-----------------------------------
编码器输出格式
----------------------------------
总的来说H264的码流的打包方式有两种，一种为annex-b byte stream format的格式，这个是绝大部分编码器的默认输出格式，就是每个帧的开头的3~4个字节是H264的start_code,0x00000001或者0x000001。
另一种是原始的NAL打包格式，就是开始的若干字节（1，2，4字节）是NAL的长度，而不是start_code,此时必须借助某个全局的数据来获得编码器的profile,level,PPS,SPS等信息才可以解码。
@之前还疑惑过PPS 和SPS是哪里来的，答案是编码器给出的。
------------------------------
编码数据流分析
------------------------------
首先明确一下，NAL数据流的组成：开始码+NAL头（forbidden_bit+nal_ref+nal_type）+RBSP
下面对一段H264编码数据流进行分析。
00 00 00 01 67 42 00 1E 99 A0 B1 31 00 00 00 01
H264的数据流分为两种，一种是NAL UNIT stream(RTP),一种是 bits stream,
两者可以互相转换。我们分析的这个是 bit stream,根据AnnexB
00 00 00 01 67 42 00 1E 99 A0 B1 31 是 一个NAL，在两个00 00 00 01之间
0110 0111 0100 0010 0000 0000 0001 1110 1001 1001 1010 0000 1011 0001 0011 0001
forbidden_zero_bit（1）＝ 0//网络传输正确
nal_ref_idc（2）＝ 11//参考值为3
nal_unit_type（5） ＝ 0 0111：seq_parameter_set_rbsp( )//7，序列参数集
说明这个NALU的RBSP里装的是SPS数据 ，所以 processSPS
profile_idc(8):42：0100 0010
constraint_set0_flag(1):0
constraint_set1_flag(1):0
constraint_set2_flag(1):0
constraint_set3_flag(1):0
reserved_zero_4bits(4):0
level_idc(8):1E
seq_parameter_set_id(UE(V)):
ue(v): unsigned integer Exp-Golomb-coded syntax element with the left bit first. The parsing process for this descriptor is specified in subclause9.1
uvlC: 1001：根据Table9.1 ， value= 0,只占1bit.
根据profile_idc忽略掉一部分。
log2_max_frame_num_minus4(ue(v): 001 1001,len = 5,value= 5
pic_order_cnt_type(ue(v)):01 1010,len = 3,value = 2
根据pic_order_cnt_type忽略几个参数
num_ref_frames（ue）：010,len = 3,value = 1
0000 1011 0001 0011 0001
gaps_in_frame_num_value_allowed_flag(1) = 0
pic_width_in_mbs_minus1(ue):000 1011 ,len = 7,value = 10;
pic_height_in_map_units_minus1(ue):0001 001,len = 7,value = 8
frame_mbs_only_flag(1) = 1
忽略1
direct_8x8_inference_flag（1）:0
忽略
vui_parameters_present_flag(1):0
忽略
NALU结束
68 CE 38 80 00 00 00 01
0110 1000
forbidden_zero_bit（1）＝ 0
nal_ref_idc（2）＝ 11
nal_unit_type（5） ＝01000：pic_parameter_set_rbsp( ),7.3.2.2//8图像参数集
1100
pic_parameter_set_id (ue)=0
seq_parameter_set_id(ue)=0
entropy_coding_mode_flag(1) :0, 重要的flag,0表示编码Exp-Golomb coded and CAVLC,1表示CABAC
pic_order_present_flag(1):0
1110
num_slice_groups_minus1(ue):0
忽略
num_ref_idx_l0_active_minus1（ue）:0
num_ref_idx_l1_active_minus1(ue):0
weighted_pred_flag(1);0
0011 1000 1000 0000
weighted_bipred_idc(2):00
pic_init_qp_minus26 /* relative to 26 */(se):0
pic_init_qs_minus26 /* relative to 26 */(se):0
chroma_qp_index_offset(se):0
deblocking_filter_control_present_flag(1);0
constrained_intra_pred_flag(1):0
redundant_pic_cnt_present_flag(1):0
忽略
NALU结束
65 88 80 21 71 27 1B 88…….3888*16 byte
65：0110 0101
forbidden_zero_bit（1）＝ 0
nal_ref_idc（2）＝ 11
nal_unit_type（5） ＝0 0101：slice_layer_without_partitioning_rbsp( )//IDR帧
Slice
Slice_Header:
first_mb_in_slice(ue):0
slice_type(ue):000 1000 = 7
pic_parameter_set_id(ue) = 0
80 21：000 0000 0010 0001
frame_num(u(v): frame_num is used as an identifier for pictures and shall be represented by log2_max_frame_num_minus4 + 4 bits,9 bits = 0
忽略
if( nal_unit_type = = 5 ) //IDR frame
idr_pic_id(u(e)):0
忽略N多
ref_pic_list_reordering( ) 见7。3。3。1忽略，Islice,SI slice,B slice
nal_ref_idc =11 所以dec_ref_pic_marking( )
nal_unit_type = 5，所以
no_output_of_prior_pics_flag（1）：0
long_term_reference_flag（1）：0
忽略
。。71 27
001 0111 0001 0010 0111
slice_qp_delta（se（v）：001 01，4：-2
忽略
slice_data( ):7.3.4
对I-Slice:忽略N多
进入if( moreDataFlag ) { if( MbaffFrameFlag && ( CurrMbAddr % 2 = = 0 | | ( CurrMbAddr % 2 = = 1 && prevMbSkipped ) ) )mb_field_decoding_flag
macroblock_layer( )}
mb_field_decoding_flag忽略
macroblock_layer( )
mb_type（ue（v）：0
mb_pred( mb_type )
prev_intra4x4_pred_mode_flag[ luma4x4BlkIdx ]（1bit,对babac是ae(v)）:1
1 27:0001 0010 0111
prev_intra4x4_pred_mode_flag[ 1 ] : 0001,0,001
0010 0111
prev_intra4x4_pred_mode_flag[ 2 ] : 0010,0,010
prev_intra4x4_pred_mode_flag[ 3] : 0111,0,111
……16个
1b 88 00 3e cf.
intra_chroma_pred_mode（ue(v)） :最后的一个1bit:0
接下来是macroblock_layer的coded_block_pattern和run level,既系数
c0 06 ad a0 18
1100 0000 0000 0110 1010 0000 0001 1000
coded_block_pattern（me(v):0,根据T= 47，0x2f
mb_qp_delta(se(v):):0 len =1
residual( )见7.3.5.3
residual_block( LumaLevel[ i8x8 * 4 + i4x4 ], 16 )
coeff_token(ce(v): 00 0000 0000 0110 1
nc = 0(left block and top block 相关的)：
len: { // 0702
{ 1, 6, 8, 9,10,11,13,13,13,14,14,15,15,16,16,16,16},
{ 0, 2, 6, 8, 9,10,11,13,13,14,14,15,15,15,16,16,16},
{ 0, 0, 3, 7, 8, 9,10,11,13,13,14,14,15,15,16,16,16},
{ 0, 0, 0, 5, 6, 7, 8, 9,10,11,13,14,14,15,15,16,16},
},
{
{ 2, 6, 6, 7, 8, 8, 9,11,11,12,12,12,13,13,13,14,14},
{ 0, 2, 5, 6, 6, 7, 8, 9,11,11,12,12,13,13,14,14,14},
{ 0, 0, 3, 6, 6, 7, 8, 9,11,11,12,12,13,13,13,14,14},
{ 0, 0, 0, 4, 4, 5, 6, 6, 7, 9,11,11,12,13,13,13,14},
},
{
{ 4, 6, 6, 6, 7, 7, 7, 7, 8, 8, 9, 9, 9,10,10,10,10},
{ 0, 4, 5, 5, 5, 5, 6, 6, 7, 8, 8, 9, 9, 9,10,10,10},
{ 0, 0, 4, 5, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9,10,10,10},
{ 0, 0, 0, 4, 4, 4, 4, 4, 5, 6, 7, 8, 8, 9,10,10,10},
},
code:
{ 1, 5, 7, 7, 7, 7,15,11, 8,15,11,15,11,15,11, 7,4},
{ 0, 1, 4, 6, 6, 6, 6,14,10,14,10,14,10, 1,14,10,6},
{ 0, 0, 1, 5, 5, 5, 5, 5,13, 9,13, 9,13, 9,13, 9,5},
{ 0, 0, 0, 3, 3, 4, 4, 4, 4, 4,12,12, 8,12, 8,12,8},
},
{
{ 3,11, 7, 7, 7, 4, 7,15,11,15,11, 8,15,11, 7, 9,7},
{ 0, 2, 7,10, 6, 6, 6, 6,14,10,14,10,14,10,11, 8,6},
{ 0, 0, 3, 9, 5, 5, 5, 5,13, 9,13, 9,13, 9, 6,10,5},
{ 0, 0, 0, 5, 4, 6, 8, 4, 4, 4,12, 8,12,12, 8, 1,4},
},
{
{15,15,11, 8,15,11, 9, 8,15,11,15,11, 8,13, 9, 5,1},
{ 0,14,15,12,10, 8,14,10,14,14,10,14,10, 7,12, 8,4},
{ 0, 0,13,14,11, 9,13, 9,13,10,13, 9,13, 9,11, 7,3},
{ 0, 0, 0,12,11,10, 9, 8,13,12,12,12, 8,12,10, 6,2},
},
根据表查的：
code = 13,len = 15，i= 12，j=2
所以numcoeff = 12,numtrailingones = 2
010 0000 0001 1000: totalzeros:根据numcoeff
int lentab[TOTRUN_NUM][16] =
{
{ 1,3,3,4,4,5,5,6,6,7,7,8,8,9,9,9},
{ 3,3,3,3,3,4,4,4,4,5,5,6,6,6,6},
{ 4,3,3,3,4,4,3,3,4,5,5,6,5,6},
{ 5,3,4,4,3,3,3,4,3,4,5,5,5},
{ 4,4,4,3,3,3,3,3,4,5,4,5},
{ 6,5,3,3,3,3,3,3,4,3,6},
{ 6,5,3,3,3,2,3,4,3,6},
{ 6,4,5,3,2,2,3,3,6},
{ 6,6,4,2,2,3,2,5},
{ 5,5,3,2,2,2,4},
{ 4,4,3,3,1,3},
{ 4,4,2,1,3}, numcoeff开始
{ 3,3,1,2},
{ 2,2,1},
{ 1,1},
};
int codtab[TOTRUN_NUM][16] =
{
{1,3,2,3,2,3,2,3,2,3,2,3,2,3,2,1},
{7,6,5,4,3,5,4,3,2,3,2,3,2,1,0},
{5,7,6,5,4,3,4,3,2,3,2,1,1,0},
{3,7,5,4,6,5,4,3,3,2,2,1,0},
{5,4,3,7,6,5,4,3,2,1,1,0},
{1,1,7,6,5,4,3,2,1,1,0},
{1,1,5,4,3,3,2,1,1,0},
{1,1,1,3,3,2,2,1,0},
{1,0,1,3,2,1,1,1,},
{1,0,1,3,2,1,1,},
{0,1,1,2,1,3},
{0,1,1,1,1}, numcoeff开始
{0,1,1,1},
{0,1,1},
{0,1},
};
Code = 1,len = 2,i=2,j = 0, totzeros = 2
Read run: 0 0000 0001 1000根据totzeros = 2
int lentab[TOTRUN_NUM][16] =
{
{1,1},
{1,2,2},
{2,2,2,2},
{2,2,2,3,3},
{2,2,3,3,3,3},
{2,3,3,3,3,3,3},
{3,3,3,3,3,3,3,4,5,6,7,8,9,10,11},
};
int codtab[TOTRUN_NUM][16] =
{
{1,0},
{1,1,0},
{3,2,1,0},
{3,2,1,1,0},
{3,2,3,2,1,0},
{3,0,1,3,2,5,4},
{7,6,5,4,3,2,1,1,1,1,1,1,1,1,1},
Code = 1,len =1,I = 0,j = 0
0.1.1 Slice data syntax
| slice_data( ) { | C | Descriptor |
| if( entropy_coding_mode_flag ) |
|
|
| while( !byte_aligned( ) ) |
|
|
| cabac_alignment_one_bit | 2 | f(1) |
| CurrMbAddr = first_mb_in_slice * ( 1 + MbaffFrameFlag ) |
|
|
| moreDataFlag = 1 |
|
|
| prevMbSkipped = 0 |
|
|
| do { |
|
|
| if( slice_type != I && slice_type != SI ) |
|
|
| if( !entropy_coding_mode_flag ) { |
|
|
| mb_skip_run | 2 | ue(v) |
| prevMbSkipped = ( mb_skip_run > 0 ) |
|
|
| for( i=0; i<mb_skip_run; i++ ) |
|
|
| CurrMbAddr = NextMbAddress( CurrMbAddr ) |
|
|
| moreDataFlag = more_rbsp_data( ) |
|
|
| } else { |
|
|
| mb_skip_flag | 2 | ae(v) |
| moreDataFlag = !mb_skip_flag |
|
|
| } |
|
|
| if( moreDataFlag ) { |
|
|
| if( MbaffFrameFlag && ( CurrMbAddr % 2 = = 0 | | ( CurrMbAddr % 2 = = 1 && prevMbSkipped ) ) ) |
|
|
| mb_field_decoding_flag | 2 | u(1) | ae(v) |
| macroblock_layer( ) | 2 | 3 | 4 |
|
| } |
|
|
| if( !entropy_coding_mode_flag ) |
|
|
| moreDataFlag = more_rbsp_data( ) |
|
|
| else { |
|
|
| if( slice_type != I && slice_type != SI ) |
|
|
| prevMbSkipped = mb_skip_flag |
|
|
| if( MbaffFrameFlag && CurrMbAddr % 2 = = 0 ) |
|
|
| moreDataFlag = 1 |
|
|
| else { |
|
|
| end_of_slice_flag | 2 | ae(v) |
| moreDataFlag = !end_of_slice_flag |
|
|
| } |
|
|
| } |
|
|
| CurrMbAddr = NextMbAddress( CurrMbAddr ) |
|
|
| } while( moreDataFlag ) |
|
|
| } |
|
|
se(v) : CABAC正式介绍。根据Table 9 5 – coeff_token mapping to TotalCoeff( coeff_token ) and TrailingOnes( coeff_token )。
chroma_format_idc 无
Table 9‑1 – Bit strings with “prefix” and “suffix” bits and assignment to codeNum ranges (informative)
| Bit string form | Range of codeNum |
| 1 | 0 |
| 0 1 x0 | 1-2 |
| 0 0 1 x1 x0 | 3-6 |
| 0 0 0 1 x2 x1 x0 | 7-14 |
| 0 0 0 0 1 x3 x2 x1 x0 | 15-30 |
| 0 0 0 0 0 1 x4 x3 x2 x1 x0 | 31-62 |
| … | … |
0.1.1.1 Slice layer without partitioning RBSP syntax
| slice_layer_without_partitioning_rbsp( ) { | C | Descriptor |
| slice_header( ) | 2 |
|
| slice_data( ) /* all categories of slice_data( ) syntax */ | 2 | 3 | 4 |
|
| rbsp_slice_trailing_bits( ) | 2 |
|
| } |
|
|
0.1.1.2 Sequence parameter set RBSP syntax
| seq_parameter_set_rbsp( ) { | C | Descriptor |
| profile_idc | 0 | u(8) |
| constraint_set0_flag | 0 | u(1) |
| constraint_set1_flag | 0 | u(1) |
| constraint_set2_flag | 0 | u(1) |
| constraint_set3_flag | 0 | u(1) |
| reserved_zero_4bits /* equal to 0 */ | 0 | u(4) |
| level_idc | 0 | u(8) |
| seq_parameter_set_id | 0 | ue(v) |
| if( profile_idc = = 100 | | profile_idc = = 110 | | |
|
|
| chroma_format_idc | 0 | ue(v) |
| if( chroma_format_idc = = 3 ) |
|
|
| residual_colour_transform_flag | 0 | u(1) |
| bit_depth_luma_minus8 | 0 | ue(v) |
| bit_depth_chroma_minus8 | 0 | ue(v) |
| qpprime_y_zero_transform_bypass_flag | 0 | u(1) |
| seq_scaling_matrix_present_flag | 0 | u(1) |
| if( seq_scaling_matrix_present_flag ) |
|
|
| for( i = 0; i < 8; i++ ) { |
|
|
| seq_scaling_list_present_flag[ i] | 0 | u(1) |
| if( seq_scaling_list_present_flag[ i ] ) |
|
|
| if( i < 6 ) |
|
|
| scaling_list( ScalingList4x4[ i ], 16, | 0 |
|
| else |
|
|
| scaling_list( ScalingList8x8[ i – 6 ], 64, | 0 |
|
| } |
|
|
| } |
|
|
| log2_max_frame_num_minus4 | 0 | ue(v) |
| pic_order_cnt_type | 0 | ue(v) |
| if( pic_order_cnt_type = = 0 ) |
|
|
| log2_max_pic_order_cnt_lsb_minus4 | 0 | ue(v) |
| else if( pic_order_cnt_type = = 1 ) { |
|
|
| 0 | u(1) | |
| offset_for_non_ref_pic | 0 | se(v) |
| offset_for_top_to_bottom_field | 0 | se(v) |
| num_ref_frames_in_pic_order_cnt_cycle | 0 | ue(v) |
| for( i = 0; i < num_ref_frames_in_pic_order_cnt_cycle; i++ ) |
|
|
| offset_for_ref_frame[ i ] | 0 | se(v) |
| } |
|
|
| num_ref_frames | 0 | ue(v) |
| gaps_in_frame_num_value_allowed_flag | 0 | u(1) |
| pic_width_in_mbs_minus1 | 0 | ue(v) |
| pic_height_in_map_units_minus1 | 0 | ue(v) |
| frame_mbs_only_flag | 0 | u(1) |
| if( !frame_mbs_only_flag ) |
|
|
| mb_adaptive_frame_field_flag | 0 | u(1) |
| direct_8x8_inference_flag | 0 | u(1) |
| frame_cropping_flag | 0 | u(1) |
| if( frame_cropping_flag ) { |
|
|
| frame_crop_left_offset | 0 | ue(v) |
| frame_crop_right_offset | 0 | ue(v) |
| frame_crop_top_offset | 0 | ue(v) |
| frame_crop_bottom_offset | 0 | ue(v) |
| } |
|
|
| vui_parameters_present_flag | 0 | u(1) |
| if( vui_parameters_present_flag ) |
|
|
| vui_parameters( ) | 0 |
|
| rbsp_trailing_bits( ) | 0 |
|
| } |
|
|
Table 7‑1 – NAL unit type codes
| nal_unit_type | Content of NAL unit and RBSP syntax structure | C |
| 0 | Unspecified |
|
| 1 | Coded slice of a non-IDR picture | 2, 3, 4 |
| 2 | Coded slice data partition A | 2 |
| 3 | Coded slice data partition B | 3 |
| 4 | Coded slice data partition C | 4 |
| 5 | Coded slice of an IDR picture | 2, 3 |
| 6 | Supplemental enhancement information (SEI) | 5 |
| 7 | Sequence parameter set | 0 |
| 8 | Picture parameter set | 1 |
| 9 | Access unit delimiter | 6 |
| 10 | End of sequence | 7 |
| 11 | End of stream | 8 |
| 12 | Filler data | 9 |
| 13 | Sequence parameter set extension | 10 |
| 14..18 | Reserved |
|
| 19 | Coded slice of an auxiliary coded picture without partitioning | 2, 3, 4 |
| 20..23 | Reserved |
|
| 24..31 | Unspecified |
|
| byte_stream_nal_unit( NumBytesInNALunit ) { | C | Descriptor |
| while( next_bits( 24 ) != 0x000001 && |
|
|
| leading_zero_8bits /* equal to 0x00 */ |
| f(8) |
| if( next_bits( 24 ) != 0x000001 ) |
|
|
| zero_byte /* equal to 0x00 */ |
| f(8) |
| start_code_prefix_one_3bytes /* equal to 0x000001 */ |
| f(24) |
| nal_unit( NumBytesInNALunit) |
|
|
| while( more_data_in_byte_stream( ) && |
|
|
| trailing_zero_8bits /* equal to 0x00 */ |
| f(8) |
| } |
|
|
0.1.1.3 Picture parameter set RBSP syntax
| pic_parameter_set_rbsp( ) { | C | Descriptor |
| pic_parameter_set_id | 1 | ue(v) |
| seq_parameter_set_id | 1 | ue(v) |
| entropy_coding_mode_flag | 1 | u(1) |
| pic_order_present_flag | 1 | u(1) |
| num_slice_groups_minus1 | 1 | ue(v) |
| if( num_slice_groups_minus1 > 0 ) { |
|
|
| slice_group_map_type | 1 | ue(v) |
| if( slice_group_map_type = = 0 ) |
|
|
| for( iGroup = 0; iGroup <= num_slice_groups_minus1; iGroup++ ) |
|
|
| run_length_minus1[ iGroup ] | 1 | ue(v) |
| else if( slice_group_map_type = = 2 ) |
|
|
| for( iGroup = 0; iGroup < num_slice_groups_minus1; iGroup++ ) { |
|
|
| top_left[ iGroup ] | 1 | ue(v) |
| bottom_right[ iGroup ] | 1 | ue(v) |
| } |
|
|
| else if( slice_group_map_type = = 3 | | |
|
|
| slice_group_change_direction_flag | 1 | u(1) |
| slice_group_change_rate_minus1 | 1 | ue(v) |
| } else if( slice_group_map_type = = 6 ) { |
|
|
| pic_size_in_map_units_minus1 | 1 | ue(v) |
| for( i = 0; i <= pic_size_in_map_units_minus1; i++ ) |
|
|
| slice_group_id[ i ] | 1 | u(v) |
| } |
|
|
| } |
|
|
| num_ref_idx_l0_active_minus1 | 1 | ue(v) |
| num_ref_idx_l1_active_minus1 | 1 | ue(v) |
| weighted_pred_flag | 1 | u(1) |
| weighted_bipred_idc | 1 | u(2) |
| pic_init_qp_minus26 /* relative to 26 */ | 1 | se(v) |
| pic_init_qs_minus26 /* relative to 26 */ | 1 | se(v) |
| chroma_qp_index_offset | 1 | se(v) |
| deblocking_filter_control_present_flag | 1 | u(1) |
| constrained_intra_pred_flag | 1 | u(1) |
| redundant_pic_cnt_present_flag | 1 | u(1) |
| if( more_rbsp_data( ) ) { |
|
|
| transform_8x8_mode_flag | 1 | u(1) |
| pic_scaling_matrix_present_flag | 1 | u(1) |
| if( pic_scaling_matrix_present_flag ) |
|
|
| for( i = 0; i < 6 + 2* transform_8x8_mode_flag; i++ ) { |
|
|
| pic_scaling_list_present_flag[ i] | 1 | u(1) |
| if( pic_scaling_list_present_flag[ i ] ) |
|
|
| if( i < 6 ) |
|
|
| scaling_list( ScalingList4x4[ i ], 16, | 1 |
|
| else |
|
|
| scaling_list( ScalingList8x8[ i – 6 ], 64, | 1 |
|
| } |
|
|
| second_chroma_qp_index_offset | 1 | se(v) |
| } |
|
|
| rbsp_trailing_bits( ) | 1 |
|
| } |
|
|
0.1.2 Slice header syntax
| slice_header( ) { | C | Descriptor |
| first_mb_in_slice | 2 | ue(v) |
| slice_type | 2 | ue(v) |
| pic_parameter_set_id | 2 | ue(v) |
| frame_num | 2 | u(v) |
| if( !frame_mbs_only_flag ) { |
|
|
| field_pic_flag | 2 | u(1) |
| if( field_pic_flag ) |
|
|
| bottom_field_flag | 2 | u(1) |
| } |
|
|
| if( nal_unit_type = = 5 ) |
|
|
| idr_pic_id | 2 | ue(v) |
| if( pic_order_cnt_type = = 0 ) { |
|
|
| pic_order_cnt_lsb | 2 | u(v) |
| if( pic_order_present_flag && !field_pic_flag ) |
|
|
| delta_pic_order_cnt_bottom | 2 | se(v) |
| } |
|
|
| if( pic_order_cnt_type = = 1 && !delta_pic_order_always_zero_flag ) { |
|
|
| delta_pic_order_cnt[ 0 ] | 2 | se(v) |
| if( pic_order_present_flag && !field_pic_flag ) |
|
|
| delta_pic_order_cnt[ 1 ] | 2 | se(v) |
| } |
|
|
| if( redundant_pic_cnt_present_flag ) |
|
|
| redundant_pic_cnt | 2 | ue(v) |
| if( slice_type = = B ) |
|
|
| direct_spatial_mv_pred_flag | 2 | u(1) |
| if( slice_type = = P | | slice_type = = SP | | slice_type = = B ) { |
|
|
| num_ref_idx_active_override_flag | 2 | u(1) |
| if( num_ref_idx_active_override_flag ) { |
|
|
| num_ref_idx_l0_active_minus1 | 2 | ue(v) |
| if( slice_type = = B ) |
|
|
| num_ref_idx_l1_active_minus1 | 2 | ue(v) |
| } |
|
|
| } |
|
|
| ref_pic_list_reordering( ) | 2 |
|
| if( ( weighted_pred_flag && ( slice_type = = P | | slice_type = = SP ) ) | | |
|
|
| pred_weight_table( ) | 2 |
|
| if( nal_ref_idc != 0 ) |
|
|
| dec_ref_pic_marking( ) | 2 |
|
| if( entropy_coding_mode_flag && slice_type != I && slice_type != SI ) |
|
|
| cabac_init_idc | 2 | ue(v) |
| slice_qp_delta | 2 | se(v) |
| if( slice_type = = SP | | slice_type = = SI ) { |
|
|
| if( slice_type = = SP ) |
|
|
| sp_for_switch_flag | 2 | u(1) |
| slice_qs_delta | 2 | se(v) |
| } |
|
|
| if( deblocking_filter_control_present_flag ) { |
|
|
| disable_deblocking_filter_idc | 2 | ue(v) |
| if( disable_deblocking_filter_idc != 1 ) { |
|
|
| slice_alpha_c0_offset_div2 | 2 | se(v) |
| slice_beta_offset_div2 | 2 | se(v) |
| } |
|
|
| } |
|
|
| if( num_slice_groups_minus1 > 0 && |
|
|
| slice_group_change_cycle | 2 | u(v) |
| } |
|
|
0.1.3 Slice data syntax
| slice_data( ) { | C | Descriptor |
| if( entropy_coding_mode_flag ) |
|
|
| while( !byte_aligned( ) ) |
|
|
| cabac_alignment_one_bit | 2 | f(1) |
| CurrMbAddr = first_mb_in_slice * ( 1 + MbaffFrameFlag ) |
|
|
| moreDataFlag = 1 |
|
|
| prevMbSkipped = 0 |
|
|
| do { |
|
|
| if( slice_type != I && slice_type != SI ) |
|
|
| if( !entropy_coding_mode_flag ) { |
|
|
| mb_skip_run | 2 | ue(v) |
| prevMbSkipped = ( mb_skip_run > 0 ) |
|
|
| for( i=0; i<mb_skip_run; i++ ) |
|
|
| CurrMbAddr = NextMbAddress( CurrMbAddr ) |
|
|
| moreDataFlag = more_rbsp_data( ) |
|
|
| } else { |
|
|
| mb_skip_flag | 2 | ae(v) |
| moreDataFlag = !mb_skip_flag |
|
|
| } |
|
|
| if( moreDataFlag ) { |
|
|
| if( MbaffFrameFlag && ( CurrMbAddr % 2 = = 0 | | ( CurrMbAddr % 2 = = 1 && prevMbSkipped ) ) ) |
|
|
| mb_field_decoding_flag | 2 | u(1) | ae(v) |
| macroblock_layer( ) | 2 | 3 | 4 |
|
| } |
|
|
| if( !entropy_coding_mode_flag ) |
|
|
| moreDataFlag = more_rbsp_data( ) |
|
|
| else { |
|
|
| if( slice_type != I && slice_type != SI ) |
|
|
| prevMbSkipped = mb_skip_flag |
|
|
| if( MbaffFrameFlag && CurrMbAddr % 2 = = 0 ) |
|
|
| moreDataFlag = 1 |
|
|
| else { |
|
|
| end_of_slice_flag | 2 | ae(v) |
| moreDataFlag = !end_of_slice_flag |
|
|
| } |
|
|
| } |
|
|
| CurrMbAddr = NextMbAddress( CurrMbAddr ) |
|
|
| } while( moreDataFlag ) |
|
|
| } |
|
|
The variable MbaffFrameFlag is derived as follows.
MbaffFrameFlag = ( mb_adaptive_frame_field_flag && !field_pic_flag ) (7-22)
0.1.4 Macroblock layer syntax
| macroblock_layer( ) { | C | Descriptor |
| mb_type | 2 | ue(v) | ae(v) |
| if( mb_type = = I_PCM ) { |
|
|
| while( !byte_aligned( ) ) |
|
|
| pcm_alignment_zero_bit | 2 | f(1) |
| for( i = 0; i < 256; i++ ) |
|
|
| pcm_sample_luma[ i ] | 2 | u(v) |
| for( i = 0; i < 2 * MbWidthC * MbHeightC; i++ ) |
|
|
| pcm_sample_chroma[ i ] | 2 | u(v) |
| } else { |
|
|
| noSubMbPartSizeLessThan8x8Flag = 1 |
|
|
| if( mb_type != I_NxN && MbPartPredMode( mb_type, 0 ) != Intra_16x16 && NumMbPart( mb_type ) = = 4 ) { |
|
|
| sub_mb_pred( mb_type ) | 2 |
|
| for( mbPartIdx = 0; mbPartIdx < 4; mbPartIdx++ ) |
|
|
| if( sub_mb_type[ mbPartIdx ] != B_Direct_8x8 ) { |
|
|
| if( NumSubMbPart( sub_mb_type[ mbPartIdx ] ) > 1 ) |
|
|
| noSubMbPartSizeLessThan8x8Flag = 0 |
|
|
| } else if( !direct_8x8_inference_flag ) |
|
|
| noSubMbPartSizeLessThan8x8Flag = 0 |
|
|
| } else { |
|
|
| if( transform_8x8_mode_flag && mb_type = = I_NxN ) |
|
|
| transform_size_8x8_flag | 2 | u(1) | ae(v) |
| mb_pred( mb_type ) | 2 |
|
| } |
|
|
| if( MbPartPredMode( mb_type, 0 ) != Intra_16x16 ) { |
|
|
| coded_block_pattern | 2 | me(v) | ae(v) |
| if( CodedBlockPatternLuma > 0 && transform_8x8_mode_flag && mb_type != I_NxN && noSubMbPartSizeLessThan8x8Flag && ( mb_type != B_Direct_16x16 | | direct_8x8_inference_flag ) ) |
|
|
| transform_size_8x8_flag | 2 | u(1) | ae(v) |
| } |
|
|
| if( CodedBlockPatternLuma > 0 | | CodedBlockPatternChroma > 0 | | |
|
|
| mb_qp_delta | 2 | se(v) | ae(v) |
| residual( ) | 3 | 4 |
|
| } |
|
|
| } |
|
|
| } |
|
|
0.1.4.1 Macroblock prediction syntax
| mb_pred( mb_type ) { | C | Descriptor |
| if( MbPartPredMode( mb_type, 0 ) = = Intra_4x4 | | |
|
|
| if( MbPartPredMode( mb_type, 0 ) = = Intra_4x4 ) |
|
|
| for( luma4x4BlkIdx=0; luma4x4BlkIdx<16; luma4x4BlkIdx++ ) { |
|
|
| prev_intra4x4_pred_mode_flag[ luma4x4BlkIdx ] | 2 | u(1) | ae(v) |
| if( !prev_intra4x4_pred_mode_flag[ luma4x4BlkIdx ] ) |
|
|
| rem_intra4x4_pred_mode[ luma4x4BlkIdx ] | 2 | u(3) | ae(v) |
| } |
|
|
| if( MbPartPredMode( mb_type, 0 ) = = Intra_8x8 ) |
|
|
| for( luma8x8BlkIdx=0; luma8x8BlkIdx<4; luma8x8BlkIdx++ ) { |
|
|
| prev_intra8x8_pred_mode_flag[ luma8x8BlkIdx ] | 2 | u(1) | ae(v) |
| if( !prev_intra8x8_pred_mode_flag[ luma8x8BlkIdx ] ) |
|
|
| rem_intra8x8_pred_mode[ luma8x8BlkIdx ] | 2 | u(3) | ae(v) |
| } |
|
|
| if( chroma_format_idc != 0 ) |
|
|
| intra_chroma_pred_mode | 2 | ue(v) | ae(v) |
| } else if( MbPartPredMode( mb_type, 0 ) != Direct ) { |
|
|
| for( mbPartIdx = 0; mbPartIdx < NumMbPart( mb_type ); mbPartIdx++) |
|
|
| if( ( num_ref_idx_l0_active_minus1 > 0 | | |
|
|
| ref_idx_l0[ mbPartIdx ] | 2 | te(v) | ae(v) |
| for( mbPartIdx = 0; mbPartIdx < NumMbPart( mb_type ); mbPartIdx++) |
|
|
| if( ( num_ref_idx_l1_active_minus1 > 0 | | |
|
|
| ref_idx_l1[ mbPartIdx ] | 2 | te(v) | ae(v) |
| for( mbPartIdx = 0; mbPartIdx < NumMbPart( mb_type ); mbPartIdx++) |
|
|
| if( MbPartPredMode ( mb_type, mbPartIdx ) != Pred_L1 ) |
|
|
| for( compIdx = 0; compIdx < 2; compIdx++ ) |
|
|
| mvd_l0[ mbPartIdx ][ 0 ][ compIdx ] | 2 | se(v) | ae(v) |
| for( mbPartIdx = 0; mbPartIdx < NumMbPart( mb_type ); mbPartIdx++) |
|
|
| if( MbPartPredMode( mb_type, mbPartIdx ) != Pred_L0 ) |
|
|
| for( compIdx = 0; compIdx < 2; compIdx++ ) |
|
|
| mvd_l1[ mbPartIdx ][ 0 ][ compIdx ] | 2 | se(v) | ae(v) |
| } |
|
|
| } |
|
|
0.1.4.2 Residual data syntax
| residual( ) { | C | Descriptor |
| if( !entropy_coding_mode_flag ) |
|
|
| residual_block = residual_block_cavlc |
|
|
| else |
|
|
| residual_block = residual_block_cabac |
|
|
| if( MbPartPredMode( mb_type, 0 ) = = Intra_16x16 ) |
|
|
| residual_block( Intra16x16DCLevel, 16 ) | 3 |
|
| for( i8x8 = 0; i8x8 < 4; i8x8++ ) /* each luma 8x8 block */ |
|
|
| if( !transform_size_8x8_flag | | !entropy_coding_mode_flag ) |
|
|
| for( i4x4 = 0; i4x4 < 4; i4x4++ ) { /* each 4x4 sub-block of block */ |
|
|
| if( CodedBlockPatternLuma & ( 1 << i8x8 ) ) |
|
|
| if( MbPartPredMode( mb_type, 0 ) = = Intra_16x16 ) |
|
|
| residual_block( Intra16x16ACLevel[ i8x8 * 4 + i4x4 ], 15 ) | 3 |
|
| else |
|
|
| residual_block( LumaLevel[ i8x8 * 4 + i4x4 ], 16 ) | 3 | 4 |
|
| else if( MbPartPredMode( mb_type, 0 ) = = Intra_16x16 ) |
|
|
| for( i = 0; i < 15; i++ ) |
|
|
| Intra16x16ACLevel[ i8x8 * 4 + i4x4 ][ i ] = 0 |
|
|
| else |
|
|
| for( i = 0; i < 16; i++ ) |
|
|
| LumaLevel[ i8x8 * 4 + i4x4 ][ i ] = 0 |
|
|
| if( !entropy_coding_mode_flag && transform_size_8x8_flag ) |
|
|
| for( i = 0; i < 16; i++ ) |
|
|
| LumaLevel8x8[ i8x8 ][ 4 * i + i4x4 ] = |
|
|
| } |
|
|
| else if( CodedBlockPatternLuma & ( 1 << i8x8 ) ) |
|
|
| residual_block( LumaLevel8x8[ i8x8 ], 64 ) | 3 | 4 |
|
| else |
|
|
| for( i = 0; i < 64; i++ ) |
|
|
| LumaLevel8x8[ i8x8 ][ i ] = 0 |
|
|
| if( chroma_format_idc != 0 ) { |
|
|
| NumC8x8 = 4 / ( SubWidthC * SubHeightC ) |
|
|
| for( iCbCr = 0; iCbCr < 2; iCbCr++ ) |
|
|
| if( CodedBlockPatternChroma & 3 ) /* chroma DC residual present */ |
|
|
| residual_block( ChromaDCLevel[ iCbCr ], 4 * NumC8x8 ) | 3 | 4 |
|
| else |
|
|
| for( i = 0; i < 4 * NumC8x8; i++ ) |
|
|
| ChromaDCLevel[ iCbCr ][ i ] = 0 |
|
|
| for( iCbCr = 0; iCbCr < 2; iCbCr++ ) |
|
|
| for( i8x8 = 0; i8x8 < NumC8x8; i8x8++ ) |
|
|
| for( i4x4 = 0; i4x4 < 4; i4x4++ ) |
|
|
| if( CodedBlockPatternChroma & 2 ) |
|
|
| residual_block( ChromaACLevel[ iCbCr ][ i8x8*4+i4x4 ], 15) | 3 | 4 |
|
| else |
|
|
| for( i = 0; i < 15; i++ ) |
|
|
| ChromaACLevel[ iCbCr ][ i8x8*4+i4x4 ][ i ] = 0 |
|
|
| } |
|
|
| residual_block_cavlc( coeffLevel, maxNumCoeff ) { | C | Descriptor |
| for( i = 0; i < maxNumCoeff; i++ ) |
|
|
| coeffLevel[ i ] = 0 |
|
|
| coeff_token | 3 | 4 | ce(v) |
| if( TotalCoeff( coeff_token ) > 0 ) { |
|
|
| if( TotalCoeff( coeff_token ) > 10 && TrailingOnes( coeff_token ) < 3 ) |
|
|
| suffixLength = 1 |
|
|
| else |
|
|
| suffixLength = 0 |
|
|
| for( i = 0; i < TotalCoeff( coeff_token ); i++ ) |
|
|
| if( i < TrailingOnes( coeff_token ) ) { |
|
|
| trailing_ones_sign_flag | 3 | 4 | u(1) |
| level[ i ] = 1 – 2 * trailing_ones_sign_flag |
|
|
| } else { |
|
|
| level_prefix | 3 | 4 | ce(v) |
| levelCode = ( Min( 15, level_prefix ) << suffixLength ) |
|
|
| if( suffixLength > 0 | | level_prefix >= 14 ) { |
|
|
| level_suffix | 3 | 4 | u(v) |
| levelCode += level_suffix |
|
|
| } |
|
|
| if( level_prefix > = 15 && suffixLength = = 0 ) |
|
|
| levelCode += 15 |
|
|
| if( level_prefix > = 16 ) |
|
|
| levelCode += ( 1 << ( level_prefix – 3 ) ) – 4096 |
|
|
| if( i = = TrailingOnes( coeff_token ) && |
|
|
| levelCode += 2 |
|
|
| if( levelCode % 2 = = 0 ) |
|
|
| level[ i ] = ( levelCode + 2 ) >> 1 |
|
|
| else |
|
|
| level[ i ] = ( –levelCode – 1 ) >> 1 |
|
|
| if( suffixLength = = 0 ) |
|
|
| suffixLength = 1 |
|
|
| if( Abs( level[ i ] ) > ( 3 << ( suffixLength – 1 ) ) && |
|
|
| suffixLength++ |
|
|
| } |
|
|
| if( TotalCoeff( coeff_token ) < maxNumCoeff ) { |
|
|
| total_zeros | 3 | 4 | ce(v) |
| zerosLeft = total_zeros |
|
|
| } else |
|
|
| zerosLeft = 0 |
|
|
| for( i = 0; i < TotalCoeff( coeff_token ) – 1; i++ ) { |
|
|
| if( zerosLeft > 0 ) { |
|
|
| run_before | 3 | 4 | ce(v) |
| run[ i ] = run_before |
|
|
| } else |
|
|
| run[ i ] = 0 |
|
|
| zerosLeft = zerosLeft – run[ i ] |
|
|
| } |
|
|
| run[ TotalCoeff( coeff_token ) – 1 ] = zerosLeft |
|
|
| coeffNum = ‑1 |
|
|
| for( i = TotalCoeff( coeff_token ) – 1; i >= 0; i-- ) { |
|
|
| coeffNum += run[ i ] + 1 |
|
|
| coeffLevel[ coeffNum ] = level[ i ] |
|
|
| } |
|
|
| } |
|
|
| } |