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• FFmpeg hangs on buffer fill c++

  2 mars 2021, par Derek Halden

  I'm processing a bunch of frames from an RTSP stream using ffmpeg. I end up doing a lot of processing on these frames, which means that I'm not always pulling in real-time. If the buffer gets full, the process hangs. I'm wondering if one of the following solutions is feasible/fixes the problem, and if so, how I would implement it using the ffmpeg libraries :

  



  1) Is there a way to clear the buffer if I ever reach a point where it's hanging ? (I can determine when it's hung, I just don't know what to do about it).

  



  2) Is there a way to make the buffer overwrite the old data, and just always read the most recent data ? It doesn't matter to me if I lose frames.

  



  3) I've already discovered that I can make the buffer arbtrarily large with : av_dict_set(&avd, "buffer_size", "655360", 0);. This could be a solution, but I don't know how large/small it needs to be, because I don't know how long the stream will post video for ?

  



  4) Is this just a bug that I need to bring up with the ffmpeg people ?

  



  5) Something else I haven't considered ?

  



  while(av_read_frame(context, &(packet)) >= 0 && fcount < fps*SECONDS) {
    clock_t start, end;
    int ret = avcodec_send_packet(codec_context, packet);
    if(!(packet->stream_index == video_stream_index)) {
      continue;
    }

    if (ret == AVERROR(EAGAIN) || ret == AVERROR(EINVAL)) {
      continue;
    } else if (ret < 0) {
      cerr << "Error while decoding frame " << fcount << endl;
      exit(1);
    }

    ret = avcodec_receive_frame(codec_context, frame);
    if (ret == AVERROR(EAGAIN) || ret == AVERROR(EINVAL)) {
      continue;
    } else if (ret < 0) {
      cerr << "Error while decoding frame " << fcount << endl;
      exit(1);
    }

    sws_scale(img_convert_ctx, frame->data, frame->linesize, 0,
              codec_context->height, picture_rgb->data, picture_rgb->linesize);

    if(!frame) {
      cerr << "Could not allocate video frame" << endl;
      exit(1);
    }

    if(codec_context == NULL) {
      cerr << "Cannot initialize the conversion context!" << endl;
      exit(1);
    }

    // Do something with the frame here

    fcount++;
    av_packet_unref(&(packet));

}


  



  I have added the code that causes the program to hang.

  


• Malloc Check Failed when opening video stream

  30 août 2017, par donturner

  I’m writing a BlackBerry 10 application which decodes an H264 video stream (from a Parrot AR Drone) using ffmpeg and libx264. These libraries have both been compiled for BlackBerry QNX.

  Here’s my code :

  av_register_all();
  
  avcodec_register_all();
  
  avformat_network_init();
  
  
  
  printf("AV setup complete\n");
  
  
  
  const char* drone_addr = "http://192.168.1.1:5555";
  
  AVFormatContext* pFormatCtx = NULL;
  
  AVInputFormat* pInputFormat = av_find_input_format("H264");
  
  
  
  printf("Opening video feed from drone\n");
  
  
  
  //THIS LINE FAILS 
  
  int result = avformat_open_input(&pFormatCtx, drone_addr, pInputFormat, NULL); 

  The last line fails with the error :

  Malloc Check Failed: :../../dlist.c:1168

  How can I fix this error or debug it further ?

  Update : The error only occurs when I supply pInputFormat to avformat_open_input. If I supply NULL I don’t get an error. But for my app I must supply this parameter since it is not possible for ffmpeg to determine the video format from the feed alone.

• Malloc Check Failed when opening video stream

  30 août 2017, par donturner

  I’m writing a BlackBerry 10 application which decodes an H264 video stream (from a Parrot AR Drone) using ffmpeg and libx264. These libraries have both been compiled for BlackBerry QNX.

  Here’s my code :

  av_register_all();
  
  avcodec_register_all();
  
  avformat_network_init();
  
  
  
  printf("AV setup complete\n");
  
  
  
  const char* drone_addr = "http://192.168.1.1:5555";
  
  AVFormatContext* pFormatCtx = NULL;
  
  AVInputFormat* pInputFormat = av_find_input_format("H264");
  
  
  
  printf("Opening video feed from drone\n");
  
  
  
  //THIS LINE FAILS 
  
  int result = avformat_open_input(&pFormatCtx, drone_addr, pInputFormat, NULL); 

  The last line fails with the error :

  Malloc Check Failed: :../../dlist.c:1168

  How can I fix this error or debug it further ?

  Update : The error only occurs when I supply pInputFormat to avformat_open_input. If I supply NULL I don’t get an error. But for my app I must supply this parameter since it is not possible for ffmpeg to determine the video format from the feed alone.