FFmpeg视音频分离器----向雷神学习

雷神博客地址：https://blog.csdn.net/leixiaohua1020/article/details/39767055

本程序可以将封装格式中的视频码流数据和音频码流数据分离出来。
在该例子中，将FLV的文件分离得到H.264视频码流文件和MP3
音频码流文件。
注意：
这个是简化版的视音频分离器。与原版的不同在于，没有初始化输出视频流和音频流的AVFormatContext。而是直接将解码后的得到的AVPacket中的的数据通过fwrite()写入文件。这样做的好处是流程比较简单。坏处是对一些格式的视音频码流是不适用的，比如说FLV/MP4/MKV等格式中的AAC码流（上述封装格式中的AAC的AVPacket中的数据缺失了7字节的ADTS文件头）。

视频源码：

/*** 最简单的基于FFmpeg的视音频分离器（简化版）* Simplest FFmpeg Demuxer Simple** 雷霄骅 Lei Xiaohua* leixiaohua1020@126.com* 中国传媒大学/数字电视技术* Communication University of China / Digital TV Technology* http://blog.csdn.net/leixiaohua1020** 本程序可以将封装格式中的视频码流数据和音频码流数据分离出来。* 在该例子中， 将FLV的文件分离得到H.264视频码流文件和MP3* 音频码流文件。** 注意：* 这个是简化版的视音频分离器。与原版的不同在于，没有初始化输出* 视频流和音频流的AVFormatContext。而是直接将解码后的得到的* AVPacket中的的数据通过fwrite()写入文件。这样做的好处是流程比* 较简单。坏处是对一些格式的视音频码流是不适用的，比如说* FLV/MP4/MKV等格式中的AAC码流（上述封装格式中的AAC的AVPacket中* 的数据缺失了7字节的ADTS文件头）。* ** This software split a media file (in Container such as * MKV, FLV, AVI...) to video and audio bitstream.* In this example, it demux a FLV file to H.264 bitstream* and MP3 bitstream.* Note:* This is a simple version of "Simplest FFmpeg Demuxer". It is * more simple because it doesn't init Output Video/Audio stream's* AVFormatContext. It write AVPacket's data to files directly.* The advantages of this method is simple. The disadvantages of* this method is it's not suitable for some kind of bitstreams. For* example, AAC bitstream in FLV/MP4/MKV Container Format(data in* AVPacket lack of 7 bytes of ADTS header).**/#include <stdio.h>#define __STDC_CONSTANT_MACROS#ifdef _WIN32
//Windows
extern "C"
{
#include "libavformat/avformat.h"
};
#else
//Linux...
#ifdef __cplusplus
extern "C"
{
#endif
#include <libavformat/avformat.h>
#ifdef __cplusplus
};
#endif
#endif//'1': Use H.264 Bitstream Filter 
#define USE_H264BSF 1int main(int argc, char* argv[])
{AVFormatContext *ifmt_ctx = NULL;AVPacket pkt;int ret, i;int videoindex=-1,audioindex=-1;const char *in_filename  = "cuc_ieschool.flv";//Input file URLconst char *out_filename_v = "cuc_ieschool.h264";//Output file URLconst char *out_filename_a = "cuc_ieschool.mp3";av_register_all();//Inputif ((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, 0)) < 0) {printf( "Could not open input file.");return -1;}if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0) {printf( "Failed to retrieve input stream information");return -1;}videoindex=-1;for(i=0; i<ifmt_ctx->nb_streams; i++) {if(ifmt_ctx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO){videoindex=i;}else if(ifmt_ctx->streams[i]->codec->codec_type==AVMEDIA_TYPE_AUDIO){audioindex=i;}}//Dump Format------------------printf("\nInput Video===========================\n");av_dump_format(ifmt_ctx, 0, in_filename, 0);printf("\n======================================\n");FILE *fp_audio=fopen(out_filename_a,"wb+");  FILE *fp_video=fopen(out_filename_v,"wb+");  /*FIX: H.264 in some container format (FLV, MP4, MKV etc.) need "h264_mp4toannexb" bitstream filter (BSF)*Add SPS,PPS in front of IDR frame*Add start code ("0,0,0,1") in front of NALUH.264 in some container (MPEG2TS) don't need this BSF.*/
#if USE_H264BSFAVBitStreamFilterContext* h264bsfc =  av_bitstream_filter_init("h264_mp4toannexb"); 
#endifwhile(av_read_frame(ifmt_ctx, &pkt)>=0){if(pkt.stream_index==videoindex){
#if USE_H264BSFav_bitstream_filter_filter(h264bsfc, ifmt_ctx->streams[videoindex]->codec, NULL, &pkt.data, &pkt.size, pkt.data, pkt.size, 0);
#endifprintf("Write Video Packet. size:%d\tpts:%lld\n",pkt.size,pkt.pts);fwrite(pkt.data,1,pkt.size,fp_video);}else if(pkt.stream_index==audioindex){/*AAC in some container format (FLV, MP4, MKV etc.) need to add 7 BytesADTS Header in front of AVPacket data manually.Other Audio Codec (MP3...) works well.*/printf("Write Audio Packet. size:%d\tpts:%lld\n",pkt.size,pkt.pts);fwrite(pkt.data,1,pkt.size,fp_audio);}av_free_packet(&pkt);}#if USE_H264BSFav_bitstream_filter_close(h264bsfc);  
#endiffclose(fp_video);fclose(fp_audio);avformat_close_input(&ifmt_ctx);if (ret < 0 && ret != AVERROR_EOF) {printf( "Error occurred.\n");return -1;}return 0;
}