使用FFMPEG对视频媒体文件进行解复用

时间:2016-02-23 15:15:09

标签: c++ ffmpeg h.264

在开始这个问题后Extracting the h264 part of a video file (demuxing)我实际上能够弄明白,

  1. 当我恢复到较旧版本的FFMPEG(avcodec-55.dll)而不是我之前使用的avcodec-57.dll时,代码运行完美,没有任何错误,并且生成的h264文件使用ffplay播放。
  2. 当我使用avcodec-57.dll版本的FFMPEG(最新版本)时跟踪我的输出时,在调用"Using AVStream.codec.time_base as a timebase hint to the muxer is deprecated. Set AVStream.time_base instead"之后实际上出现了错误avformat_write_header(ofmt_ctx_v, NULL)而在调用之后出现了另一个错误avformat_write_header(ofmt_ctx_a, NULL) Press any key to continue . . . Press any key to continue . . . Press any key to continue . . . Press any key to continue . . . ==============Input Video============= Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'sample.mp4': Metadata: major_brand : isom minor_version : 512 compatible_brands: isomiso2avc1mp41 title : 10153755968775490 encoder : Lavf57.19.100 Duration: 00:01:07.27, start: 0.020021, bitrate: 1058 kb/s Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 400x224 [ SAR 199:200 DAR 199:112], 927 kb/s, 15 fps, 15 tbr, 15360 tbn, 30 tbc (default) Metadata: handler_name : VideoHandler Stream #0:1(eng): Audio: mp3 (mp4a / 0x6134706D), 48000 Hz, stereo, s16p, 12 8 kb/s (default) Metadata: handler_name : SoundHandler ==============Output Video============ Output #0, h264, to 'sample.h264': Stream #0:0: Video: h264 (High), yuv420p, 400x224 [SAR 199:200 DAR 199:112], q=2-31, 927 kb/s, 30 tbc ==============Output Audio============ Output #0, mp3, to 'sample.mp3': Stream #0:0: Audio: mp3, 48000 Hz, stereo, s16p, 128 kb/s ====================================== [h264 @ 00a3ee20] Using AVStream.codec.time_base as a timebase hint to the muxer is deprecated. Set AVStream.time_base instead. [mp3 @ 00a4fec0] Using AVStream.codec.time_base as a timebase hint to the muxer is deprecated. Set AVStream.time_base instead. Press any key to continue . . . 。程序继续执行,音频很好,但.h264文件不是。
  3. 输出

    #include <stdio.h>
    
    #define __STDC_CONSTANT_MACROS
    
    extern "C"
    {
        #include "libavformat/avformat.h"
    }
    
    
    #define USE_H264BSF 1
    
    int main()
    {
        AVOutputFormat *ofmt_a = NULL,*ofmt_v = NULL;
        AVFormatContext *ifmt_ctx = NULL, *ofmt_ctx_a = NULL, *ofmt_ctx_v = NULL;
        AVPacket pkt;
        int ret, i;
        int videoindex=-1,audioindex=-1;
        int frame_index=0;
    
        const char *in_filename  = "sample.mp4";
        const char *out_filename_v = "sample.h264";
        const char *out_filename_a = "sample.mp3";
    
        av_register_all();
        //Input
        if ((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, 0)) < 0) {
            printf( "Could not open input file.");
            goto end;
        }
        if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0) {
            printf( "Failed to retrieve input stream information");
            goto end;
        }
    system("pause");
    
        //Output
        avformat_alloc_output_context2(&ofmt_ctx_v, NULL, NULL, out_filename_v);
        if (!ofmt_ctx_v) {
            printf( "Could not create output context\n");
            ret = AVERROR_UNKNOWN;
            goto end;
        }
        ofmt_v = ofmt_ctx_v->oformat;
    
    system("pause");
    
        avformat_alloc_output_context2(&ofmt_ctx_a, NULL, NULL, out_filename_a);
        if (!ofmt_ctx_a) {
            printf( "Could not create output context\n");
            ret = AVERROR_UNKNOWN;
            goto end;
        }
        ofmt_a = ofmt_ctx_a->oformat;
    system("pause");
        for (i = 0; i < ifmt_ctx->nb_streams; i++) {
                //Create output AVStream according to input AVStream
                AVFormatContext *ofmt_ctx;
                AVStream *in_stream = ifmt_ctx->streams[i];
                AVStream *out_stream = NULL;
    
                if(ifmt_ctx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO){
                    videoindex=i;
                    out_stream=avformat_new_stream(ofmt_ctx_v, in_stream->codec->codec);
                    ofmt_ctx=ofmt_ctx_v;
                }else if(ifmt_ctx->streams[i]->codec->codec_type==AVMEDIA_TYPE_AUDIO){
                    audioindex=i;
                    out_stream=avformat_new_stream(ofmt_ctx_a, in_stream->codec->codec);
                    ofmt_ctx=ofmt_ctx_a;
                }else{
                    break;
                }
    
                if (!out_stream) {
                    printf( "Failed allocating output stream\n");
                    ret = AVERROR_UNKNOWN;
                    goto end;
                }
                //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;
        }
    system("pause");
        //Dump Format------------------
        printf("\n==============Input Video=============\n");
        av_dump_format(ifmt_ctx, 0, in_filename, 0);
        printf("\n==============Output Video============\n");
        av_dump_format(ofmt_ctx_v, 0, out_filename_v, 1);
        printf("\n==============Output Audio============\n");
        av_dump_format(ofmt_ctx_a, 0, out_filename_a, 1);
        printf("\n======================================\n");
        //Open output file
        if (!(ofmt_v->flags & AVFMT_NOFILE)) {
            if (avio_open(&ofmt_ctx_v->pb, out_filename_v, AVIO_FLAG_WRITE) < 0) {
                printf( "Could not open output file '%s'", out_filename_v);
                goto end;
            }
        }
    
        if (!(ofmt_a->flags & AVFMT_NOFILE)) {
            if (avio_open(&ofmt_ctx_a->pb, out_filename_a, AVIO_FLAG_WRITE) < 0) {
                printf( "Could not open output file '%s'", out_filename_a);
                goto end;
            }
        }
    
        //Write file header
        if (avformat_write_header(ofmt_ctx_v, NULL) < 0) {
            printf( "Error occurred when opening video output file\n");
            goto end;
        }
    
        if (avformat_write_header(ofmt_ctx_a, NULL) < 0) {
            printf( "Error occurred when opening audio output file\n");
            goto end;
        }
        system("pause");
    #if USE_H264BSF
        AVBitStreamFilterContext* h264bsfc =  av_bitstream_filter_init("h264_mp4toannexb"); 
    #endif
    
        while (1) {
            AVFormatContext *ofmt_ctx;
            AVStream *in_stream, *out_stream;
            //Get an AVPacket
            if (av_read_frame(ifmt_ctx, &pkt) < 0)
                break;
            in_stream  = ifmt_ctx->streams[pkt.stream_index];
    
    
            if(pkt.stream_index==videoindex){
                out_stream = ofmt_ctx_v->streams[0];
                ofmt_ctx=ofmt_ctx_v;
                #if USE_H264BSF
                    av_bitstream_filter_filter(h264bsfc, in_stream->codec, NULL, &pkt.data, &pkt.size, pkt.data, pkt.size, 0);
                #endif
                printf("Write Video Packet. size:%d\tpts:%lld\n",pkt.size,pkt.pts);
            }else if(pkt.stream_index==audioindex){
                out_stream = ofmt_ctx_a->streams[0];
                ofmt_ctx=ofmt_ctx_a;
                printf("Write Audio Packet. size:%d\tpts:%lld\n",pkt.size,pkt.pts);
            }else{
                continue;
            }
    
    
            //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=0;
            //Write
            if (av_interleaved_write_frame(ofmt_ctx, &pkt) < 0) {
                printf( "Error muxing packet\n");
                break;
            }
            //printf("Write %8d frames to output file\n", frame_index);
            av_free_packet(&pkt);
            frame_index++;
        }
    system("pause");
    #if USE_H264BSF
        av_bitstream_filter_close(h264bsfc);  
    #endif
    
        //Write file trailer
        av_write_trailer(ofmt_ctx_a);
        av_write_trailer(ofmt_ctx_v);
    end:
        avformat_close_input(&ifmt_ctx);
        /* close output */
        if (ofmt_ctx_a && !(ofmt_a->flags & AVFMT_NOFILE))
            avio_close(ofmt_ctx_a->pb);
    
        if (ofmt_ctx_v && !(ofmt_v->flags & AVFMT_NOFILE))
            avio_close(ofmt_ctx_v->pb);
    
        avformat_free_context(ofmt_ctx_a);
        avformat_free_context(ofmt_ctx_v);
    
        system("pause");
        if (ret < 0 && ret != AVERROR_EOF) {
            printf( "Error occurred.\n");
            return -1;
        }
    
        return 0;
    }
    

    代码

    "Using AVStream.codec.time_base as a timebase hint to the muxer is deprecated. Set AVStream.time_base instead"

    编辑1 阅读http://lists.libav.org/pipermail/libav-devel/2014-June/060048.html后,我想出了导致out_stream->time_base = in_stream->time_base;的原因。我通过在调用avformat_write_header之前添加{{1}}来修复它。代码现在运行没有任何错误!使用旧的FFMPEG(avcodec-55.dll)创建的h264文件工作正常,而最近的avcodec-57.dll创建的文件仍然无效。

0 个答案:

没有答案