mp4split_stderr.py

mp4box = 'c:\Programs\GPAC\MP4Box.exe'


def tosec(s):
    # convert time signature to seconds as float
    from datetime import datetime
    dt = datetime.strptime(s, '%H:%M:%S.%f')
    return dt.hour * 3600 + dt.minute * 60 + dt.second + dt.microsecond * 10e-7


def main(arg):
    import re, os, time, subprocess
    from subprocess import check_call, check_output

    fn = arg[0]
    if os.path.isfile(fn):
        folder = os.path.dirname(fn)
        try:
            info = subprocess.check_output([mp4box, "-info", fn], stderr=subprocess.STDOUT)
            # extract all chapter time signatures
            time_fmt = '\d{2}:\d{2}:\d{2}.\d{3}'
            m = re.findall('Chapter #\d+ - (%s)' % (time_fmt,), info)
            if len(m) > 1:
                m.append(re.search('Duration (%s)' % time_fmt, info).group(1))
                # find chapter titles
                chapters = re.findall('Chapter #\d+ - %s - "(.*?)"' % time_fmt, info)
                # add default values to chapthers w/o title
                chapters = ['Chapter %02d' % (x+1) if y == "" else y for (x, y) in enumerate(chapters)]
                # make convenient filename for each chapter
                chapters = ['%02d - %s.m4a' % (x+1, ''.join(z for z in y if (z.isalnum() or z in ' _'))) for x, y in enumerate(chapters)]
                # iterate over each chapter range
                for z, (x, y) in enumerate(zip(m[0::1], m[1::1])):
                    if len(arg) == 1 or int(arg[1]) == z+1:
                        check_call([mp4box, '-splitx', '%s:%s' % (tosec(x), tosec(y)),
                                   fn, '-out', os.path.join(folder, chapters[z])])
                        check_call([mp4box, '-add', '%s#1' % os.path.join(folder, chapters[z]),
                                   '-new', os.path.join(folder, chapters[z])])
            else:
                msg = 'File "%s" doesn\'t contain chapters' % fn
        except Exception as e:
            msg = str(e)
    else:
        msg = 'File "%s" doesn\'t exist' % fn

    if 'msg' in vars():
        print(msg)

if __name__ == '__main__':
    import sys
    if len(sys.argv) > 1:
        main(sys.argv[1:])
    else:
        print('Usage: python.exe mp4split.py input.m4a [chapter_number]')