ffmpeg 实现转码一个普通视频文件为视频mpeg4,音频mp3的功能的程序(摘)

旧城等待， 2021-09-19 09:44 231阅读 0赞

本程序实现转码一个普通视频文件为视频mpeg4,音频mp3的功能

#include <avcodec.h>
    #include <avformat.h>
    #include <stdio.h>
    #include <avutil.h>
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>

main(int argc,char **argv)
    {   
      const char *input_file_name="/root/movies/ddh1.mpg";
      av_register_all();//注册库中所有可用的文件格式和编码器
      AVFormatContext *ic;
      //输入文件处理部分
      ic=av_alloc_format_context();
      if(av_open_input_file(&ic,input_file_name,NULL,0,NULL)!=0)
      {
         printf("can't open the file %s\n",input_file_name);
         exit(1);
      }//打开输入文件
      if(av_find_stream_info(ic)<0)
      {
         printf("can't find suitable codec parameters\n");
         exit(1);
      }//取出流信息
      dump_format(ic,0,input_file_name,0);//列出输入文件的相关流信息
      int i;
      int videoindex=-1;int audioindex=-1;
      for(i=0;i<ic->nb_streams;i++)
      {    
         if(ic->streams[i]->codec->codec_type==CODEC_TYPE_VIDEO)
             {
                videoindex=i;
              //printf("video\n");
             }
             else if(ic->streams[i]->codec->codec_type==CODEC_TYPE_AUDIO)
             {
              //printf("audio\n");
                audioindex=i;
             }
      }
       if(videoindex==-1)
       {
              printf("can't find video stream\n");
              exit(1);
       }//没有找到视频流
      AVCodecContext *vCodecCtx;
      vCodecCtx=ic->streams[videoindex]->codec;//取得视频流编码上下文指针
      AVCodec *vCodec;
      vCodec=avcodec_find_decoder(vCodecCtx->codec_id);
      if(vCodec==NULL)
      {
         printf("can't find suitable video decoder\n");
         exit(1);
      }//找到合适的视频解码器
      if(avcodec_open(vCodecCtx,vCodec)<0)
      {
         printf("can't open the video decoder\n");
         exit(1);
      }//打开该视频解码器
       if(audioindex==-1)
         {
            printf("can't find audio stream\n");
            exit(1);
         }//没有找到音频流
      AVCodecContext *aCodecCtx;
      aCodecCtx=ic->streams[audioindex]->codec;
      AVCodec *aCodec;
      aCodec=avcodec_find_decoder(aCodecCtx->codec_id);
      if(aCodec==NULL)
      {
         printf("can't find suitable audio decoder\n");
         exit(1);
      }//找到合适的音频解码器
      if(avcodec_open(aCodecCtx,aCodec)<0)
      {
         printf("can't open the audio decoder\n");
         exit(1);
      }//打开该音频解码器
    //下面为输出文件处理部分
        const char *output_file_name="/root/123.avi";
        AVOutputFormat *fmt;
        AVFormatContext *oc;
        AVCodecContext *oVcc,*oAcc;
        AVCodec *oVc,*oAc;
        AVStream *video_st,*audio_st;
        AVFrame *oVFrame,*oAFrame;
        double video_pts;
        oVFrame=avcodec_alloc_frame();
        fmt=guess_format(NULL,output_file_name,NULL);
        if(!fmt)
        {
               printf("could not deduce output format from outfile extension\n");
               exit(0);
        }//判断是否可以判断输出文件的编码格式
        oc=av_alloc_format_context();
        if(!oc)
        {
               printf("Memory error\n");
               exit(0);
        }
        oc->oformat=fmt;
        pstrcpy(oc->filename,sizeof(oc->filename),output_file_name);
        video_st=av_new_stream(oc,0);
        if(!video_st)
        {
              printf("could not alloc video stream\n");
              exit(0);
        }
        oVcc=avcodec_alloc_context();
        oVcc=video_st->codec;
        oVcc->codec_id=CODEC_ID_MPEG4;
        oVcc->codec_type=CODEC_TYPE_VIDEO;
        oVcc->bit_rate=2500000;
        oVcc->width=704;
        oVcc->height=480;
        oVcc->time_base=vCodecCtx->time_base;
        oVcc->gop_size=vCodecCtx->gop_size;
        //oVcc->pix_fmt=vCodecCtx->pix_fmt;
        oVcc->pix_fmt=vCodecCtx->pix_fmt;
        oVcc->max_b_frames=vCodecCtx->max_b_frames;
        video_st->r_frame_rate=ic->streams[videoindex]->r_frame_rate;
        audio_st=av_new_stream(oc,oc->nb_streams);
        if(!audio_st)
        {
               printf("could not alloc audio stream\n");
               exit(0);
        }  
        avcodec_get_context_defaults2(audio_st->codec,CODEC_TYPE_AUDIO);
        oAcc=avcodec_alloc_context();
        oAcc=audio_st->codec;
        oAcc->codec_id=CODEC_ID_MP3;
        oAcc->codec_type=CODEC_TYPE_AUDIO;
        oAcc->bit_rate=aCodecCtx->bit_rate;
        oAcc->sample_rate=aCodecCtx->sample_rate;
        oAcc->channels=2;
        if (av_set_parameters(oc, NULL) < 0) 
        {
               printf( "Invalid output format parameters\n");                         
                  exit(0);                               
        }//设置必要的输出参数
        strcpy(oc->title,ic->title);
        strcpy(oc->author,ic->author);
        strcpy(oc->copyright,ic->copyright);
        strcpy(oc->comment,ic->comment);
        strcpy(oc->album,ic->album);
        oc->year=ic->year;
        oc->track=ic->track;
        strcpy(oc->genre,ic->genre);
        dump_format(oc,0,output_file_name,1);//列出输出文件的相关流信息
        oVc=avcodec_find_encoder(CODEC_ID_MPEG4);
        if(!oVc)
        {
           printf("can't find suitable video encoder\n");
               exit(0);
        }//找到合适的视频编码器
        if(avcodec_open(oVcc,oVc)<0)
        {
               printf("can't open the output video codec\n");
               exit(0);
        }//打开视频编码器
        oAc=avcodec_find_encoder(CODEC_ID_MP3);
        if(!oAc)
        {
               printf("can't find suitable audio encoder\n");
               exit(0);
        }//找到合适的音频编码器
        if(avcodec_open(oAcc,oAc)<0)
        {
               printf("can't open the output audio codec");
               exit(0);
        }//打开音频编码器
        /*if(url_exist(output_file_name))
        {
           printf("the output file name %s has exist,please select other\n",output_file_name);
           exit(0);
        }//判断该输出文件是否已经存在*/
        if (!(oc->flags & AVFMT_NOFILE))
        {
           if(url_fopen(&oc->pb,output_file_name,URL_WRONLY)<0)
           {
                  printf("can't open the output file %s\n",output_file_name);
                  exit(0);
           }//打开输出文件
        }
        if(!oc->nb_streams)
        {
               fprintf(stderr,"output file dose not contain any stream\n");
               exit(0);
        }//查看输出文件是否含有流信息
      if(av_write_header(oc)<0)
      {
          fprintf(stderr, "Could not write header for output file\n");
          exit(1);
      }[/i][/i]
    AVPacket packet;
      uint8_t *ptr,*out_buf;
      int out_size;
      static short *samples=NULL;
      static unsigned int samples_size=0;
      uint8_t *video_outbuf,*audio_outbuf;int video_outbuf_size,audio_outbuf_size;
      video_outbuf_size=400000;
      video_outbuf= (unsigned char *) malloc(video_outbuf_size);
      audio_outbuf_size = 10000;
      audio_outbuf = av_malloc(audio_outbuf_size);
      int flag;int frameFinished;int len;int frame_index=0,ret;
              while(av_read_frame(ic,&packet)>=0)//从输入文件中读取一个包
           {
              if(packet.stream_index==videoindex)//判断是否为当前视频流中的包
              {
             len=avcodec_decode_video(vCodecCtx,oVFrame,&frameFinished,packet.data,packet.size);//若为视频包，解码该视频包
                     if(len<0)
                     {
                        printf("Error while decoding\n");
                        exit(0);
                     }
             if(frameFinished)//判断视频祯是否读完
             {
                 fflush(stdout);
                 oVFrame->pts=av_rescale(frame_index,AV_TIME_BASE*(int64_t)oVcc->time_base.num,oVcc->time_base.den);
                 oVFrame->pict_type=0;
                 out_size = avcodec_encode_video(oVcc, video_outbuf, video_outbuf_size, oVFrame);   
                 if (out_size > 0)            
                 {                   
                     AVPacket pkt;               
                     av_init_packet(&pkt);                               
                     if(oVcc->coded_frame && oVcc->coded_frame->key_frame)                                       
                         pkt.flags |= PKT_FLAG_KEY;                                        
                         pkt.flags = packet.flags;                      
                         pkt.stream_index= video_st->index;                                               
                         pkt.data= video_outbuf;                                                         
                         pkt.size= out_size;                                             
                         ret=av_write_frame(oc, &pkt);                                       
                 }
                 frame_index++;
             }
             else
                 ret=av_write_frame(oc, &packet); 
                        //img_convert((AVPicture *)vFrame, PIX_FMT_RGB24, (AVPicture*)oVFrame, oVcc->pix_fmt,oVcc->width,oVcc-
    >height);
                //SaveFrame(vFrame,oVcc->width,oVcc->height,frame_index); 
                        if(ret!=0)
                        {
                          printf("while write video frame error\n");
                          exit(0);
                        }
              }
              else if(packet.stream_index==audioindex)
          {
             len=packet.size;
             ptr=packet.data;
                 int ret=0;
                 while(len>0)
                 {
                        out_buf=NULL;
                        out_size=0;
                        if(&packet)
                   samples=av_fast_realloc(samples,&samples_size,FFMAX(packet.size*sizeof
    (*samples),AVCODEC_MAX_AUDIO_FRAME_SIZE));
                        out_size=samples_size;
                        ret=avcodec_decode_audio(aCodecCtx,samples,&out_size,ptr,len);//若为音频包，解码该音频包
                        if(ret<0)
                        {
                           printf("while decode audio failure\n");
                           exit(0);
                        }
                fflush(stdout);
                ptr+=ret;
                len-=ret;
                if(out_size<=0)
                   continue;
                out_buf=(uint8_t *)samples;
                AVPacket pkt;
                av_init_packet(&pkt);
                pkt.size= avcodec_encode_audio(oAcc, audio_outbuf, audio_outbuf_size, out_buf);
                pkt.pts= av_rescale_q(oAcc->coded_frame->pts, oAcc->time_base, audio_st->time_base);
                pkt.flags |= PKT_FLAG_KEY;
                pkt.stream_index= audioindex;
                pkt.data= audio_outbuf;
                if (av_write_frame(oc, &pkt) != 0) 
                {
                   fprintf(stderr, "Error while writing audio frame\n");
                   exit(1);
                    }
             }
              } 
              av_free_packet(&packet);
           } 
    av_write_trailer(oc);
    for(i = 0; i < oc->nb_streams; i++) 
    {            
      av_freep(&oc->streams[i]->codec);                       
      av_freep(&oc->streams[i]);                           
    }
    url_fclose(oc);
    av_free(oc);
    av_free(oVFrame);
    av_free(out_buf);
    avcodec_close(vCodecCtx);
    avcodec_close(aCodecCtx);
    av_close_input_file(ic);
    }
    
    
    本文转自94cool博客园博客，原文链接：http://www.cnblogs.com/94cool/archive/2009/09/04/1560165.html，如需转载请自行联系原作者