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• FFMPEG thumbnail image gives black image

  24 mars 2015, par user3772344

  I am trying to get the thumbnail image of video using ffmpeg. but for some of the video it shows the black image. I have done the following code.

   KxMovieDecoder * decoder = [[KxMovieDecoder alloc] init];
  
  [decoder openFile:videoURL error:nil];
  
  gHistory = [[NSUserDefaults standardUserDefaults]objectForKey:[decoder.path lastPathComponent]];;
  
  
  
  NSArray *ar =  [decoder decodeFrames:1.0f];
  
  KxMovieFrame *frame;
  
  
  
  for (KxMovieFrame *frames in ar)
  
  {
  
      if (frames.type == KxMovieFrameTypeVideo) {
  
          frame =  ar.lastObject;
  
          break;
  
      }
  
  }
  
     KxVideoFrameRGB *rgbFrame = (KxVideoFrameRGB *)frame;
  
  UIImage *imageKX = [rgbFrame asImage];

  I don’t know whats the wrong in this method

• FFMPEG exported video is all black

  5 mars 2024, par Kartikey

  I am trying to generate a video wall of 4 videos using ffmpeg like the given image

  


  

  


  I am exceuting this below script to get the desired result

  


  def merge_videos(output_file):
    command = [
        'path_to_ffmpeg/ffmpeg.exe',
        '-i', 'path/playblasts/front.mp4',
        '-i', 'path/playblasts/side.mp4',
        '-i', 'path/playblasts/persp1.mp4',
        '-i', 'path/playblasts/persp2.mp4',
        '-filter_complex', '[0:v][1:v][2:v][3:v]xstack=inputs=4:layout=0_0|w0_0|0_h0|w0_h0[v]',
        '-map', '[v]',
        output_file
    ]
    subprocess.run(command)


  


  where as passing output file path as argument, but I am getting below result

  


  

  


  Any help would be appreciated.
Thanks & Best Regards

  


• Intermitent Connection Issues for FFMPEG Stream capture

  22 novembre 2014, par Quentin Spottiswoode

  I intend to create a Python shell script to open a connection to an MP3 stream and record the stream over a specified period and save the file to a .mp3 file for distribution. ffmpeg will likely be involved through a shell command, rather than using any kind of python wrapper class.

  Occasionally, the source of the stream may encounter connection issues with the internet, resulting in the listening client (ffmpeg) losing it’s connection with the host. Currently ffmpeg discards the recording entirely and forgets about attempting to reconnect to the host.

  having had a look through ffmpeg’s extensive documentation, I found myself very confused...

  • Is there some method to retain the recording up to the point of the connection failure ?
  • Is there a method of automatically re-connecting to the stream when the host reappears, or do I have to catch the error and try a certain number of times ?
  • Is there a method of passing the error to the python script in order to create a suitable response ?

  Many thanks for your insight :)