分离ts媒体文件中每个pid的数据

ts的包大小：188字节
ts包的开始字节:0x47
TS包头定义：
（包头定义转载自：http://blog.csdn.net/shuyong1999/article/details/7095032）

typedef struct TS_packet_header{    unsigned sync_byte                        : 8; //同步字节, 固定为0x47,表示后面的是一个TS分组    unsigned transport_error_indicator        : 1; //传输误码指示符    unsigned payload_unit_start_indicator    : 1; //有效荷载单元起始指示符    unsigned transport_priority              : 1; //传输优先, 1表示高优先级,传输机制可能用到，解码用不着    unsigned PID                            : 13; //PID    unsigned transport_scrambling_control    : 2; //传输加扰控制     unsigned adaption_field_control            : 2; //自适应控制 01仅含有效负载，10仅含调整字段，11含有调整字段和有效负载。为00解码器不进行处理    unsigned continuity_counter                : 4; //连续计数器 一个4bit的计数器，范围0-15} TS_packet_header;

因为要分离出ts文件中每个pid的数据，所以，最重要的当然是先获取pid的值：

int pid = ((buf[1] & 0x1f) << 8) + buf[2];

其它就是逻辑问题了，详细代码如下：

#include <stdio.h>#include <stdlib.h>#include <string.h>#include <stdint.h>#include <iostream>#include <sys/types.h>#include <sys/stat.h>#include <unistd.h>#include <map>using namespace std;#define TS_SIZE 188bool dir_exists (const string &dir){     struct stat statx = {0};     int ret = stat (dir.c_str(), &statx);     if (ret == 0) {         if (S_ISDIR (statx.st_mode))             return true;     }     return false;}string i2str(int i){    char buffer[20];    sprintf (buffer, "%d", i);    return buffer;}int main(int argc, char **argv){    if (argc != 3) {        cout << argv[0] << " ts_file save_dir" << endl;        return 0;    }    const string ts_file = argv[1];    const string save_dir = argv[2];    if (!dir_exists (save_dir)) {        mkdir (save_dir.c_str (), 0777);    }    FILE *stream = NULL; //to fopen input ts file    FILE *save_file_fp = NULL;// to fopen save ts file    unsigned char buf[TS_SIZE];    int len;    string pid_file = save_dir + "/pid.file"; //init ts save file    if ((stream = fopen (ts_file.c_str (), "rb"))== NULL) {        fclose (stream);        cout << "ts file open error" << endl;        return -1;    }    while (!feof (stream)) {        len = fread (buf, sizeof (unsigned char), TS_SIZE, stream);        cout << "read len:" << len << endl;        if (buf[0] != 0x47) {            cout << "Sync byte of TS isn't 0x47!, skip it." << endl;            //long curpos = ftell (stream);            fseek (stream, (1 - TS_SIZE), SEEK_CUR);            continue;        }        int pid = ((buf[1] & 0x1f) << 8) + buf[2];        cout << "pid: " << pid << endl;        pid_file = save_dir + "/" + i2str(pid) + ".file";        save_file_fp = fopen (pid_file.c_str (), "ab");        len = fwrite (buf, sizeof (unsigned char), TS_SIZE, save_file_fp);        cout << "write len:" << len << endl;        fclose (save_file_fp);    }    fclose (stream);    return 0;}