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分析一段H264视频数据

Posted on 2007-05-31 09:42 vcommon 阅读(12841) 评论(11)  编辑 收藏 引用
 

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Annex B

00 00 00 01 67 42 00 1E 99 A0 B1 31 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_bit1 0

nal_ref_idc2)= 11

nal_unit_type5 0 0111seq_parameter_set_rbsp( )

所以 processSPS

profile_idc(8):420100 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 subclause 9.1

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_framesue):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_flag1:0

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_bit1 0

nal_ref_idc2)= 11

nal_unit_type5 01000pic_parameter_set_rbsp( ),7.3.2.2

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_minus1ue: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

650110 0101

forbidden_zero_bit1 0

nal_ref_idc2)= 11

nal_unit_type5 0 0101slice_layer_without_partitioning_rbsp( ),IDR

Slice

Slice_Header:

first_mb_in_slice(ue):0

slice_type(ue):000 1000 = 7

pic_parameter_set_id(ue) = 0

80 21000 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

ref_pic_list_reordering( ) 7331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_flag1):0

long_term_reference_flag1):0

忽略

。。71 27

001 0111 0001 0010 0111

slice_qp_deltasev):001 01 4-2

忽略

 

slice_data( ):7.3.4

I-Slice:忽略N

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_typeuev):0

mb_pred( mb_type )

prev_intra4x4_pred_mode_flag[ luma4x4BlkIdx ] 1bit, babacae(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

1b 88 00 3e cf.

intra_chroma_pred_modeue(v) : 最后的一个1bit:0

 

接下来是macroblock_layercoded_block_patternrun level,既系数

c0 06 ad a0 18

1100 0000 0000 0110 1010 0000 0001 1000

coded_block_patternme(v):0,根据Table 94= 470x2f

mb_qp_delta(se(v):):0 len =1

residual( )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 = 15i= 12j=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

 

 

 

Table 91 – 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 | |
          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 ) {

 

 

         delta_pic_order_always_zero_flag

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 71 – 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)

}

 

 

 

 

 

 

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_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

 

}

 

 

 

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 ) ) | |
         ( 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)

}

 

 

 

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 | |
              MbPartPredMode( mb_type, 0 ) = = Intra_16x16 ) {

 

 

              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 | | 
         MbPartPredMode( mb_type, 0 ) = = Intra_8x8 | | 
         MbPartPredMode( mb_type, 0 ) = = Intra_16x16 ) {

 

 

         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 | |
                       mb_field_decoding_flag ) && 
             
     MbPartPredMode( mb_type, mbPartIdx ) != Pred_L1 )

 

 

                  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 | |
                       mb_field_decoding_flag ) && 
                  MbPartPredMode( mb_type, mbPartIdx ) != Pred_L0 )

 

 

                  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 ] =
                                                     LumaLevel[ i8x8 * 4 + i4x4 ][ i ]

 

 

              }

 

 

         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 )
                                                             /* chroma AC residual present */

 

 

                           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 ) && 
                   TrailingOnes( coeff_token ) < 3 )

 

 

                  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 < 6 )

 

 

                  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 ]

 

 

       }

 

 

    }

 

 

}

 

 

 

 

Feedback

# re: 分析一段H264视频数据[未登录]  回复  更多评论   

2007-08-17 10:15 by WANG
谢谢你了 很感谢

# re: 分析一段H264视频数据  回复  更多评论   

2007-10-12 15:22 by Beno
刚开始接触,了解的不多,请问:为什么某些地方要忽略,并且忽略的位数是如何知道的?希望能介绍的详细点

# re: 分析一段H264视频数据[未登录]  回复  更多评论   

2007-10-12 17:36 by vcommon
忽略是一般是根据Slice data syntax等详细的语法来的,忽略的位数参考语法,文法,都在标准里边,很多很多的表.

# re: 分析一段H264视频数据  回复  更多评论   

2007-10-24 14:33 by lala
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 subclause 9.1

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



这里是怎么分析的呢,对于ue(v)文档好像说是从当前位开始读,直到第一个非0位停止。可是我分析来,不是很明白,楼主帮忙解一下,谢谢

# re: 分析一段H264视频数据  回复  更多评论   

2007-11-18 16:55 by liyali
读过你的分析。很好。有个问题:
PES包长最长64K,打包成很多TS.TS包长固定为188字节.计数器最大16个。16*184<64k.那么接收端如何才能正确恢复pes包?

# re: 分析一段H264视频数据[未登录]  回复  更多评论   

2007-11-19 15:13 by vcommon
TS包的计数器是循环的,只是表明连续的TS包不是重复或者错误的,对于重建pes包是根据PES的Packet头来实现,和TS层没有关系.

# re: 分析一段H264视频数据  回复  更多评论   

2007-11-27 11:57 by liyali
@vcommon
谢谢你的TS包的计数器解答。

# re: 分析一段H264视频数据  回复  更多评论   

2008-04-09 16:00 by dxy
@lala
楼主的value指的应该就是codeNum吧

log2_max_frame_num_minus4(ue(v): 001 1001,len = 5,value= 5

参照9.1节,先计算一下leadingZeroBits = 2,此时一共读了3个bit;当前指针指向1001
001 ^1001
|
pos
然后再读2bit(结果值为2), codeNum = 2^leadingZeroBits -1+ 2 = 5


不知我说的对否?

# re: 分析一段H264视频数据  回复  更多评论   

2009-08-07 13:40 by TS,MPEG2,dvbc专家
对于一个,1920 * 1080的stream,分析参数为下:
pic_width_in_mbs_minus1 = 119 (1920)
pic_height_in_map_units_minus1 = 33 (544)

(119 + 1) * 16 = 1920,这个很好理解,但是
(33 + 1) * 120= 4080, 这与1080差别很大的呀。不理解。

# re: 分析一段H264视频数据  回复  更多评论   

2009-08-12 10:31 by TS,MPEG2,dvbc专家
发现一个奇怪的事情:
如果h264的 profile是 main,那么在vui parameters里面,
num_units_in_tick:1200 time_scale:60000, nFrame_rate = sps->time_scale / sps->num_units_in_tick ; 50 fps --- ok.
但是,如果profile 是high,那么值是这样:
num_units_in_tick:48 time_scale:16777216 ,Frame_rate:349525 fps
奇怪的,我的code到底那里错误了,
第二,若说我的code错误了,那sps里面包含,vui parameters,以前的任何值都没有错误呀,偏偏这两个值错误了,

若果换一个high的h264文件,那值是这样的,
num_units_in_tick:384 time_scale:16777217 fixed_frame_rate_flag:1 Frame_rate:43690 ,
用其它的分析工具看,num_units_in_tick = 1, time_scale = 50,50 fps,
我到底怎么排除这个错误呢。

# re: 分析一段H264视频数据  回复  更多评论   

2009-08-14 10:58 by vcommon
不好意思,换工作了,最近对codec没有在研究,回答不了你的问题.谢谢你关注我的博客.
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