ITU-T H.265高效率视频编码官方文档

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"h265官方文档__T-REC-H.265-201504-I!!PDF-E.pdf 是一份关于高效率视频编码（High Efficiency Video Coding，简称HEVC），也就是H.265标准的官方文档。这份文档由国际电信联盟（International Telecommunication Union, ITU-T）发布，属于视听和多媒体系统系列，具体在H.260到H.279编码移动视频的范畴内。文档日期为2015年4月，是该标准的重要参考材料。" H.265，也称为HEVC，是继H.264之后的下一代视频压缩标准，旨在显著提高视频编码效率，以适应4K、8K超高清视频以及移动设备上对带宽有限的需求。H.265标准的核心目标是在不牺牲画质的情况下，将视频文件的大小减少约50%，这极大地优化了视频流传输和存储。文档中可能涵盖了以下关键知识点： 1. **编码架构**：HEVC采用了更复杂的编码结构，如基于块的编码，包括更小的编码单元（CU）、预测单元（PU）和变换单元（TU），使得编码更加灵活，能更好地适应视频内容的变化。 2. **熵编码**：HEVC使用改进的熵编码方法，如上下文自适应二进制算术编码（Context-Adaptive Binary Arithmetic Coding, CABAC）和上下文自适应变量长度编码（Context-Adaptive Variable Length Coding, CAVLC），提高了编码效率。 3. **多模式预测**：HEVC引入了更多的预测模式，包括双向预测、多角度预测以及像素级别的自适应预测，减少了冗余信息。 4. **分层编码**：支持不同层次的编码，允许在网络条件变化时进行自适应流传输，确保视频质量与带宽之间的平衡。 5. **多参考帧**：HEVC可以利用更多的参考帧进行运动补偿预测，提高了预测的准确性。 6. **高级去块效应滤波器**：改进了去块效应滤波器，减少因压缩产生的块状失真，提升视觉质量。 7. **色度子采样**：HEVC支持更灵活的色度子采样模式，以适应不同应用场景的需求。 8. **语法元素**：文档会详细解释编码过程中的语法元素，如NAL单元（Network Abstraction Layer units）和VCL单元（Video Coding Layer units），它们是视频数据在网络中传输的基础。 9. **编码效率优化**：HEVC还包括了多种技术来优化编码效率，如自适应循环滤波器、增强的帧内预测、改进的运动估计等。 10. **应用与实现**：文档可能会涵盖标准的应用场景，如在线视频、电视广播、移动通信等，并提供实现HEVC编码器和解码器的技术指导。此官方文档对于理解H.265编码机制、开发相关软件或硬件，以及优化视频编码和传输策略都具有重要的参考价值。

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xiv Rec. ITU-T H.265 v3 (04/2015)

LIST OF FIGURES

Figure 6-1 – Nominal vertical and horizontal locations of 4:2:0 luma and chroma samples in a picture .............. 22

Figure 6-2 – Nominal vertical and horizontal locations of 4:2:2 luma and chroma samples in a picture .............. 22

Figure 6-3 – Nominal vertical and horizontal locations of 4:4:4 luma and chroma samples in a picture .............. 23

Figure 6-4 – A picture with 11 by 9 luma coding tree blocks that is partitioned into two slices, the first of which is

partitioned into three slice segments (informative) ............................................................................... 24

Figure 6-5 – A picture with 11 by 9 luma coding tree blocks that is partitioned into two tiles and one slice (left) or

is partitioned into two tiles and three slices (right) (informative) ......................................................... 24

Figure 7-1 – Structure of an access unit not containing any NAL units with nal_unit_type equal to FD_NUT,

SUFFIX_SEI_NUT, VPS_NUT, SPS_NUT, PPS_NUT, RSV_VCL_N10, RSV_VCL_R11,

RSV_VCL_N12, RSV_VCL_R13, RSV_VCL_N14, RSV_VCL_R15, RSV_IRAP_VCL22 or

RSV_IRAP_VCL23, or in the range of RSV_VCL24..RSV_VCL31, RSV_NVCL41..RSV_NVCL47

or UNSPEC48..UNSPEC63 ................................................................................................................. 69

Figure 8-1 – Intra prediction mode directions (informative) ............................................................................... 118

Figure 8-2 – Intra prediction angle definition (informative) ................................................................................ 126

Figure 8-3 – Spatial motion vector neighbours (informative) ............................................................................. 142

Figure 8-4 – Integer samples (shaded blocks with upper-case letters) and fractional sample positions (un-shaded

blocks with lower-case letters) for quarter sample luma interpolation ............................................... 150

Figure 8-5 – Integer samples (shaded blocks with upper-case letters) and fractional sample positions (un-shaded

blocks with lower-case letters) for eighth sample chroma interpolation ............................................. 152

Figure 9-1 – Illustration of CABAC parsing process for a syntax element synEl (informative) ......................... 185

Figure 9-2 – Spatial neighbour T that is used to invoke the coding tree block availability derivation process relative

to the current coding tree block (informative) .................................................................................... 186

Figure 9-3 – Illustration of CABAC initialization process (informative) ............................................................ 187

Figure 9-4 – Illustration of CABAC storage process (informative) ..................................................................... 197

Figure 9-5 – Overview of the arithmetic decoding process for a single bin (informative) .................................. 213

Figure 9-6 – Flowchart for decoding a decision .................................................................................................. 214

Figure 9-7 – Flowchart of renormalization .......................................................................................................... 216

Figure 9-8 – Flowchart of bypass decoding process ............................................................................................ 217

Figure 9-9 – Flowchart of decoding a decision before termination ..................................................................... 218

Figure 9-10 – Flowchart for encoding a decision ................................................................................................ 220

Figure 9-11 – Flowchart of renormalization in the encoder ................................................................................ 221

Figure 9-12 – Flowchart of PutBit(B) .................................................................................................................. 221

Figure 9-13 – Flowchart of encoding bypass ....................................................................................................... 222

Figure 9-14 – Flowchart of encoding a decision before termination ................................................................... 223

Figure 9-15 – Flowchart of flushing at termination ............................................................................................. 223

Figure C.1 – Structure of byte streams and NAL unit streams for HRD conformance checks ............................ 244

Figure C.2 – HRD buffer model .......................................................................................................................... 247

Figure D.1 – Nominal vertical and horizontal sampling locations of 4:2:0 samples in top and bottom fields .... 284

Figure D.2 – Nominal vertical and horizontal sampling locations of 4:2:2 samples in top and bottom fields .... 285

Figure D.3 – Nominal vertical and horizontal sampling locations of 4:4:4 samples in top and bottom fields .... 285

Figure D.4 – Rearrangement and upconversion of side-by-side packing arrangement with

frame_packing_arrangement_type equal to 3, quincunx_sampling_flag equal to 0 and ( x, y ) equal to

( 0, 0 ) or ( 4, 8 ) for both constituent frames ...................................................................................... 307

Figure D.5 – Rearrangement and upconversion of side-by-side packing arrangement with

frame_packing_arrangement_type equal to 3, quincunx_sampling_flag equal to 0, ( x, y ) equal to

( 12, 8 ) for constituent frame 0 and ( x, y ) equal to ( 0, 0 ) or ( 4, 8 ) for constituent frame 1 .......... 308

Figure D.6 – Rearrangement and upconversion of top-bottom packing arrangement with

frame_packing_arrangement_type equal to 4, quincunx_sampling_flag equal to 0 and ( x, y ) equal to

( 0, 0 ) or ( 8, 4 ) for both constituent frames ...................................................................................... 308

Rec. ITU-T H.265 v3 (04/2015) xv

Figure D.7 – Rearrangement and upconversion of top-bottom packing arrangement with

frame_packing_arrangement_type equal to 4, quincunx_sampling_flag equal to 0, ( x, y ) equal to

( 8, 12 ) for constituent frame 0 and ( x, y ) equal to ( 0, 0 ) or ( 8, 4 ) for constituent frame 1 .......... 309

Figure D.8 – Rearrangement and upconversion of side-by-side packing arrangement with quincunx sampling

(frame_packing_arrangement_type equal to 3 with quincunx_sampling_flag equal to 1) ................. 309

Figure D.9 – Rearrangement of a temporal interleaving frame arrangement (frame_packing_arrangement_type

equal to 5) ........................................................................................................................................... 310

Figure D.10 – Rearrangement of a segmented rectangular frame packing arrangement ..................................... 324

Figure D.11 – A knee function with num_knee_points_minus1 equal to 2 ......................................................... 337

Figure E.1 – Location of chroma samples for top and bottom fields for chroma_format_idc equal to 1 (4:2:0 chroma

format) as a function of chroma_sample_loc_type_top_field and

chroma_sample_loc_type_bottom_field ............................................................................................. 353

Figure F.1 – Bitstream-partition-specific HRD buffer model .............................................................................. 436

LIST OF FIGURES

Table 5-1 – Operation precedence from highest (at top of table) to lowest (at bottom of table) ........................... 18

Table 6-1 – SubWidthC and SubHeightC values derived from chroma_format_idc and separate_colour_plane_flag

.............................................................................................................................................................. 21

Table 7-1 – NAL unit type codes and NAL unit type classes ................................................................................ 63

Table 7-2 – Interpretation of pic_type ................................................................................................................... 83

Table 7-3 – Specification of sizeId ........................................................................................................................ 87

Table 7-4 – Specification of matrixId according to sizeId, prediction mode and colour component .................... 87

Table 7-5 – Specification of default values of ScalingList[ 0 ][ matrixId ][ i ] with i = 0..15 ............................... 87

Table 7-6 – Specification of default values of ScalingList[ 1..3 ][ matrixId ][ i ] with i = 0..63 ........................... 88

Table 7-7 – Name association to slice_type .......................................................................................................... 90

Table 7-8 – Specification of the SAO type ............................................................................................................ 98

Table 7-9 – Specification of the SAO edge offset class....................................................................................... 100

Table 7-10 – Name association to prediction mode and partitioning type ........................................................... 101

Table 7-11 – Name association to inter prediction mode .................................................................................... 102

Table 8-1 – Specification of intra prediction mode and associated names .......................................................... 118

Table 8-2 – Specification of modeIdx ................................................................................................................. 120

Table 8-3 – Specification of intraPredModeC when ChromaArrayType is equal to 2 ........................................ 120

Table 8-4 – Specification of intraHorVerDistThres[ nTbS ] for various transform block sizes .......................... 124

Table 8-5 – Specification of intraPredAngle ....................................................................................................... 126

Table 8-6 – Specification of invAngle ................................................................................................................. 126

Table 8-7 – Specification of l0CandIdx and l1CandIdx ...................................................................................... 139

Table 8-8 – Assignment of the luma prediction sample predSampleLX

............................................................ 151

Table 8-9 – Assignment of the chroma prediction sample predSampleLX

for ( X, Y ) being replaced by ( 1, b ),

( 2, c ), ( 3, d ), ( 4, e ), ( 5, f ), ( 6, g ) and ( 7, h ), respectively ......................................................... 153

Table 8-10 – Specification of Qp

as a function of qPi for ChromaArrayType equal to 1 .................................. 160

Table 8-11 – Name of association to edgeType ................................................................................................... 167

Table 8-12 – Derivation of threshold variables β′ and t

′ from input Q .............................................................. 175

Table 8-13 – Specification of hPos and vPos according to the sample adaptive offset class .............................. 182

Table 9-1 – Bit strings with "prefix" and "suffix" bits and assignment to codeNum ranges (informative) ......... 183

Table 9-2 – Exp-Golomb bit strings and codeNum in explicit form and used as ue(v) (informative) ................. 183

Table 9-3 – Assignment of syntax element to codeNum for signed Exp-Golomb coded syntax elements se(v) . 184

Table 9-4 – Association of ctxIdx and syntax elements for each initializationType in the initialization process 189

Table 9-5 – Values of initValue for ctxIdx of sao_merge_left_flag and sao_merge_up_flag ............................. 190

xvi Rec. ITU-T H.265 v3 (04/2015)

Table 9-6 – Values of initValue for ctxIdx of sao_type_idx_luma and sao_type_idx_chroma ........................... 190

Table 9-7 – Values of initValue for ctxIdx of split_cu_flag ................................................................................ 190

Table 9-8 – Values of initValue for ctxIdx of cu_transquant_bypass_flag ......................................................... 190

Table 9-9 – Values of initValue for ctxIdx of cu_skip_flag ................................................................................ 190

Table 9-10 – Values of initValue for ctxIdx of pred_mode_flag ......................................................................... 191

Table 9-11 – Values of initValue for ctxIdx of part_mode .................................................................................. 191

Table 9-12 – Values of initValue for ctxIdx of prev_intra_luma_pred_flag ....................................................... 191

Table 9-13 – Values of initValue for ctxIdx of intra_chroma_pred_mode .......................................................... 191

Table 9-14 – Values of initValue for ctxIdx of rqt_root_cbf ............................................................................... 191

Table 9-15 – Values of initValue for ctxIdx of merge_flag ................................................................................. 191

Table 9-16 – Values of initValue for ctxIdx of merge_idx .................................................................................. 192

Table 9-17 – Values of initValue for ctxIdx of inter_pred_idc............................................................................ 192

Table 9-18 – Values of initValue for ctxIdx of ref_idx_l0 and ref_idx_l1 .......................................................... 192

Table 9-19 – Values of initValue for ctxIdx of mvp_l0_flag and mvp_l1_flag .................................................. 192

Table 9-20 – Values of initValue for ctxIdx of split_transform_flag .................................................................. 192

Table 9-21 – Values of initValue for ctxIdx of cbf_luma .................................................................................... 192

Table 9-22 – Values of initValue for ctxIdx of cbf_cb and cbf_cr ...................................................................... 193

Table 9-23 – Values of initValue for ctxIdx of abs_mvd_greater0_flag and abs_mvd_greater1_flag ................ 193

Table 9-24 – Values of initValue for ctxIdx of cu_qp_delta_abs ........................................................................ 193

Table 9-25 – Values of initValue for ctxIdx of transform_skip_flag .................................................................. 193

Table 9-26 – Values of initValue for ctxIdx of last_sig_coeff_x_prefix ............................................................. 193

Table 9-27 – Values of initValue for ctxIdx of last_sig_coeff_y_prefix ............................................................. 194

Table 9-28 – Values of initValue for ctxIdx of coded_sub_block_flag ............................................................... 194

Table 9-29 – Values of initValue for ctxIdx of sig_coeff_flag ............................................................................ 194

Table 9-30 – Values of initValue for ctxIdx of coeff_abs_level_greater1_flag .................................................. 195

Table 9-31 – Values of initValue for ctxIdx of coeff_abs_level_greater2_flag .................................................. 195

Table 9-32 – Values of initValue for ctxIdx of explicit_rdpcm_flag .................................................................. 195

Table 9-33 – Values of initValue for ctxIdx of explicit_rdpcm_dir_flag ............................................................ 195

Table 9-34 – Values of initValue for ctxIdx of cu_chroma_qp_offset_flag ........................................................ 195

Table 9-35 – Values of initValue for ctxIdx of cu_chroma_qp_offset_idx ......................................................... 196

Table 9-36 – Values of initValue for ctxIdx of log2_res_scale_abs_plus1 ......................................................... 196

Table 9-37 – Values of initValue for ctxIdx of res_scale_sign_flag ................................................................... 196

Table 9-38 – Syntax elements and associated binarizations ................................................................................ 198

Table 9-39 – Bin string of the unary binarization (informative) .......................................................................... 201

Table 9-40 – Binarization for part_mode ............................................................................................................. 203

Table 9-41 – Binarization for intra_chroma_pred_mode..................................................................................... 203

Table 9-42 – Binarization for inter_pred_idc ...................................................................................................... 204

Table 9-43 – Assignment of ctxInc to syntax elements with context coded bins ................................................ 206

Table 9-44 – Specification of ctxInc using left and above syntax elements ........................................................ 208

Table 9-45 – Specification of ctxIdxMap[ i ] ...................................................................................................... 211

Table 9-46 – Specification of rangeTabLps depending on the values of pStateIdx and qRangeIdx .................... 215

Table 9-47 – State transition table ....................................................................................................................... 216

Table A.1 – Allowed values for syntax elements in the format range extensions profiles .................................. 229

Table A.2 – Bitstream indications for conformance to format range extensions profiles .................................... 231

Table A.3 – Bitstream indications for conformance to format range extensions high throughput profiles ......... 233

Table A.4 – General tier and level limits ............................................................................................................. 235

Rec. ITU-T H.265 v3 (04/2015) xvii

Table A.5 – Tier and level limits for the video profiles ....................................................................................... 237

Table A.6 – Specification of CpbVclFactor, CpbNalFactor, FormatCapabilityFactor and MinCrScaleFactor ... 238

Table A.7 – Maximum picture rates (pictures per second) at level 1 to 4.1 for some example picture sizes when

MinCbSizeY is equal to 64 ................................................................................................................. 239

Table A.8 – Maximum picture rates (pictures per second) at level 5 to 6.2 for some example picture sizes when

MinCbSizeY is equal to 64 ................................................................................................................. 240

Table D.1 – Persistence scope of SEI messages (informative) ............................................................................ 277

Table D.2 – Interpretation of pic_struct ............................................................................................................... 284

Table D.3 – scene_transition_type values ........................................................................................................... 290

Table D.4 – film_grain_model_id values ............................................................................................................ 293

Table D.5 – blending_mode_id values ................................................................................................................ 295

Table D.6 – filter_hint_type values ..................................................................................................................... 299

Table D.7 – Interpretation of camera_iso_speed_idc and exposure_index_idc ................................................... 302

Table D.8 – Definition of frame_packing_arrangement_type ............................................................................. 304

Table D.9 – Definition of content_interpretation_type ........................................................................................ 305

Table D.10 – Interpretation of hash_type ............................................................................................................ 312

Table D.11 – Definition of counting_type[ i ] values .......................................................................................... 320

Table D.12 – Definition of segmented_rect_content_interpretation_type ........................................................... 323

Table D.13 – ver_chroma_filter_idc values ......................................................................................................... 328

Table D.14 – hor_chroma_filter_idc values ........................................................................................................ 328

Table D.15 – Chroma sampling format indicated by target_format_idc ............................................................. 329

Table D.16 – Constraints on the value of num_vertical_filters ........................................................................... 330

Table D.17 – Constraints on the value of num_horizontal_filters ....................................................................... 330

Table D.18 – Values of verFilterCoeff and verTapLength when ver_chroma_filter_idc is equal to 2 ................ 331

Table D.19 – Values of horFilterCoeff and horTapLength when hor_chroma_filter_idc is equal to 2 ............... 331

Table D.20 – Usage of chroma filter in the vertical direction ............................................................................. 334

Table D.21 – Usage of chroma filter in the horizontal direction ......................................................................... 336

Table E.1 – Interpretation of sample aspect ratio indicator ................................................................................. 345

Table E.2 – Meaning of video_format ................................................................................................................. 346

Table E.3 – Colour primaries ............................................................................................................................... 347

Table E.4 – Transfer characteristics..................................................................................................................... 348

Table E.5 – Matrix coefficients ........................................................................................................................... 352

Table E.6 – Divisor for computation of DpbOutputElementalInterval[ n ] ......................................................... 359

Table F.1 – Mapping of ScalabiltyId to scalability dimensions ........................................................................... 386

Table F.2 – Mapping of AuxId to the type of auxiliary pictures ......................................................................... 387

Table F.3 – Specification of CompatibleProfileList ............................................................................................ 432

Table F.4 – Persistence scope of SEI messages (informative) ............................................................................. 455

Table G.1 – Persistence scope of SEI messages (informative) ............................................................................ 485

Table G.2 – Association between camera parameter variables and syntax elements .......................................... 487

Table G.3 – Definition of depth_representation_type ......................................................................................... 489

Table G.4 – Association between depth parameter variables and syntax elements ............................................. 489

Table G.5 – Association between camera parameter variables and syntax elements. ......................................... 494

Table H.1 – 16-phase luma resampling filter ....................................................................................................... 502

Table H.2 – 16-phase chroma resampling filter ................................................................................................... 503

Table I.1 – Name association to prediction mode and partitioning type .............................................................. 544

Table I.2 – Specification of intra prediction mode and associated names ........................................................... 550

xviii Rec. ITU-T H.265 v3 (04/2015)

Table I.3 – Specification of divCoeff depending on sDenomDiv ........................................................................ 579

Table I.4 – Association of ctxIdx and syntax elements for each initializationType in the initialization process 592

Table I.5 – Values of initValue for skip_intra_flag ctxIdx .................................................................................. 593

Table I.6 – Values of initValue for no_dim_flag ctxIdx ...................................................................................... 593

Table I.7 – Values of initValue for depth_intra_mode_idx_flag ctxIdx .............................................................. 593

Table I.8 – Values of initValue for skip_intra_mode_idx ctxIdx ........................................................................ 593

Table I.9 – Values of initValue for dbbp_flag ctxIdx .......................................................................................... 593

Table I.10 – Values of initValue for dc_only_flag ctxIdx ................................................................................... 593

Table I.11 – Values of initValue for iv_res_pred_weight_idx ctxIdx ................................................................. 594

Table I.12 – Values of initValue for illu_comp_flag ctxIdx ................................................................................ 594

Table I.13 – Values of initValue for depth_dc_present_flag ctxIdx .................................................................... 594

Table I.14 – Values of initValue for depth_dc_abs ctxIdx .................................................................................. 594

Table I.15 – Syntax elements and associated binarizations ................................................................................. 595

Table I.16 – Binarization for part_mode .............................................................................................................. 596

Table I.17 – Assignment of ctxInc to syntax elements with context coded bins ................................................. 597

Table I.18 – Specification of ctxInc using left and above syntax elements ......................................................... 598

Table I.19 – Persistence scope of SEI messages (informative)............................................................................ 603

Table I.20 – Interpretation of depth_type ............................................................................................................ 603