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• Trying to fetch all audio streams with FFmpeg Python

  27 juillet 2022, par Apollo

  I'm using ffmpeg-python to fetch streams from a video and write some parameters (codec_name, resolution, etc.) for each stream into csv.

  


  video = 'test.mkv'
probe = ffmpeg.probe(video)
video_stream = next((stream for stream in probe['streams'] if stream['codec_type'] == 'video'), None)
print(video_stream['codec_long_name'])
audio_stream = next((stream for stream in probe['streams'] if stream['codec_type'] == 'audio'), None)
...


  


  My problem is that it works well for a video stream, but not for multiple audio (or subtitles) streams. If the video has several audio streams it returns only one audio stream.

  


  I've tried another approach, but it returns some streams 2-3 times and I get duplicates. So if the video sample has 4 audio tracks, I end up with 9 audio streams instread of 4.

  


  audio_streams = []
for audio in (probe['streams']):
    if (audio['codec_type'] == 'audio'):
        audio_streams.append(audio)
        pprint(audio_streams)


  


  All other ideas I tried don't work, I'm new to programming and I'm stuck with it.
How can I get all audio streams from a file without duplicates ?

  


• How do I get the last line of a popen() callback in every iteration ?

  29 mai 2017, par Mike

  I’m trying to create a progress bar with FFMPEG using php and AJAX. When a user uploads a video file I want to be able to display the current percent until completion. I have managed to get everything working but I have one issue.

  The data returns what I want, but it also returns all the data from the previous iterations... like it just keeps stacking everything on top rather than flushing out the data from previous iterations. I tried to work with tail thinking it would return only the last line, but it did not return anything.

  Here is the code I’m working with :

  encode.php

  $video_path = 'test.mp4';
  
  $cmd        = 'ffmpeg -i ' . $video_path .' -y -hide_banner output.mp4 2>&1';
  
  
  
  while (@ ob_end_flush());
  
  
  
  $proc = popen($cmd, 'r');
  
  
  
  while (!feof($proc))
  
  {
  
  
  
      $file = escapeshellarg(fread($proc, 4096));
  
      //$line = `tail -n 1 $file`; // <-tried this with no luck
  
      echo fread($file, 4096) . "\n";
  
      @ flush();
  
  }
  
  return 'complete';
  
  pclose($proc);

  The above code returns :

  // first iteration
  
  frame=   52 fps= 13 q=29.0 size=     279kB time=00:00:00.10 bitrate=22856.9kbits/s
  
  
  
  // second iteration
  
  frame=   52 fps= 13 q=29.0 size=     279kB time=00:00:00.10 bitrate=22856.9kbits/s    
  
  frame=   54 fps= 12 q=29.0 size=     329kB time=00:00:00.16 bitrate=16146.6kbits/s 
  
  
  
  // third iteration
  
  frame=   52 fps= 13 q=29.0 size=     279kB time=00:00:00.10 bitrate=22856.9kbits/s    
  
  frame=   54 fps= 12 q=29.0 size=     329kB time=00:00:00.16 bitrate=16146.6kbits/s    
  
  frame=   57 fps= 11 q=29.0 size=     464kB time=00:00:00.26 bitrate=14233.2kbits/s 

  As you can see the data stacks, I need only the new line of data, not the data stacking.

  ** EDIT ** this has been marked as a duplicate, rather than me explain how it’s different, I’d like to hear how this is the same thing ? I am not writing to a log file and, like most people, do not feel that’s a good solution.

• Evolution #3787 : Pouvoir échapper fins de lignes et espaces

  3 juin 2016, par jluc -

  Il est aussi parfois très difficile de manipuler, dans les expressions SPIP, les quotes simples ou doubles ’ ou " ainsi que la virgule.

  Exemple

  #VAL’0000-00-00’ / #VAL"0000-00-00" 

  
  sont compris comme

  0000-00-00/ 0000-00-00/ 1

  
  grâce à la magie de SPIP, mais du coup c’est difficile d’intégrer les ’ les " dans les valeurs.

  Pareil pour la virgule, qui étant séparateur d’argument des filtres perturbe la lecture des arguments quand on veut l’utiliser comme simple caractère.

  Il serait pratique de pouvoir les échapper pour que SPIP ne les prenne pas pour des caractères spéciaux.