old_contents: from multiprocessing import cpu_count
  
  
  ENCODING_OPTIONS = {
      'mp3': '-c:a libmp3lame '
             '-vbr 3 ',
      'h264': '-c:v libx264 '
              '-preset ultrafast '
              '-crf 21 ',
      'mp4': '-f mp4'
  }
  
  COPY_OPTIONS = {
      'audio': '-c:a copy',
      'video': '-c:v copy',
      'container': ''
  }
  
  THREADS = cpu_count()
  
  AUDIO_CODEC = 'mp3'
  VIDEO_CODEC = 'h264'
  CONTAINER_TYPE = 'mp4'
  
  NEW_FILE_FMT = '%s_castconvert.mp4'
new_contents: from multiprocessing import cpu_count
  
  
  ENCODING_OPTIONS = {
      'mp3': '-c:a libmp3lame '
             '-q:a 3 ',
      'h264': '-c:v libx264 '
              '-preset ultrafast '
              '-crf 21 ',
      'mp4': '-f mp4'
  }
  
  COPY_OPTIONS = {
      'audio': '-c:a copy',
      'video': '-c:v copy',
      'container': ''
  }
  
  THREADS = cpu_count()
  
  AUDIO_CODEC = 'mp3'
  VIDEO_CODEC = 'h264'
  CONTAINER_TYPE = 'mp4'
  
  NEW_FILE_FMT = '%s_castconvert.mp4'
subject: USe -q:a flag for mp3 encoder