目錄(?)[-]
- 分析00 00 00 01 67 42 00 1E 99 A0 B1 31 00 00 00 01
- 分析00 00 00 01 68 CE 38 80 00 00 00 01
?
分析00 00 00 01 67 42 00 1E 99 A0 B1 31 00 00 00 01
H264的數據流分為兩種，一種是NAL UNIT stream(RTP),一種是 bits stream,
兩者可以互相轉換。我們分析的這個是 bit stream,根據Annex B
00 00 00 01 67 42 00 1E 99 A0 B1 31 是 一個NAL，在兩個00 00 00 01之間
0110 0111?0100 0010 0000 0000 0001 1110 1001 1001 1010 0000 1011 0001 0011 0001
forbidden_zero_bit（1）?＝ 0
nal_ref_idc（2）＝ 11
nal_unit_type（5）?＝ 0 0111：seq_parameter_set_rbsp( )
所以 processSPS
0110 0111?0100 0010?0000 0000 0001 1110 1001 1001 1010 0000 1011 0001 0011 0001
profile_idc(8):42：0100 0010
0110 0111 0100 0010?0000 0000?0001 1110 1001 1001 1010 0000 1011 0001 0011 0001
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
0110 0111 0100 0010 0000 0000?0001 1110 1001 1001 1010?0000 1011 0001 0011 0001
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：根據Table9.1 ， value= 0,只占1bit.
根據profile_idc忽略掉一部分。
log2_max_frame_num_minus4(ue(v): 001 10,len = 5,value= 5
pic_order_cnt_type(ue(v)):01 1,len = 3,value = 2
根據pic_order_cnt_type忽略幾個參數
num_ref_frames（ue）：010,len = 3,value = 1
0110 0111 0100 0010 0000 0000 0001 1110 1001 1001 1010?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結束
分析00 00 00 01 68 CE 38 80 00 00 00 01
0110 1000(68)
forbidden_zero_bit（1）?＝ 0
nal_ref_idc（2）＝ 11
nal_unit_type（5）?＝01000：pic_parameter_set_rbsp( ),7.3.2.2
1100?(C)
pic_parameter_set_id (ue)=0
seq_parameter_set_id(ue)=0
entropy_coding_mode_flag(1) :0,?重要的flag,0?表示編碼Exp-Golomb coded and CAVLC,1表示CABAC
pic_order_present_flag(1):0
1110?(E)
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?(38 80)
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結束
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湞
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( ) 見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
對I-Slice:忽略N多
進入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,?對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個
1b 88 00 3e cf.?
intra_chroma_pred_mode（ue(v)）?:?最后的一個1bit:0
接下來是macroblock_layer的coded_block_pattern和run level,既系數
c0 06 ad a0 18
1100 0000 0000 0110 1010 0000 0001 1000
coded_block_pattern（me(v):0,根據，= 47，0x2f
mb_qp_delta(se(v):0 len =1
residual( )見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?相關的)：
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},
},
根據表查的：
code = 13,len = 15，i= 12，j=2
所以numcoeff = 12,numtrailingones = 2
010 0000 0001 1000: totalzeros:根據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開始
{ 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開始
{0,1,1,1},
{0,1,1},
{0,1},
};
?
