Python 3 script for using ffmpeg to split mp3 files on chapters (from metadata)

convert.py

import os
import re
import pprint
import sys
from os.path import basename
from optparse import OptionParser
from subprocess import (
    check_output,
    STDOUT,
    CalledProcessError
)


def parseChapters(filename):
    chapters = []
    command = ["ffmpeg", '-i', filename]
    output = ""
    m = None
    title = None
    chapter_match = None
    try:
        # ffmpeg requires an output file and so it errors
        # when it does not get one so we need to capture stderr,
        # not stdout.
        output = check_output(
            command, stderr=STDOUT, universal_newlines=True)
    except CalledProcessError as e:
        output = e.output

    num = 1

    for line in iter(output.splitlines()):
        x = re.match(r".*title.*: (.*)", line)
        print("x:")
        pprint.pprint(x)

        print("title:")
        pprint.pprint(title)

        if x == None:
            m1 = re.match(
                r".*Chapter #(\d+:\d+): start (\d+\.\d+), end (\d+\.\d+).*", line)
            title = None
        else:
            title = x.group(1)

        if m1 != None:
            chapter_match = m1

        print("chapter_match:")
        pprint.pprint(chapter_match)

        if title != None and chapter_match != None:
            m = chapter_match
            pprint.pprint(title)
        else:
            m = None

        if m != None:
            chapters.append({"name": "{:03}".format(
                num) + " - " + title, "start": m.group(2), "end": m.group(3)})
            num += 1

    return chapters


def getChapters():
    parser = OptionParser(
        usage="usage: %prog [options] filename", version="%prog 1.0")
    parser.add_option("-f", "--file", dest="infile",
                      help="Input File", metavar="FILE")
    (options, args) = parser.parse_args()
    if not options.infile:
        parser.error('Filename required')
    chapters = parseChapters(options.infile)
    fbase, fext = os.path.splitext(options.infile)
    path, file = os.path.split(options.infile)
    newdir, fext = os.path.splitext(basename(options.infile))

    os.mkdir(path + "/" + newdir)

    for chap in chapters:
        chap['name'] = chap['name'].replace('/', ':')
        chap['name'] = chap['name'].replace("'", "\'")
        print("start:" + chap['start'])
        chap['outfile'] = path + "/" + newdir + "/" + \
            re.sub("[^-a-zA-Z0-9_.():' ]+", '', chap['name']) + fext
        chap['origfile'] = options.infile
        print(chap['outfile'])
    return chapters


def convertChapters(chapters):
    for chap in chapters:
        print("start:" + chap['start'])
        print(chap)
        command = [
            "ffmpeg", '-i', chap['origfile'],
            '-vcodec', 'copy',
            '-acodec', 'copy',
            '-ss', chap['start'],
            '-to', chap['end'],
            chap['outfile']]
        output = ""
        try:
            # ffmpeg requires an output file and so it errors
            # when it does not get one
            output = check_output(
                command, stderr=STDOUT, universal_newlines=True)
        except CalledProcessError as e:
            output = e.output
            raise RuntimeError("command '{}' return with error (code {}): {}".format(
                e.cmd, e.returncode, e.output))


if __name__ == '__main__':
    chapters = getChapters()
    convertChapters(chapters)