ffmpeg实现视频切割

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

/*
*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
};
#endifint _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 decoderif(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 fileif (!(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 fileif (!(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 headerif (avformat_write_header(ofmt1_ctx, NULL) < 0){printf( "Error occurred when opening video output file\n");goto end;}//write out 2 file headerif (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 ptsint splitDtsV = 0;int splitPtsA = 0;//the real split audio ptsint splitDtsA = 0;int videoIndex = 0;//the real video indexint 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 fileif (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

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ffmpeg实现视频切割

1、概述

2、代码

3、下载地址

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