如何使用ffmpeg直接将H264原始流写入mp4 [英] How to write H264 raw stream into mp4 using ffmpeg directly

问题描述

我想使用ffmpeg（SDK 2.1）将H264 Nalus（x264编码）包装到mp4中，但输出mp4文件无法播放。我不知道如何设置pts和dts。以下是我的代码，使用使用libavcodec的mpegts容器中的原始H264框架的代码和muxing.c从www.ffmpeg.org。我的H264流没有B帧，每个nalu从00 00 00 01开始，流以sps pps然后h264数据开始。

I want to wrap the H264 Nalus(x264 encoded) into mp4 using ffmpeg(SDK 2.1), but the output mp4 file could not play. I don't know how to set the pts and dts. Here's my code, using the code from Raw H264 frames in mpegts container using libavcodec and muxing.c from www.ffmpeg.org. My H264 stream has no B-Frame, every nalu starts with 00 00 00 01,the stream begins with sps pps then the h264 data.

#include "stdafx.h"
#include <stdlib.h>
#include <stdio.h>
#include "Stream2Mp4.h"

#include <libavutil/opt.h>
#include <libavutil/mathematics.h>
#include <libavutil/timestamp.h>
#include <libavformat/avformat.h>
#include <libswresample/swresample.h>
#include <libswresample/swresample.h>

#define STREAM_FRAME_RATE 25
#define STREAM_PIX_FMT    AV_PIX_FMT_YUV420P /* default pix_fmt */

static int ptsInc = 0;
static int vi = -1;
static int waitkey = 1;

// < 0 = error
// 0 = I-Frame
// 1 = P-Frame
// 2 = B-Frame
// 3 = S-Frame
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;
}

int get_nal_type( void *p, int len )
{
if ( !p || 5 >= 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;

return *b;
}


/* 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:
    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:
    c->codec_id = codec_id;
    c->bit_rate = 90000;
    c->width = 480;
    c->height = 354;
    c->time_base.den = 15;
    c->time_base.num = 1;
    c->gop_size = 12;
    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(AVFormatContext *&m_pOc, void *p, int len)
{
int ret; 
const char* pszFileName = "output002.mp4";
AVOutputFormat *fmt;
AVCodec *video_codec;
AVStream *m_pVideoSt;

if (0x67 != get_nal_type(p, len))
{
    printf("can not detect nal type");
    return -1;
}
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)
{
    m_pVideoSt = add_stream(m_pOc, &video_codec, fmt->video_codec);
}

if (m_pVideoSt)
{
    open_video(m_pOc, video_codec, m_pVideoSt); 
}

av_dump_format(m_pOc, 0, pszFileName, 1);

/* 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': %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*/


void WriteVideo(AVFormatContext *&m_pOc,void* data, int nLen)
{
int ret;

if ( 0 > vi )
{
    printf("vi less than 0");
    //return -1;
}
AVStream *pst = m_pOc->streams[ vi ];

// Init packet
AVPacket pkt;

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.dts = (ptsInc++) * (90000/STREAM_FRAME_RATE);

ret = av_interleaved_write_frame( m_pOc, &pkt );
if (ret < 0)
{
    printf("cannot write frame");
}


}

void CloseMp4(AVFormatContext *&m_pOc)
{
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;
}

}

有人可以帮助我吗？非常感谢！

could anybody help me? Thank you very much!

推荐答案

你可以试试这个。

if(pkt.pts != AV_NOPTS_VALUE)
{
    pkt.pts = av_rescale_q_rnd(ptsInc++, c->time_base, pst->time_base, 
        (AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));
}

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