#!/usr/bin/env python2
 
 import sys, subprocess
 

 if len(sys.argv) > 2:

     ifile  = sys.argv[1]
     encopt = sys.argv[2:-1]
     ofile  = sys.argv[-1]
 else:
     print 'usage: %s <input> [encode_options] <output>' % sys.argv[0]
     sys.exit(1)
 
 analysis_cmd  = 'ffprobe -v error -of compact=p=0:nk=1 '
 analysis_cmd += '-show_entries frame_tags=lavfi.r128.I -f lavfi '
 analysis_cmd += "amovie='%s',ebur128=metadata=1" % ifile
 try:
     probe_out = subprocess.check_output(analysis_cmd, shell=True)
 except subprocess.CalledProcessError, e:
     sys.exit(e.returncode)
 loudness = ref = -23
 for line in probe_out.splitlines():
     sline = line.rstrip()
     if sline:
         loudness = sline
 adjust = ref - float(loudness)
 if abs(adjust) < 0.0001:
     print 'No normalization needed for ' + ifile
 else:
     print "Adjust %s by %.1fdB" % (ifile, adjust)
     norm_cmd  = ['ffmpeg', '-i', ifile, '-af', 'volume=%fdB' % adjust]
     norm_cmd += encopt + [ofile]
     print ' => %s' % ' '.join(norm_cmd)
     subprocess.call(norm_cmd)