基于FFmpeg的一个智能转码例程

#include <Windows.h>#pragma comment(lib, "avutil.lib")#pragma comment(lib, "avcodec.lib")#pragma comment(lib, "avformat.lib")#pragma comment(lib, "swscale.lib")extern "C" {#include "libavcodec/avcodec.h"#include "libavformat/avformat.h"#include "libswscale/swscale.h"}void usage(char* szExeName){printf("usage: %s InputFile OutputFile/n", szExeName);}char* input_file_name = NULL;char* output_file_name = NULL;int main(int argc,char **argv){if ( 3 != argc ){usage(argv[0]);return -1;}else{input_file_name = argv[1];output_file_name = argv[2];}av_register_all();AVFormatContext *ic = av_alloc_format_context();if (av_open_input_file(&ic,input_file_name,NULL,0,NULL)!=0){return -1;}if (av_find_stream_info(ic)<0){return -1;}// 列出输入文件的相关流信息，然后停顿1秒，以便有时间看清这些信息。printf("--------------------------------/n");dump_format(ic,0,input_file_name,0);printf("--------------------------------/n/n");Sleep(1000);unsigned int i = 0;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;}else if (ic->streams[i]->codec->codec_type==CODEC_TYPE_AUDIO){audioindex=i;}}AVCodecContext *vCodecCtx = NULL;if (videoindex!=-1){vCodecCtx=ic->streams[videoindex]->codec;AVCodec *vCodec=avcodec_find_decoder(vCodecCtx->codec_id);if (vCodec==NULL){printf("can't find video decoder/n");return -1;}if (avcodec_open(vCodecCtx,vCodec)<0){printf("can't open video decoder/n");return -1;}}AVCodecContext *aCodecCtx = NULL;if (audioindex!=-1){aCodecCtx=ic->streams[audioindex]->codec;AVCodec *aCodec=avcodec_find_decoder(aCodecCtx->codec_id);if (aCodec==NULL){printf("can't find audio decoder/n");return -1;}if (avcodec_open(aCodecCtx,aCodec)<0){printf("can't open audio decoder/n");return -1;}}AVStream *video_st=NULL;AVStream *audio_st=NULL;AVCodecContext *oVcc=NULL;AVCodecContext *oAcc=NULL;AVCodec *oVc=NULL;AVCodec *oAc=NULL;AVOutputFormat *fmt = guess_format(NULL,output_file_name,NULL);if (!fmt){return -1;}AVFormatContext *oc = av_alloc_format_context();if (!oc){return -1;}oc->oformat=fmt;strcpy(oc->filename, output_file_name);if ( vCodecCtx != NULL ){video_st=av_new_stream(oc,0);if(!video_st){return -1;}oVcc = video_st->codec;oVcc->codec_id=CODEC_ID_H264;oVcc->codec_type=CODEC_TYPE_VIDEO;oVcc->bit_rate=vCodecCtx->bit_rate;oVcc->width=vCodecCtx->width;oVcc->height=vCodecCtx->height;oVcc->time_base=vCodecCtx->time_base;oVcc->gop_size=vCodecCtx->gop_size;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;oVc=avcodec_find_encoder(CODEC_ID_H264);if(!oVc){return -1;}if(avcodec_open(oVcc,oVc)<0){return -1;}}if ( aCodecCtx != NULL ){audio_st=av_new_stream(oc,1);if(!audio_st){return -1;}avcodec_get_context_defaults(audio_st->codec);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;oAc=avcodec_find_encoder(CODEC_ID_MP3);if(!oAc){return -1;}if(avcodec_open(oAcc,oAc)<0){return -1;}}if (av_set_parameters(oc, NULL) < 0){return -1;}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);// 列出输出文件的相关流信息，然后停顿1秒，以便有时间看清这些信息。printf("--------------------------------/n");dump_format(oc,0,output_file_name,1);printf("--------------------------------/n/n");Sleep(1000);/*if (url_exist(output_file_name)){// 如果输出文件已存在，则退出。return -1;}*/if (!(oc->flags & AVFMT_NOFILE)){if(url_fopen(&oc->pb,output_file_name,URL_WRONLY)<0){return -1;}}if (!oc->nb_streams){fprintf(stderr,"output file dose not contain any stream/n");return -1;}AVPacket packet;uint8_t *ptr,*out_buf;int out_size;static short *samples=NULL;static unsigned int samples_size=0;int frame_index=0,ret,len,frameFinished;const int video_outbuf_size = 512*1024; // 512KBuint8_t *video_outbuf = (unsigned char *)malloc(video_outbuf_size);const int audio_outbuf_size = 16*1024; // 16KBuint8_t *audio_outbuf = (unsigned char *)malloc(audio_outbuf_size);AVFrame *oVFrame = avcodec_alloc_frame();if (av_write_header(oc)<0){fprintf(stderr, "Could not write header for output file/n");return -1;}while (av_read_frame(ic,&packet)>=0){if (packet.stream_index==videoindex){len = avcodec_decode_video(vCodecCtx,oVFrame,&frameFinished,packet.data,packet.size);if (len<0){printf("avcodec_decode_video is err!/n");return -1;}if (frameFinished){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;if ( av_write_frame(oc, &pkt) != 0 ){printf("v av_write_frame is err!/n");return -1;}else{printf("v.../n");}}frame_index++;}}else if (packet.stream_index==audioindex){len=packet.size;ptr=packet.data;while (len>0){out_buf=NULL;out_size=0;if (&packet){samples = (short *)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);if(ret<0){printf("avcodec_decode_audio is err!/n");return -1;}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, (short int*)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){printf("a av_write_frame is err!/n");return -1;}else{printf("a.../n");}}}av_free_packet(&packet);}if (av_write_trailer(oc)<0){return -1;}for(i = 0; i < oc->nb_streams; i++){av_freep(&oc->streams[i]->codec);av_freep(&oc->streams[i]);}if ( video_outbuf ) free(video_outbuf);if ( audio_outbuf ) free(audio_outbuf);if ( oc->pb ) url_fclose(oc->pb);if ( oVFrame ) av_free(oVFrame);if ( vCodecCtx ) avcodec_close(vCodecCtx);if ( aCodecCtx ) avcodec_close(aCodecCtx);if ( ic ) av_close_input_file(ic);if ( oc ) av_free(oc);printf("Ok.../n");return 0;}