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• Output black when I decode h264 720p with ffmpeg

  6 décembre 2017, par José Marqueses Saxo

  First, sorry for my english. When I decode h264 720p in ardrone2.0 my output is black and I cant see anything.

  I have try to change the value of pCodecCtx->pix_fmt = AV_PIX_FMT_BGR24; to pCodecCtx->pix_fmt = AV_PIX_FMT_YUV420P; and the value of pCodecCtxH264->pix_fmt = AV_PIX_FMT_BGR24; to pCodecCtxH264->pix_fmt = AV_PIX_FMT_YUV420P; but my program crash. What am I doing wrong ?. Thank you, see part of my code :

  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);
  
  }

• How to speed up black video creation with FFMPEG ?

  2 décembre 2017, par Rick Sullivan

  I have been generating static black videos as backgrounds using FFMPEG’s color source. This works fine for smaller and shorter videos, but I need to be able to generate long 1080p black videos quickly.

  For example, I can generate a two hour long 1080p@30fps video using :

  ffmpeg -f lavfi -i color=black:s=1920x1080:r=30 -t 7200 test.mp4

  But this will take over 45 minutes to run.

  There are options that speed up runtime, like using the ultrafast preset :

  ffmpeg -f lavfi -i color=black:s=1920x1080:r=30 -preset ultrafast -t 7200 test.mp4

  Which will take around 20 minutes to run. Better, but not good enough for doing this en masse.

  Are there any other options to drastically speed up runtime ?

  Intuitively, I am generating a static video where only video duration varies, so it seems like there should be an approach that is restricted only by disk write speed. All of these options are very CPU intensive and seem to be doing more processing than is necessary for my use case.

• Convert video to hequirect while setting the background black and blur the transitional area [closed]

  11 février 2024, par Zurechtweiser

  I am using

  


  ffmpeg -i input.mp4 -vf "v360=input=fisheye:ih_fov=122.6:iv_fov=94.4:output=hequirect:h_fov=180:v_fov=180:in_stereo=2d:out_stereo=sbs,format=yuv420p" -b:v 25M -maxrate 60M -bufsize 25M output.mp4


  


  Which works as advertised to convert a fisheye to hequirect except for two problems :

  


  


  1. The background is not black but seems to try and set it to the average color of the video. It should be black throughout.

     


  


  2. The corners are not blurred but should be, there should be a soft transition from the corner of the video into black.