首先得跳过 9字节的ＦＬＶ文件头，然后在分析tag头 （11 字节）确定是否为视频 tag. 09:视频 08：音频
00 00 2D: tag data size：（并不全是h264裸流，还有些一下其他信息）
蓝色部分即为 tag data 区：
第一个字节分析 ： 17 --视频格式信息
c=fgetc(myopen); video_type=(c&0xf0); video_type =video_type>>4; switch(video_type){ case 1:strcat(str,"key frame ");break; case 2:strcat(str,"inter frame");break; case 3:strcat(str,"disposable inter frame");break; case 4:strcat(str,"generated keyframe");break; case 5:strcat(str,"video info/command frame");break; default:strcat(str,"UNKNOWN");break; } video_type=(c&0x0f); strcat(str,"| "); switch (video_type) { case 1:strcat(str,"JPEG (currently unused)");break; case 2:strcat(str,"Sorenson H.263");break; case 3:strcat(str,"Screen video");break; case 4:strcat(str,"On2 VP6");break; case 5:strcat(str,"On2 VP6 with alpha channel");break; case 6:strcat(str,"Screen video version 2");break; case 7:strcat(str,"AVC");break; default:strcat(str,"UNKNOWN");break; }提取 h264代码： void H264JIEXI(int datelength)//关键 { int info = 0; Read8(info, flvfile); // 17 int avctype = 0; Read8(avctype, flvfile); //第一个视频关键帧 tag ：00 FSEEK(3, flvfile); // 跳过之后 3字节 int templength = 0; char*tempbuff = NULL; if (avctype == 0) // 提取 sps pps { FSEEK(6, flvfile); // 后移6 Read16(templength, flvfile); // 读取 sps 长度 --2字节 printf("sssize:%d\n", templength); tempbuff = (char*)malloc(templength); fread(tempbuff, 1, templength, flvfile); //读sps fwrite(&h264space, 1, 4, h264file); //nal 头 00 00 00 01 fwrite(tempbuff, 1, templength, h264file); free(tempbuff); Read8(templength, flvfile);//ppsnum // 读pps 个数 Read16(templength, flvfile);//ppssize // 读pps 长度 ----2字节 printf("ppsize:%d\n", templength); tempbuff = (char*)malloc(templength); fread(tempbuff, 1, templength, flvfile); fwrite(&h264space, 1, 4, h264file); fwrite(tempbuff, 1, templength, h264file); free(tempbuff); } else { // Read32(templength,flvfile); // tempbuff=(char*)malloc(templength); // fread(tempbuff,1,templength,flvfile); // fwrite(&h264space,1,4,h264file); // fwrite(tempbuff,1,templength,h264file); // free(tempbuff); //可能存在多个nal，需全部读取 int countsize = 2 + 3; static int gg = 0; while (countsize < datelength) { Read32(templength, flvfile); // 四个字节长度 tempbuff = (char*)malloc(templength); printf("templength =%d\n", templength); fread(tempbuff, 1, templength, flvfile); fwrite(&h264space, 1, 4, h264file); fwrite(tempbuff, 1, templength, h264file); free(tempbuff); countsize += (templength + 4); } } }