Extract audio from typical YouTube video files with ffmpeg

xa.py

#!/usr/bin/python

import os
import sys
import subprocess
import argparse

parser = argparse.ArgumentParser(description="Extract audio from video files")
parser.add_argument("files", metavar="file", nargs="+")
parser.add_argument("-w", "--wav", dest="codec", action="store_const", const="pcm_s16le", default="copy")
args = parser.parse_args()

for a in args.files:
  print a
  ext = ".m4a" if args.codec is "copy" else ".wav"
  outfile = os.path.splitext(a)[0] + ext

  cmd = ['ffmpeg',
    '-i', a,
    '-vn', '-acodec', args.codec,
    outfile]
  subprocess.check_call(cmd)