avcodec_decode_video2（）解码不成功_course

调用ffmpeg的库从文件中读出视频流信息，利用av_read_frame提取帧，最后调用avcodec_decode_video2接口对帧进行解码，代码如下： AVFormatContext *pFormatCtx; AVCodecContext *pCodecCtx; AVCodec *pCodec; AVFrame *pFrame2; AVPacket packet2; int H264GetStream() { int i, videoindex; char filepath[]="sample.mp4"; av_register_all(); pFormatCtx = avformat_alloc_context(); if(avformat_open_input(&pFormatCtx,filepath,NULL,NULL)!=0){ printf("无法打开文件\n"); return -1; } if(avformat_find_stream_info(pFormatCtx,NULL)<0) { printf("Couldn't find stream information.\n"); return -1; } videoindex=-1; for(i=0; i<pFormatCtx->nb_streams; i++) if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO) { videoindex=i; break; } if(videoindex==-1) { printf("Didn't find a video stream.\n"); return -1; } pCodecCtx=pFormatCtx->streams[videoindex]->codec; pCodec=avcodec_find_decoder(pCodecCtx->codec_id); if(pCodec==NULL) { printf("Codec not found.\n"); return -1; } printf("pCodec=%d\n",pCodec->id); if(avcodec_open2(pCodecCtx, pCodec,NULL)<0) { printf("Could not open codec.\n"); return -1; } pFrame2=avcodec_alloc_frame(); int ret, got_picture; int y_size = pCodecCtx->width * pCodecCtx->height; //packet2=(AVPacket *)malloc(sizeof(AVPacket)); //av_new_packet(packet2, y_size); av_init_packet(&packet2); char filepath_out[]="bigbuckbunny_1920x1080.yuv"; fp_out = fopen(filepath_out, "wb"); if (!fp_out) { printf("Could not open output YUV file\n"); return -1; } //输出一下信息----------------------------- printf("文件信息-----------------------------------------\n"); av_dump_format(pFormatCtx,0,filepath,0); printf("-------------------------------------------------\n"); //------------------------------ while(av_read_frame(pFormatCtx, &packet2)>=0) { printf("packet2->stream_index=%d\n",packet2.stream_index); printf("videoindex=%d\n",videoindex); if(packet2.stream_index==videoindex) { printf("decode start!"); //packet->data[0]=0;packet->data[1]=0;packet->data[2]=0;packet->data[3]=1; // packet->size-=4; printf("packet2->data=%d %d %d %d\n",packet2.data[0],packet2.data[1],packet2.data[2],packet2.data[3]); printf("packet2->size=%d\n",packet2.size); ret = avcodec_decode_video2(pCodecCtx, pFrame2, &got_picture, &packet2); printf("got_picture=%x\n",got_picture); if(ret < 0) { printf("decode error!\n"); return -1; } if(got_picture) { printf("got_picture=%x\n",got_picture); //Y, U, V int i; for(i=0;i<pFrame->height;i++) { fwrite(pFrame->data[0]+pFrame->linesize[0]*i,1,pFrame->width,fp_out); } for(i=0;i<pFrame->height/2;i++) { fwrite(pFrame->data[1]+pFrame->linesize[1]*i,1,pFrame->width/2,fp_out); } for(i=0;i<pFrame->height/2;i++) { fwrite(pFrame->data[2]+pFrame->linesize[2]*i,1,pFrame->width/2,fp_out); } printf("Succeed to decode 1 frame!\n"); } } av_free_packet(&packet2); } //av_free(pFrameYUV); avcodec_close(pCodecCtx); avformat_close_input(&pFormatCtx); return 0; } 每次运行到ret = avcodec_decode_video2(pCodecCtx, pFrame2, &got_picture, &packet2)这一步程序就不再运行下去了，也没有任何返回值。 在这里打印信息检查了一下 while(av_read_frame(pFormatCtx, &packet2)>=0) { printf("packet2->stream_index=%d\n",packet2.stream_index); printf("videoindex=%d\n",videoindex); 发现packet2.stream_index的值一直不变，按道理应该还有一路音频流。 程序是在linux平台下运行的，求问哪里出错了！

ffmpeg解码H264，avcodec_decode_video2返回值问题_course

为什么有时候解码返回值不是0，有时候又是0？

FFmpeg 调用avcodec_encode_video2()的时候出错_course

参考大神的代码写了个用dshow抓取摄像头，实时编码h265的程序。但是调用avcodec_encode_video2()的时候，就会报这样的错 下面是关键部分代码for (int i = 0; i

摄像头编码h264 编码avcodec_encode_video2失败，求指点_course

#define WIDTH 320 #define HEIGHT 240 void CFileTransferH264Dlg::OnBnClickedButton1() { // TODO: 在此添加

ffmpeg avcodec_open2问题_course

AVCodecContext *c; c->bit_rate = 400000; c->width = width; c->height = height; c->time_base = avRate; c->lmin = 1; c->lmax = 1000; c->me_method = 8; c->me_range = 16; c->me_subpel_quality = 7; c->qmin = 10; c->qmax = 51; c->gop_size = 12; /* emit one intra frame every twelve frames at most */ c->pix_fmt = PIX_FMT_YUV420P; if (c->codec_id == CODEC_ID_MPEG2VIDEO) { c->max_b_frames = 2; } if (c->codec_id == CODEC_ID_MPEG1VIDEO){ c->mb_decision=2; avcodec_open2宽度和高度不同时有时打开成功，有时失败,如1366*768打开成功,1365*767打开失败

用ffmpeg编码后的音频为什么播放速度会加快_course

获取音频数据后保存在samp里，又按如下函数写入文件里，转出来后的声音用正常的播放器播放速度加快，总时间缩短，不知道是哪里出了问题了，不知道有人碰到过该问题么？ 如果输出是PCM格式，输出就是正常的，

MediaCodec编码后保存的视频时间不正确,视频播放太快_course

最近在做摄像头录像的时候,用MediaCodec编码摄像头的yuv数据成h264, 但是发现编码后的h264文件时间不对..比如录像录了50秒，但是h264文件就只有18秒..视频播放速度加快了..但

ffmpeg编码avcodec_open2(pCodecCtx, pCodec,NULL)打开失败_course

首先，用于android平台的。 在编码过程中，音频和视频（音频和视频都是从外界获取的，麦克风和摄像头设备）同时进行存放在.mp4中，这个编码流程是？ 我的思路是： 音频编码ID是AV_CODEC_I

FFMPEG之调用avcodec_open2的问题_course

av_register_all(); if (avformat_alloc_output_context2(&ofmtctx, NULL, NULL, (const char*)argv) < 0)

ffmpeg avcodec_encode_video2编码失败 got_picture总为0_course

如题，每次编码得到的got_picture总为0，也加入了： av_opt_set(pCodecCtx->priv_data, "preset", "superfast", 0); av_opt_se

ffmpeg 工程avcodec_decode_video2() 解码fail_course

初学ffmpeg, 写个demon. 想法是用ffmpeg解码, 然后讲一帧图像转换为RGB24， 保存为bmp格式的图片。 遇到的问题： avcodec_decode_video2(AVCodecC

avcodec_encode_video2 出帧问题_course

avcodec_encode_video2对 AV_PIX_FMT_YUV420P进行h264编码时，我需要输入60帧后它才会给我编码出来第一帧，就是说61帧->1帧，6帧->2帧..........

FFmpeg C++ 的 avcodec_encode_video2 返回 -40_course

我想通過avcodec_encode_video2 覆蓋packet中的memory來達到刷新我做過特殊渲染的影像，但avcodec_encode_video2 的返回值是不成功-40問題: 我正常撥放輸出都沒問題 就是沒辦法蓋過圖層，是不是哪邊memory寫法不正確呢? 代碼如下: AVOutputFormat* ofmt = NULL; //Input AVFormatContext and Output AVFormatContext AVFormatContext* i_pFormatCtx = NULL, * out_pFormatCtx = NULL; AVCodecContext* pCodecCtx;//視頻解碼器 AVCodecContext* pCodecCtxAudio;//音頻解碼器 AVCodec* pCodec; AVCodec* pCodecAudio; AVPacket packet; string in_filename; string out_filename; int ret, i; int videoindex = -1; int audioindex = -1; int frame_index = 0; int64_t start_time = 0; uint8_t* buffer; AVFrame* pFrame; AVFrame* pFrameRGB; int frameFinished; int frameAudioFinished; int numBytes; AVStream* in_stream, * out_stream; vector<AVPacket> BIGpacket; in_filename = "D:/yolo/data_movie/f1.mp4"; out_filename = "rtmp://localhost:1935/live/home";//怀堤 URLㄗOutput URLㄘ[RTMP] //================ // 註冊: av_register_all(); //================ //Network avformat_network_init(); //======================= //Input if ((ret = avformat_open_input(&i_pFormatCtx, in_filename.c_str(), 0, 0)) < 0) { //printf("Could not open input file."); goto end; } if ((ret = avformat_find_stream_info(i_pFormatCtx, 0)) < 0) { //printf("Failed to retrieve input stream information"); goto end; } for (i = 0; i < i_pFormatCtx->nb_streams; i++) { if (i_pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO) { videoindex = i; } if (i_pFormatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_AUDIO) { audioindex = i; } } av_dump_format(i_pFormatCtx, 0, in_filename.c_str(), 0); //Output avformat_alloc_output_context2(&out_pFormatCtx, NULL, "flv", out_filename.c_str()); //RTMP if (!out_pFormatCtx) { //printf("Could not create output context\n"); ret = AVERROR_UNKNOWN; goto end; } ofmt = out_pFormatCtx->oformat; for (i = 0; i < i_pFormatCtx->nb_streams; i++) { //Create output AVStream according to input AVStream AVStream* in_stream = i_pFormatCtx->streams[i]; AVStream* out_stream = avformat_new_stream(out_pFormatCtx, in_stream->codec->codec); if (!out_stream) { AfxMessageBox(L"Failed allocating output stream"); //printf("Failed allocating output stream\n"); ret = AVERROR_UNKNOWN; goto end; } //Copy the settings of AVCodecContext ret = avcodec_copy_context(out_stream->codec, in_stream->codec); if (ret < 0) { //printf("Failed to copy context from input to output stream codec context\n"); goto end; } out_stream->codec->codec_tag = 0; if (out_pFormatCtx->oformat->flags & AVFMT_GLOBALHEADER) out_stream->codec->flags |= AV_CODEC_FLAG_GLOBAL_HEADER; } //====================================================================== // 打开視頻解码器 pCodecCtx = i_pFormatCtx->streams[videoindex]->codec; pCodec = avcodec_find_decoder(pCodecCtx->codec_id); if (avcodec_open2(pCodecCtx, pCodec, 0) < 0) { DbgPrint("Could not open codec"); return; } //====================================================================== // 打开音頻解码器 pCodecCtxAudio= i_pFormatCtx->streams[audioindex]->codec; pCodecAudio= avcodec_find_decoder(pCodecCtxAudio->codec_id); if (avcodec_open2(pCodecCtxAudio, pCodecAudio, 0) < 0) { DbgPrint("Could not open codec"); return; } #if OUTPUT_PCM pFile = fopen("output.pcm", "wb"); #endif** packet = *(AVPacket*)av_malloc(sizeof(AVPacket)); av_init_packet(&packet); //===================================================================== // 破解視頻某些编解码器可能生成的错误帧速率 if (pCodecCtx->time_base.num > 1000 && pCodecCtx->time_base.den == 1) { pCodecCtx->time_base.den = 1000; } // 分配视频帧 pFrame = av_frame_alloc(); // Allocate an AVFrame structure pFrameRGB = av_frame_alloc(); if (pFrameRGB == NULL) return; numBytes = avpicture_get_size(AV_PIX_FMT_RGB24, pCodecCtx->width,pCodecCtx->height);// Determine required buffer size and allocate buffer buffer = (uint8_t*)av_malloc(numBytes * sizeof(uint8_t)); avpicture_fill((AVPicture*)pFrameRGB, buffer, AV_PIX_FMT_RGB24,pCodecCtx->width, pCodecCtx->height);// Assign appropriate parts of buffer to image planes in pFrameRGB long prepts = 0; //Dump Format------------------ av_dump_format(out_pFormatCtx, 0, out_filename.c_str(), 1); //Open output URL if (!(ofmt->flags & AVFMT_NOFILE)) { ret = avio_open(&out_pFormatCtx->pb, out_filename.c_str(), AVIO_FLAG_WRITE); if (ret < 0) { AfxMessageBox(L"Could not open output URL"); //printf("Could not open output URL '%s'", out_filename); goto end; } } //Write file header ret = avformat_write_header(out_pFormatCtx, NULL); if (ret < 0) { //printf("Error occurred when opening output URL\n"); goto end; } start_time = av_gettime(); while (1) { //Get an AVPacket ret = av_read_frame(i_pFormatCtx, &packet); if (ret < 0) { break; } if (G_PAUSE) { break; } /* if (packet.stream_index == audioindex) { //聲音: ret = avcodec_decode_audio4(pCodecCtx, pFrame, &frameAudioFinished,&packet); } */ //Important:Delay if (packet.stream_index == videoindex) { //==================================================================================== //幀解碼器: int a=avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet);// Decode video frame //ret = avcodec_encode_video2(pCodecCtx, &packet, pFrameRGB, &frameFinished); if (frameFinished) { static struct SwsContext* img_convert_ctx; if (img_convert_ctx == NULL) { int w = pCodecCtx->width; int h = pCodecCtx->height; img_convert_ctx = sws_getContext(w, h, pCodecCtx->pix_fmt, w, h, AV_PIX_FMT_RGB24, 4, NULL, NULL, NULL); if (img_convert_ctx == NULL) { fprintf(stderr, "Cannot initialize the conversion context!\n"); exit(1); } } int ret = sws_scale(img_convert_ctx, pFrame->data, pFrame->linesize, 0, pCodecCtx->height, pFrameRGB->data, pFrameRGB->linesize); if (ret == 0) { fprintf(stderr, "SWS_Scale failed [%d]!\n", ret); continue; } // Save the frame to disk if (i++ <= 5) { SaveFrame(pFrameRGB, pCodecCtx->width, pCodecCtx->height, i); } CopyDate(pFrameRGB, pCodecCtx->width, pCodecCtx->height, packet.pts - prepts); ret =avcodec_encode_video2(pCodecCtx, &packet, pFrameRGB, &frameFinished); if (ret < 0) { AfxMessageBox(L"Encoding失敗"); } prepts = packet.pts; } //============================================================================================== AVRational time_base = i_pFormatCtx->streams[videoindex]->time_base; AVRational time_base_q = { 1,AV_TIME_BASE }; int64_t pts_time = av_rescale_q(packet.dts, time_base, time_base_q); int64_t now_time = av_gettime() - start_time; if (pts_time > now_time) { av_usleep(pts_time - now_time); } } //Simple Write PTS if (packet.pts == AV_NOPTS_VALUE) { //Write PTS AVRational time_base1 = i_pFormatCtx->streams[videoindex]->time_base; //Duration between 2 frames (us) int64_t calc_duration = (double)AV_TIME_BASE / av_q2d(i_pFormatCtx->streams[videoindex]->r_frame_rate); //Parameters packet.pts = (double)(frame_index * calc_duration) / (double)(av_q2d(time_base1) * AV_TIME_BASE); packet.dts = packet.pts; packet.duration = (double)calc_duration / (double)(av_q2d(time_base1) * AV_TIME_BASE); } in_stream = i_pFormatCtx->streams[packet.stream_index]; out_stream = out_pFormatCtx->streams[packet.stream_index]; /* copy packet */ //Convert PTS/DTS packet.pts = av_rescale_q_rnd(packet.pts, in_stream->time_base, out_stream->time_base, (AVRounding)(AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX)); packet.dts = av_rescale_q_rnd(packet.dts, in_stream->time_base, out_stream->time_base, (AVRounding)(AV_ROUND_NEAR_INF | AV_ROUND_PASS_MINMAX)); packet.duration = av_rescale_q(packet.duration, in_stream->time_base, out_stream->time_base); packet.pos = -1; //Print to Screen if (packet.stream_index == videoindex) { //printf("Send %8d video frames to output URL\n", frame_index); frame_index++; //ret = av_interleaved_write_frame(out_pFormatCtx, &packet); } //ret = av_write_frame(ofmt_ctx, &pkt); ret = av_interleaved_write_frame(out_pFormatCtx, &packet); if (ret < 0) { //printf("Error muxing packet\n"); break; } av_free_packet(&packet); } //Write file trailer av_write_trailer(out_pFormatCtx); end: AfxMessageBox(L"Stream is closed"); avformat_close_input(&i_pFormatCtx); /* close output */ if (out_pFormatCtx && !(ofmt->flags & AVFMT_NOFILE)) avio_close(out_pFormatCtx->pb); avformat_free_context(out_pFormatCtx); if (ret < 0 && ret != AVERROR_EOF) { //printf("Error occurred.\n"); return ; } return;

我用av_read_frame读取h264的Mp4文件。需要用avcodec_decode_video2进行解码_course

我想请教一下，我查阅网上的资料，将取出来的数据，加上sps以及pps头，将数据开始的四个字节换成00 00 00 01.但是调用avcodec_decode_video2接口还是不能取出来完整的一帧数