ffmpeg视频分割，视频合成

ffmpeg实现视频切割：
http://blog.csdn.net/dancing_night/article/details/45720255

1、概述

本程序实现把一个视频切割为2个视频，不涉及编解码，最难理解的地方在于pts和dts的计算，要好好看看，不够完美的地方在于没有按照关键帧切割，所以会在切割点花屏，以后改善。

*注：只处理一个视频流和一个音频流，若流多了，估计会crash。

简单说下流程：

打开输入---->打开输出---->根据输入来创建流---->拷贝流设置---->循环读帧---->判断时间点是否到达切割点，并做设置---->设置pts和dts---->写入---->善后

2、代码

[cpp] view
plain copy

/*

*最简单的视频切割

*缪国凯 Mickel

*821486004@qq.com

*本程序实现把一个视频切割为2个视频，不涉及编解码，最难理解的地方在于pts和dts的计算，要好好看看

*不够完美的地方在于没有按照关键帧切割，所以会在切割点花屏，以后改善

*注：只处理一个视频流和一个音频流，若流多了，估计会crash

*2015-5-14

*/

#include "stdafx.h"

#ifdef __cplusplus

extern"C"

{

#endif

#include <libavformat/avformat.h>

#include "libavcodec/avcodec.h"

#include "libavfilter/avfiltergraph.h"

#include "libavfilter/buffersink.h"

#include "libavfilter/buffersrc.h"

#include "libavutil/avutil.h"

#include "libavutil/opt.h"

#include "libavutil/pixdesc.h"

#include "libswresample\swresample.h"

#include "libavutil\fifo.h"

#include "libavutil/audio_fifo.h"

#pragma comment(lib, "avcodec.lib")

#pragma comment(lib, "avformat.lib")

#pragma comment(lib, "avutil.lib")

//#pragma comment(lib, "avdevice.lib")

#pragma comment(lib, "avfilter.lib")

//#pragma comment(lib, "postproc.lib")

#pragma comment(lib, "swresample.lib")

//#pragma comment(lib, "swscale.lib")

#ifdef __cplusplus

};

#endif

int _tmain(int argc, _TCHAR* argv[])

{

if(argc < 3)

{

printf("no input file!\n");

return -1;

}

AVFormatContext *ifmt_ctx = NULL, *ofmt1_ctx = NULL, *ofmt2_ctx = NULL;

AVStream *out1_vstream = NULL, *out1_astream = NULL;

AVStream *out2_vstream = NULL, *out2_astream = NULL;

char str_out1_filename[10];

char str_out2_filename[10];

sprintf(str_out1_filename, "test1.%s", argv[2]);

sprintf(str_out2_filename, "test2.%s", argv[2]);

int inVideo_StreamIndex = -1,inAudio_StreamIndex = -1;

int ret;

av_register_all();

if ((ret = avformat_open_input(&ifmt_ctx, argv[1], NULL, NULL)) < 0)

{

printf("can not open the in put file format context!\n");

return -1;

}

if ((ret = avformat_find_stream_info(ifmt_ctx, NULL)) < 0)

{

printf("can not find the input stream info!\n");

goto end;

}

avformat_alloc_output_context2(&ofmt1_ctx, NULL, NULL, str_out1_filename);

if (!ofmt1_ctx)

{

printf( "Could not create output1 context\n");

ret = AVERROR_UNKNOWN;

goto end;

}

avformat_alloc_output_context2(&ofmt2_ctx, NULL, NULL, str_out2_filename);

if (!ofmt2_ctx)

{

printf( "Could not create output2 context\n");

ret = AVERROR_UNKNOWN;

goto end;

}

for (int i = 0; i < ifmt_ctx->nb_streams; i++)

{

if (ifmt_ctx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO)

{

inVideo_StreamIndex = i;

out1_vstream = avformat_new_stream(ofmt1_ctx, NULL);

out2_vstream = avformat_new_stream(ofmt2_ctx, NULL);

//open decoder

if(0 > avcodec_open2(ifmt_ctx->streams[i]->codec, avcodec_find_decoder(ifmt_ctx->streams[i]->codec->codec_id), NULL))

{

printf("can not find or open video decoder!\n");

goto end;

}

if (!out1_vstream)

{

printf("Failed allocating output1 video stream\n");

ret = AVERROR_UNKNOWN;

goto end;

}

else

{

//copy the settings of AVCodecContext;

if (avcodec_copy_context(out1_vstream->codec, ifmt_ctx->streams[i]->codec) < 0)

{

printf( "Failed to copy context from input to output stream codec context\n");

goto end;

}

out1_vstream->codec->codec_tag = 0;

if(ofmt1_ctx->oformat->flags & AVFMT_GLOBALHEADER)

{

out1_vstream->codec->flags |= CODEC_FLAG_GLOBAL_HEADER;

}

}

if (!out2_vstream)

{

printf("Failed allocating output1 video stream\n");

ret = AVERROR_UNKNOWN;

goto end;

}

else

{

//copy the settings of AVCodecContext;

if (avcodec_copy_context(out2_vstream->codec, ifmt_ctx->streams[i]->codec) < 0)

{

printf( "Failed to copy context from input to output stream codec context\n");

goto end;

}

out2_vstream->codec->codec_tag = 0;

if(ofmt2_ctx->oformat->flags & AVFMT_GLOBALHEADER)

{

out2_vstream->codec->flags |= CODEC_FLAG_GLOBAL_HEADER;

}

}

}

else if (ifmt_ctx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO)

{

inAudio_StreamIndex = i;

out1_astream = avformat_new_stream(ofmt1_ctx, NULL);

out2_astream = avformat_new_stream(ofmt2_ctx, NULL);

if (!out1_astream)

{

printf("Failed allocating output1 video stream\n");

ret = AVERROR_UNKNOWN;

goto end;

}

else

{

//copy the settings of AVCodecContext;

if (avcodec_copy_context(out1_astream->codec, ifmt_ctx->streams[i]->codec) < 0)

{

printf( "Failed to copy context from input to output stream codec context\n");

goto end;

}

out1_astream->codec->codec_tag = 0;

if(ofmt1_ctx->oformat->flags & AVFMT_GLOBALHEADER)

{

out1_astream->codec->flags |= CODEC_FLAG_GLOBAL_HEADER;

}

}

if (!out2_astream)

{

printf("Failed allocating output1 video stream\n");

ret = AVERROR_UNKNOWN;

goto end;

}

else

{

//copy the settings of AVCodecContext;

if (avcodec_copy_context(out2_astream->codec, ifmt_ctx->streams[i]->codec) < 0)

{

printf( "Failed to copy context from input to output stream codec context\n");

goto end;

}

out2_astream->codec->codec_tag = 0;

if(ofmt2_ctx->oformat->flags & AVFMT_GLOBALHEADER)

{

out2_astream->codec->flags |= CODEC_FLAG_GLOBAL_HEADER;

}

}

}

}

//Dump Format------------------

printf("\n==============Input Video=============\n");

av_dump_format(ifmt_ctx, 0, argv[1], 0);

printf("\n==============Output1============\n");

av_dump_format(ofmt1_ctx, 0, str_out1_filename, 1);

printf("\n==============Output2============\n");

av_dump_format(ofmt2_ctx, 0, str_out1_filename, 1);

printf("\n======================================\n");

//open output1 file

if (!(ofmt1_ctx->oformat->flags & AVFMT_NOFILE))

{

if (avio_open(&ofmt1_ctx->pb, str_out1_filename, AVIO_FLAG_WRITE) < 0)

{

printf( "Could not open output file '%s'", str_out1_filename);

goto end;

}

}

//open output2 file

if (!(ofmt2_ctx->oformat->flags & AVFMT_NOFILE))

{

if (avio_open(&ofmt2_ctx->pb, str_out2_filename, AVIO_FLAG_WRITE) < 0)

{

printf( "Could not open output file '%s'", str_out2_filename);

goto end;

}

}

//write out 1 file header

if (avformat_write_header(ofmt1_ctx, NULL) < 0)

{

printf( "Error occurred when opening video output file\n");

goto end;

}

//write out 2 file header

if (avformat_write_header(ofmt2_ctx, NULL) < 0)

{

printf( "Error occurred when opening video output file\n");

goto end;

}

int splitPtsV = 0;//the real split video pts

int splitDtsV = 0;

int splitPtsA = 0;//the real split audio pts

int splitDtsA = 0;

int videoIndex = 0;//the real video index

int splitTime = 30;//the split time (sec)

AVPacket pkt;

while(1)

{

AVFormatContext *ofmt_ctx;

AVStream *in_stream, *out_stream;

if (av_read_frame(ifmt_ctx, &pkt) < 0)

{

break;

}

in_stream = ifmt_ctx->streams[pkt.stream_index];

if (pkt.stream_index == inVideo_StreamIndex)

{

videoIndex++;

int time = pkt.pts * (((float)in_stream->time_base.num) / ((float)in_stream->time_base.den));

if (time <= splitTime)

{

splitPtsV = pkt.pts;

splitDtsV = pkt.dts;

out_stream = ofmt1_ctx->streams[pkt.stream_index];

ofmt_ctx = ofmt1_ctx;

}

else

{

pkt.pts = pkt.pts - splitPtsV;

pkt.dts = pkt.dts - splitDtsV;

out_stream = ofmt2_ctx->streams[pkt.stream_index];

ofmt_ctx = ofmt2_ctx;

}

}

else if (pkt.stream_index == inAudio_StreamIndex)

{

int time = pkt.pts * (((float)in_stream->time_base.num) / ((float)in_stream->time_base.den));

if (time <= splitTime)

{

splitPtsA = pkt.pts;

splitDtsA = pkt.dts;

out_stream = ofmt1_ctx->streams[pkt.stream_index];

ofmt_ctx = ofmt1_ctx;

}

else

{

pkt.pts = pkt.pts - splitPtsA;

pkt.dts = pkt.dts - splitDtsA;

out_stream = ofmt2_ctx->streams[pkt.stream_index];

ofmt_ctx = ofmt2_ctx;

}

}

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;

//write into file

if (av_interleaved_write_frame(ofmt_ctx, &pkt) < 0)

{

printf( "Error muxing packet\n");

break;

}

av_free_packet(&pkt);

}

av_write_trailer(ofmt1_ctx);

av_write_trailer(ofmt2_ctx);

end:

avformat_close_input(&ifmt_ctx);

/* close output */

if (ofmt1_ctx && !(ofmt1_ctx->oformat->flags & AVFMT_NOFILE))

avio_close(ofmt1_ctx->pb);

avformat_free_context(ofmt1_ctx);

/* close output */

if (ofmt2_ctx && !(ofmt2_ctx->oformat->flags & AVFMT_NOFILE))

avio_close(ofmt2_ctx->pb);

avformat_free_context(ofmt2_ctx);

return 0;

}

3、下载地址

http://download.csdn.net/detail/dancing_night/8699109

ffmpeg实现视频合并
http://blog.csdn.net/dancing_night/article/details/45724215

1、概述

简单说下流程：

打开输入---->打开输出---->根据输入来创建流---->拷贝流设置---->循环读帧---->判断第一个读完，改输入为第二个---->设置pts和dts---->写入---->善后

2、代码

[cpp] view
plain copy

/*

*最简单的视频合并

*缪国凯 Mickel

*821486004@qq.com

*本程序实现把2个视频合并为一个视频，不涉及编解码，但是对视频源有要求，必须是相同的参数

*着重理解第二个视频开始的时候的pts和dts计算

*注：只处理一个视频流和一个音频流，若流多了，估计会crash

*2015-5-14

*/

#include "stdafx.h"

#ifdef __cplusplus

extern"C"

{

#endif

#include <libavformat/avformat.h>

#include "libavcodec/avcodec.h"

#include "libavfilter/avfiltergraph.h"

#include "libavfilter/buffersink.h"

#include "libavfilter/buffersrc.h"

#include "libavutil/avutil.h"

#include "libavutil/opt.h"

#include "libavutil/pixdesc.h"

#include "libswresample\swresample.h"

#include "libavutil\fifo.h"

#include "libavutil/audio_fifo.h"

#pragma comment(lib, "avcodec.lib")

#pragma comment(lib, "avformat.lib")

#pragma comment(lib, "avutil.lib")

//#pragma comment(lib, "avdevice.lib")

#pragma comment(lib, "avfilter.lib")

//#pragma comment(lib, "postproc.lib")

#pragma comment(lib, "swresample.lib")

//#pragma comment(lib, "swscale.lib")

#ifdef __cplusplus

};

#endif

AVFormatContext *in1_fmtctx = NULL, *in2_fmtctx = NULL, *out_fmtctx = NULL;

AVStream *out_video_stream = NULL, *out_audio_stream = NULL;

int video_stream_index = -1, audio_stream_index = -1;

int open_input(const char * in1_name, const char * in2_name)

{

int ret = -1;

if ((ret = avformat_open_input(&in1_fmtctx, in1_name, NULL, NULL)) < 0)

{

printf("can not open the first input context!\n");

return ret;

}

if ((ret = avformat_find_stream_info(in1_fmtctx, NULL)) < 0)

{

printf("can not find the first input stream info!\n");

return ret;

}

if ((ret = avformat_open_input(&in2_fmtctx, in2_name, NULL, NULL)) < 0)

{

printf("can not open the first input context!\n");

return ret;

}

if ((ret = avformat_find_stream_info(in2_fmtctx, NULL)) < 0)

{

printf("can not find the second input stream info!\n");

return ret;

}

}

int open_output(const char * out_name)

{

int ret = -1;

if ((ret = avformat_alloc_output_context2(&out_fmtctx, NULL, NULL, out_name)) < 0)

{

printf("can not alloc context for output!\n");

return ret;

}

//new stream for out put

for (int i = 0; i < in1_fmtctx->nb_streams; i++)

{

if (in1_fmtctx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO)

{

video_stream_index = i;

out_video_stream = avformat_new_stream(out_fmtctx, NULL);

if (!out_video_stream)

{

printf("Failed allocating output1 video stream\n");

ret = AVERROR_UNKNOWN;

return ret;

}

if ((ret = avcodec_copy_context(out_video_stream->codec, in1_fmtctx->streams[i]->codec)) < 0)

{

printf("can not copy the video codec context!\n");

return ret;

}

out_video_stream->codec->codec_tag = 0;

if(out_fmtctx->oformat->flags & AVFMT_GLOBALHEADER)

{

out_video_stream->codec->flags |= CODEC_FLAG_GLOBAL_HEADER;

}

}

else if (in1_fmtctx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO)

{

audio_stream_index = i;

out_audio_stream = avformat_new_stream(out_fmtctx, NULL);

if (!out_audio_stream)

{

printf("Failed allocating output1 video stream\n");

ret = AVERROR_UNKNOWN;

return ret;

}

if ((ret = avcodec_copy_context(out_audio_stream->codec, in1_fmtctx->streams[i]->codec)) < 0)

{

printf("can not copy the video codec context!\n");

return ret;

}

out_audio_stream->codec->codec_tag = 0;

if(out_fmtctx->oformat->flags & AVFMT_GLOBALHEADER)

{

out_audio_stream->codec->flags |= CODEC_FLAG_GLOBAL_HEADER;

}

}

}

//open output file

if (!(out_fmtctx->oformat->flags & AVFMT_NOFILE))

{

if ((ret = avio_open(&out_fmtctx->pb, out_name, AVIO_FLAG_WRITE)) < 0)

{

printf("can not open the out put file handle!\n");

return ret;

}

}

//write out file header

if ((ret = avformat_write_header(out_fmtctx, NULL)) < 0)

{

printf( "Error occurred when opening video output file\n");

return ret;

}

}

int _tmain(int argc, _TCHAR* argv[])

{

if(argc < 4)

{

printf("no input file!\n");

return -1;

}

char out_name[20];

sprintf(out_name, "combine.%s", argv[3]);

av_register_all();

if (0 > open_input(argv[1], argv[2]))

{

goto end;

}

if(0 > open_output(out_name))

{

goto end;

}

AVFormatContext *input_ctx = in1_fmtctx;

AVPacket pkt;

int pts_v, pts_a, dts_v, dts_a;

while(1)

{

if(0 > av_read_frame(input_ctx, &pkt))

{

if (input_ctx == in1_fmtctx)

{

float vedioDuraTime, audioDuraTime;

//calc the first media dura time

vedioDuraTime = ((float)input_ctx->streams[video_stream_index]->time_base.num /

(float)input_ctx->streams[video_stream_index]->time_base.den) * ((float)pts_v);

audioDuraTime = ((float)input_ctx->streams[audio_stream_index]->time_base.num /

(float)input_ctx->streams[audio_stream_index]->time_base.den) * ((float)pts_a);

//calc the pts and dts end of the first media

if (audioDuraTime > vedioDuraTime)

{

dts_v = pts_v = audioDuraTime / ((float)input_ctx->streams[video_stream_index]->time_base.num /

(float)input_ctx->streams[video_stream_index]->time_base.den);

dts_a++;

pts_a++;

}

else

{

dts_a = pts_a = vedioDuraTime / ((float)input_ctx->streams[audio_stream_index]->time_base.num /

(float)input_ctx->streams[audio_stream_index]->time_base.den);

dts_v++;

pts_v++;

}

input_ctx = in2_fmtctx;

continue;

}

break;

}

if (pkt.stream_index == video_stream_index)

{

if (input_ctx == in2_fmtctx)

{

pkt.pts += pts_v;

pkt.dts += dts_v;

}

else

{

pts_v = pkt.pts;

dts_v = pkt.dts;

}

}

else if (pkt.stream_index == audio_stream_index)

{

if (input_ctx == in2_fmtctx)

{

pkt.pts += pts_a;

pkt.dts += dts_a;

}

else

{

pts_a = pkt.pts;

dts_a = pkt.dts;

}

}

pkt.pts = av_rescale_q_rnd(pkt.pts, input_ctx->streams[pkt.stream_index]->time_base,

out_fmtctx->streams[pkt.stream_index]->time_base, (AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));

pkt.dts = av_rescale_q_rnd(pkt.dts, input_ctx->streams[pkt.stream_index]->time_base,

out_fmtctx->streams[pkt.stream_index]->time_base, (AVRounding)(AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));

pkt.pos = -1;

if (av_interleaved_write_frame(out_fmtctx, &pkt) < 0)

{

printf( "Error muxing packet\n");

//break;

}

av_free_packet(&pkt);

}

av_write_trailer(out_fmtctx);

end:

avformat_close_input(&in1_fmtctx);

avformat_close_input(&in2_fmtctx);

/* close output */

if (out_fmtctx && !(out_fmtctx->oformat->flags & AVFMT_NOFILE))

avio_close(out_fmtctx->pb);

avformat_free_context(out_fmtctx);

return 0;

}

3、下载地址

http://download.csdn.net/detail/dancing_night/8700439