Bulk transcoding of files to MP3 using multiple cores and FFMPEG

convert_to_mp3.py

#!/usr/bin/env python

"""
Transcodes list of audio files specified as command-line arguments into
standard MP3s.

Actual transcoding is done via a subprocess call to ffmpeg. If multiple
cores are available, transcoding is parallelized via a pool of workers, each
of which transcodes one file at a time.
"""

import multiprocessing
import os
import signal
import subprocess
import sys

def init_worker():
    signal.signal(signal.SIGINT, signal.SIG_IGN)

def worker(fileurl):
    # Print informational message
    print multiprocessing.current_process().name,
    print ': converting ', fileurl
    sys.stdout.flush()

    # Derive output filename
    (root, ext) = os.path.splitext(fileurl)
    outfile = root + ".mp3"

    # If output file exists, break out
    if os.path.exists(outfile):
        return

    # Call out to ffmpeg
    subprocess.call(["ffmpeg", "-y", "-loglevel", "quiet", "-i", \
            fileurl, outfile])

if __name__ == '__main__':
    # Create a pool of workers (equal to number returned by cpu_count())
    pool = multiprocessing.Pool(initializer=init_worker)

    # Map conversion of files to pool of workers. Skip the program name itself.
    try:
        pool.map(worker, sys.argv[1:])

    except KeyboardInterrupt:
        print "Caught KeyboardInterrupt, terminating"
        pool.terminate()
        pool.join()

That is beatiful. Reused your code in my Bulk transcoding of video files using multiple cores and FFMPEG. Thanks, @thinkski!