMaxBinIdx, is derived as follows: lmcsDeltaCW i = 1 − 2 * lmcs_delta_sign_cw_flag i * lmcs_delta_abs_cw i

[0113] The variable lmcsCW[ i ] is derived as follows: For i = 0.. lmcs_min_bin_idx - 1, lmcsCW[ i ] is set equal 0. For i = lmcs_min_bin_idx..LmcsMaxBinIdx, the following applies: lmcsCW i = OrgCW + lmcsDeltaCW i The value of lmcsCW[ i ] shall be in the range of ( OrgCW >> 3) to ( OrgCW << 3 - 1 ), inclusive. For i = LmesMaxBinIdx + 1..15, lmcsCW[ i ] is set equal 0.

[0114] It is a requirement of bitstream conformance that the following condition is true: ∑ i = 0 15 lmcsCW i < = 1 ≪ BitDepth − 1

[0115] The variable InputPivot[ i ], with i = 0..16, is derived as follows: InputPivot i = i * OrgCW

[0116] The variable LmcsPivot[ i ] with i = 0..16, the variables ScaleCoeff[ i ] and InvScaleCoeff[ i ] with i = 0..15, are derived as follows:

[0117] It is a requirement of bitstream conformance that, for i = lmcs_min_bin_idx..LmcsMaxBinIdx, when the value of LmcsPivot[ i ] is not a multiple of 1 << ( BitDepth - 5 ), the value of ( LmcsPivot[ i ] >> (BitDepth - 5 ) ) shall not be equal to the value of (LmcsPivot[ i + 1 ] >> ( BitDepth - 5 ) ). lmcs_delta_abs_crs specifies the absolute codeword value of the variable lmcsDeltaCrs. The value of lmcs_delta_abs_crs shall be in the range of 0 and 7, inclusive. When not present, lmcs_delta_abs_crs is inferred to be equal to 0. lmcs_delta_sign_crs_flag specifies the sign of the variable lmcsDeltaCrs. When not present, lmcs_delta_sign_crs_flag is inferred to be equal to 0.

[0118] The variable lmcsDeltaCrs is derived as follows: lmcsDeltaCrs = 1 − 2 * lmcs_delta_sign_crs_flag * lmcs_delta_abs_crs

[0119] It is a requirement of bitstream conformance that, when lmcsCW[ i ] is not equal to 0, ( lmcsCW[ i ] + lmcsDeltaCrs ) shall be in the range of ( OrgCW >> 3 ) to ( ( OrgCW << 3 ) - 1 ), inclusive.

[0120] The variable ChromaScaleCoeff[ i ], with i = 0...15, is derived as follows: scaling_matrix_for_lfnst_disabled_flag equal to 1 specifies that scaling matrices are not applied to blocks coded with LFNST. scaling_matrix_for_lfnst_disabled_flag equal to 0 specifies that the scaling matrices may apply to the blocks coded with LFNST. scaling_list_chroma_present_flag equal to 1 specifies that chroma scaling lists are present in scaling_list_data( ). scaling_list_chroma_present_flag equal to 0 specifies that chroma scaling lists are not present in scaling_list_data( ). It is a requirement of bitstream conformance that scaling_list_chroma_present_flag shall be equal to 0 when ChromaArrayType is equal to 0, and shall be equal to 1 when ChromaArrayType is not equal to 0. scaling_list_copy_mode_flag [ id ] equal to 1 specifies that the values of the scaling list are the same as the values of a reference scaling list. The reference scaling list is specified by scaling_list_id_delta[ id ]. scaling_list_copy_mode_flag[ id ] equal to 0 specifies that scaling_list_pred_mode_flag is present. scaling_list_pred_mode_flag [ id ] equal to 1 specifies that the values of the scaling list can be predicted from a reference scaling list. The reference scaling list is specified by scaling_list_id_delta[ id ]. scaling_list_pred_mode_flag[ id ] equal to 0 specifies that the values of the scaling list are explicitly signalled. When not present, the value of scaling_list_pred_mode_flag[id] is inferred to be equal to 0. scaling_list_pred_id_delta [ id ] specifies the reference scaling list used to derive the predicted scaling matrix ScalingMatrixPred[ id ]. When not present, the value of scaling_list_pred_id_delta[ id ] is inferred to be equal to 0. The value of scaling_list_pred_id_delta[ id ] shall be in the range of 0 to maxIdDelta with maxIdDelta derived depending on id as follows: maxIdDelta = id < 2 ? id : id < 8 ? id − 2 : id − 8

[0121] The variables refId and matrixSize are derived as follows: refId = id − scaling_list_pred_id_delta id matrixSize = id < 2 ? 2 : id < 8 ? 4 : 8

[0122] The (matrixSize)x(matrixSize) array ScalingMatrixPred[ x ][ y ] with x = 0..matrixSize - 1, y = 0..matrixSize - 1 and the variable ScalingMatrixDCPred are derived as follows: When both scaling_list_copy_mode_flag[ id ] and scaling_list_pred_mode_flag[ id ] are equal to 0, all elements of ScalingMatrixPred are set equal to 8, and the value of ScalingMatrixDCPred is set equal to 8. Otherwise, when scaling_list_pred_id_delta[ id ] is equal to 0, all elements of ScalingMatrixPred are set equal to 16, and ScalingMatrixDCPred is set equal to 16. Otherwise (either scaling_list_copy_mode_flag[ id ] or scaling_list_pred_mode_flag[ id ] is equal to 1 and scaling_list_pred_id_delta[ id ] is greater than 0), ScalingMatrixPred is set equal to ScalingMatrixRec[ refId ], and the following applies for ScalingMatrixDCPred: If refId is greater than 13, ScalingMatrixDCPred is set equal to ScalingMatrixDCRec[ refId - 14 ]. Otherwise (refId is less than or equal to 13), ScalingMatrixDCPred is set equal to ScalingMatrixPred[ 0 ][ 0 ]. scaling_list_dc_coef[ id - 14 ] is used to derive the value of the variable ScalingMatrixDC[ id - 14 ] when id is greater than 13 as follows: ScalingMatrixDCRecid−14=ScalingMatrixDCPred+scaling_list_dc_coefid−14&255

[0123] When not present, the value of scaling_list_dc_coef[ id - 14 ] is inferred to be equal to 0. The value of scaling_list_dc_coef[ id - 14 ] shall be in the range of -128 to 127, inclusive. The value of ScalingMatrixDCRec[ id - 14 ] shall be greater than 0. scaling_list_delta_coef [ id ][ i ] specifies the difference between the current matrix coefficient ScalingList[ id ][ i ] and the previous matrix coefficient ScalingList[ id ][ i - 1 ], when scaling_list_copy_mode_flag[ id ] is equal to 0. The value of scaling_list_delta_coef[ id ][ i ] shall be in the range of -128 to 127, inclusive. When scaling_list_copy_mode_flag[ id ] is equal to 1, all elements of ScalingList[ id ] are set equal to 0.

[0124] The (matrixSize)x(matrixSize) array ScalingMatrixRec[ id ] is derived as follows: with k = 0..( matrixSize * matrixSize - 1 ), x = DiagScanOrder[ Log2( matrixSize ) ][ Log2( matrixSize ) ][ k ][ 0 ], and y = DiagScanOrder[ Log2( matrixSize ) ][ Log2( matrixSize ) ][ k ][ 1 ]

[0125] The value of ScalingMatrixRec[ id ][ x ][ y ] shall be greater than 0.3.5. PH syntax and semantics

[0126] In the latest VVC draft text, the PH syntax and semantics are as follows: picture_header_rbsp( ) {Descriptor  picture_header_structure( ) rbsp_trailing_bits( )}

[0127] The PH RBSP contains a PH syntax structure, i.e., picture_header_structure(). picture_header_structure( ) {Descript or  gdr_or_irap_pic_flag u(1) if( gdr_or_irap_pic_flag )  gdr_pic_flag u(1) ph_inter_slice_allowed_flag u(1) if( ph_inter_slice_allowed_flag )  ph_intra_slice_allowed_flag u(1) non_reference_picture_flag u(1) ph_pic_parameter_set_id ue(v) ph_pic_order_cnt_lsb u(v) if( gdr_or_irap_pic_flag )  no_output_of_prior_pics_flag u(1) if( gdr_pic_flag )  recovery_poc_cnt ue(v) for( i = 0; i < NumExtraPhBits; i++ )  ph_extra_bit [ i ]u(1) if( sps_poc_msb_flag ) {  ph_poc_msb_present_flag u(1)  if( ph_poc_msb_present_flag )   poc_msb_val u(v) } if( sps_alf_enabled_flag && alf_info_in_ph_flag ) {  ph_alf_enabled_flag u(1)  if( ph_alf_enabled_flag ) {   ph_num_alf_aps_ids_luma u(3)   for( i = 0; i < ph_num_alf_aps_ids_luma; i++)    ph_alf_aps_id_luma [ i ]u(3)   if( ChromaArrayType != 0)    ph_alf_chroma_idc u(2)   if( ph_alf_chroma_idc > 0 )    ph_alf_aps_id_chroma u(3)   if( sps_ccalf_enabled_flag ) {    ph_cc_alf_cb_enabled_flag u(1)    if( ph_cc_alf_cb_enabled_flag )     ph_cc_alf_cb_aps_id u(3)    ph_cc_alf_cr_enabled_flag u(1)    if( ph_cc_alf_cr_enabled_flag )     ph_cc_alf_cr_aps_id u(3)   }  } } if( sps_lmcs_enabled_flag ) {  ph_lmcs_enabled_flag u(1)  if( ph_lmcs_enabled_flag ) {   ph_lmcs_aps_id u(2)   if( ChromaArrayType != 0 )    ph_chroma_residual_scale_flag u(1)  } } if( sps_scaling_list_enabled_flag ) {  ph_scaling_list_present_flag u(1)  if( ph_scaling_list_present_flag)   ph_scaling_list_aps_id u(3) } if( sps_virtual_boundaries_enabled_flag &&!sps_virtual_boundaries_present_flag ) {  ph_virtual_boundaries_present_flag u(1)  if( ph_virtual_boundaries_present_flag ) {   ph_num_ver_virtual_boundaries u(2)   for( i = 0; i < ph_num_ver_virtual_boundaries; i++ )    ph_virtual_boundaries_pos_x [ i ]u(13)   ph_num_hor_virtual_boundaries u(2)   for( i = 0; i < ph_num_hor_virtual_boundaries; i++ )    ph_virtual_boundaries_pos_y [ i ]u(13)  } } if( output_flag_present_flag )  pic_output_flag u(1) if( rpl_info_in_ph_flag )  ref_pic_lists( ) if( partition_constraints_override_enabled_flag )  partition_constraints_override_flag u(1) if( ph_intra_slice_allowed_flag ) {  if( partition_constraints_override_flag ) {   ph_log2_diff_min_qt_min_cb_intra_slice_luma ue(v)   ph_max_mtt_hierarchy_depth_intra_slice_luma ue(v)   if( ph_max_mtt_hierarchy_depth_intra_slice_luma != 0 ) {    ph_log2_diff_max_bt_min_qt_intra_slice_luma ue(v)    ph_log2_diff_max_tt_min_qt_intra_slice_luma ue(v)   }   if( qtbtt_dual_tree_intra_flag ) {    ph_log2_diff_min_qt_min_cb_intra_slice_chroma ue(v)    ph_max_mtt_hierarchy_depth_intra_slice_chroma ue(v)    if( ph_max_mtt_hierarchy_depth_intra_slice_chroma != 0) {     ph_log2_diff_max_bt_min_qt_intra_slice_chroma ue(v)     ph_log2_diff_max_tt_min_qt_intra_slice_chroma ue(v)    }   }  }  if( cu_qp_delta_enabled_flag )   ph_cu_qp_delta_subdiv_intra_slice ue(v)  if( pps_cu_chroma_qp_offset_list_enabled_flag )   ph_cu_chroma_qp_offset_subdiv_intra_slice ue(v) } if( ph_inter_slice_allowed_flag ) {  if( partition_constraints_override_flag ) {   ph_log2_diff_min_qt_min_cb_inter_slice ue(v)   ph_max_mtt_hierarchy_depth_inter_slice ue(v)   if( ph_max_mtt_hierarchy_depth_inter_slice != 0 ) {    ph_log2_diff_max_bt_min_qt_inter_slice ue(v)    ph_log2_diff_max_tt_min_qt_inter_slice ue(v)   }  }  if( cu_qp_delta_enabled_flag )   ph_cu_qp_delta_subdiv_inter_slice ue(v)  if( pps_cu_chroma_qp_offset_list_enabled_flag )   ph_cu_chroma_qp_offset_subdiv_inter_slice ue(v)  if( sps_temporal_mvp_enabled_flag ) {   ph_temporal_mvp_enabled_flag u(1)   if( ph_temporal_mvp_enabled_flag && rpl_info_in_ph_flag ) {    ph_collocated_from_l0_flag u(1)    if( ( ph_collocated_from_l0_flag &&     num_ref_entries[ 0 ][ RplsIdx[ 0 ] ] > 1 ) ∥      ( !ph_collocated_from_l0_flag &&      num_ref_entries[ 1 ][ RplsIdx[ 1 ] ] > 1 ) )    ph_collocated_ref_idx ue(v)   }  }  mvd_l1_zero_flag u(1)  if( sps_fpel_mmvd_enabled_flag )   ph_fpel_mmvd_enabled_flag u(1)  if( sps_bdof_pic_present_flag )   ph_disable_bdof_flag u(1)  if( sps_dmvr_pic_present_flag )   ph_disable_dmvr_flag u(1)  if( sps_prof_pic_present_flag )   ph_disable_prof_flag u(1)  if( ( pps_weighted_pred_flag ∥ pps_weighted_bipred_flag ) && wp_info_in_ph_flag )   pred_weight_table( ) } if( qp_delta_info_in_ph_flag )  ph_qp_delta se(v) if( sps_joint_cbcr_enabled_flag )  ph_joint_cbcr_sign_flag u(1) if( sps_sao_enabled_flag && sao_info_in_ph_flag ) {  ph_sao_luma_enabled_flag u(1)  if( ChromaArrayType != 0 )   ph_sao_chroma_enabled_flag u(1) } if( sps_dep_quant_enabled_flag )  ph_dep_quant_enabled_flag u(1) if( sps_sign_data_hiding_enabled_flag && !ph_dep_quant_enabled_flag )  pic_sign_data_hiding_enabled_flag u(1) if( deblocking_filter_override_enabled_flag && dbf_info_in_ph_flag ) {  ph_deblocking_filter_override_flag u(1)  if( ph_deblocking_filter_override_flag ) {   ph_deblocking_filter_disabled_flag u(1)   if( !ph_deblocking_filter_disabled_flag ) {    ph_beta_offset_div2 se(v)    ph_tc_offset_div2 se(v)    ph_cb_beta_offset_div2 se(v)    ph_cb_tc_offset_div2 se(v)    ph_cr_beta_offset_div2 se(v)    ph_cr_tc_offset_div2 se(v)   }  } } if( picture_header_extension_present_flag ) {  ph_extension_length ue(v)  for( i = 0; i < ph_extension_length; i++)   ph_extension_data_byte [ i ]u(8) }}

[0128] The PH syntax structure contains information that is common for all slices of the coded picture associated with the PH syntax structure. 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. gdr_pic_flag equal to 1 specifies 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. ph_inter_slice_allowed_flag equal to 0 specifies that all coded slices of the picture have slice_type equal to 2. ph_inter_slice_allowed_flag equal to 1 specifies that there may or may not be one or more coded slices in the picture that have slice_type equal to 0 or 1. ph_intra_slice_allowed_flag equal to 0 specifies that all coded 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 coded slices in the picture that have slice_type equal to 2.When not present, the value of ph_intra_slice_allowed_flag is inferred to be equal to 1. NOTE 1 - For bitstreams that are suppposed to work subpicure based bitstream merging without the need of changing PH NAL units, the encoder is expected to set the values of both ph_inter_slice_allowed_flag and ph_intra_slice_allowed_flag equal to 1. non_reference_picture_flag equal to 1 specifies the picture associated with the PH is never used as a reference picture. non_reference_picture_flag equal to 0 specifies the picture associated with the PH may or may not be used as a reference picture. ph_pic_parameter_set_id specifies the value of pps_pic_parameter_set_id for the PPS in use. The value of ph_pic_parameter_set_id shall be in the range of 0 to 63, inclusive.

[0129] It is a requirement of bitstream conformance that the value of TemporalId of the PH shall be greater than or equal to the value of TemporalId of the PPS that has pps_pic_parameter_set_id equal to ph_pic_parameter_set_id. ph_pic_order_cnt_lsb specifies the picture order count modulo MaxPicOrderCntLsb for the current picture. The length of the ph_pic_order_cnt_lsb syntax element is log2_max_pic_order_cnt_lsb_minus4 + 4 bits. The value of the ph_pic_order_cnt_lsb shall be in the range of 0 to MaxPicOrderCntLsb - 1, inclusive. no_output_of_prior_pics_flag affects the output of previously-decoded pictures in the DPB after the decoding of a CLVSS picture that is not the first picture in the bitstream as specified in Annex C. recovery_poc_cnt specifies the recovery point of decoded pictures in output order. If the current picture is a GDR picture that is associated with the PH, and there is a picture picA that follows the current GDR picture in decoding order in the CLVS that has PicOrderCntVal equal to the PicOrderCntVal of the current GDR picture plus the value of recovery_poc_cnt, the picture picA is referred to as the recovery point picture. Otherwise, the first picture in output order that has PicOrderCntVal greater than the PicOrderCntVal of the current picture plus the value of recovery_poc_cnt is referred to as the recovery point picture. The recovery point picture shall not precede the current GDR picture in decoding order. The value of recovery_poc_cnt shall be in the range of 0 to MaxPicOrderCntLsb - 1, inclusive.

[0130] When the current picture is a GDR picture, the variable RpPicOrderCntVal is derived as follows: RpPicOrderCntVal = PicOrderCntVal + recovery_poc_cnt NOTE 2 - When gdr_enabled_flag is equal to 1 and PicOrderCntVal of the current picture is greater than or equal to RpPicOrderCntVal of the associated GDR picture, the current and subsequent decoded pictures in output order are exact match to the corresponding pictures produced by starting the decoding process from the previous IRAP picture, when present, preceding the associated GDR picture in decoding order. ph_extra_bit [ i ] may be equal to 1 or 0. Decoders conforming to this version of this Specification shall ignore the value of ph_extra_bit[ i ]. Its value does not affect decoder conformance to profiles specified in this version of specification. ph_poc_msb_present_flag equal to 1 specifies that the syntax element poc_msb_val is present in the PH. ph_poc_msb_present_flag equal to 0 specifies that the syntax element poc_msb_val is not present in the PH. When vps_independent_layer_flag[ GeneralLayerIdx[ nuh_layer_id ] ] is equal to 0 and there is a picture in the current AU in a reference layer of the current layer, the value of ph_poc_msb_present_flag shall be equal to 0. 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. ph_alf_enabled_flag equal to 1 specifies that adaptive loop filter is enabled for all slices associated with the PH and may be applied to Y, Cb, or Cr colour component in the slices. ph_alf_enabled_flag equal to 0 specifies that adaptive loop filter may be disabled for one, or more, or all slices associated with the PH. When not present, ph _alf_enabled_flag is inferred to be equal to 0. ph_num_alf_aps_ids_luma specifies the number of ALF APSs that the slices associated with the PH refers to. ph_alf_aps_id_luma [ i ] specifies the adaptation_parameter_set_id of the i-th ALF APS that the luma component of the slices associated with the PH refers to.

[0131] The value of alf_luma_filter_signal_flag of the APS NAL unit having aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_alf_aps_id_luma[ i ] shall be equal to 1.

[0132] The TemporalId of the APS NAL unit having 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. ph_alf_chroma_idc equal to 0 specifies that the adaptive loop filter is not applied to Cb and Cr colour components. ph_alf_chroma_idc equal to 1 indicates that the adaptive loop filter is applied to the Cb colour component. ph_alf_chroma_idc equal to 2 indicates that the adaptive loop filter is applied to the Cr colour component. ph_alf_chroma_idc equal to 3 indicates that the adaptive loop filter is applied to Cb and Cr colour components. When ph_alf_chroma_idc is not present, it is inferred to be equal to 0. ph_alf_aps_id_chroma specifies the adaptation_parameter_set_id of the ALF APS that the chroma component of the slices associated with the PH refers to.

[0133] The value of alf_chroma_filter_signal_flag of the APS NAL unit having aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_alf_aps_id_chroma shall be equal to 1.

[0134] The TemporalId of the APS NAL unit having 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. ph_cc_alf_cb_enabled_flag equal to 1 specifies that cross-component filter for Cb colour component is enabled for all slices associated with the PH and may be applied to Cb colour component in the slices. ph_cc_alf_cb_enabled_flag equal to 0 specifies that cross-component filter for Cb colour component may be disabled for one, or more, or all slices associated with the PH. When not present, ph_cc_alf_cb_enabled_flag is inferred to be equal to 0. ph_ce_alf_cb_aps_id specifies the adaptation_parameter_set_id of the ALF APS that the Cb colour component of the slices associated with the PH refers to.

[0135] The value of alf_cc_cb_filter_signal_flag of the APS NAL unit having aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_cc_alf_cb_aps_id shall be equal to 1.

[0136] The TemporalId of the APS NAL unit having 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. ph_cc_alf_cr_enabled_flag equal to 1 specifies that cross-compoent filter for Cr colour component is enabled for all slices associated with the PH and may be applied to Cr colour component in the slices. ph_cc_alf_cr_enabled_flag equal to 0 specifies that cross-component filter for Cr colour component may be disabled for one, or more, or all slices associated with the PH. When not present, ph_cc_alf_cr_enabled_flag is inferred to be equal to 0. ph_cc_alf_cr_aps_id specifies the adaptation_parameter_set_id of the ALF APS that the Cr colour component of the slices associated with the PH refers to.

[0137] The value of alf_cc_cr_filter_signal_flag of the APS NAL unit having aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to ph_cc_alf_cr_aps_id shall be equal to 1.

[0138] The TemporalId of the APS NAL unit having 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. ph_lmcs_enabled_flag equal to 1 specifies that luma mapping with chroma scaling is enabled for all slices associated with the PH. ph_lmcs_enabled_flag equal to 0 specifies that luma mapping with chroma scaling may be disabled for one, or more, or all slices associated with the PH. When not present, the value of ph_lmes_enabled_flag is inferred to be equal to 0. ph_lmcs_aps_id specifies the adaptation_parameter_set_id of the LMCS APS that the slices associated with the PH refers to. The TemporalId of the APS NAL unit having 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 PH. ph_chroma_residual_scale_flag equal to 1 specifies that chroma residual scaling is enabled for the all slices associated with the PH. ph_chroma_residual_scale_flag equal to 0 specifies that chroma residual scaling may be disabled for one, or more, or all slices associated with the PH. When ph_chroma_residual_scale_flag is not present, it is inferred to be equal to 0. ph_scaling_list_present_flag equal to 1 specifies that the scaling list data used for the slices associated wih 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 used for the slices associated with the PH is set to be equal to 16. When not present, the value of ph_scaling_list_present_flag is inferred to be equal to 0. ph_scaling_list_aps_id specifies the adaptation_parameter_set_id of the scaling list APS. The TemporalId of the APS NAL unit having 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 PH. ph_virtual_boundaries_present_flag equal to 1 specifies that information of virtual boundaries is signalled in the PH. ph_virtual_boundaries_present_flag equal to 0 specifies that information of virtual boundaries is not signalled in the PH. When there is one or more than one virtual boundaries signalled in the PH, the in-loop filtering operations are disabled across the virtual boundaries in the picture. The in-loop filtering operations include the 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.

[0139] It is a requirement of bitstream conformance that, when subpic_info_present_flag is equal to 1, the value of ph_virtual_boundaries_present_ flag shall be equal to 0.

[0140] The variable VirtualBoundariesPresentFlag is derived as follows: VirtualBoundariesPresentFlag = 0 if( sps_virtual_boundaries_enabled_flag ) VirtualBoundariesPresentFlag = sps_virtual_boundaries_present_flag | | ph_virtual_boundaries_present_flag (83)ph_num_ver_virtual_boundaries specifies the number of ph_virtual_boundaries_pos_x[ i ] syntax elements that are present in the PH. When ph_num_ver_virtual_boundaries is not present, it is inferred to be equal to 0.

[0141] The variable NumVerVirtualBoundaries is derived as follows: NumVerVirtualBoundaries = 0 if( sps_virtual_boundaries_enabled_flag ) NumVerVirtualBoundaries = sps_virtual_boundaries_present_flag ? sps_num_ver_virtual_boundaries : ph_num_ver_virtual_boundaries (84)ph_virtual_boundaries_pos_x[ i ] specifies the location 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.

[0142] The list VirtualBoundariesPosX[ i ] for i ranging from 0 to NumVerVirtualBoundaries - 1, inclusive, in units of luma samples, specifying the locations of the vertical virtual boundaries, is derived as follows: for( i = 0; i < NumVerVirtualBoundaries; i++) VirtualBoundariesPosX[ i ] = ( sps_virtual_boundaries_present_flag ? sps_virtual_boundaries_pos_x[ i ] : ph_virtual_boundaries_pos_x[ i ] ) * 8 (85)

[0143] The distance between any two vertical virtual boundaries shall be greater than or equal to CtbSizeY luma samples. ph_num_hor_virtual_boundaries specifies the number of ph_virtual_boundaries_pos_y[ i ] syntax elements that are present in the PH. When ph_num_hor_virtual_boundaries is not present, it is inferred to be equal to 0.

[0144] The parameter NumHorVirtualBoundaries is derived as follows: NumHorVirtualBoundaries = 0 if( sps_virtual_boundaries_enabled_flag ) NumHorVirtualBoundaries = sps_virtual_boundaries_present_flag ? sps_num_hor_virtual_boundaries : ph_num_hor_virtual_boundaries (86)

[0145] 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 0. ph_virtual_boundaries_pos_y [ i ] specifies the location 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.

[0146] The list VirtualBoundariesPosY[ i ] for i ranging from 0 to NumHorVirtualBoundaries - 1, inclusive, in units of luma samples, specifying the locations of the horizontal virtual boundaries, is derived as follows: for( i = 0; i < NumHorVirtualBoundaries; i++) VirtualBoundariesPosY[ i ] = ( sps_virtual_boundaries_present_flag ? sps_virtual_boundaries_pos_y[ i ] : ph_virtual_boundaries_pos_y[ i ] ) * 8 (87)

[0147] The distance between any two horizontal virtual boundaries shall be greater than or equal to CtbSizeY luma samples. pic_output_flag affects the decoded picture output and removal processes as specified in Annex C. When pic_output_flag is not present, it is inferred to be equal to 1. partition_constraints _override_flag equal to 1 specifies that partition constraint parameters are present in the PH. partition_constraints_override_flag equal to 0 specifies that partition constraint parameters are not present in the PH. When not present, the value of partition_constraints_override_flag is inferred to be equal to 0. ph_log2_diff_min_qt_min_cb_intra_slice_luma specifies the difference between the base 2 logarithm of the minimum size in luma samples of a luma leaf block resulting from quadtree splitting of a CTU and the base 2 logarithm of the minimum coding block size in luma samples for luma CUs in the slices with slice_type equal to 2 (I) associated with the PH. The value of ph_log2_diff_min_qt_min_cb_intra_slice_luma shall be in the range of 0 to CtbLog2SizeY - MinCbLog2SizeY, inclusive. When not present, the value of ph_log2_diff_min_qt_min_cb_luma is inferred to be equal to sps_log2_diff_min_qt_min_cb_intra_slice_luma. ph_max_mtt_hierarchy_depth_intra_slice_luma specifies the maximum hierarchy depth for coding units resulting from multi-type tree splitting of a quadtree leaf in slices with slice_type equal to 2 (I) associated with the PH. The value of ph_max_mtt_hierarchy_depth_intra_slice_luma shall be in the range of 0 to 2*( CtbLog2SizeY - MinCbLog2SizeY ), inclusive. When not present, the value of ph_max_mtt_hierarchy_depth_intra_slice_luma is inferred to be equal to sps_max_mtt_hierarchy_depth_intra_slice_luma. ph_log2_diff_max_bt_min_qt_intra_slice_luma specifies the difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a luma coding block that can be split using a binary split and the minimum size (width or height) in luma samples of a luma leaf block resulting from quadtree splitting of a CTU 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. ph_log2_diff_max_tt_min_qt_intra_slice_luma specifies the difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a luma coding block that can be split using a ternary split and the minimum size (width or height) in luma samples of a luma leaf block resulting from quadtree splitting of a CTU 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. ph_log2_diff_min_qt_min_cb_intra_slice_chroma specifies the difference between the base 2 logarithm of the minimum size in luma samples of a chroma leaf block resulting from quadtree splitting of a chroma CTU with tree Type equal to DUAL_TREE_CHROMA and the base 2 logarithm of the minimum coding block size in luma samples for chroma CUs with tree Type equal to DUAL_TREE_CHROMA in slices with slice_type equal to 2 (I) associated with the PH. The value of ph_log2_diff_min_qt_min_cb_intra_slice_chroma shall be in the range of 0 to CtbLog2SizeY - MinCbLog2SizeY, inclusive. When not present, the value of ph_log2_diff_min_qt_min_cb_intra_slice_chroma is inferred to be equal to sps_log2_diff_min_qt_min_cb_intra_slice_chroma. ph_max_mtt_hierarchy_depth_intra_slice_chroma specifies the maximum hierarchy depth for chroma coding units resulting from multi-type tree splitting of a chroma quadtree leaf 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. ph_log2_diff_max_bt_min_qt_intra_slice_ chroma specifies the difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a chroma coding block that can be split using a binary split and the minimum size (width or height) in luma samples of a chroma leaf block resulting from quadtree splitting of a chroma CTU 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. ph_log2_diff_max_tt_min_qt_intra_slice_chroma specifies the difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a chroma coding block that can be split using a ternary split and the minimum size (width or height) in luma samples of a chroma leaf block resulting from quadtree splitting of a chroma CTU 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_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 ph_cu_qp_delta_subdiv_intra_slice specifies the maximum cbSubdiv value of coding units in intra slice 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.

[0148] When not present, the value of ph _cu_qp_delta_subdiv_intra_slice is inferred to be equal to 0. ph_cu_chroma_qp_offset_subdiv_intra_slice specifies the maximum cbSubdiv value of coding units in intra slice that convey 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.

[0149] When not present, the value of ph_cu _chroma_qp_offset_subdiv _intra_slice is inferred to be equal to 0. ph_log2_diff_min_qt_min_cb_inter_slice specifies the difference between the base 2 logarithm of the minimum size in luma samples of a luma leaf block resulting from quadtree splitting of a CTU and the base 2 logarithm of the minimum luma coding block size in luma samples for luma CUs 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. ph_max_mtt_hierarchy_depth_inter_slice specifies the maximum hierarchy depth for coding units resulting from multi-type tree splitting of a quadtree leaf in slices with slice_type equal to 0 (B) or 1 (P) associated with the PH. The value of phmax_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. ph_log2_diff_max_bt_min_qt_inter_slice specifies the difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a luma coding block that can be split using a binary split and the minimum size (width or height) in luma samples of a luma leaf block resulting from quadtree splitting of a CTU in the slices 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. ph_log2_diff_max_tt_min_qt_inter_slice specifies the difference between the base 2 logarithm of the maximum size (width or height) in luma samples of a luma coding block that can be split using a ternary split and the minimum size (width or height) in luma samples of a luma leaf block resulting from quadtree splitting of a CTU in slices 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_shall be in the range of 0 to CtbLog2SizeY - MinQtLog2SizeInterY, inclusive. When not present, the value of ph_log2_diff_max_tt_min_qt_inter_slice is inferred to be equal to sps_log2_diff_max_tt_min_qt_inter_slice. ph_cu_qp_delta_subdiv_inter_slice specifies the maximum cbSubdiv value of coding units that in inter slice 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. ph_cu_chroma_qp_offset_subdiv_inter_slice specifies the maximum cbSubdiv value of coding units in inter slice that convey 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.

[0151] When not present, the value of ph_cu _chroma_qp_offset_subdiv_inter_slice is inferred to be equal to 0. ph_temporal_mvp_enabled_flag specifies whether temporal motion vector predictors can be used for inter prediction for slices associated with the PH. If ph_temporal _mvp_enabled _flag is equal to 0, the syntax elements of the slices associated with the PH shall be constrained such that no temporal motion vector predictor is used in decoding of the slices. Otherwise (ph_temporal_mvp_enabled _flag is equal to 1), temporal motion vector predictors may be used in decoding of the slices associated with the PH. When not present, the value of ph_temporal_mvp_enabled_flag is inferred to be equal to 0. When no reference picture in the DPB has the same spatial resolution as the current picture, the value of ph_temporal_mvp_enabled_flag shall be equal to 0.

[0152] The maximum number of subblock-based merging MVP candidates, MaxNumSubblockMergeCand, is derived as follows:

[0153] The value of MaxNumSubblockMergeCand shall be in the range of 0 to 5, inclusive. 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. ph_collocated_ref_idx specifies the reference index of the collocated picture used for temporal motion vector prediction.

[0154] When ph_collocated_from_10_flag is equal to 1, ph_collocated_ref_idx refers to an entry in reference picture list 0, and the value of ph_collocated_ref_idx shall be in the range of 0 to num_ref_entries[ 0 ][ RplsIdx[ 0 ] ] - 1, inclusive.

[0155] When ph_collocated_from_1l_flag is equal to 0, ph_collocated_ref_idx refers to an entry in reference picture list 1, and the value of ph_collocated_ref_idx shall be in the range of 0 to num_ref_entries[ 1 ][ RplsIdx[ 1 ] ] - 1, inclusive.

[0156] When not present, the value of ph_collocated_ref_idx is inferred to be equal to 0. mvd_11_zero_flag equal to 1 indicates that the mvd_coding( x0, y0, 1 ) syntax structure is not parsed and MvdL1[ x0 ][ y0 ][ compIdx ] and MvdCpL1[ x0 ][ y0 ][ cpIdx ][ compIdx ] are set equal to 0 for compIdx = 0..1 and cpIdx = 0..2. mvd_l1_zero_flag equal to 0 indicates that the mvd_coding( x0, y0, 1 ) syntax structure is parsed. ph_fpel_mmvd_enabled_flag equal to 1 specifies that merge mode with motion vector difference uses integer sample precision in the slices associated with the PH. ph_fpel_mmvd_enabled_flag equal to 0 specifies that merge mode with motion vector difference can use fractional sample precision in the slices associated with the PH. When not present, the value of ph_fpel_mmvd_enabled_flag is inferred to be 0. ph_disable_bdof_flag equal to 1 specifies that bi-directional optical flow inter prediction based inter bi-prediction is disabled in the slices associated with the PH. ph_disable_bdof_flag equal to 0 specifies that bi-directional optical flow inter prediction based inter bi-prediction may or may not be enabled in the slices associated with the PH.

[0157] When ph_disable_bdof_flag is not present, the following applies: If sps_bdof_enabled_flag is equal to 1, the value of ph_disable_bdof_flag is inferred to be equal to 0. Otherwise (sps_bdof_enabled_flag is equal to 0), the value of ph_disable_bdof_flag is inferred to be equal to 1. ph_disable_dmvr_flag equal to 1 specifies that decoder motion vector refinement based inter bi-prediction is disabled in the slices associated with the PH. ph_disable_dmvr_flag equal to 0 specifies that decoder motion vector refinement based inter bi-prediction may or may not be enabled in the slices associated with the PH.

[0158] When ph_disable_dmvr_flag is not present, the following applies: If sps_dmvr_enabled_flag is equal to 1, the value of ph_disable_dmvr_flag is inferred to be equal to 0. Otherwise (sps_dmvr_enabled_flag is equal to 0), the value of ph_disable_dmvr_flag is inferred to be equal to 1. ph_disable_prof_flag equal to 1 specifies that prediction refinement with optical flow is disabled in the 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 the slices associated with the PH.

[0159] When ph_disable_prof_flag is not present, the following applies: If sps_affine_prof_enabled _flag is equal to 1, the value of ph_disable_prof_flag is inferred to be equal to 0. Otherwise (sps_affine_prof_enabled _flag is equal to 0), the value of ph_disable_prof_ flag is inferred to be equal to 1. ph_qp_delta specifies the initial value of QpY to be used for the coding blocks in the picture until modified by the value of CuQpDeltaVal in the coding unit layer.

[0160] When qp_delta_info_in_ph_flag is equal to 1, the initial value of the Qp Y quantization parameter for all slices of the picture, SliceQpy, is derived as follows: SliceQp Y = 26 + init_qp_minus 26 + ph_qp_delta

[0161] The value of SliceQpy shall be in the range of -QpBdOffset to +63, inclusive. ph_joint_cber_sign_flag specifies whether, in transform units with tu_joint_cbcr_residual_flag[ x0 ][ y0 ] equal to 1, the collocated residual samples of both chroma components have inverted signs. When tu_joint_cbcr_residual_flag[ x0 ][ y0 ] equal to 1 for a 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 identical to the sign of the collocated 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 collocated Cb (or Cr) residual sample. ph_sao_luma_enabled_flag equal to 1 specifies that SAO is enabled for the luma component in all slices associated with the PH; ph_sao_luma_enabled_flag equal to 0 specifies that SAO for the luma component may be disabled for one, or more, or all slices associated with the PH. When ph_sao_luma_enabled_flag is not present, it is inferred to be equal to 0. ph_sao_chroma_enabled_flag equal to 1 specifies that SAO is enabled for the chroma component in all slices associated with the PH; ph_sao_chroma_enabled_flag equal to 0 specifies that SAO for chroma component may be disabled for one, or more, or all slices associated with the PH. When ph_sao_chroma_enabled_flag is not present, it is inferred to be equal to 0. 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. 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. ph_deblocking_filter_override_flag equal to 1 specifies that deblocking parameters are present in the PH. ph_deblocking_filter_override_flag equal to 0 specifies that deblocking parameters are not present in the PH. When not present, the value of ph_deblocking _filter_override_flag is inferred to be equal to 0. ph_deblocking_filter_disabled_flag equal to 1 specifies that the operation of the deblocking filter is not applied for the slices associated with the PH. ph_deblocking_filter_disabled_flag equal to 0 specifies that the operation of the deblocking filter is applied for 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. ph_beta_offset_div2 and ph_tc_offset_div2 specify the deblocking parameter offsets for β and tC (divided by 2) that are applied to the luma component for the slices associated with the PH. The values of ph_beta_offset_div2 and ph_tc_offset_div2 shall both be in the range of -12 to 12, inclusive. When not present, the values of ph_beta_offset_div2 and ph_tc_offset_div2 are inferred to be equal to pps_beta_offset_div2 and pps_tc_offset_div2, respectively. ph_cb_beta_offset_div2 and ph_cb_tc_offset_div2 specify the deblocking parameter offsets for β and tC (divided by 2) that are applied to the Cb component for the slices associated with the PH. The values of ph_cb_beta_offset_div2 and ph_cb_tc_offset_div2 shall both be in the range of -12 to 12, inclusive. When not present, the values of ph_cb_beta_offset_div2 and ph_cb_tc_offset_div2 are inferred to be equal to pps_cb_beta_offset_div2 and pps_cb_tc_offset_div2, respectively. ph_cr_beta_offset_div2 and ph_cr_tc_offset_div2 specify the deblocking parameter offsets for β and tC (divided by 2) that are applied to the Cr component for the slices associated with the PH. The values of ph_cr_beta_offset_div2 and ph_cr_tc_offset_div2 shall 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. ph_extension_length specifies the length of the PH extension data in bytes, not including the bits used for signalling 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. ph_extension_data_byte may have any value. Decoders conforming to this version of this Specification shall ignore the value of ph_extension_data_byte. Its value does not affect decoder conformance to profiles specified in this version of specification. 3.6. SH syntax and semantics

[0162] In the latest VVC draft text, the SH syntax and semantics are as follows: slice_header( ) {Descript or  picture_header_in_slice_heade_flag u(1)  if( picture_header_in_slice_header_flag )   picture_header_structure( )  if( subpic_info_present_flag )  slice_subpic_id u(v)  if( ( rect_slice_flag && NumSlicesInSubpic[ CurrSubpicIdx ] > 1 ) ∥ ( !rect_slice_flag && NumTilesInPic > 1 ) )  slice_address u(v)  for( i = 0; i < NumExtraShBits; i++ )  sh_extra_bit [ i ]u(1)  if( !rect_slice_flag && NumTilesInPic > 1 )  num_tiles_in_slice_minus1 ue(v)  if( ph_inter_slice_allowed_flag )  slice_type ue(v)  if( sps_alf_enabled_flag && !alf_info_in_ph_flag ) {  slice_alf_enabled_flag u(1)   if( slice_alf_enabled) {   slice_num_alf_aps_ids_luma u(3)    for( i = 0; i < slice_num_alf_aps_ids_luma; i++ )    slice_alf_aps_id_luma [ i ]u(3)    if( ChromaArrayType != 0)    slice_alf_chroma_idc u(2)    if( slice_alf_chroma_idc )    slice_alf_aps_id_chroma u(3)    if( sps_ccalf_enabled_flag ) {    slice_cc_alf_cb_enabled_flag u(1)     if( slice_cc_alf_cb_enabled_flag )     slice_cc_alf_cb_aps_id u(3)    slice_cc_alf_cr_enabled_flag u(1)     if( slice_cc_alf_cr_enabled_flag )     slice_cc_alf_cr_aps_id u(3)    }   }  }  if( separate_colour_plane_flag == 1 )  colour_plane_id u(2)  if( !rpl_info_in_ph_flag && ( (nal_unit_type != IDR_W_RADL && nal_unit_type !=   IDR_N_LP ) ∥ sps_idr_rpl_present_flag ) )  ref_pic_lists( )  if( ( rpl_info_in_ph_flag ∥ ( ( nal_unit_type != IDR_W_RADL && nal_unit_type !=   IDR_N_LP ) ∥ sps_idr_rpl_present_flag ) ) &&   ( slice_type != I && num_ref_entries[ 0 ][ RplsIdx[ 0 ] ] > 1 ) ∥   ( slice_type = = B && num_ref_entries[ 1 ][ RplsIdx[ 1 ] ] > 1 ) ) {  num_ref_idx_active_override_flag u(1)   if( num_ref_idx_active_override_flag )    for( i = 0; i < ( slice_type = = B? 2: 1 ); i++ )     if( num_ref_entries[ i ][ RplsIdx[ i ] ] > 1 )     num_ref_idx_active_minus1 [ i ]ue(v)  }  if( slice_type != I ) {   if( cabac_init_present_flag )   cabac_init_flag u(1)   if( ph_temporal_mvp_enabled_flag && !rpl_info_in_ph_flag ) {    if( _slice__type == B )    slice_collocated_from_l0_flag u(1)    if( ( slice_collocated_from_l0_flag && NumRefIdxActive[ 0 ] > 1 ) ∥     ( ! slice_collocated_from_l0_flag && NumRefIdxActive[ 1 ] > 1 ) )   slice_collocated_ref_idx ue(v)   }   if( !wp_info_in_ph_flag && ( ( pps_weighted_pred_flag && slice_type == P) ∥    (pps_weighted_bipred_flag && slice_type == B)))   pred_weight_table( )  }  if( !qp_delta_info_in_ph_flag )  slice_qp_delta se(v)  if( pps_slice_chroma_qp_offsets_present_flag ) {  slice_cb_qp_offset se(v)  slice_cr_qp_offset se(v)   if( sps_joint_cbcr_enabled_flag )   slice_joint_cbcr_qp_offset se(v)  }  if( pps_cu_chroma_qp_offset_list_enabled_flag )  cu_chroma_qp_offset_enabled_flag u(1)  if( sps_sao_enabled_flag && !sao_info_in_ph_flag ) {  slice_sao_luma_flag u(1)   if( ChromaArrayType != 0)   slice_sao_chroma_flag u(1)  }  if( deblocking_filter_override_enabled_flag && !dbf_info_in_ph_flag )  slice_deblocking_filter_override_flag u(1)  if( slice_deblocking_filter_override_flag ) {  slice_deblocking_filter_disabled_flag u(1)   if( !slice_deblocking_filter_disabled_flag ) {   slice_beta_offset_div2 se(v)   slice_tc_offset_div2 se(v)   slice_cb_beta_offset_div2 se(v)   slice_cb_tc_offset_div2 se(v)   slice_cr_beta_offset_div2 se(v)   slice_cr_tc_offset_div2 se(v)   }  } slice_ts_residual_coding_disabled_flag u(1)  if( ph_lmcs_enabled_flag )  slice_lmcs_enabled_flag u(1)  if( ph_scaling_list_enabled_flag )  slice_scaling_list_present_flag u(1)  if( NumEntryPoints > 0 ) {  offset_len_minus1 ue(v)   for( i = 0; i < NumEntryPoints; i++ )   entry_point_offset_minus1 [ i ]u(v)  }  if( slice_header_extension_present_flag ) {  slice_header_extension_length ue(v)   for( i = 0; i < slice_header_extension_length; i++)   slice_header_extension_data_byte [ i ]u(8)  }  byte_alignment( )}

[0163] The variable CuQpDeltaVal, specifying the difference between a luma quantization parameter for the coding unit containing cu_qp_delta_abs and its prediction, is set equal to 0. The variables CuQpOffset Cb , CuQpOffset Cr , and CuQpOffset CbCr , specifying values to be used when determining the respective values of the Qp' Cb , Qp' Cr , and Qp' CbCr quantization parameters for the coding unit containing cu_chroma_qp_offset_flag, are all set equal to 0. 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.

[0164] It is a requirement of bitstream conformance that the value of picture_header_in_slice_header_flag shall be the same in all coded slices in a CLVS.

[0165] When picture_header_in_slice_header_flag is equal to 1 for a coded slice, it is a requirement of bitstream conformance that no VCL NAL unit with nal_unit_type equal to PH_NUT shall be present in the CLVS.

[0166] When picture_header_in_slice_header_flag is equal to 0, all coded slices in the current picture shall have picture_header_in_slice_header_flag is equal to 0, and the current PU shall have a PH NAL unit. slice_subpic_id specifies the subpicture ID of the subpicture that contains the slice. If slice_subpic_id is present, the value of the variable CurrSubpicIdx is derived to be such that SubpicIdVal[ CurrSubpicIdx ] is equal to slice_subpic_id. Otherwise (slice_subpic_id is not present), CurrSubpicIdx is derived to be equal to 0. The length of slice_subpic_id is sps_subpic_id_len_minus1 + 1 bits. 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.

[0167] If rect_slice _flag is equal to 0, the following applies: The slice address is the raster scan tile index. The length of slice_address is Ceil( Log2 ( NumTilesInPic ) ) bits. The value of slice_address shall be in the range of 0 to NumTilesInPic - 1, inclusive.

[0168] Otherwise (rect_slice_flag is equal to 1), the following applies: The slice address is the subpicture-level slice index of the slice. The length of slice_address is Ceil( Log2( NumSlicesInSubpic[ CurrSubpicIdx ] )) bits. The value of slice_address shall be in the range of 0 to NumSlicesInSubpic[ CurrSubpicIdx ] - 1, inclusive.

[0169] It is a requirement of bitstream conformance that the following constraints apply: 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 coded slice NAL unit of the same coded picture. Otherwise, the pair of slice_subpic_id and slice_address values shall not be equal to the pair of slice_subpic_id and slice_address values of any other coded slice NAL unit of the same coded picture. The shapes of the slices of a picture shall be such that each CTU, when decoded, shall have its entire left boundary and entire top boundary consisting of a picture boundary or consisting of boundaries of previously decoded CTU(s). 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 decoder conformance to profiles specified in this version of specification. num_tiles_in_slice_minus1 plus 1, when present, specifies the number of tiles in the slice. The value of num_tiles_in_slice_minus1 shall be in the range of 0 to NumTilesInPic - 1, inclusive.

[0170] The variable NumCtusInCurrSlice, which specifies the number of CTUs in the current slice, and the list CtbAddrInCurrSlice[ i ], for i ranging from 0 to NumCtusInCurrSlice - 1, inclusive, specifying the picture raster scan address of the i-th CTB within the slice, are derived as follows:

[0171] The variables SubpicLeftBoundaryPos, SubpicTopBoundaryPos, SubpicRightBoundaryPos, and SubpicBotBoundaryPos are derived as follows: slice_type specifies the coding type of the slice according to Table 9. Table 9 - Name association to slice_type slice_type Name of slice_type 0B (B slice)1P (P slice)2I (I slice)

[0172] When not present, the value of slice_type is inferred to be equal to 2.

[0173] When ph_intra_slice_allowed_flag is equal to 0, the value of slice_type shall be equal to 0 or 1. When nal_unit_type is in the range of IDR_W_RADL to CRA_NUT, inclusive, and vps_independent_layer_flag[ GeneralLayerIdx[ nuh_layer_id ] ] is equal to 1, slice_type shall be equal to 2.

[0174] The variables MinQtLog2SizeY, MinQtLog2SizeC, MinQtSizeY, MinQtSizeC, MaxBtSizeY, MaxBtSizeC, MinBtSizeY, MaxTtSizeY, MaxTtSizeC, MinTtSizeY, MaxMttDepthY and MaxMttDepthC are derived as follows: If slice_type equal to 2 (I), the following applies: MinQtLog 2 SizeY = MinCbLog 2 SizeY + ph_log 2 _diff_min_qt_min_cb_intra_slice_luma MinQtLog 2 SizeC = MinCbLog 2 SizeY + ph_log 2 _diff_min_qt_min_cb_intra_slice_chroma MaxBtSizeY = 1 ≪ MinQtLog 2 SizeY + ph_log 2 _diff_max_bt_min_qt_intra_slice_luma MaxBtSizeC = 1 ≪ MinQtLog 2 SizeC + ph_log 2 _diff_max_bt_min_qt_intra_slice_chroma MaxTtSizeY = 1 ≪ MinQtLog 2 SizeY + ph_log 2 _diff_max_tt_min_qt_intra_slice_luma MaxTtSizeC = 1 ≪ MinQtLog 2 SizeC + ph_log 2 _diff_max_tt_min_qt_intra_slice_chroma MaxMttDepthY = ph_max_mtt_hierarchy_depth_intra_slice_luma MaxMttDepthC = ph_max_mtt_hierarchy_depth_intra_slice_chroma CuQpDeltaSubdiv = ph_cu_qp_delta_subdiv_intra_slice CuChromaQpOffsetSubdiv = ph_cu_chroma_qp_offset_subdiv_intra_slice Otherwise (slice_type equal to 0 (B) or 1 (P)), the following applies: MinQtLog 2 SizeY = MinCbLog 2 SizeY + ph_log 2 _diff_min_qt_min_cb_inter_slice MinQtLog 2 SizeC = MinCbLog 2 SizeY + ph_log 2 _diff_min_qt_min_cb_inter_slice MaxBtSizeY = 1 ≪ MinQtLog 2 SizeY + ph_log 2 _diff_max_bt_min_qt_inter_slice MaxBtSizeC = 1 ≪ MinQtLog 2 SizeC + ph_log 2 _diff_max_bt_min_qt_inter_slice MaxTtSizeY = 1 ≪ MinQtLog 2 SizeY + ph_log 2 _diff_max_tt_min_qt_inter_slice MaxTtSizeC = 1 ≪ MinQtLog 2 SizeC + ph_log 2 _diff_max_tt_min_qt_inter_slice MaxMttDepthY = ph_max_mtt_hierarchy_depth_inter_slice MaxMttDepthC = ph_max_mtt_hierarchy_depth_inter_slice CuQpDeltaSubdiv = ph_cu_qp_delta_subdiv_inter_slice CuChromaQpOffsetSubdiv = ph_cu_chroma_qp_offset_subdiv_inter_slice The following applies: MinQtSizeY = 1 ≪ MinQtLog 2 SizeY MinQtSizeC = 1 ≪ MinQtLog 2 SizeC MinBtSizeY = 1 ≪ MinCbLog 2 SizeY MinTtSizeY = 1 ≪ MinCbLog 2 SizeY slice_alf_enabled_flag equal to 1 specifies that adaptive loop filter is enabled and may be applied to Y, Cb, or Cr colour component in a slice. slice_alf_enabled _flag equal to 0 specifies that adaptive loop filter is disabled for all colour components in a slice. When not present, the value of slice_alf_enabled _flag is inferred to be equal to ph_alf_enabled_flag. slice_num_alf_aps_ids_luma specifies the number of ALF APSs that the slice refers to. 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. slice_alf_aps_id_luma [ i ] specifies the adaptation_parameter_set_id of the i-th ALF APS that the luma component of the slice refers to. The TemporalId of the APS NAL unit having 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 ].

[0175] The value of alf_luma_filter_signal_flag of the APS NAL unit having aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_alf_aps_id_luma[ i ] shall be equal to 1. slice_alf_chroma_idc equal to 0 specifies that the adaptive loop filter is not applied to Cb and Cr colour components. slice_alf_chroma_idc equal to 1 indicates that the adaptive loop filter is applied to the Cb colour component. slice_alf_chroma_idc equal to 2 indicates that the adaptive loop filter is applied to the Cr colour component. slice_alf_chroma_idc equal to 3 indicates that the adaptive loop filter is applied to Cb and Cr colour components. When slice_alf_chroma_idc is not present, it is inferred to be equal to ph_alf_chroma_idc. slice_alf_aps_id_chroma specifies the adaptation_parameter_set_id of the ALF APS that the chroma component of the slice refers to. The TemporalId of the APS NAL unit having 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 coded 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.

[0176] The value of alf_chroma_filter_signal _flag of the APS NAL unit having aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_alf_aps_id_chroma shall be equal to 1. slice_cc_alf_cb_enabled_flag equal to 0 specifies that the cross-component filter is not applied to the Cb colour 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 colour component. When slice_cc_alf_cb_enabled_flag is not present, it is inferred to be equal to ph_cc_alf_cb_enabled_flag. slice_ce_alf_cb_aps_id specifies the adaptation_parameter_set_id that the Cb colour component of the slice refers to.

[0177] The TemporalId of the APS NAL unit having 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 coded 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.

[0178] The value of alf_cc_cb_filter_signal _flag of the APS NAL unit having aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_cc_alf_cb_aps_id shall be equal to 1. slice_ce_alf_cr_enabled_flag equal to 0 specifies that the cross-component filter is not applied to the Cr colour component. 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 colour component. When slice_cc_alf_cr_enabled_flag is not present, it is inferred to be equal to ph_cc_alf_cr_enabled_flag. slice_cc_alf_cr_aps_id specifies the adaptation_parameter_set_id that the Cr colour component of the slice refers to. The TemporalId of the APS NAL unit having 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 coded 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.

[0179] The value of alf_cc_cr_filter_signal _flag of the APS NAL unit having aps_params_type equal to ALF_APS and adaptation_parameter_set_id equal to slice_cc_alf_cr_aps_id shall be equal to 1. colour_plane_id identifies the colour plane associated with the current slice when separate_colour_plane_flag is equal to 1. The value of colour_plane_id shall be in the range 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. NOTE 1 - There is no dependency between the decoding processes of different colour planes of one picture. num_ref_idx_active_override_flag equal to 1 specifies that the syntax element num_ref_idx_active_minus1[ 0 ] is present for P 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. num_ref_idx_active_minus1 [ i ] is used for the derivation of the variable NumRefIdxActive[ i ] as specified by Equation 143. The value of num_ref_idx_active_minus1[ i ] shall be in the range of 0 to 14, inclusive.

[0180] For i equal to 0 or 1, when the current slice is a B slice, num_ref_idx_active_override_flag is equal to 1, and num_ref_idx_active_minus1[ i ] is not present, num_ref_idx_active_minus1[ i ] is inferred to be equal to 0.

[0181] 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.

[0182] The variable NumRefIdxActive[ i ] is derived as follows:

[0183] The value of NumRefIdxActive[ i ] - 1 specifies the maximum reference index for reference picture list i that may be used to decode the slice. When the value of NumRefIdxActive[ i ] is equal to 0, no reference index for reference picture list i may be used to decode the slice.

[0184] When the current slice is a P slice, the value of NumRefIdxActive[ 0 ] shall be greater than 0.

[0185] When the current slice is a B slice, both NumRefIdxActive[ 0 ] and NumRefIdxActive[ 1 ] shall be greater than 0. cabac_init_flag specifies the method for determining the initialization table used in the initialization process for context variables. When cabac_init_flag is not present, it is inferred to be equal to 0. 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.

[0186] 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: 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. 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. slice_collocated_ref_idx specifies the reference index of the collocated picture used for temporal motion vector prediction.

[0187] 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 an entry in reference picture list 0, and the value of slice_collocated_ref_idx shall be in the range of 0 to NumRefIdxActive[ 0 ] - 1, inclusive.

[0188] When slice_type is equal to B and slice_collocated_from_l0_flag is equal to 0, slice_collocated_ref_idx refers to an 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.

[0189] When slice_collocated_ref_idx is not present, the following applies: 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. Otherwise (rpl_info_in_ph_flag is equal to 0), the value of slice_collocated _ref_ idx is inferred to be equal to 0.

[0190] It is a requirement of bitstream conformance that the picture referred to by slice_collocated_ref_idx shall be the same for all slices of a coded picture.

[0191] It is a requirement of bitstream conformance 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, respectively, of the current picture, and RprConstraintsActive[ slice_collocated_from_l0_flag ? 0 : 1 ][ slice_collocated_ref_idx ] shall be equal to 0. slice_qp_delta specifies the initial value of Qp Y to be used for the coding blocks in the slice until modified by the value of CuQpDeltaVal in the coding unit layer.

[0192] When qp_delta_info_in_ph_flag is equal to 0, the initial value of the Qp Y quantization parameter for the slice, SliceQpy, is derived as follows: SliceQp Y = 26 + init_qp_minus 26 + slice_qp_delta

[0193] The value of SliceQpy shall be in the range of -QpBdOffset to +63, inclusive.

[0194] When either of the following conditions is true: 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. 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. the following applies: The value of NumRefIdxActive[ 0 ] shall be less than or equal to the value of NumWeightsL0. For each reference picture index RefPicList[ 0 ][ i ] for i in the range of 0 to NumRefIdxActive[ 0 ] - 1, inclusive, the luma weight, Cb weight, and Cr weight that apply to the reference picture index are LumaWeightL0[ i ], ChromaWeightL0[ 0 ][ i ], and ChromaWeightL0[ 1 ][ i ], respectively.

[0195] 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: The value of NumRefIdxActive[ 1 ] shall be less than or equal to the value of NumWeightsL1 . For each reference picture index RefPicList[ 1 ][ i ] for i in the range of 0 to NumRefIdxActive[ 1 ] - 1, inclusive, the luma weight, Cb weight, and Cr weight that apply to the reference picture index are LumaWeightL1[ i ], ChromaWeightL1[ 0 ][ i ], and ChromaWeightL1[ 1 ][ i ], respectively. slice_cb_qp_offset specifies a difference to be added to the value of pps_cb_qp_offset when determining the value of the Qp' Cb quantization parameter. 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. slice_cr_qp_offset specifies a difference to be added to the value of pps_cr_qp_offset when determining the value of the Qp' Cr quantization parameter. 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. slice_joint_cbcr_qp_offset specifies a difference to be added to the value of pps_joint_cber_qp_offset_value when determining the value of the Qp' CbCr . 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_cber_qp_offset_value + slice_joint_cbcr_qp_offset shall be in the range of -12 to +12, inclusive. cu_chroma_qp_offset_enabled_flag equal to 1 specifies that the cu_chroma_qp_offset_flag may be present in the transform unit and palette coding syntax. cu_chroma_qp_offset_enabled_flag equal to 0 specifies that the cu_chroma_qp_offset_flag is not present in the transform unit or palette coding syntax. When not present, the value of cu_chroma_qp_offset_enabled_flag is inferred to be equal to 0. slice_sao_luma_flag equal to 1 specifies that SAO is enabled for the luma component in the current slice; slice_sao_luma_flag equal to 0 specifies that SAO is disabled for the luma component in the current slice. When slice_sao_luma_flag is not present, it is inferred to be equal to ph_sao_luma_enabled_flag. slice_sao_chroma_flag equal to 1 specifies that SAO is enabled for the chroma component in the current slice; slice_sao_chroma_flag equal to 0 specifies that SAO is disabled for the chroma component in the current slice. When slice _sao_chroma_flag is not present, it is inferred to be equal to ph_sao_chroma_enabled_flag. slice_deblocking_filter_override_flag equal to 1 specifies that deblocking parameters are present in the slice header. slice_deblocking_filter_override_flag equal to 0 specifies that 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. slice_deblocking_filter_disabled_flag equal to 1 specifies that the operation of the deblocking filter is not applied for the current slice. slice_deblocking_filter_disabled_flag equal to 0 specifies that the operation of the deblocking filter is applied for the current slice. When slice_deblocking_filter_disabled_flag is not present, it is inferred to be equal to ph_deblocking_filter_disabled_flag. slice_beta_offset_div2 and slice_tc_offset_div2 specify the deblocking parameter offsets for β and tC (divided by 2) that are applied to the luma component for the current slice. The values of slice_beta_offset_div2 and slice_tc_offset_div2 shall 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. slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 specify the deblocking parameter offsets for β and tC (divided by 2) that are applied to the Cb component for the current slice. The values of slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 shall 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. slice_cb_beta_offset_div2 and slice_cb_tc_offset_div2 specify the deblocking parameter offsets for β and tC (divided by 2) that are applied to the Cr component for the current slice. The values of slice_cr_beta_offset_div2 and slice_cr_tc_offset_div2 shall 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. slice_ts_residual_coding_disabled_flag equal to 1 specifies that the residual_coding( ) syntax structure is used to parse the residual samples of a transform skip block for 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 a transform skip block for the current slice. When slice_tsresidual_coding_disabled_flag is not present, it is infered to be equal to 0. slice_lmcs_enabled_flag equal to 1 specifies that luma mapping with chroma scaling is enabled for the current slice. slice_lmcs_enabled _flag equal to 0 specifies that luma mapping with chroma scaling is not enabled for the current slice. When slice_lmcs_enabled_flag is not present, it is inferred to be equal to 0. slice_scaling_list_present_flag equal to 1 specifies that the scaling list data used for the current slice is derived based on the scaling list data contained in the referenced 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 used for the current picture is the default scaling list data derived 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.

[0196] The variable NumEntryPoints, which specifies the number of entry points in the current slice, is derived as follows: offset_len_minus1 plus 1 specifies the length, in bits, of the entry_offset_minus1[ i ] syntax elements. The value of offset_len_minus1 shall be in the range of 0 to 31, inclusive. 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 bits. The slice data that follow the slice header consists of NumEntryPoints + 1 subsets, with subset index values ranging from 0 to NumEntryPoints, inclusive. The first byte of the slice data is considered byte 0. When present, emulation prevention bytes that appear in the slice data portion of the coded slice NAL unit are counted as part of the slice data for purposes of subset identification. Subset 0 consists of bytes 0 to entry_point_offset_minus1[ 0 ], inclusive, of the coded slice data, subset k, with k in the range of 1 to NumEntryPoints - 1, inclusive, consists of bytes firstByte[ k ] to lastByte[ k ], inclusive, of the coded slice data with firstByte[ k ] and lastByte[ k ] defined as: firstByte k = ∑ n = 1 k entry_point_offset_minus 1 n − 1 + 1 lastByte k = firstByte k + entry_point_offset_minus 1 k

[0197] The last subset (with subset index equal to NumEntryPoints) consists of the remaining bytes of the coded slice data.

[0198] When sps_entropy_coding_sync_enabled_flag is equal to 0 and the slice contains one or more complete tiles, each subset shall consist of all coded bits of all CTUs in the slice that are within the same tile, and the number of subsets (i.e., the value of NumEntryPoints + 1) shall be equal to the number of tiles in the slice.

[0199] When sps_entropy_coding_sync_enabled _flag is equal to 0 and the slice contains a subset of CTU rows from a single tile, the NumEntryPoints shall be 0, and the number of subsets shall be 1. The subset shall consist of all coded bits of all CTUs in the slice.

[0200] When sps_entropy_coding_sync_enabled_flag is equal to 1, each subset k with k in the range of 0 to NumEntryPoints, inclusive, shall consist of all coded bits of all CTUs in a CTU row within a tile, and the number of subsets ( i.e., the value of NumEntryPoints + 1 ) shall be equal to the total number of tile-specific CTU rows in the slice. slice_header_extension_length specifies the length of the slice header extension data in bytes, not including the bits used for signalling 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. slice_header_extension_data_byte [ i ] may have any value. Decoders conforming to this version of this Specification shall ignore the values of all the slice_header_extension_data_byte[ i ] syntax elements. Its value does not affect decoder conformance to profiles specified in this version of specification. 3.7. Transform unit syntax (slice data)

[0201] In the latest VVC draft text, the transform unit syntax and semantics are as follows: transform_unit( x0, y0, tbWidth, tbHeight, treeType, subTuIndex, chType ) {Descript or  if( IntraSubPartitionsSplitType != ISP_NO_SPLIT &&   treeType = = SINGLE_TREE && subTuIndex = = NumIntraSubPartitions - 1 ) {  xC = CbPosX[ chType ][ x0 ][ y0 ]  yC = CbPosY[ chType ][ x0 ][ y0 ]  wC = CbWidth[ chType ][ x0 ][ y0 ] / SubWidthC  hC = CbHeight[ chType ][ x0 ][ y0 ] / SubHeightC } else {  xC = x0  yC = y0  wC = tbWidth / SubWidthC  hC = tbHeight / SubHeightC } chromaAvailable = treeType != DUAL_TREE_LUMA && ChromaArrayType != 0 &&  ( IntraSubPartitionsSplitType = = ISP_NO_SPLIT ∥  (IntraSubPartitionsSplitType != ISP_NO_SPLIT &&  subTuIndex = = NumIntraSubPartitions - 1 ) ) if( (treeType = = SINGLE_TREE ∥ treeType = = DUAL_TREE_CHROMA ) &&   ChromaArrayType != 0 && (IntraSubPartitionsSplitType = = ISP_NO_SPLIT &&   ( ( subTuIndex = = 0 && cu_sbt_pos_flag ) ∥   ( subTuIndex = = 1 && !cu_sbt_pos_flag ) ) ) ) ∥   ( IntraSubPartitionsSplitType != ISP_NO_SPLIT &&   ( subTuIndex = = NumIntraSubPartitions - 1 ) ) ) {  tu_cbf_cb [ xC ][ yC ]ae(v)  tu_cbf_cr [ xC ][ yC ]ae(v) } if( treeType = = SINGLE_TREE ∥ treeType = = DUAL_TREE_LUMA) {  if( ( IntraSubPartitionsSplitType = = ISP_NO_SPLIT && !( cu_sbt_flag &&    ( ( subTuIndex = = 0 && cu_sbt_pos_flag ) ∥    ( subTuIndex = = 1 && !cu_sbt_pos_flag ) ) ) &&    ( CuPredMode[ chType ][ x0 ][ y0 ] = = MODE_INTRA ∥    ( chromaAvailable && ( tu_cbf_cb[ xC ][ yC ] ∥tu_cbf_cr[ xC ][ yC ] ) ) | |    CbWidth[ chType ][ x0 ][ y0 ] > MaxTbSizeY ∥    CbHeight[ chType ][ x0 ][ y0 ] > MaxTbSizeY ) ) ∥    ( IntraSubPartitionsSplitType != ISP_NO_SPLIT &&    ( subTuIndex < NumIntraSubPartitions - 1 ∥ !InferTuCbfLuma ) ) )   tu_cbf_luma [ x0 ][ y0 ]ae(v)  if(IntraSubPartitionsSplitType != ISP_NO_SPLIT )   InferTuCbfLuma = InferTuCbfLuma && !tu_cbf_luma[ x0 ][ y0 ] } if( ( CbWidth[ chType ][ x0 ][ y0 ] > 64 ∥CbHeight[ chType ][ x0 ][ y0 ] > 64 ∥   tu_cbf_luma[ x0 ][ y0 ] ∥ ( chromaAvailable && (tu_cbf_cb[ xC ][ yC ] ∥   tu_cbf_cr[ xC ][ yC ] ) ) && treeType != DUAL_TREE_CHROMA &&   cu_qp_delta_enabled_flag && !IsCuQpDeltaCoded ) {  cu_qp_delta_abs ae(v)  if( cu_qp_delta_abs )   cu_qp_delta_sign_flag ae(v) } if( ( CbWidth[ chType ][ x0 ][ y0 ] > 64 ∥CbHeight[ chType ][ x0 ][ y0 ] > 64 ∥   ( chromaAvailable && ( tu_cbf_cb[ xC ][ yC ] ∥ tu_cbf_cr[ xC ][ yC ] ) ) ) &&   treeType != DUAL_TREE_LUMA &&cu_chroma_qp_offset_enabled _flag &&   !IsCuChromaQpOffsetCoded ) {  cu_chroma_qp_offset_flag ae(v)  if( cu_chroma_qp_offset_flag && chroma_qp_offset_list_len_minus1 > 0 )   cu_chroma_qp_offset_idx ae(v) } if( sps_joint_cbcr_enabled_flag && ( ( CuPredMode[ chType ][ x0 ][ y0 ] = = MODE_INTRA   && ( tu_cbf_cb[ xC ][ yC ] ∥ tu_cbf_cr[ xC ][ yC ] ) ) ∥   ( tu_cbf_cb[ xC ][ yC ] && tu_cbf_cr[ xC ][ yC ] ) ) && chromaAvailable )  tu_joint_cbcr_residual_flag [ xC ][ yC ]ae(v) if( tu_cbf_luma[ x0 ][ y0 ] && treeType != DUAL_TREE_CHROMA ) {   if( sps_transform_skip_enabled_flag && !BdpcmFlag[ x0 ][ y0 ][ 0 ] &&    tbWidth <= MaxTsSize && tbHeight <= MaxTsSize &&    (IntraSubPartitionsSplitType = = ISP_NO_SPLIT ) && !cu_sbt_flag )   transform_skip_flag [ x0 ][ y0 ][ 0 ]ae(v)  if( !transform_skip_flag[ x0 ][ y0 ][ 0 ] ∥slice_ts_residual_coding_disabled_flag )   residual_coding( x0, y0, Log2( tbWidth ), Log2( tbHeight ), 0 )  else   residual_ts_coding( x0, y0, Log2( tbWidth ), Log2( tbHeight ), 0 ) } if( tu_cbf_cb[ xC ][ yC ] && treeType != DUAL_TREE_LUMA ) {  if( sps_transform_skip_enabled_flag && !BdpcmFlag[ x0 ][ y0 ][ 1 ] &&    wC <= MaxTsSize && hC <= MaxTsSize && !cu_sbt_flag )   transform_skip_flag [ xC ][ yC ][ 1 ]ae(v)  if( !transform_skip_flag[ xC ][ yC ][ 1 ] ∥slice_ts_residual_coding_disabled_flag )   residual_coding( xC, yC, Log2( wC ), Log2( hC ), 1 )  else   residual_ts_coding( xC, yC, Log2( wC ), Log2( hC ), 1 ) }  if( tu_cbf_cr[ xC ][ yC ] && treeType != DUAL_TREE_LUMA &&    !( tu_cbf_cb[ xC ][ yC ] && tu_joint_cbcr_residual_flag[ xC ][ yC ] ) ) {   if( sps_transform_skip_enabled_flag && !BdpcmFlag[ x0 ][ y0 ][ 2 ] &&    wC <= MaxTsSize && hC <= MaxTsSize && !cu_sbt_flag )   transform_skip_flag [ xC ][ yC ][ 2 ]ae(v)  if( !transform_skip_flag[ xC ][ yC ][ 2 ] ∥slice_ts_residual_coding_disabled_flag )    residual_coding( xC, yC, Log2( wC ), Log2( hC ), 2 )   else    residual_ts_coding( xC, yC, Log2( wC ), Log2( hC ), 2 ) }}

[0202] The transform coefficient levels are represented by the arrays TransCoeffLevel[ x0 ][ y0 ][ cIdx ][ xC ][ yC ]. The array indices x0, y0 specify the location ( x0, y0 ) of the top-left luma sample of the considered transform block relative to the top-left luma sample of the picture. The array index cIdx specifies an indicator for the colour component; it is equal to 0 for Y, 1 for Cb, and 2 for Cr. The array indices xC and yC specify the transform coefficient location ( xC, yC ) within the current transform block. When the value of TransCoeffLevel[ x0 ][ y0 ][ cIdx ][ xC ][ yC ] is not specified in clause 7.3.10.11, it is inferred to be equal to 0. tu_cbf_cb [ x0 ][ y0 ] equal to 1 specifies that the Cb transform block contains one or more transform coefficient levels not equal to 0. The array indices x0, y0 specify the top-left location ( x0, y0 ) of the considered transform block.

[0203] When tu_cbf_cb[ x0 ][ y0 ] is not present, its value is inferred to be equal to 0. tu_cbf _cr [ x0 ][ y0 ] equal to 1 specifies that the Cr transform block contains one or more transform coefficient levels not equal to 0. The array indices x0, y0 specify the top-left location ( x0, y0 ) of the considered transform block.

[0204] When tu_cbf_cr[ x0 ][ y0 ] is not present, its value is inferred to be equal to 0. tu_cbf_luma [ x0 ][ y0 ] equal to 1 specifies that the luma transform block contains one or more transform coefficient levels not equal to 0. The array indices x0, y0 specify the location ( x0, y0 ) of the top-left luma sample of the considered transform block relative to the top-left luma sample of the picture.

[0205] When tu_cbf_luma[ x0 ][ y0 ] is not present, its value is inferred as follows: If cu_sbt_flag is equal to 1 and one of the following conditions is true, tu_cbf_luma[ x0 ][ y0 ] is inferred to be equal to 0: subTuIndex is equal to 0 and cu_sbt_pos _flag is equal to 1. subTuIndex is equal to 1 and cu_sbt_pos _flag is equal to 0. Otherwise, if treeType is equal to DUAL_TREE_CHROMA, tu_cbf_luma[ x0 ][ y0 ] is inferred to be equal to 0. Otherwise, tu_cbf_luma[ x0 ][ y0 ] is inferred to be equal to 1. tu_joint_cbcr_residual_flag [ x0 ][ y0 ] specifies whether the residual samples for both chroma components Cb and Cr are coded as a single transform block. The array indices x0, y0 specify the location ( x0, y0 ) of the top-left luma sample of the considered transform block relative to the top-left luma sample of the picture. tu_joint_cbcr_residual_flag[ x0 ][ y0 ] equal to 1 specifies that the transform unit syntax includes the transform coefficient levels for a single transform block from which the residual samples for both Cb and Cr are derived. tu_joint_cbcr_residual_flag[ x0 ][ y0 ] equal to 0 specifies that the transform coefficient levels of the chroma components are coded as indicated by the syntax elements tu_cbf_cb[ x0 ][ y0 ] and tu_cbf_cr[ x0 ][ y0 ].

[0206] When tu_joint_cbcr_residual_flag[ x0 ][ y0 ] is not present, it is inferred to be equal to 0.

[0207] Depending on tu_joint_cbcr_residual_flag[ x0 ][ y0 ], tu_cbf_cb[ x0 ][ y0 ], and tu_cbf_cr[ x0 ][ y0 ], the variable TuCResMode[ x0 ][ y0 ] is derived as follows: If tu_joint_cbcr_residual_flag[ x0 ][ y0 ] is equal to 0, the variable TuCResMode[ x0 ][ y0 ] is set equal to 0. Otherwise, if tu_cbf_cb[ x0 ][ y0 ] is equal to 1 and tu_cbf_cr[ x0 ][ y0 ] is equal to 0, the variable TuCResMode[ x0 ][ y0 ] is set equal to 1. Otherwise, if tu_cbf_cb[ x0 ][ y0 ] is equal to 1, the variable TuCResMode[ x0 ][ y0 ] is set equal to 2. Otherwise, the variable TuCResMode[ x0 ][ y0 ] is set equal to 3. cu_qp_delta_abs specifies the absolute value of the difference CuQpDeltaVal between the quantization parameter of the current coding unit and its prediction. cu_qp_delta_sign_flag specifies the sign of CuQpDeltaVal as follows: If cu_qp_delta_sign_flag is equal to 0, the corresponding CuQpDeltaVal has a positive value. Otherwise (cu_qp_delta_sign_flag is equal to 1), the corresponding CuQpDeltaVal has a negative value.

[0208] When cu_qp_delta_sign_flag is not present, it is inferred to be equal to 0.

[0209] When cu_qp_delta_abs is present, the variables IsCuQpDeltaCoded and CuQpDeltaVal are derived as follows: IsCuQpDeltaCoded = 1 CuQpDeltaVal = cu_qp_delta_abs * 1 − 2 * cu_qp_delta_sign_flag

[0210] The value of CuQpDeltaVal shall be in the range of -( 32 + QpBdOffset / 2 ) to +( 31 + QpBdOffset / 2 ), inclusive. cu_chroma_qp_offset_flag when present and equal to 1, specifies that an entry in the cb_qp_offset_list[ ] is used to determine the value of CuQpOffset Cb , a corresponding entry in the cr_qp offset_list[ ] is used to determine the value of CuQpOffset Cr , and a corresponding entry in the joint_cbcr_qp_offset_list[ ] is used to determine the value of CuQpOffset CbCr . cu_chroma_qp_offset_flag equal to 0 specifies that these lists are not used to determine the values of CuQpOffset Cb , CuQpOffset Cr , and CuQpOffset CbCr . cu_chroma_qp_offset_idx, when present, specifies the index into the cb_qp_offset_list[ ], cr_qp_offset_list[ ], and joint_cber_qp_offset_list[ ] that is used to determine the value of CuQpOffset Cb , CuQpOffset Cr , and CuQpOffset CbCr . When present, the value of cu_chroma_qp_offset_idx shall be in the range of 0 to chroma_qp_offset_list_len_minus1, inclusive. When not present, the value of cu_chroma_qp_offset_ idx is inferred to be equal to 0.

[0211] When cu_chroma_qp_offset_ flag is present, the following applies: The variable IsCuChromaQpOffsetCoded is set equal to 1. The variables CuQpOffset Cb , CuQpOffset Cr , and CuQpOffset CbCr are derived as follows: If cu_chroma_qp_offset_flag is equal to 1, the following applies: CuQpOffset Cb = cb_qp_offset_list cu_chroma_qp_offset_idx CuQpOffset Cr = cr_qp_offset_list cu_chroma_qp_offset_idx CuQpOffset CbCr = joint_cbcr_qp_offset_list cu_chroma_qp_offset_idx Otherwise (cu_chroma_qp_offset_flag is equal to 0), CuQpOffset Cb , CuQpOffset Cr , and CuQpOffset CbCr are all set equal to 0. transform_skip_flag[ x0 ][ y0 ][ cIdx ] specifies whether a transform is applied to the associated transform block or not. The array indices x0, y0 specify the location ( x0, y0 ) of the top-left luma sample of the considered transform block relative to the top-left luma sample of the picture. The array index cIdx specifies an indicator for the colour component; it is equal to 0 for Y, 1 for Cb, and 2 for Cr. transform_skip_flag[ x0 ][ y0 ][ cIdx ] equal to 1 specifies that no transform is applied to the associated transform block. transform_skip_flag[ x0 ][ y0 ][ cIdx ] equal to 0 specifies that the decision whether transform is applied to the associated transform block or not depends on other syntax elements.

[0212] When transform_skip_flag[ x0 ][ y0 ][ cIdx ] is not present, it is inferred as follows: If BdpcmFlag[ x0 ][ y0 ][ cIdx ] is equal to 1, transform_skip_flag[ x0 ][ y0 ][ cIdx ] is inferred to be equal to 1. Otherwise (BdpcmFlag[ x0 ][ y0 ][ cIdx ] is equal to 0), transform_skip_flag[ x0 ][ y0 ][ cIdx ] is inferred to be equal to 0. 4. Examples of technical problems by disclosed embodiments

[0213] The existing designs for SH, PPS, APS syntax elements (SEs) have the following problems: 1) In the latest VVC draft text, the APS syntax element scaling_list_chroma_present_flag is signaled to control the number of scaling / quantization matrices (QMs) signaled in an SCALING APS, i.e., 28 QMs are signaled for both luma and chroma when scaling_list_chroma_present_flag is equal to 1; otherwise (when scaling_list_chroma_present_flag is equal to 0), 10 QMs are signaled for luma only. Currently, the value of scaling_list_chroma_present_flag is constrained based on ChromaArrayType (derived from SPS syntax element) , i.e., the value of scaling_list_chroma_present_flag is required to be equal to 1 when ChromaArrayType is not equal to 0, while the value of scaling_list_chroma_present_flag is required to be equal to 0 when ChromaArrayType is equal to 0. Such constraints in semantics introduce dependencies of APS on SPS, which should not occur, as an APS may be applied to pictures (or slices of pictures) that refer to different SPSs, which may be associated with different values of ChromaArrayType. a. Moreover, currently, once a block is coded with user-defined scaling lists, both luma and chroma (if available) should apply user-defined scaling lists, i.e., the user-defined scaling lists for luma and chroma can't be turned on / off separately. Such design may be not efficient / flexible. 2) In the latest VVC draft text, when the LMCS APS syntax structure is signaled, the APS syntax elements related to chroma residual scaling are always signaled, regardless whether ChromaArrayType is equal to 0 (e.g., no chroma component in the video content). This may cause unnecessary transmission of chroma-related syntax elements while there is no chroma treated in the video content. 3) In the latest VVC draft text, the SH syntax elementslice_ts_residual_coding_disabled_flag is used to specify whether transform skip based residual coding (TSRC) or regular residual coding (RRC) is used for a transform skip block. However, right now slice_ts_residual_coding_disabled_flag is always signaled in SH, regardless the disabling of the SPS level transform skip. If sps_transform_skip_enabled_flag, transform_skip_flag is always equal to 0, and the condition ( !transform_skip_flag[ xC ][ yC ][ 1 ] ∥ slice_ts_residual_coding_disabled_flag ) to swich TSRC and RRC would always be true, in such case, the slice_tsresidual_coding_disabled_flag becomes meaningless. a. Moreover, currently, a non-TS block can only use RRC and is unable to switch between TSRC and RRC, which may be not efficient for non-TS block compression. 4) In the latest VVC draft text, multi-level control is used to enable the cu_qp_delta for a luma block, i.e., firstly signal a PPS on / off control flag cu_qp_delta_enabled_flag, then specify the quantization group (QG) size in PH, finally signal the vale of cu_qp_delta_abs in each QG. By designing like this, for a picture consists of multiple slices, when some slices use cu qp delta but other slices never use it, the block level cu_qp_delta_abs is still required to be signaled for every QG. Therefore there is a block level bits waste, which can be avoided. 5) In the latest VVC draft text, when the PPS syntax element single_slice_per_subpic_flag is equal to 0, each subpicture of the pictures referring to the PPS may consist of one or more rectangular slices. When single_slice_per_subpic _flag is equal to 0, for pictures referring to such PPS, below cases might happen: a. Redundant case: when sps_num_subpics_minus1 is greater than 0 but there is only one slice in each subpicture. In such a case, each picture contains multiple subpictures and multiple rectangular slices but single _slice_per_subpic_flag is equal to 0, therefore, num_slices_in_pic_minus1 needs to be signalled. However, it is redundantly signalled because such case is conceptually identical with single_slice_per_subpic_flag equal to 1 and there is no need to signal this SE at all. b. Redundant case: when sps_num_subpics_minus1 is equal to 0 and there is only one slice in each picture referring to the PPS. In such case, each picture contains one subpicture consisting of only one slice, but single_slice_per_subpic _flag is still allowed to be equal to 0, thus num_slices_in_pic_minus1 needs to be signalled. However, it is redundantly signalled because such case is conceptually identical with single _slice_per_subpic _flag equal to 1 and there is no need to signal this SE at all. c. Furthermore, if all of the above redundant cases are prohibited / avoided, it would turn out that single_slice_per_subpic _flag equal to 0 is always used for the cases that pictures have multiple subpictures (either each subpicture contain single slice or multiple slices) or pictures have multiple slices (either each picture contain single subpicture or multiple subpictures). And for both cases, the value of num_slices_in_pic_minus1 is always greater than 1. It also turns out not necessary to conditionally signal the PPS syntax element tile_idx_delta_present_flag. 6) In the latest VVC draft text, the tile layout such as the width and height of tiles are designed in a way of explicit signaling associated with implicit inferring. If a picture is divided into multiple tile rows with tiles of the same height, then the current design allows to just signal the height of the first tile row, and the height of the remaining tile rows can be inferred. Otherwise, if a picture is divided into multiple tile rows with tiles of different heights, then it would explicitly signal the heights of each tile row. Otherwise, if a picture is divided into multiple tile rows with first few tile rows of different heights and last few tile rows of the same height, then it would explicitly signal the heights of first few tile rows and only one of the last few tile rows, and then the heights of the remaining tile rows of the same height would be inferred without signaling. The current design works well for those three cases by combining the explicit signaling and implicit inferring. But however, there would be another case that if a picture is divided into multiple tile rows with first few tile rows of the same height and last few tile rows of different heights. In such case, the current design seems not that efficient since implicit inference can't be applied to that case and it still needs to explicitly signal the heights for every tile row. Likewise, there are same situations for tile columns signaling, and rectangular slice layout signaling, i.e., the slice heights signaling in case of a slice is smaller than a tile. Modifications can be applied here for improvement. 7) Currently, the GCI syntax element no_aps_constraint_flag is used to disable NAL unit with nuh_unit_type equal to PREFIX_APS_NUT or SUFFIX_APS_NUT. More constraints are expected to be addressed in the draft text regarding if there is no ALF APS. 8) Currently, the conformance window parameters are always signalled in the PPS, including when the picture width and height are identical to the max picture width and height signalled in the SPS referenced by the PPS, while on the other hand the conformance window parameters for pictures with the max picture width and height are also signalled in the SPS. The signalling of conformance window parameters for pictures with the max picture width and height in the PPS is redundant. 9) When the no_APS_constraint_flag is equal to 1, the intention was to disable the use of APS NAL units that are either present in the bitstream (also known as in-band) or provided to the decoder through an external means (e.g., through an API in the implementation, through out-of-band transmission, etc.). However, in the current VVC specification, the semantics of no_APS_constraint_flag only applies to the case of the APS NAL units being present in the bitstream. Therefore, even no_APS_constraint_flag is equal to 1, the APS may be still available through an external means. 10) Currently, most of the coding tools / features can be controlled / deactivated by GCI flags. However, there are still some features / coding tools don't have GCI flag control. The deactivation control of features / coding tools as much as possible might be desirable. 11) Currently, when local dual tree is used, it defines that only intra and IBC coding modes can be used for MODE_TYPE_INTRA. Moreover, it defines intra (MODE_INTRA), IBC (MODE_IBC), and inter coding modes can be used for MODE_TYPE_ALL. However, palette mode (MODE_PLT) should also be used for MODE_TYPE_INTRA and MODE_TYPE_ALL. It is asserted that the current definition is incomplete. 12)For a coding tree node, the allowed prediction modes for CUs within the coding tree node are defined by the derived modeTypeCondition, and the signaled mode_constraint_flag when modeTypeCondition is equal to 2. However, it is noticed that when modeTypeCondition is equal to 2 and mode_constraint_flag is equal to 1, only prediction mode equal to INTRA and IBC are allowed; while when modeTypeCondition is equal to 2 and mode_constraint_flag is equal to 0, only prediction mode equal to INTER is allowed. Therefore, the PALETTE MODE is always disallowed for this case which is undesiable. coding_tree( x0, y0, cbWidth, cbHeight, qgOnY, qgOnC, cbSubdiv, cqtDepth, mttDe pth, depthOffset,Descript or       partIdx, treeTypeCurr, modeTypeCurr ) {...  if( modeTypeCondition = = 1 )   modeType = MODE_TYPE_INTRA  else if( modeTypeCondition = = 2 ) {   mode_constraint_flag ae(v)   modeType = mode_constraint_flag ? MODE_TYPE_INTRA :MODE_TYPE_INTER  } else   modeType = modeTypeCurr  treeType = ( modeType = = MODE_TYPE_INTRA ) ?DUAL_TREE_LUMA : treeTypeCurr The variable modeTypeCondition is derived as follows:5. Example listing of embodiments and techniques

[0214] To solve the above problems and some other problems not mentioned, methods as summarized below are disclosed. The inventions should be considered as examples to explain the general concepts and should not be interpreted in a narrow way. Furthermore, these inventions can be applied individually or combined in any manner.

[0215] In below description, regarding the protentional text changes based on the latest working draft JVET-Q2001-vD, the deleted parts are highlighted in open and close double brackets (e.g., [[ ]]) with deleted text in between the double brackets, while the added parts are bold italics. 1. Regarding the value of APS syntax element scaling_list_chroma_present_flag relying on a SPS syntax element for solving the first problem, one or more of the following approaches are disclosed: 1) In one example, VPS ID and / or SPS ID and / or PPS ID may be added to APS syntax structure, i.e., adaptation_parameter_set_rbsp(), e.g., the syntax structure of adaptation_parameter_set_rbsp( ) may be changed as follows: adaptation_parameter_set_rbsp( ) {Descriptor  adaptation_parameter_set_id u(5) aps_seq_parameter_set_id u(4)  aps_params_type u(3) if( aps_params_type = = ALF_APS )  alf_data( ) aps_seq_parameter_set_id specifies the value of sps_seq_parameter_set_id for the APS. The value of aps_seq_parameter_set_id shall be in the range of 0 to 15, inclusive. The value of aps_seq_parameter_set_id shall be the same in all APSs that are referred to by coded pictures in a CLVS. a. Additionally, alternatively, the signalling of chroma scaling lists may explicitly conditioned based on the value of ChromaArrayType, e.g., the syntax table of scaling_list_data() may be changed as follows: scaling_list_data() {Descriptor   scaling_matrix_for_lfnst_disabled_flag u(1)  [[scaling_list_chroma_present_flag]] u(1)  for( id = 0; id < 28; id ++ )   matrixSize = (id < 2 ) ? 2 : ( ( id < 8 ) ? 4 : 8 )   if( [[scaling_list_chroma_present_flag]] ( ChromaArrayType != 0 ) ∥ ( id % 3 == 2) ∥ ( id = = 27 ) ) {    scaling_list_copy_mode_flag [ id ]u(1)... And the semantics of scaling_list_chroma_present_ flag is changed as follows:[[scaling_list_chroma_present_flag equal to 1 specifies that chroma scaling lists are present in scaling_list_data(). scaling_list_chroma_present_flag equal to 0 specifies that chroma scaling lists are not present in scaling_list_data( ). It is a requirement of bitstream conformance that scaling_list_chroma_present_flag shall be equal to 0 when ChromaArrayType is equal to 0, and shall be equal to 1 when ChromaArrayType is not equal to 0.]] 2) In one example, the VPS and / or SPS and / or PPS associated with an APS may be implicitly derived. a. For example, if an APS is referred by a video unit (such as a picture header or a slice header), and the video unit depend on a VPS and / or a SPS and / or a PPS, then the APS is implicitly associated with the VPS and / or the SPS and / or the PPS. 3) In one example, instead of using a user-defined scaling list (also referred to as explicit scaling list), the flat quantization (default scaling list) may be used for chroma blocks even when explicit scaling list is applied luma blocks. a. Alternatively, furthermore, even when the explicit scaling list for luma blocks are signaled in the bitstream, explicit scaling list for chroma blocks may be not signalled. 4) Alternatively, the value of scaling_list_chroma_present_flag may be decoupled with the value of ChromaArrayType. a. Indications of whether to use explicit scaling list or default scaling list for different color components (e.g., luma and chroma blocks) may be separately signalled / controlled. i. In one example, syntax elements (e.g., one or more flags) may be added to SPS / PPS / PH / SH to specify whether to enable the user-defined scaling list (also referred to as explicit scaling list) for luma and / or chroma components. ii. For example, a flag may be added in SPS to make the luma transform coefficients to be able to switch between flat quantization (default scaling list) and user-defined scaling list. iii. For example, one ore more flags may be added in SPS to make the chroma-U and / or chroma-V transform coefficients to be able to switch between flat quantization (default scaling list) and user-defined scaling list. b. For example, scaling_list_chroma_present_flag may be equal to 1 when ChromaArrayType is equal to 0. i. In one example, for the coding pictures in 4:0:0 chroma format, N (such as N=28) sets of scaling matrices may be signalled in APS. ii. In one example, for the coding pictures in 4:4:4 chroma format with separate_colour_plane_flag equal to 1, M (such as M=28) sets of scaling matrices may be signalled in APS. a) For example, in case of separate_colour_plane_flag equal to 1 and M (such as M=28) sets of scaling matrices signalled in APS, each of the Y (Luma), U (Cb), and V (Cr) channel transform coefficients may be treated as luma-Y-channel and the scaling matrix identifier variable id for Y, U, and V transform coefficients are derived regarding the colour component as equal to the Y-component (e.g. a value of 0). b) Altenatively, in case of separate_colour_plane_flag equal to 1 and M (such as M=28) sets of scaling matrices signalled in APS, the scaling matrix identifier variable id for luma-Y transform coefficients is derived regarding the colour component as equal to the Y-component (e.g. a value of 0), while the scaling matrix identifier variable id for chroma-U is derived regarding the colour component as equal to the U-component (e.g. a value of 1), and the scaling matrix identifier variable id for chroma-V is derived regarding the colour component as equal to the V-component (e.g. a value of 2). c. For example, scaling_list_chroma_present_flag may be equal to 0 when ChromaArrayType is equal to 1. i. In one example, whether the chroma transform coefficients are allowed to use user-defined scaling lists or not may depend on the value of scaling_list_chroma_present_flag. a) For example, when scaling_list_chroma_present_flag is equal to 0, the user-defined scaling lists are not allowed to be used for chroma transform coefficients regardless the values of sps_scaling_list_enabled_flag, ph scaling_list_enabled_flag, and slice_scaling_list_enabled_flag (e.g., the value of the added flag that used to specify the usage of user-defined scaling list for chroma is required to be equal to a certain number such as 0 or 1). b) For example, when scaling_list_chroma_present_flag is equal to 1, the user-defined scaling lists may be allowed to be used for chroma transform coefficients. ii. In one example, for the coding pictures in 4:2:0, and / or 4:2:2 chroma format, and / or 4:4:4 chroma format with separate_colour_plane_flag equal to 0, N (such as N=10) sets of scaling matrices may be signalled in APS. a) For example, in case of ChromaArrayType greater than 0, and N (such as N=10) sets of scaling matrices signalled in APS, the scaling matrices for U and / or V transform coefficients may be derived from the signalled N sets of scaling matrices of Y transform coefficients. b) Alternatively, in case of ChromaArrayType greater than 0, and N (such as N=10) sets of scaling matrices signalled in APS, the U and / or V transform coefficients may not use user-defined scaling lists (instead, the U and / or V transform coefficients may use flat quantization with default scaling factors). d. For example, the semantics constraints regarding scaling list_chroma_present_ flag based on ChromaArrayType may not be associated with the syntax element scaling_list_chroma_present_flag, e.g., as follows: scaling_list_chroma_present_flag equal to 1 specifies that chroma scaling lists are present in scaling _list_data( ). scaling_list_chroma_present_flag equal to 0 specifies that chroma scaling lists are not present in scaling_list_data(). [[It is a requirement of bitstream conformance that scaling_list_chroma_present_flag shall be equal to 0 when ChromaArrayType is equal to 0, and shall be equal to 1 when ChromaArrayType is not equal to 0.]] e. For example, the semantics constraints regarding scaling_list_chroma_present_flag based on ChromaArrayType may be changed as follows: scaling_list_chroma_present_flag equal to 1 specifies that chroma scaling lists are present in scaling _list_data( ). scaling_list_chroma_present_flag equal to 0 specifies that chroma scaling lists are not present in scaling_list_data(). It is a requirement of bitstream conformance that scaling_list_chroma_present_flag shall be equal to 0 when ChromaArrayType is equal to 0[[, and shall be equal to 1 when ChromaArrayType is not equal to 0]]. 5) Alternatively, a constraint may be added associated with the PH and / or SH syntax elements, to constrain the value of scaling list_chroma_present_ flag to a certain value (such as 0 or 1) according to ChromaArrayType derived by PH / SH syntax elements, e.g., as follows: In one example, the semantics of ph_scalinglist_aps_id are changes as follows: ph_scaling_list_aps_id specifies the adaptation_parameter_set_id of the scaling list APS. The TemporalId of the APS NAL unit having 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 PH. The value of scalinglist_chroma_present_flag of the APS NAL unit having aps_params_type equal to SCALING_APS and adaptation_parameter_set_id equal to ph_scaling_list_aps_id shall be equal to ChromaArrayType = = 0 ? 0 : 1. Alternatively, the semantics of ph_scaling_list_aps_id are changes as follows: ph_scaling_list_aps_id specifies the adaptation_parameter_set_id of the scaling list APS. The TemporalId of the APS NAL unit having 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 PH. When ChromaArrayType is equal to 1, the value of scaling_list_chroma_present_flag of the APS NAL unit having aps_params_type equal to SCALING_APS and adaptation_parameter_set_id equal to ph_scaling_list_aps_id shall be equal to 1. Alternatively, the semantics of ph_scaling_list_aps_id are changes as follows: ph_scaling_list_aps_id specifies the adaptation_parameter_set_id of the scaling list APS. The TemporalId of the APS NAL unit having 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 PH. When ChromaArrayType is equal to 0, the value of scaling_list_chroma_present_flag of the APS NAL unit having aps_params_type equal to SCALING_APS and adaptation_parameter_set_id equal to ph_scaling_list_aps_id shall be equal to 0. And the semantics of APS SE are changed as follows: scaling_list_chroma_present_flag equal to 1 specifies that chroma scaling lists are present in scaling_list_data( ). scaling_list_chroma_present_flag equal to 0 specifies that chroma scaling lists are not present in scaling_list_data(). [[It is a requirement of bitstream conformance that scaling_list_chroma_present_flag shall be equal to 0 when ChromaArrayType is equal to 0, and shall be equal to 1 when ChromaArrayType is not equal to 0.]] 2. Regarding the unnecessary chroma-related APS syntax elements signalling in case of ChromaArrayType is equal to 0, and for solving the second problem, one or more of the following approaches are disclosed: 1) In one example, a syntax element (e.g., a flag) may be added to the APS syntax structure lmcs_data( ), in order to control the presence of chroma residual scaling related APS syntax elements (e.g., lmcs_delta_abs_crs, lmcs_delta_sign_crs_flag, et al.) a. For example, when ChromaArrayType is equal to 0, the chroma residual scaling related APS syntax elements (e.g., lmcs_delta_abs_crs, lmcs_delta_sign_crs_flag, et al.) are required to be not allowed to be signaled, e.g., the added flag is required to be equal to certain value such as 0 or 1. b. For example, when ChromaArrayType is not equal to 0, the chroma residual scaling related APS syntax elements (e.g., lmcs_delta_abs_crs, Imcs_delta_sign crs flag, et al.) are required to be signaled, e.g., the added flag is required to be equal to certain value such as 0 or 1. c. For example, whether the current slice is allowed to use chroma residual scaling or not may be dependent on the added flag, e.g., if the added flag indicating that the chroma residual scaling related APS syntax elements are not signalled, then the chroma residual scaling would be never used regardless the values of sps_lmcs_enabled_flag, ph_lmcs_flag, ph_chroma_residual_scale_flag, and sh_lmcs_enabled_flag. 2) A bitstream constraint may be added under the semantics of PH / SH / APS syntax elements to constrain the value of lmcs_delta_abs_crs regarding the value of ChromaArrayType, e.g., as follows: ph_lmcs_aps_id specifies the adaptation_parameter_set_id of the LMCS APS that the slices associated with the PH refers to. The TemporalId of the APS NAL unit having 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 PH. When ChromaArrayType is equal to 0, the value of lmcs_delta_abs_crs of the APS NAL unit having aps_params_type equal to LMCS APS and adaptation_parameter_set_id equal to ph_lmcs_aps_id shall be equal to 0. Alternatively, the semantics of ph _lmcs_aps_id is changed as follows: ph_lmcs_aps_id specifies the adaptation_parameter_set_id of the LMCS APS that the slices associated with the PH refers to. The TemporalId of the APS NAL unit having 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 PH. When ChromaArrayType is equal to 1, the value of lmcs_delta_abs_crs of the APS NAL unit having aps_params_type equal to LMCS APS and adaptation_parameter_set_id equal to ph_lmcs_aps_id shall be greater than 0. Alternatively, the semantics of ph_lmcs_aps_id is changed as follows: ph_lmcs_aps_id specifies the adaptation_parameter_set_id of the LMCS APS that the slices associated with the PH refers to. The TemporalId of the APS NAL unit having 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 PH. If ChromaArrayType is equal to 0, the value of lmcs_delta_abs_crs of the APS NAL unit having aps_params_type equal to LMCS APS and adaptation_parameter_set_id equal to ph_lmcs_aps_id shall be equal to 0. Otherwise, the value of lmcs_delta_abs_crs of the APS NAL unit having aps_params_type equal to LMCS_APS and adaptation_parameter_set_id equal to ph_lmcs_aps_id shall be greater than 0. 3. In above example, the term 'ChromaArrayType' may be replaced by 'checking the color format being equal to 4:0:0'. 4. Regarding the usage of RRC and TSRC for solving the third problem, one or more of the following approaches are disclosed: 1) The signalling of the TSRC enabling / disabling flag (e.g., slice_ts_residual_coding_disabled_flag) may be conditioned on whether transform skip is enabled (e.g., sps_transform_skip_enabled_flag in SPS). a. In one example, the following may be applied:   if( !sps_transform_skip_enabled_flag )    slice_ts_residual_coding_disabled_flag u(1) b. Alternatively, furthermore, when slice_ts_residual_coding_disabled_flag is not present, it is infered to be equal to 1. 2) Alternatively, the value of the TSRC enabling flag (e.g., slice_ts_residual_coding_disabled_flag) may be constrained by sps_transform_skip_enabled_flag in SPS, e.g., the semantics of slice_ts_residual_coding_disabled_flag may be changed as follows:slice_ts_residual_coding_disabled_flag equal to 1 specifies that the residual_coding() syntax structure is used to parse the residual samples of a transform skip block for 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 a transform skip block for the current slice. When [[slice_ts_residual_coding_disabled_flag ]] sps_transform_skip_enabled_flag is [[not present]] equal to 0, the value of slice_ts_residual_coding_disabled_flag shall [[it is infered to]] be equal to [[0]]1. 3) Alternatively, if the signalling of the TSRC enabling flag (e.g., slice_ts_residual_coding_disabled_flag) is not conditioned on any other syntax elements, it may always present, e.g., the semantics of slice_ts_residual_coding_disabled_flag may be changed as follows:slice_ts_residual_coding_disabled_flag equal to 1 specifies that the residual_coding() syntax structure is used to parse the residual samples of a transform skip block for 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 a transform skip block for the current slice. [[When slice_ts_residual_coding_disabled_flag is not present, it is infered to be equal to 0.]] 4) Additionally, furthermore, TSRC may be applied to non-transform-skip (non-TS) coded block. a. In one example, one or more syntax flag may be added to specify whether to enable TSRC or RRC for a non-TS block. i. In one example, one or more block level (CTU / CU / TU) syntax flag may be added to specify whether the current video unit is using TSRC or RRC. ii. Additionally, alternatively, one or more high level (SPS / PPS / PH / SH) syntax flag may be added to specify whether the TSRC is allowed for the video unit. b. In one example, whether to use TSRC for non-TS coded blocks or whether to allow TSRC for non-TS coded blocks may depend on the coded information, such as the QP value for the block. i. In one example, for a non-TS block with QP equal to or no grater than X (such as X=4), it may be allowed to use either TSRC or RRC for residual coding. 5. Regarding the on / off control of the cu qp delta for a luma block for solving the fourth problem, one or more of the following approaches are disclosed: a. An SH level syntax element (e.g., a flag represented by slice _cu_qp_delta_enabled_flag) may be added to control the enabling and / or disabling of the cu qp delta for a specific slice. i. In one example, the presence of the proposed slice_cu_qp_delta_enabled_flag is conditioned on the cu_qp_delta_enabled_flag in PPS, e.g., only if cu_qp_delta_enabled_flag in PPS is equal to 1, the proposed slice_cu_qp_delta_enabled_flag is signaled, otherwise (cu_qp_delta_enabled_flag in PPS is equal to 0), the proposed slice_cu_qp_delta_enabled_flag is not signaled and inferred to be equal to 0. a) Alternatively, the value of the proposed slice_cu_qp_delta_enabled_flag is constrained on the value of cu_qp_delta_enabled_flag in PPS, i.e., when cu_qp_delta_enabled_flag in PPS is equal to 0, the value of the proposed slice_cu_qp_delta_enabled_flag shall be equal to 0. ii. In one example, the cu_qp_ delta_enabled _flag in PPS may be used to control the presence of SH-level cu qp delta enabled flag in SHs, and / or the presence of cu_qp_delta_abs and / or cu_qp_delta_sign_flag in the transform unit syntax and the palette coding syntax. iii. In one example, the syntax structures may be changed as follows: The PPS syntax structure is changed as follows: pic_parameter_set_rbsp( ) {Descriptor  pps_pic_parameter_set_id ue(v)... init_qp_minus26 se(v) pps_-cu_qp_delta_enabled_flag u(1) pps_chroma_tool_offsets_present_flag u(1) pps_cu_qp_delta_enabled_flag equal to 1 specifies that the ph_cu_qp_delta_subdiv_intra_slice and ph_cu_qp_delta_subdiv_inter_slice syntax elements are present in PHs referring to the PPS and cu_qp_delta_abs may be present in the transform unit syntax and the palette coding syntax. pps_cu_qp_delta_enabled_flag equal to 0 specifies that the ph_cu_qp_delta_subdiv_intra_slice and ph_cu_qp_delta _subdiv_inter_slice syntax elements are not present in PHs referring to the PPS and cu_qp_delta _abs is not present in the transform unit syntax and the palette coding syntax. And the PH syntax structure is changed as follows: picture_header_structure( ) {Descriptor  gdr_or_irap_pic_flag u(1)...  if( ph_intra_slice_allowed_flag ) {...   if( pps _cu_qp_delta_enabled_flag )   ph_cu_qp_delta_subdiv_intra_slice ue(v)...  if( ph_inter_slice_allowed_flag ) {...   if( pps _cu_qp_delta_enabled_flag )   ph_cu_qp_delta_subdiv_inter_slice ue(v)... And the SH syntax structure is changed as follows: slice_header() {Descriptor  picture_header_in_slice_header_flag u(1)... if(pps_cu_qp_delta_enabled_flag)   cu_qp_delta_enabled_flag u(1)   if( pps_cu_chroma_qp_offset_list_enabled_flag )  cu_chroma_qp_offset_enabled_flag u(1) cu_gp-delta_enabled_flag equal to 1 specifies that the cu_qp_delta_abs may be present in the transform_unit and palette coding syntax. cu_qp_delta_enabled_flag equal to 0 specifies that the cu_qp_delta_abs is not present in the transform_unit or palette coding syntax. When not present, the value of cu_qp_delta_enabled_flag is inferred to be equal to 0. b. Additionally, the presence of cu_qp_delta_abs in the syntax structure palette _coding () and / or the syntax structure transform_unit() is conditioned on the proposed slice _cu_qp_delta_enabled_flag, e.g., only if the value of the proposed slicecu_qp_delta_enabled_flag is equal to 1, cu_qp_delta_abs is signaled; otherwise (the proposed slice_cu_qp_delta_enabled_flag is equal to 0), the value of cu_qp_delta_abs is not signaled and inferred to be equal to 0. Alternatively, the chroma cu qp offset may be not controlled by slice level on / off flag, e.g., whether the chroma cu qp offset is applied to the current slice or not may be dependent on a PH / PPS / SPS level flag. c. Alternatively, a PH level syntax element (e.g., a flag represented by ph_cu_qp_delta_enabled_flag) may be added to control the enabling and / or disabling of the cu qp delta for a specific slice. 6. Regarding the design of PPS SEs single _slice_per_subpic flag, num_slices_in_pic_minus1, tile_idx_delta_present_flag and for solving the fifth problem, one or more of the following approaches are disclosed: a. In one example, a constraint may be added to the semantics of PH / SH / PPS syntax elements, e.g., as follows: ph_pic_parameter_set_id specifies the value of pps_pic_parameter_set_id for the PPS in use. The value of ph_pic_parameter_set_id shall be in the range of 0 to 63, inclusive. It is a requirement of bitstream conformance that the value of TemporalId of the PH shall be greater than or equal to the value of TemporalId of the PPS that has pps_pic_parameter_set_id equal to ph_pic_parameter_set_id. When sps_num_subpics_minus1 is equal to 0, rect_slice_flag is equal to 1, a picture contains only one slice and another picture contains more than one slice, the two pictures shall refer to different PPSs. b. In one example, the semantics of single_slice_per_subpic_flag may be changes as follows:single_slice_per_subpic_flag equal to 1 specifies that each subpicture consists of one and only one rectangular slice. single_slice_per_subpic_flag equal to 0 specifies that, if sps_num_subpics_minus1 is greater than 0 (and in this case each picture contains more than one slice), each subpicture may consist of one or more rectangular slices but not each of all subpictures contain only one rectangular slice, and otherwise (sps_num_subpics_minus1 is equal to 0, and in this case each picture contains only one subpicture) each picture contains more than one slice. When not present, the value of single _slice_per_subpic_flag is inferred to be equal to 0. c. In one example, a constraint may be added to the semantics of single _slice_per_subpicflag, e.g., as follows: single_slice_per_subpic_flag equal to 1 specifies that each subpicture consists of one and only one rectangular slice. single _slice_per_subpic_flag equal to 0 specifies that each subpicture may consist of one or more rectangular slices. When not present, the value of single_slice_per_subpic_flag is inferred to be equal to 0. When sps_num_subpics_minus1 is equal to 0 and there is only one slice in each picture referring to the PPS, the value of single_slice_per_subpic_flag shall be equal to 1. d. Additionally, alternatively, a constraint may be added to the semantics of single _slice_per _subpicflag, e.g., as follows: single_slice_per_subpic_flag equal to 1 specifies that each subpicture consists of one and only one rectangular slice. single _slice_per_subpic_flag equal to 0 specifies that each subpicture may consist of one or more rectangular slices. When not present, the value of single_slice_per _subpic_flag is inferred to be equal to 0. When sps_num_subpics_minus1 is greater than 0 and there is only one slice in each subpicture, the value of single_slice_per_subpic_flag shall be equal to 1. e. In one example, it is constrained that, single_slice_per_subpic_flag shall be equal to 1 when each subpicture consists of one and only one rectangular slice. f. Additionally, alternatively, the presence of PPS syntax element tile_idx_delta_present_flag may be not conditioned based on num_slices_in_pic_minus1, e.g., as follows:    [[if( num_slices_in_pic_minus1 > 0 )]]   tile_idx_delta_present_flag u(1) g. In one example, it is constrained that num_slices_in_pic_minus] shall be equal to sps_num_subpics_minus1 when single _slice_per _subpic_flag is equal to 1. h. Additionally, alternatively, the PPS syntax element num_slices_in_pic_minus1 may be changed to be num_slices_in_pic_minus2. i. Additionally, condition the presence of tile_idx_delta_present_flag based on num_slices_in_pic_minus2, e.g., as follows:   num_slices_in_pic_minus[[1]]2 ue(v)   [[if( num_slices_in_pic_minus1 > 0 )]]  tile_idx_delta_present_flag u(1) num_slices_in_pic_minus[[1]]2 plus [[1]]2 specifies the number of rectangular slices in each picture referring to the PPS. The value of num_slices_in_pic_minus[[1]]2 shall be in the range of 0 to MaxSlicesPerPicture - [[1]]2, inclusive, where MaxSlicesPerPicture is specified in Annex A. The value of the variable NumSlicesInPic is derived to be equal to num_slices_in_pic_minus2 + 2. When no_pic_partition_flag is equal to 1, the value of the variable NumSlicesInPic is derived to be equal to 1 [[num_slices_in_pic_minus1 is inferred to be equal to 0]]. When single _slice_per_subpic_flag is equal to 1, NumSlicesInPic is derived [[num_slices_in_pic_minus1 is inferred]] to be equal to sps_num_subpics_minus1 - 1. And in addition, "num_slices_in_pic_minus1" in all other places in the VVC draft text is replaced with "NumSlicesInPic - 1". 7. Regarding the signalling for slice and tile layout for solving the sixth problem, one or more of the following approaches are disclosed: a. Syntax elements (e.g., one or more flag) may be added in PPS to specify whether a picture is divided into multiple tile rows / columns with first few tile rows / columns of the same height and last few tile rows / columns of different heights / widths. i. For example, the proposed syntax flag is dependent on no_pic_partition_flag and / or the number of explicit tile rows / columns (such as num_exp_tile_columns_minus1 and / or num_exp_tile_rows_minus1), e.g., as follows:  no_pic_partition_flag u(1)  if( !no_pic_ partition ) {  pps_log2_ctu_size_minus5 u(2)  num_exp_tile_columns_minus1 ue(v)  num_exp_tile_rows_minus1 ue(v)  if(num_exp_tile_ columns_minus1 > 1 )    exp_tile_columns_in_reverse_order u(1)   if(num exp_tile_ rows_minus1 > 1 )    exp_tile_rows_in_reverse_order u(1)    for( i = 0; i <= num_exp_tile_columns_minus1; i++ )   tile_column_width_minus1 [ i ]ue(v)   for( i = 0; i <= num_exp_ti...

Claims

1. A method of processing video data, comprising: performing a conversion between a video comprising a video block and a bitstream of the video according to a rule, characterized in that the video block is a coding tree node that includes one or more coding blocks, and wherein the rule specifies that, when a local dual tree is applied to the one or more coding blocks inside the coding tree node, the following coding modes are allowed to be used for one or more luma blocks of the one or more coding blocks: an intra prediction coding mode, an intra block copy (IBC) mode and a palette coding mode, and the intra prediction coding mode is applied to all chroma block(s) of the one or more coding blocks.

2. The method of claim 1, wherein the rule specifies that more than one coding modes of the intra prediction coding mode, the IBC mode and the palette coding mode are allowed to be applied to multiple luma blocks, wherein the more than one coding modes comprise any two or more of the intra prediction coding mode, the IBC mode and the palette coding mode, and optionally, wherein the rule specifies that an inter prediction coding mode is not allowed for the one or more coding blocks in the coding tree node to which the local dual tree is applied.

3. The method of claim 1 or 2, wherein the rule specifies that a presence of a first syntax element indicating whether the palette coding mode is enabled for a coding block is at least based on that a value of a variable named mode type of the coding block is a certain mode type, wherein the certain mode type is MODE_TYPE_INTRA or MODE_TYPE_ALL and is not MODE_TYPE_INTER, optionally, wherein MODE_TYPE_INTER specifies that only an inter prediction coding mode is allowed to be used for the coding block; wherein MODE_TYPE_INTRA specifies that only the intra prediction coding mode, the IBC mode and the palette coding mode are allowed to be used for the coding block; and wherein MODE_TYPE_ALL specifies that the inter prediction coding mode, the intra prediction coding mode, the IBC mode and the palette coding mode are allowed to be used for the coding block; optionally, wherein the variable named mode type is based on a variable named modeTypeCondition and a second syntax element non_inter_flag indicating whether only an inter prediction coding mode is allowed; and optionally, wherein MODE_TYPE_INTER, MODE_TYPE _INTRA and MODE_TYPE_ALL are also used in a partition process, and wherein the partition process includes at least one of a quad split process, a binary split process or a ternary split process.

4. The method of any one of claims 1-3, wherein the rule specifies that a third syntax element in a general constraint information syntax structure controls a value of a fourth syntax element in a sequence parameter set, wherein the fourth syntax element indicates whether subpicture information is present in a coded layer video sequence and whether more than one subpictures are included in each picture of the coded layer video sequence, and optionally, wherein the rule specifies that a fifth syntax element in a general constraint information syntax structure controls a value of a sixth syntax element in a sequence parameter set, wherein the sixth syntax element indicates whether a maximum transform size in luma samples is equal to 64.

5. The method of any one of claims 1-4, wherein the performing the conversion comprises encoding the video into the bitstream.

6. The method of any one of claims 1-4, wherein the performing the conversion comprises decoding the video from the bitstream.

7. An apparatus (3600) for processing video data comprising a processor (3602) and a non-transitory memory (3604) with instructions thereon, wherein the instructions upon execution by the processor (3602), cause the processor (3602) to: perform a conversion between a video comprising a video block and a bitstream of the video according to a rule, wherein the video block is a coding tree node that includes one or more coding blocks, and characterized in that the rule specifies that, when a local dual tree is applied to the one or more coding blocks inside the coding tree node, the following coding modes are allowed to be used for one or more luma blocks of the one or more coding blocks: an intra prediction coding mode, an intra block copy (IBC) mode and a palette coding mode, and the intra prediction coding mode is applied to all chroma block(s) of the one or more coding blocks.

8. The apparatus (3600) of claim 7, wherein the rule specifies that more than one coding modes of the intra prediction coding mode, the IBC mode and the palette coding mode are allowed to be applied to multiple luma blocks, wherein the more than one coding modes comprise any two or more of the intra prediction coding mode, the IBC mode and the palette coding mode, and optionally, wherein the rule specifies that an inter prediction coding mode is not allowed for the one or more coding blocks in the coding tree node to which the local dual tree is applied.

9. The apparatus (3600) of claim 7 or 8, wherein the rule specifies that a presence of a first syntax element indicating whether the palette coding mode is enabled for a coding block is at least based on that a value of a variable named mode type of the coding block is a certain mode type, wherein the certain mode type is MODE_TYPE_INTRA or MODE_TYPE_ALL and is not MODE_TYPE_INTER, optionally, wherein MODE_TYPE_INTER specifies that only an inter prediction coding mode is allowed to be used for the coding block, wherein MODE_TYPE_INTRA specifies that only the intra prediction coding mode, the IBC mode and the palette coding mode are allowed to be used for the coding block, wherein MODE_TYPE_ALL specifies that the inter prediction coding mode, the intra prediction coding mode, the IBC mode and the palette coding mode are allowed to be used for the coding block, optionally, wherein the variable named mode type is based on a variable named modeTypeCondition and a second syntax element non_inter_flag indicating whether only an inter prediction coding mode is allowed, and optionally, wherein MODE_TYPE_INTER, MODE_TYPE _INTRA and MODE_TYPE_ALL are also used in a partition process, and wherein the partition process includes at least one of a quad split process, a binary split process or a ternary split process.

10. The apparatus (3600) of any one of claims 7-9, wherein the rule specifies that a third syntax element in a general constraint information syntax structure controls a value of a fourth syntax element in a sequence parameter set, wherein the fourth syntax element indicates whether subpicture information is present in a coded layer video sequence and whether more than one subpictures are included in each picture of the coded layer video sequence, and optionally, wherein the rule specifies that a fifth syntax element in the general constraint information syntax structure controls a value of a sixth syntax element in a sequence parameter set, wherein the sixth syntax element indicates whether a maximum transform size in luma samples is equal to 64.

11. A non-transitory computer-readable storage medium storing instructions that cause a processor to: perform a conversion between a video comprising a video block and a bitstream of the video according to a rule, wherein the video block is a coding tree node that includes one or more coding blocks, and characterized in that the rule specifies that, when a local dual tree is applied to the one or more coding blocks inside the coding tree node, of the following coding modes are allowed to be used for one or more luma blocks of the one or more coding blocks: an intra prediction coding mode, an intra block copy (IBC) mode and a palette coding mode, and the intra prediction coding mode is applied to all chroma block(s) of the one or more coding blocks.

12. The non-transitory computer-readable storage medium of claim 11, wherein the rule specifies that more than one coding modes of the intra prediction coding mode, the IBC mode and the palette coding mode are allowed to be applied to multiple luma blocks, wherein the more than one coding modes comprise any two or more of the intra prediction coding mode, the IBC mode and the palette coding mode, wherein the rule specifies that an inter prediction coding mode is not allowed for the one or more coding blocks in the coding tree node to which the local dual tree is applied, wherein the rule specifies that a presence of a first syntax element indicating whether the palette coding mode is enabled for a coding block is at least based on that a value of a variable named mode type of the coding block is a certain mode type, wherein the certain mode type is MODE_TYPE_INTRA or MODE_TYPE_ALL and is not MODE_TYPE_INTER, optionally, wherein MODE_TYPE_INTER specifies that only an inter prediction coding mode is allowed to be used for the coding block, wherein MODE_TYPE_INTRA specifies that only the intra prediction coding mode, the IBC mode and the palette coding mode are allowed to be used for the coding block, and wherein MODE_TYPE_ALL specifies that the inter prediction coding mode, the intra prediction coding mode, the IBC mode and the palette coding mode are allowed to be used for the coding block, optionally, wherein the variable named mode type is based on a variable named modeTypeCondition and a second syntax element non_inter_flag indicating whether only an inter prediction coding mode is allowed, optionally, wherein MODE_TYPE_INTER, MODE_TYPE_INTRA and MODE_TYPE_ALL are also used in a partition process, and wherein the partition process includes at least one of a quad split process, a binary split process or a ternary split process, optionally, wherein the rule specifies that a third syntax element in a general constraint information syntax structure controls a value of a fourth syntax element in a sequence parameter set, wherein the fourth syntax element indicates whether subpicture information is present in a coded layer video sequence and whether more than one subpictures are included in each picture of the coded layer video sequence, and optionally, wherein the rule specifies that a fifth syntax element in the general constraint information syntax structure controls a value of a sixth syntax element in a sequence parameter set, wherein the sixth syntax element indicates whether a maximum transform size in luma samples is equal to 64.

13. The method of any one of claims 1-4, wherein the conversion comprises: generating the bitstream of the video comprising the video block according to the rule, and wherein the method further comprises: storing the bitstream in a non-transitory computer-readable recording medium.