Ausgang schwarz, wenn ich dekodieren h264 720p mit ffmpeg

Question

Erste, sorry für mein Englisch. Wenn ich h264 720p in ardrone2.0 dekodiere, ist meine Ausgabe schwarz und ich kann nichts sehen.

Ich habe versucht, den Wert von pCodecCtx->pix_fmt = AV_PIX_FMT_BGR24; zu pCodecCtx->pix_fmt = AV_PIX_FMT_YUV420P; und den Wert von pCodecCtxH264->pix_fmt = AV_PIX_FMT_BGR24; zu pCodecCtxH264->pix_fmt = AV_PIX_FMT_YUV420P; aber meinen Programmabsturz zu ändern. Was mache ich falsch?. Danke, siehe Teil meines Codes:

av_register_all(); 
avcodec_register_all(); 
avformat_network_init(); 

// 1.2. Open video file 
if(avformat_open_input(&pFormatCtx, drone_addr, NULL, NULL) != 0) { 
    mexPrintf("No conecct with Drone"); 
    EndVideo(); 
    return; 
} 

pCodec = avcodec_find_decoder(AV_CODEC_ID_H264); 

pCodecCtx = avcodec_alloc_context3(pCodec); 
pCodecCtx->pix_fmt = AV_PIX_FMT_BGR24; 
pCodecCtx->skip_frame = AVDISCARD_DEFAULT; 
pCodecCtx->error_concealment = FF_EC_GUESS_MVS | FF_EC_DEBLOCK; 
pCodecCtx->err_recognition = AV_EF_CAREFUL; 
pCodecCtx->skip_loop_filter = AVDISCARD_DEFAULT; 
pCodecCtx->workaround_bugs = FF_BUG_AUTODETECT; 
pCodecCtx->codec_type = AVMEDIA_TYPE_VIDEO; 
pCodecCtx->codec_id = AV_CODEC_ID_H264; 
pCodecCtx->skip_idct = AVDISCARD_DEFAULT; 
pCodecCtx->width = 1280; 
pCodecCtx->height = 720; 

pCodecH264 = avcodec_find_decoder(AV_CODEC_ID_H264); 
pCodecCtxH264 = avcodec_alloc_context3(pCodecH264); 


pCodecCtxH264->pix_fmt = AV_PIX_FMT_BGR24; 
pCodecCtxH264->skip_frame = AVDISCARD_DEFAULT; 
pCodecCtxH264->error_concealment = FF_EC_GUESS_MVS | FF_EC_DEBLOCK; 
pCodecCtxH264->err_recognition = AV_EF_CAREFUL; 
pCodecCtxH264->skip_loop_filter = AVDISCARD_DEFAULT; 
pCodecCtxH264->workaround_bugs = FF_BUG_AUTODETECT; 
pCodecCtxH264->codec_type = AVMEDIA_TYPE_VIDEO; 
pCodecCtxH264->codec_id = AV_CODEC_ID_H264; 
pCodecCtxH264->skip_idct = AVDISCARD_DEFAULT; 

if(avcodec_open2(pCodecCtxH264, pCodecH264, &optionsDict) < 0) 
{ 
    mexPrintf("Error opening H264 codec"); 
    return ; 
} 

pFrame_BGR24 = av_frame_alloc(); 


if(pFrame_BGR24 == NULL) { 
    mexPrintf("Could not allocate pFrame_BGR24\n"); 
    return ; 
} 

// Determine required buffer size and allocate buffer 

buffer_BGR24 = 
(uint8_t *)av_mallocz(av_image_get_buffer_size(AV_PIX_FMT_BGR24, 
pCodecCtx->width, ((pCodecCtx->height == 720) ? 720 : pCodecCtx->height) * 
sizeof(uint8_t)*3,1)); 

// Assign buffer to image planes 

av_image_fill_arrays(pFrame_BGR24->data, pFrame_BGR24->linesize, 
buffer_BGR24,AV_PIX_FMT_BGR24, pCodecCtx->width, pCodecCtx->height,1); 

// format conversion context 
pConvertCtx_BGR24 = sws_getContext(pCodecCtx->width, pCodecCtx->height, 
pCodecCtx->pix_fmt, pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_BGR24, 
           SWS_BILINEAR | SWS_ACCURATE_RND, 0, 0, 0); 

// 1.6. get video frames 
pFrame = av_frame_alloc(); 

av_init_packet(&packet); 
packet.data = NULL; 
packet.size = 0; 
} 

//Captura un frame 
void video::capture(mxArray *plhs[]) { 

    if(av_read_frame(pFormatCtx, &packet) < 0){ 
     mexPrintf("Error al leer frame"); 
     return; 
    } 
    do { 
     do { 
      rest = avcodec_send_packet(pCodecCtxH264, &packet); 
     } while(rest == AVERROR(EAGAIN)); 

     if(rest == AVERROR_EOF || rest == AVERROR(EINVAL)) { 
       printf("AVERROR(EAGAIN): %d, AVERROR_EOF: %d, 
       AVERROR(EINVAL): %d\n", AVERROR(EAGAIN), AVERROR_EOF, 
       AVERROR(EINVAL)); 
      printf("fe_read_frame: Frame getting error (%d)!\n", rest); 
      return; 
     } 

     rest = avcodec_receive_frame(pCodecCtxH264, pFrame); 
    } while(rest == AVERROR(EAGAIN)); 

    if(rest == AVERROR_EOF || rest == AVERROR(EINVAL)) { 

    // An error or EOF occured,index break out and return what 
    // we have so far. 
     printf("AVERROR(EAGAIN): %d, AVERROR_EOF: %d, AVERROR(EINVAL): %d\n", 
     AVERROR(EAGAIN), AVERROR_EOF, AVERROR(EINVAL)); 
     printf("fe_read_frame: EOF or some othere decoding error (%d)!\n", 
     rest); 
     return; 
    } 


    // 2.1.1. convert frame to GRAYSCALE [or BGR] for OpenCV 
    sws_scale(pConvertCtx_BGR24, (const uint8_t* const*)pFrame->data, 
     pFrame->linesize, 0,pCodecCtx->height, pFrame_BGR24->data, 
      pFrame_BGR24->linesize); 
//} 
    av_packet_unref(&packet); 
    av_init_packet(&packet); 
    mwSize dims[] = {(pCodecCtx->width)*((pCodecCtx->height == 720) ? 720 : 
    pCodecCtx->height)*sizeof(uint8_t)*3}; 
    plhs[0] = mxCreateNumericArray(1,dims,mxUINT8_CLASS, mxREAL); 
    //plhs[0]=mxCreateDoubleMatrix(pCodecCtx->height,pCodecCtx- 
    >width,mxREAL); 
    point=mxGetPr(plhs[0]); 
    memcpy(point, pFrame_BGR24->data[0],(pCodecCtx->width)*(pCodecCtx- 
    >height)*sizeof(uint8_t)*3); 
} 

Answer 1

Gehen Sie zum Debugger und sehen Sie Ihren memcpy. Ich bin mir nicht sicher, ob es für alle Dimensionen funktioniert, die Sie wollen. Außerdem kann es mehr Speicherprobleme geben. Versucht zum Beispiel zu sehen, was der Wert von buffer_BGR24 und pFrame ist. Ich wette, dass sie manchmal keine richtigen Werte zurückgeben. Überprüfen Sie sie im Code.