multitranscode.py

#!/usr/bin/env python3

"""
Multitranscode - Perform a series of h264 video transcodes on the input video

Usage:
  multitranscode <input> [-p PRESET] [-t TUNE] CRF ...
  multitranscode (-h | --help)
  multitranscode --version

Arguments:
  CRF ...  The CRF value to use for libx264, 0 is lossless and the standard
           range for lossy is usually 18 to 28.
  PRESET   The libx264 presets will be recognized here to modify encode rate.
           examples: veryslow, slow, fast, ultrafast
  TUNE     The libx264 tune settings will be recognized here to modify certain
           encoding parameters. examples: film, zerolatency, fastdecode

Options:
  -p --preset <preset>  libx264 preset to use [default: veryslow]
  -t --tune <tune>      libx264 tune setting to use [default: film]
  -h --help             Show this screen.
  --version             Show version.

https://trac.ffmpeg.org/wiki/Encode/H.264 is your friend!
"""

from docopt import docopt
import subprocess

if __name__ == '__main__':
    args = docopt(__doc__, version='Multitranscode 1.0')

    for crf_val in args['CRF']:
        if crf_val == '0':
            name = 'xcode_lossless_h264.mkv'
        else:
            name = 'xcode_crf{}_h264.mkv'.format(crf_val.zfill(2))

        #Perform the transcodes
        subprocess.run(['ffmpeg', '-i', args['<input>'],
                        '-map', '0',
                        '-c:a', 'copy',
                        '-c:v', 'libx264', '-preset', args['--preset'], '-tune', args['--tune'], '-crf', crf_val, name])