ffmpeg編解碼詳細(xì)過程

1、1.注冊(cè)所有容器格式和CODEC:av_register_all()2.打開文件:av_open_input_file()3.從文件中提取流信息:av_find_stream_info()4.窮舉所有的流，查找其中種類為CODEC_TYPE_VIDEO5.查找對(duì)應(yīng)的解碼器:avcodec_find_decoder()6.打開編解碼器:avcodec_open()7.為解碼幀分配內(nèi)存:avcodec_alloc_frame()8.不停地從

2、碼流中提取出幀數(shù)據(jù):av_read_frame()9.判斷幀的類型，對(duì)于視頻幀調(diào)用:avcodec_decode_video()10.解碼完后，釋放解碼器:avcodec_close()11.關(guān)閉輸入文件:av_close_input_file()X264結(jié)束ffmpeg開始AVFmatContextoc=NULLAVOutputFmatfmtAVStreamvideo_st=NULLdoublevideo_pts=0uint8_tvi

3、deo_outbuf=NULLuint8_tpicture_buf=NULLAVFramepicture=NULLAVCodecContextc=NULLAVCodeccodec=NULLAVPacketpktintsize=0consttestfilename=“test2.h264“voidInitFFmpeg()av_register_all()1.1.注冊(cè)所有容器格式和注冊(cè)所有容器格式和CODEC:av_register_all

4、()CODEC:av_register_all()#endifvoidFFmpegEncode(uint8_tbufunsignedintbufsizeunsignedintwidthunsignedintheight)decodeStart=clock()memcpy(picture_bufbufbufsize)picturedata[0]=picture_bufYpicturedata[2]=picture_bufDEFAULT_S

5、IZEVpicturedata[1]=picture_bufDEFAULT_SIZE54Uav_init_packet(if(ocofmatflagspkt.size=sizeof(AVPicture)elseintout_size=avcodec_encode_video(cvideo_outbufDEFAULT_SIZEpicture)99判斷幀的類型，對(duì)于視頻幀調(diào)用判斷幀的類型，對(duì)于視頻幀調(diào)用intgot_size=0intout

6、_size=avcodec_encode_video2(cTRACE(“%dn“out_size)if(out_size0)pkt.data=video_outbufpkt.size=out_sizeret=av_write_frame(oc#ifWRITEDATATOFILEfwrite(pkt.data1pkt.sizeVideofile)#endifdecodeEnd=clock()TRACE(“decodeusetimeis%d