ffmpeg封装H246为MP4

前言

文章主要对H264视频流封装为MP4格式文件的讲述，有实时H264视频流的封装和h264文件的封装，本文主要针对飞思卡尔I.MX6Q-vpu视频编码后的视频封装，所以没涉及到音频，

一、h264视频文件的封装

这部分代码主要是从雷博那里借鉴过来的，雷博的文章是音频和视频封装，我这里只实现视频的封装，雷博的文章网站：http://blog.csdn.net/leixiaohua1020/article/details/39802913/，具体实现方法差不多，就是少了音频这一路，代码如下：

#include <stdio.h>#define __STDC_CONSTANT_MACROS#include <libavformat/avformat.h>/*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 AVFormatContextAVFormatContext *ifmt_ctx_v = NULL, *ifmt_ctx_a = NULL,*ofmt_ctx = NULL;AVPacket pkt;int ret, i;int videoindex_v=0,videoindex_out=0;int frame_index=0;int64_t cur_pts_v=0,cur_pts_a=0;//const char *in_filename_v = "cuc_ieschool.ts";//Input file URLconst char *in_filename_v = "vpu.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 = "vpu.mp4";//Output file URLav_register_all();//Inputif ((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");//Outputavformat_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;printf("ifmt_ctx_v->nb_streams=%d\n",ifmt_ctx_v->nb_streams);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 AVCodecContextif (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 AVStreamif(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 AVCodecContextif (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 fileif (!(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 headerif (avformat_write_header(ofmt_ctx, NULL) < 0) {printf( "Error occurred when opening output file\n");goto end;}//FIX#if USE_H264BSFAVBitStreamFilterContext* h264bsfc =  av_bitstream_filter_init("h264_mp4toannexb"); #endif#if USE_AACBSFAVBitStreamFilterContext* aacbsfc =  av_bitstream_filter_init("aac_adtstoasc"); #endifwhile (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];printf("stream_index==%d,pkt.stream_index==%d,videoindex_v=%d\n", stream_index,pkt.stream_index,videoindex_v);if(pkt.stream_index==videoindex_v){//FIX：No PTS (Example: Raw H.264)//Simple Write PTSif(pkt.pts==AV_NOPTS_VALUE){printf("frame_index==%d\n",frame_index);//Write PTSAVRational 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);//Parameterspkt.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 PTSif(pkt.pts==AV_NOPTS_VALUE){//Write PTSAVRational 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);//Parameterspkt.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_H264BSFav_bitstream_filter_filter(h264bsfc, in_stream->codec, NULL, &pkt.data, &pkt.size, pkt.data, pkt.size, 0);#endif#if USE_AACBSFav_bitstream_filter_filter(aacbsfc, out_stream->codec, NULL, &pkt.data, &pkt.size, pkt.data, pkt.size, 0);#endif//Convert PTS/DTSpkt.pts = av_rescale_q_rnd(pkt.pts, in_stream->time_base, out_stream->time_base, (AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));pkt.dts = av_rescale_q_rnd(pkt.dts, in_stream->time_base, out_stream->time_base, (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);//Writeif (av_interleaved_write_frame(ofmt_ctx, &pkt) < 0) {printf( "Error muxing packet\n");break;}av_free_packet(&pkt);}//Write file trailerav_write_trailer(ofmt_ctx);#if USE_H264BSFav_bitstream_filter_close(h264bsfc);#endif#if USE_AACBSFav_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;}

二、h264视频实时流的封装

    大体思路和上面文件操作是差不多的，区别在于不能像上面一样可以获取文件中视频流的信息，这样你就得自己去设置这些参数，下面程序是根据我自己的视频流设置的，如果你的不同，需要修改;具体参数如下：

（1）AVCodecContext 的配置参数

enum AVMediaType codec_type：编解码器的类型（视频，音频...）

struct AVCodec  *codec：采用的解码器AVCodec（H.264,MPEG2...）

int bit_rate：平均比特率

uint8_t *extradata; int extradata_size：针对特定编码器包含的附加信息（例如对于H.264解码器来说，存储SPS，PPS等）

AVRational time_base：根据该参数，可以把PTS转化为实际的时间（单位为秒s）

int width, height：如果是视频的话，代表宽和高

int refs：运动估计参考帧的个数（H.264的话会有多帧，MPEG2这类的一般就没有了）

int sample_rate：采样率（音频）

int channels：声道数（音频）

enum AVSampleFormat sample_fmt：采样格式

int profile：型（H.264里面就有，其他编码标准应该也有）

int level：级（和profile差不太多）

（2）还有一个结构体参数也需要去设置，在AVPacket结构体中，重要的变量有以下几个：

uint8_t *data：压缩编码的数据。

例如对于H.264来说。1个AVPacket的data通常对应一个NAL。

注意：在这里只是对应，而不是一模一样。他们之间有微小的差别：使用FFMPEG类库分离出多媒体文件中的H.264码流

因此在使用FFMPEG进行视音频处理的时候，常常可以将得到的AVPacket的data数据直接写成文件，从而得到视音频的码流文件。

int   size：data的大小

int64_t pts：显示时间戳

int64_t dts：解码时间戳

int   stream_index：标识该AVPacket所属的视频/音频流。

总体代码如下：

#include"ffmpeg_mp4.h"int getVopType( const void *p, int len ){    if ( !p || 6 >= len )        return -1;    unsigned char *b = (unsigned char*)p;    // Verify NAL marker    if ( b[ 0 ] || b[ 1 ] || 0x01 != b[ 2 ] )    {   b++;if ( b[ 0 ] || b[ 1 ] || 0x01 != b[ 2 ] )return -1;    } // end if    b += 3;    // Verify VOP id    if ( 0xb6 == *b )    {   b++;return ( *b & 0xc0 ) >> 6;    } // end if    switch( *b )    {  case 0x65 : return 0;case 0x61 : return 1;case 0x01 : return 2;    } // end switch    return -1;}/* Add an output stream */AVStream *add_stream(AVFormatContext *oc, AVCodec **codec, enum AVCodecID codec_id){    AVCodecContext *c;    AVStream *st;    /* find the encoder */    *codec = avcodec_find_encoder(codec_id);    if (!*codec)    {        printf("could not find encoder for '%s' \n", avcodec_get_name(codec_id));        exit(1);    }    st = avformat_new_stream(oc, *codec);    if (!st)    {        printf("could not allocate stream \n");        exit(1);    }    st->id = oc->nb_streams-1;    c = st->codec;    vi = st->index;    switch ((*codec)->type)    {    case AVMEDIA_TYPE_AUDIO:        printf("AVMEDIA_TYPE_AUDIO\n");        c->sample_fmt = (*codec)->sample_fmts ? (*codec)->sample_fmts[0] : AV_SAMPLE_FMT_FLTP;        c->bit_rate = 64000;        c->sample_rate = 44100;        c->channels = 2;        break;    case AVMEDIA_TYPE_VIDEO:        printf("AVMEDIA_TYPE_VIDEO\n");        c->codec_id = AV_CODEC_ID_H264;        c->bit_rate = 0;        c->width = 1920;        c->height = 1080;        c->time_base.den = 50;        c->time_base.num = 1;        c->gop_size = 1;        c->pix_fmt = STREAM_PIX_FMT;        if (c->codec_id == AV_CODEC_ID_MPEG2VIDEO)        {            c->max_b_frames = 2;        }        if (c->codec_id == AV_CODEC_ID_MPEG1VIDEO)        {            c->mb_decision = 2;        }        break;    default:        break;    }    if (oc->oformat->flags & AVFMT_GLOBALHEADER)    {        c->flags |= CODEC_FLAG_GLOBAL_HEADER;    }    return st;}void open_video(AVFormatContext *oc, AVCodec *codec, AVStream *st){    int ret;    AVCodecContext *c = st->codec;    /* open the codec */    ret = avcodec_open2(c, codec, NULL);    if (ret < 0)    {        printf("could not open video codec");       //exit(1);    }}int CreateMp4(){    int ret; // 成功返回0，失败返回1    const char* pszFileName = "/udisk/vpu.mp4";    AVOutputFormat *fmt;    AVCodec *video_codec;    AVStream *m_pVideoSt;    av_register_all();    avformat_alloc_output_context2(&m_pOc, NULL, NULL, pszFileName);    if (!m_pOc)    {        printf("Could not deduce output format from file extension: using MPEG. \n");        avformat_alloc_output_context2(&m_pOc, NULL, "mpeg", pszFileName);    }    if (!m_pOc)    {        return 1;    }    fmt = m_pOc->oformat;    if (fmt->video_codec != AV_CODEC_ID_NONE)    {        printf("1111111111111111add_stream\n");        m_pVideoSt = add_stream(m_pOc, &video_codec, fmt->video_codec);    }    if (m_pVideoSt)    {        printf("1111111111111111open_video\n");        open_video(m_pOc, video_codec, m_pVideoSt);    }    printf("==========Output Information==========\n");    av_dump_format(m_pOc, 0, pszFileName, 1);    printf("======================================\n");    /* open the output file, if needed */    if (!(fmt->flags & AVFMT_NOFILE))    {        ret = avio_open(&m_pOc->pb, pszFileName, AVIO_FLAG_WRITE);        if (ret < 0)        {            printf("could not open %s\n", pszFileName);            return 1;        }    }    /* Write the stream header, if any */    ret = avformat_write_header(m_pOc, NULL);    if (ret < 0)    {        printf("Error occurred when opening output file");        return 1;    }}/* write h264 data to mp4 file * 创建mp4文件返回2；写入数据帧返回0 */void WriteVideo(void* data, int nLen){    int ret;    if ( 0 > vi )    {       printf("vi less than 0");        //return -1;    }    AVStream *pst = m_pOc->streams[ vi ];    //printf("vi=====%d\n",vi);    // Init packet    AVPacket pkt;    // 我的添加，为了计算pts    AVCodecContext *c = pst->codec;    av_init_packet( &pkt );    pkt.flags |= ( 0 >= getVopType( data, nLen ) ) ? AV_PKT_FLAG_KEY : 0;    pkt.stream_index = pst->index;    pkt.data = (uint8_t*)data;    pkt.size = nLen;    // Wait for key frame    if ( waitkey )        if ( 0 == ( pkt.flags & AV_PKT_FLAG_KEY ) )            return ;        else            waitkey = 0;    pkt.pts = (ptsInc++) * (90000/STREAM_FRAME_RATE);    pkt.pts = av_rescale_q((ptsInc++)*2, pst->codec->time_base,pst->time_base);    //pkt.dts = (ptsInc++) * (90000/STREAM_FRAME_RATE);  //  pkt.pts=av_rescale_q_rnd(pkt.pts, pst->time_base,pst->time_base,(AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));    pkt.dts=av_rescale_q_rnd(pkt.dts, pst->time_base,pst->time_base,(AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));    pkt.duration = av_rescale_q(pkt.duration,pst->time_base, pst->time_base);    pkt.pos = -1;    printf("pkt.size=%d\n",pkt.size);    ret = av_interleaved_write_frame( m_pOc, &pkt );    if (ret < 0)    {        printf("cannot write frame");    }}void CloseMp4(){    waitkey = -1;    vi = -1;    if (m_pOc)        av_write_trailer(m_pOc);    if (m_pOc && !(m_pOc->oformat->flags & AVFMT_NOFILE))        avio_close(m_pOc->pb);    if (m_pOc)    {        avformat_free_context(m_pOc);        m_pOc = NULL;    }}