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