关于从海康威视或者大华摄像头获取PS数据流中的H264视频数据
PS流数据原理网上基本能够搜索到，这里我也就没必要粘贴复制，解析PS数据包主要分 00 00 00 ba 这是ps头，然后是系统头00 00 00 bb ，然后是Program Stream map包 00 00 00 bc 然后是H264数据00 00 00 e0 。
下面我附上代码，网上有类似的代码，但是有点问题，直接用的话会在视频下半部分出现花屏显现。这里所附C++代码形成两个文件可直接编译使用。
MediaPsAnaly.h：
MediaPsAnaly.h：
#ifndef MEDIAPSANALY_H
#define MEDIAPSANALY_H
#pragma pack(1)
union littel_endian_size {
unsigned short int length;
unsigned char byte[2];
};
struct pack_start_code {
unsigned char start_code[3];
unsigned char stream_id[1];
};
struct program_stream_pack_header { //14字节
pack_start_code PackStart;// 4
unsigned char Buf[9];
unsigned char stuffinglen;
};
struct program_stream_system_head { //可能有系统头，pack_start_code为00 00 01 BB
pack_start_code PackStart;
littel_endian_size PackLength;
};
struct program_stream_map {
pack_start_code PackStart;
littel_endian_size PackLength;
};
struct program_stream_e {
pack_start_code PackStart; //4字节
littel_endian_size PackLength;//we mast do exchange 2字节
char PackInfo1[2]; //2字节
unsigned char stuffing_length; //1字节
};
#pragma pack()
class MediaPsAnaly {
private:
MediaPsAnaly();
~MediaPsAnaly();
public:
/* 获取MediaManage对象唯一实例 */
static MediaPsAnaly* getInstance();
/* 获取h264数据 */
int GetH246FromPs(unsigned char* buffer,int length, unsigned char *h264Buffer, int *h264length);
private:
/* 解析ps头 */
int inline ProgramStreamPackHeader(unsigned char* Pack, int length, unsigned char **NextPack, int *leftlength);
/* 去掉系统头 */
inline int ProgramStreamSystemHead(unsigned char* Pack,int length,unsigned char **NextPack,int *leftlength);
/* 去掉programstreammap */
inline int ProgramStreamMap(unsigned char* Pack, int length, unsigned char **NextPack, int *leftlength, unsigned char **PayloadData, int *PayloadDataLen);
/* 解pes包 */
inline int Pes(unsigned char* Pack, int length, unsigned char **NextPack, int *leftlength, unsigned char **PayloadData, int *PayloadDataLen);
private:
static MediaPsAnaly* p;
};
#endif //MEDIAPSANALY_HMediaPsAnaly.cpp：
#include "MediaPsAnaly.h"
#include
#include
#include
using namespace std;
#if 1
/*构造函数*/
MediaPsAnaly::MediaPsAnaly()
{
}
/* 析构函数 */
MediaPsAnaly::~MediaPsAnaly()
{
}
/* 对象实例指针 */
MediaPsAnaly* MediaPsAnaly::p = NULL;
/* 获取MediaPsAnaly对象唯一实例 */
MediaPsAnaly* MediaPsAnaly::getInstance() {
if( p == NULL) {
p = new MediaPsAnaly();
}
return p;
}
/* 解析ps头 */
int inline MediaPsAnaly::ProgramStreamPackHeader(unsigned char* Pack, int length, unsigned char **NextPack, int *leftlength)
{
program_stream_pack_header *PsHead = (program_stream_pack_header *)Pack;
unsigned char pack_stuffing_length = PsHead->stuffinglen & '\x07';
*leftlength = length - sizeof(program_stream_pack_header) - pack_stuffing_length;//剩余字节：length减去头和填充的字节
*NextPack = Pack+sizeof(program_stream_pack_header) + pack_stuffing_length;
if(*leftlength<4) return 0; //无后续头部和数据
return *leftlength;
}
/* 去掉系统头 */
inline int MediaPsAnaly::ProgramStreamSystemHead(unsigned char* Pack,int length,unsigned char **NextPack,int *leftlength)
{
program_stream_system_head *PssHead = (program_stream_system_head*)Pack;
littel_endian_size pssh_length;
pssh_length.byte[0] = PssHead->PackLength.byte[1];
pssh_length.byte[1] = PssHead->PackLength.byte[0];
*leftlength = length - pssh_length.length - sizeof(program_stream_system_head);
*NextPack = Pack + sizeof(program_stream_system_head) + pssh_length.length;
if(*leftlength<4) return 0;
return *leftlength;
}
/* 去掉programstreammap */
inline int MediaPsAnaly::ProgramStreamMap(unsigned char* Pack, int length, unsigned char **NextPack, int *leftlength, unsigned char **PayloadData, int *PayloadDataLen) {
program_stream_map* PSMPack = (program_stream_map*)Pack;
*PayloadData = 0;
*PayloadDataLen = 0;
if(length < sizeof(program_stream_map)) return 0;
littel_endian_size psm_length;
psm_length.byte[0] = PSMPack->PackLength.byte[1];
psm_length.byte[1] = PSMPack->PackLength.byte[0];
*leftlength = length - psm_length.length - sizeof(program_stream_map);
if(*leftlength<=0) return 0;
*NextPack = Pack + psm_length.length + sizeof(program_stream_map);
return *leftlength;
}
/* 解pes包 */
inline int MediaPsAnaly::Pes(unsigned char* Pack, int length, unsigned char **NextPack, int *leftlength, unsigned char **PayloadData, int *PayloadDataLen) {
program_stream_e* PSEPack = (program_stream_e*)Pack;
*PayloadData = 0;
*PayloadDataLen = 0;
if(length < sizeof(program_stream_e)) return 0;
littel_endian_size pse_length;
pse_length.byte[0] = PSEPack->PackLength.byte[1];
pse_length.byte[1] = PSEPack->PackLength.byte[0];
pse_length.byte[4] = PSEPack->stuffing_length;
*PayloadDataLen = pse_length.length - 2 - 1 - pse_length.byte[4];
if(*PayloadDataLen>0) {
*PayloadData = Pack + sizeof(program_stream_e) + pse_length.byte[4];
}
*leftlength = length - pse_length.length - sizeof(pack_start_code) - sizeof(littel_endian_size);
if(*leftlength<=0) return 0;
*NextPack = Pack + sizeof(pack_start_code) + sizeof(littel_endian_size) + pse_length.length;
return *leftlength;
}
/* 获取h264数据 */
int MediaPsAnaly::GetH246FromPs(unsigned char* buffer,int length, unsigned char *h264Buffer, int *h264length) {
int leftlength = 0;
unsigned char *NextPack = 0;
*h264length = 0;
if(ProgramStreamPackHeader(buffer, length, &NextPack, &leftlength)==0) {//跳过PS头
return 0;
}
unsigned char *PayloadData=NULL;
int PayloadDataLen=0;
if(NextPack && NextPack[0]==0 && NextPack[1]==0 && NextPack[2]==1 && NextPack[3]==0xbb) {//有系统头的话，跳过它
if(ProgramStreamSystemHead(NextPack, leftlength, &NextPack, &leftlength)==0)
return 0;
}
if(NextPack && NextPack[0]==0 && NextPack[1]==0 && NextPack[2]==1 && NextPack[3]==0xbc ) {//Program Stream map，直接跳过该包
if(ProgramStreamMap(NextPack, leftlength, &NextPack, &leftlength, &PayloadData, &PayloadDataLen)==0)
return 0;
}
//printf("[%s] %x %x %x %x\n", __FUNCTION__, NextPack[0], NextPack[1], NextPack[2], NextPack[3]);
while(leftlength >= sizeof(pack_start_code)) //处理pes包：目前所知的pes包的类型有Program Stream map和H264
{
PayloadData=NULL;
PayloadDataLen=0;
if(NextPack && NextPack[0]==00 && NextPack[1]==00 && NextPack[2]==01 && NextPack[3]==0xE0) { //H264，需要提取出pes包的有效载荷，即H264码流
//接着就是流包，说明是非i帧；若中间隔着Program Stream map，则是i帧； 提取H264流时，不需要区分i帧与非i帧
if(Pes(NextPack, leftlength, &NextPack, &leftlength, &PayloadData, &PayloadDataLen)) {
if(PayloadDataLen) {
memcpy(h264Buffer, PayloadData, PayloadDataLen);
h264Buffer += PayloadDataLen;
*h264length += PayloadDataLen;
}
}
else {//说明是最后一个pes包
if(PayloadDataLen) {
memcpy(h264Buffer, PayloadData, PayloadDataLen);
h264Buffer += PayloadDataLen;
*h264length += PayloadDataLen;
}
break;
}
}
#if 1
else if(NextPack && NextPack[0]==00 && NextPack[1]==00 && NextPack[2]==01 && NextPack[3]==0xBC) {//Program Stream map，直接跳过该包
if(ProgramStreamMap(NextPack, leftlength, &NextPack, &leftlength, &PayloadData, &PayloadDataLen)==0) {
break;
}
}
#endif
else {
//printf("[%s]no konw %02x %02x %02x %02x %02x %02x %02x %02x\n", __FUNCTION__, NextPack[0], NextPack[1], NextPack[2], NextPack[3],NextPack[4], NextPack[5], NextPack[6], NextPack[7]);
break;
}
}
return *h264length;
}
#endif