H264视频数据格式

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
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

 

 

 

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
…	…

 

 

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
}

 

 

 

 

 

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 | |           profile_idc = = 122 | | profile_idc = = 144 ) {
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,                                                 UseDefaultScalingMatrix4x4Flag[ i ])	0
else
scaling_list( ScalingList8x8[ i – 6 ], 64,                                                 UseDefaultScalingMatrix8x8Flag[ i – 6 ] )	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
}

 

 

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 slice_layer_without_partitioning_rbsp( )	2, 3, 4
2	Coded slice data partition A slice_data_partition_a_layer_rbsp( )	2
3	Coded slice data partition B slice_data_partition_b_layer_rbsp( )	3
4	Coded slice data partition C slice_data_partition_c_layer_rbsp( )	4
5	Coded slice of an IDR picture slice_layer_without_partitioning_rbsp( )	2, 3
6	Supplemental enhancement information (SEI) sei_rbsp( )	5
7	Sequence parameter set seq_parameter_set_rbsp( )	0
8	Picture parameter set pic_parameter_set_rbsp( )	1
9	Access unit delimiter access_unit_delimiter_rbsp( )	6
10	End of sequence end_of_seq_rbsp( )	7
11	End of stream end_of_stream_rbsp( )	8
12	Filler data filler_data_rbsp( )	9
13	Sequence parameter set extension seq_parameter_set_extension_rbsp( )	10
14..18	Reserved
19	Coded slice of an auxiliary coded picture without partitioning slice_layer_without_partitioning_rbsp( )	2, 3, 4
20..23	Reserved
24..31	Unspecified

 

 

 

 

byte_stream_nal_unit( NumBytesInNALunit ) {	C	Descriptor
while( next_bits( 24 ) != 0x000001 &&                   next_bits( 32 ) != 0x00000001 )
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( ) &&                   next_bits( 24 ) != 0x000001 &&                   next_bits( 32 ) != 0x00000001 )
trailing_zero_8bits /* equal to 0x00 */		f(8)
}

 

 

 

 

 

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_map_type = = 4 | |                         slice_group_map_type = = 5 ) {
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,                                                 UseDefaultScalingMatrix4x4Flag[ i ] )	1
else
scaling_list( ScalingList8x8[ i – 6 ], 64,                                                 UseDefaultScalingMatrix8x8Flag[ i – 6 ] )	1
}
second_chroma_qp_index_offset	1	se(v)
}
rbsp_trailing_bits( )	1
}

 

 

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 ) ) | |          ( weighted_bipred_idc = = 1 && slice_type = = B ) )
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_map_type >= 3 && slice_group_map_type <= 5)
slice_group_change_cycle	2	u(v)
}

 

 

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
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)

 

 

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 | |               MbPartPredMode( mb_type, 0 ) = = Intra_16x16 ) {
mb_qp_delta	2	se(v) | ae(v)
residual( )	3 | 4
}
}
}