最简单的基于FFmpeg的封装格式处理 视音频复用器 muxer

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最简单的基于FFmpeg的封装格式处理系列文章列表：

最简单的基于FFmpeg的封装格式处理：视音频分离器简化版（demuxer-simple）

最简单的基于FFmpeg的封装格式处理：视音频分离器（demuxer）

最简单的基于FFmpeg的封装格式处理：视音频复用器（muxer）

最简单的基于FFMPEG的封装格式处理：封装格式转换（remuxer）

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简介

打算记录一下基于FFmpeg的封装格式处理方面的例子。包括了视音频分离，复用，封装格式转换。这是第3篇。

本文记录一个基于FFmpeg的视音频复用器（Simplest FFmpeg muxer）。视音频复用器（Muxer）即是将视频压缩数据（例如H.264）和音频压缩数据（例如AAC）合并到一个封装格式数据（例如MKV）中去。如图所示。在这个过程中并不涉及到编码和解码。

流程

avformat_open_input()：打开输入文件。
avcodec_copy_context()：赋值AVCodecContext的参数。
avformat_alloc_output_context2()：初始化输出文件。
avio_open()：打开输出文件。
avformat_write_header()：写入文件头。
av_compare_ts()：比较时间戳，决定写入视频还是写入音频。这个函数相对要少见一些。
av_read_frame()：从输入文件读取一个AVPacket。
av_interleaved_write_frame()：写入一个AVPacket到输出文件。
av_write_trailer()：写入文件尾。

代码

下面贴上代码：

/** * 最简单的基于FFmpeg的视音频复用器 * Simplest FFmpeg Muxer * * 雷霄骅 Lei Xiaohua * [email protected] * 中国传媒大学/数字电视技术 * Communication University of China / Digital TV Technology * http://blog.csdn.net/leixiaohua1020 * * 本程序可以将视频码流和音频码流打包到一种封装格式中。 * 程序中将AAC编码的音频码流和H.264编码的视频码流打包成 * MPEG2TS封装格式的文件。 * 需要注意的是本程序并不改变视音频的编码格式。 * * This software mux a video bitstream and a audio bitstream  * together into a file. * In this example, it mux a H.264 bitstream (in MPEG2TS) and  * a AAC bitstream file together into MP4 format file. * */#include <stdio.h>#define __STDC_CONSTANT_MACROS#ifdef _WIN32//Windowsextern "C"{#include "libavformat/avformat.h"};#else//Linux...#ifdef __cplusplusextern "C"{#endif#include <libavformat/avformat.h>#ifdef __cplusplus};#endif#endif/*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.*///'1': Use H.264 Bitstream Filter #define USE_H264BSF 0/*FIX:AAC in some container format (FLV, MP4, MKV etc.) need "aac_adtstoasc" bitstream filter (BSF)*///'1': Use AAC Bitstream Filter #define USE_AACBSF 0int main(int argc, char* argv[]){ AVOutputFormat *ofmt = NULL; //Input AVFormatContext and Output AVFormatContext AVFormatContext *ifmt_ctx_v = NULL, *ifmt_ctx_a = NULL,*ofmt_ctx = NULL; AVPacket pkt; int ret, i; int videoindex_v=-1,videoindex_out=-1; int audioindex_a=-1,audioindex_out=-1; int frame_index=0; int64_t cur_pts_v=0,cur_pts_a=0; //const char *in_filename_v = "cuc_ieschool.ts";//Input file URL const char *in_filename_v = "cuc_ieschool.h264"; //const char *in_filename_a = "cuc_ieschool.mp3"; //const char *in_filename_a = "gowest.m4a"; //const char *in_filename_a = "gowest.aac"; const char *in_filename_a = "huoyuanjia.mp3"; const char *out_filename = "cuc_ieschool.mp4";//Output file URL av_register_all(); //Input if ((ret = avformat_open_input(&ifmt_ctx_v, in_filename_v, 0, 0)) < 0) {  printf( "Could not open input file.");  goto end; } if ((ret = avformat_find_stream_info(ifmt_ctx_v, 0)) < 0) {  printf( "Failed to retrieve input stream information");  goto end; } if ((ret = avformat_open_input(&ifmt_ctx_a, in_filename_a, 0, 0)) < 0) {  printf( "Could not open input file.");  goto end; } if ((ret = avformat_find_stream_info(ifmt_ctx_a, 0)) < 0) {  printf( "Failed to retrieve input stream information");  goto end; } printf("===========Input Information==========\n"); av_dump_format(ifmt_ctx_v, 0, in_filename_v, 0); av_dump_format(ifmt_ctx_a, 0, in_filename_a, 0); printf("======================================\n"); //Output avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, out_filename); if (!ofmt_ctx) {  printf( "Could not create output context\n");  ret = AVERROR_UNKNOWN;  goto end; } ofmt = ofmt_ctx->oformat; for (i = 0; i < ifmt_ctx_v->nb_streams; i++) {  //Create output AVStream according to input AVStream  if(ifmt_ctx_v->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO){  AVStream *in_stream = ifmt_ctx_v->streams[i];  AVStream *out_stream = avformat_new_stream(ofmt_ctx, in_stream->codec->codec);  videoindex_v=i;  if (!out_stream) {   printf( "Failed allocating output stream\n");   ret = AVERROR_UNKNOWN;   goto end;  }  videoindex_out=out_stream->index;  //Copy the settings of AVCodecContext  if (avcodec_copy_context(out_stream->codec, in_stream->codec) < 0) {   printf( "Failed to copy context from input to output stream codec context\n");   goto end;  }  out_stream->codec->codec_tag = 0;  if (ofmt_ctx->oformat->flags & AVFMT_GLOBALHEADER)   out_stream->codec->flags |= CODEC_FLAG_GLOBAL_HEADER;  break;  } } for (i = 0; i < ifmt_ctx_a->nb_streams; i++) {  //Create output AVStream according to input AVStream  if(ifmt_ctx_a->streams[i]->codec->codec_type==AVMEDIA_TYPE_AUDIO){   AVStream *in_stream = ifmt_ctx_a->streams[i];   AVStream *out_stream = avformat_new_stream(ofmt_ctx, in_stream->codec->codec);   audioindex_a=i;   if (!out_stream) {    printf( "Failed allocating output stream\n");    ret = AVERROR_UNKNOWN;    goto end;   }   audioindex_out=out_stream->index;   //Copy the settings of AVCodecContext   if (avcodec_copy_context(out_stream->codec, in_stream->codec) < 0) {    printf( "Failed to copy context from input to output stream codec context\n");    goto end;   }   out_stream->codec->codec_tag = 0;   if (ofmt_ctx->oformat->flags & AVFMT_GLOBALHEADER)    out_stream->codec->flags |= CODEC_FLAG_GLOBAL_HEADER;   break;  } } printf("==========Output Information==========\n"); av_dump_format(ofmt_ctx, 0, out_filename, 1); printf("======================================\n"); //Open output file if (!(ofmt->flags & AVFMT_NOFILE)) {  if (avio_open(&ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE) < 0) {   printf( "Could not open output file '%s'", out_filename);   goto end;  } } //Write file header if (avformat_write_header(ofmt_ctx, NULL) < 0) {  printf( "Error occurred when opening output file\n");  goto end; } //FIX#if USE_H264BSF AVBitStreamFilterContext* h264bsfc =  av_bitstream_filter_init("h264_mp4toannexb"); #endif#if USE_AACBSF AVBitStreamFilterContext* aacbsfc =  av_bitstream_filter_init("aac_adtstoasc"); #endif while (1) {  AVFormatContext *ifmt_ctx;  int stream_index=0;  AVStream *in_stream, *out_stream;  //Get an AVPacket  if(av_compare_ts(cur_pts_v,ifmt_ctx_v->streams[videoindex_v]->time_base,cur_pts_a,ifmt_ctx_a->streams[audioindex_a]->time_base) <= 0){   ifmt_ctx=ifmt_ctx_v;   stream_index=videoindex_out;   if(av_read_frame(ifmt_ctx, &pkt) >= 0){    do{     in_stream  = ifmt_ctx->streams[pkt.stream_index];     out_stream = ofmt_ctx->streams[stream_index];     if(pkt.stream_index==videoindex_v){      //FIX：No PTS (Example: Raw H.264)      //Simple Write PTS      if(pkt.pts==AV_NOPTS_VALUE){       //Write PTS       AVRational time_base1=in_stream->time_base;       //Duration between 2 frames (us)       int64_t calc_duration=(double)AV_TIME_BASE/av_q2d(in_stream->r_frame_rate);       //Parameters       pkt.pts=(double)(frame_index*calc_duration)/(double)(av_q2d(time_base1)*AV_TIME_BASE);       pkt.dts=pkt.pts;       pkt.duration=(double)calc_duration/(double)(av_q2d(time_base1)*AV_TIME_BASE);       frame_index++;      }      cur_pts_v=pkt.pts;      break;     }    }while(av_read_frame(ifmt_ctx, &pkt) >= 0);   }else{    break;   }  }else{   ifmt_ctx=ifmt_ctx_a;   stream_index=audioindex_out;   if(av_read_frame(ifmt_ctx, &pkt) >= 0){    do{     in_stream  = ifmt_ctx->streams[pkt.stream_index];     out_stream = ofmt_ctx->streams[stream_index];     if(pkt.stream_index==audioindex_a){      //FIX：No PTS      //Simple Write PTS      if(pkt.pts==AV_NOPTS_VALUE){       //Write PTS       AVRational time_base1=in_stream->time_base;       //Duration between 2 frames (us)       int64_t calc_duration=(double)AV_TIME_BASE/av_q2d(in_stream->r_frame_rate);       //Parameters       pkt.pts=(double)(frame_index*calc_duration)/(double)(av_q2d(time_base1)*AV_TIME_BASE);       pkt.dts=pkt.pts;       pkt.duration=(double)calc_duration/(double)(av_q2d(time_base1)*AV_TIME_BASE);       frame_index++;      }      cur_pts_a=pkt.pts;      break;     }    }while(av_read_frame(ifmt_ctx, &pkt) >= 0);   }else{    break;   }  }  //FIX:Bitstream Filter#if USE_H264BSF  av_bitstream_filter_filter(h264bsfc, in_stream->codec, NULL, &pkt.data, &pkt.size, pkt.data, pkt.size, 0);#endif#if USE_AACBSF  av_bitstream_filter_filter(aacbsfc, out_stream->codec, NULL, &pkt.data, &pkt.size, pkt.data, pkt.size, 0);#endif  //Convert PTS/DTS  pkt.pts = av_rescale_q_rnd(pkt.pts, in_stream->time_base, out_stream->time_base, (AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));  pkt.dts = av_rescale_q_rnd(pkt.dts, in_stream->time_base, out_stream->time_base, (AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));  pkt.duration = av_rescale_q(pkt.duration, in_stream->time_base, out_stream->time_base);  pkt.pos = -1;  pkt.stream_index=stream_index;  printf("Write 1 Packet. size:%5d\tpts:%lld\n",pkt.size,pkt.pts);  //Write  if (av_interleaved_write_frame(ofmt_ctx, &pkt) < 0) {   printf( "Error muxing packet\n");   break;  }  av_free_packet(&pkt); } //Write file trailer av_write_trailer(ofmt_ctx);#if USE_H264BSF av_bitstream_filter_close(h264bsfc);#endif#if USE_AACBSF av_bitstream_filter_close(aacbsfc);#endifend: avformat_close_input(&ifmt_ctx_v); avformat_close_input(&ifmt_ctx_a); /* close output */ if (ofmt_ctx && !(ofmt->flags & AVFMT_NOFILE))  avio_close(ofmt_ctx->pb); avformat_free_context(ofmt_ctx); if (ret < 0 && ret != AVERROR_EOF) {  printf( "Error occurred.\n");  return -1; } return 0;}

结果

音频：huoyuanjia.mp3

下载

simplest ffmpeg format

项目主页

SourceForge：https://sourceforge.net/projects/simplestffmpegformat/

Github：https://github.com/leixiaohua1020/simplest_ffmpeg_format

开源中国：http://git.oschina.net/leixiaohua1020/simplest_ffmpeg_format

http://download.csdn.net/detail/leixiaohua1020/8005317

工程中包含4个例子：

simplest_ffmpeg_demuxer_simple：视音频分离器（简化版）。

simplest_ffmpeg_demuxer：视音频分离器。

simplest_ffmpeg_muxer：视音频复用器。

simplest_ffmpeg_remuxer：封装格式转换器。

//FIX：No PTS//Simple Write PTSif(pkt.pts==AV_NOPTS_VALUE){ //Write PTS AVRational time_base1=in_stream->time_base; //Duration between 2 frames (us) int64_t calc_duration=(double)AV_TIME_BASE/av_q2d(in_stream->r_frame_rate); //Parameters pkt.pts=(double)(frame_index*calc_duration)/(double)(av_q2d(time_base1)*AV_TIME_BASE); pkt.dts=pkt.pts; pkt.duration=(double)calc_duration/(double)(av_q2d(time_base1)*AV_TIME_BASE); frame_index++;}

VC++：打开sln文件即可编译，无需配置。

cl.exe：打开compile_cl.bat即可命令行下使用cl.exe进行编译，注意可能需要按照VC的安装路径调整脚本里面的参数。编译命令如下。

::VS2010 Environmentcall "D:\Program Files\Microsoft Visual Studio 10.0\VC\vcvarsall.bat"::[email protected] INCLUDE=include;%INCLUDE%::[email protected] LIB=lib;%LIB%::compile and linkcl simplest_ffmpeg_muxer.cpp /link avcodec.lib avformat.lib avutil.lib ^avdevice.lib avfilter.lib postproc.lib swresample.lib swscale.lib /OPT:NOREF

MinGW：MinGW命令行下运行compile_mingw.sh即可使用MinGW的g++进行编译。编译命令如下。

g++ simplest_ffmpeg_muxer.cpp -g -o simplest_ffmpeg_muxer.exe \-I /usr/local/include -L /usr/local/lib -lavformat -lavcodec -lavutil

GCC：Linux或者MacOS命令行下运行compile_gcc.sh即可使用GCC进行编译。编译命令如下。

gcc simplest_ffmpeg_muxer.cpp -g -o simplest_ffmpeg_muxer.out -I /usr/local/include -L /usr/local/lib \-lavformat -lavcodec -lavutil