rename-m4a.py

from mutagen.mp4 import MP4
import argparse
import os
import os.path
import pprint
import re


def _main():
    parser = argparse.ArgumentParser(
        description='Rename M4A files based on their title metadata')
    parser.add_argument('directory', help='M4A scan directory')
    parser.add_argument('--start', type=int, default=1,
                        help='Start number for renaming (default: 1)')
    args = parser.parse_args()

    files = [os.path.join(args.directory, x)
             for x in os.listdir(args.directory) if x.endswith(".m4a")]
    files.sort()
    pprint.pprint(files)

    for i, one_file in enumerate(files):

        audio = MP4(one_file)
        if '\xa9nam' in audio:
            title = audio['\xa9nam'][0]
            title = re.sub(r'^\d+ ', '', title)
            new_title = f"{(i+args.start):03d} {title}"
            print(f"\"{title}\" -> \"{new_title}\"")
            audio['\xa9nam'] = new_title
            audio.save()
            os.rename(one_file, os.path.join(
                args.directory, f"{new_title}.m4a"))
        else:
            print(f"No title metadata found in {one_file}")


if __name__ == '__main__':
    _main()