阐述H264裸流与TS流之间的关系(一)

H264(ES)如何打包成H264(PES)

一直在网上搜集各种资料，心累啊！下面由九把锁为你们阐述TS和H264之间不为人知的关系，还真是比较复杂。

一、总的大致关系图

这个我也不知道是在哪个CSDN高手那弄来的图，帮了我很大的忙，上图时间到：

二、如何由ES数据封装成PES数据

1、如何提取一帧ES数据, 就是这么简单，So Easy...

#include "stdafx.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

typedef struct
{
int startcodeprefix_len;      //! 4 for parameter sets and first slice in picture, 3 for everything else (suggested)
unsigned len;                 //! Length of the NAL unit (Excluding the start code, which does not belong to the NALU)
unsigned max_size;            //! Nal Unit Buffer size

int forbidden_bit;            //! should be always FALSE
int nal_reference_idc;        //! NALU_PRIORITY_xxxx
int nal_unit_type;            //! NALU_TYPE_xxxx

char *buf;                    //! contains the first byte followed by the EBSP
unsigned short lost_packets;  //! true, if packet loss is detected
} NALU_t;

FILE *bits = NULL;                //!< the bit stream file
static int FindStartCode2 (unsigned char *Buf);//查找开始字符0x000001
static int FindStartCode3 (unsigned char *Buf);//查找开始字符0x00000001
//static bool flag = true;
static int info2=0, info3=0;

NALU_t *AllocNALU(int buffersize)
{
NALU_t *n;

if ((n = (NALU_t*)calloc (1, sizeof (NALU_t))) == NULL)
{
printf("AllocNALU: n");
exit(0);
}

n->max_size=buffersize;

if ((n->buf = (char*)calloc (buffersize, sizeof (char))) == NULL)
{
free (n);
printf ("AllocNALU: n->buf");
exit(0);
}

return n;
}

void FreeNALU(NALU_t *n)
{
if (n)
{
if (n->buf)
{
free(n->buf);
n->buf=NULL;
}
free (n);
}
}

void OpenBitstreamFile (char *fn)
{
if (NULL == (bits=fopen(fn, "rb")))
{
printf("open file error\n");
exit(0);
}
}

int GetAnnexbNALU (NALU_t *nalu)
{
int pos = 0;
int StartCodeFound, rewind;
unsigned char *Buf;

if ((Buf = (unsigned char*)calloc (nalu->max_size , sizeof(char))) == NULL)
printf ("GetAnnexbNALU: Could not allocate Buf memory\n");

nalu->startcodeprefix_len=3;//初始化码流序列的开始字符为3个字节

if (3 != fread (Buf, 1, 3, bits))//从码流中读3个字节
{
free(Buf);
return 0;
}
info2 = FindStartCode2 (Buf);//判断是否为0x000001
if(info2 != 1) {//如果不是，再读一个字节
if(1 != fread(Buf+3, 1, 1, bits))//读一个字节
{
free(Buf);
return 0;
}
info3 = FindStartCode3 (Buf);//判断是否为0x00000001
if (info3 != 1)//如果不是，返回-1
{
free(Buf);
return -1;
}
else {//如果是0x00000001,得到开始字符为4个字节
pos = 4;
nalu->startcodeprefix_len = 4;
}
}

else{//如果是0x000001,得到开始字符为3个字节
nalu->startcodeprefix_len = 3;
pos = 3;
}

StartCodeFound = 0;//查找下一个开始字符的标志位
info2 = 0;
info3 = 0;

while (!StartCodeFound)
{
if (feof (bits))//判断是否到了文件尾
{
nalu->len = (pos-1)-nalu->startcodeprefix_len;
memcpy (nalu->buf, &Buf[nalu->startcodeprefix_len], nalu->len);
nalu->forbidden_bit = (nalu->buf[0]>>7) & 1;
nalu->nal_reference_idc = (nalu->buf[0]>>5) & 3;
nalu->nal_unit_type = (nalu->buf[0]) & 0x1f;
free(Buf);
return pos-1;
}
Buf[pos++] = fgetc (bits);//读一个字节到BUF中
info3 = FindStartCode3(&Buf[pos-4]);//判断是否为0x00000001
if(info3 != 1)
info2 = FindStartCode2(&Buf[pos-3]);//判断是否为0x000001
StartCodeFound = (info2 == 1 || info3 == 1);
}
//flag = false;

// Here, we have found another start code (and read length of startcode bytes more than we should
// have.  Hence, go back in the file
rewind = (info3 == 1)? -4 : -3;

if (0 != fseek (bits, rewind, SEEK_CUR))//把文件指针向后退开始字节的字节数
{
free(Buf);
printf("GetAnnexbNALU: Cannot fseek in the bit stream file");
}

// Here the Start code, the complete NALU, and the next start code is in the Buf.
// The size of Buf is pos, pos+rewind are the number of bytes excluding the next
// start code, and (pos+rewind)-startcodeprefix_len is the size of the NALU

nalu->len = (pos+rewind)-nalu->startcodeprefix_len;
memcpy (nalu->buf, &Buf[nalu->startcodeprefix_len], nalu->len);

nalu->forbidden_bit = nalu->buf[0] & 0x80; //(nalu->buf[0]>>7) & 1;
nalu->nal_reference_idc = nalu->buf[0] & 0x60; //(nalu->buf[0]>>5) & 3;
nalu->nal_unit_type = (nalu->buf[0]) & 0x1f;
/*write by qiuliangbin in 2015-7-18 where is rongle changsha*/
if (nalu->nal_unit_type == 7)//7 序列参数集 8个字节
{
printf("\t NALU->RBSP->SPS->profile_idc(8):%d\n",nalu->buf[1]);
printf("\t constraint_set0_flag(1):%d\n",(nalu->buf[2]>>7) & 1);
printf("\t constraint_set1_flag(1):%d\n",(nalu->buf[2]>>6) & 1);
printf("\t constraint_set2_flag(1):%d\n",(nalu->buf[2]>>5) & 1);
printf("\t constraint_set3_flag(1):%d\n",(nalu->buf[2]>>4) & 1);
printf("\t reserved_zero_4bits(4):%d\n",(nalu->buf[2]>>0) & 0x0f);
printf("\t level_idc(8):%d\n",nalu->buf[3]);
printf("\t seq_parameter_set_id(UE(V)):uvlC(1):%d\n",(nalu->buf[4]>>7) & 1);//表示往后的数据忽略掉最高位
//	根据profile_idc忽略掉一部分。
printf("\t log2_max_frame_num_minus4(ue(v):len=5,value=%d\n",(nalu->buf[4]>>5) & 0x1f);
printf("\t pic_order_cnt_type(ue(v)):len=3,value=%d\n",((nalu->buf[4]) & 0x03)<<1);
//	根据pic_order_cnt_type忽略几个参数
printf("\t num_ref_frames（ue）:len=3,value=%d\n",(nalu->buf[5]>>4) & 0x07);
printf("\t gaps_in_frame_num_value_allowed_flag(1):value=%d\n",(nalu->buf[5]>>3) & 1);
printf("\t pic_width_in_mbs_minus1-ue-:len=7 ,value=%d\n", (((nalu->buf[5])&0x07)<<4)| (((nalu->buf[6])>>4)&0x0e) );
printf("\t pic_height_in_map_units_minus1-ue-:len=7 ,value=%d\n",(((nalu->buf[6])&0x0f)<<3) |((((nalu->buf[7])>>5))&0x06) );
printf("\t frame_mbs_only_flag(1):%d\n",(nalu->buf[7]>>4) & 1);
//忽略1
printf("\t flag(4):%d\n",(nalu->buf[7]) & 0x0f);
}
if (nalu->nal_unit_type == 8)//8 图像参数集  4个字节
{
/*  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
*/
}
if (nalu->nal_unit_type == 5) //5  IDR帧
{
}

free(Buf);

return (pos+rewind);//返回两个开始字符之间间隔的字节数
}
void dump(NALU_t *n)
{
if (!n)return;
//printf("a new nal:");
printf(" len: %d  ", n->len);
printf("nal_unit_type: %x\n", n->nal_unit_type);
}
int main(int argc, char* argv[])
{
OpenBitstreamFile("./my.h264");
NALU_t *n;
n = AllocNALU(8000000);
while(!feof(bits)) {
GetAnnexbNALU(n);
dump(n);
}
FreeNALU(n);
return 0;
}
static int FindStartCode2 (unsigned char *Buf)
{
if(Buf[0]!=0 || Buf[1]!=0 || Buf[2] !=1) return 0; //判断是否为0x000001,如果是返回1
else return 1;
}

static int FindStartCode3 (unsigned char *Buf)
{
if(Buf[0]!=0 || Buf[1]!=0 || Buf[2] !=0 || Buf[3] !=1) return 0;//判断是否为0x00000001,如果是返回1
else return 1;
}

这是一个纯c语言的例子，应该是很好理解的，不谢！接下来会有更猛的料，尽请期待，觉得不错可以关注下......