Script to convert 'tagged' or incorrectly numbered chapters to correctly numbered chapters

auto_ogm_chapters.py

from pathlib import Path
from typing import Union

from pymediainfo import MediaInfo


def generate_chapters(mode: str, mode_input: Union[Path, str] = None):
    """
    Generate proper chapters with existing timestamps

    :param mode: Accepts selection via strings 'chapter_data' or 'parse_file'.
    :param mode_input: 'chapter_data' = pymediainfo dictionary of menu data, 'parse_file' = mediafile input
    :return: Correctly numbered chapters based off of the input timestamps
    """

    # check which mode
    if mode == "chapter_data":
        mi_parse = mode_input
    elif mode == "parse_file":
        if not Path(mode_input).is_file():
            raise FileNotFoundError("You must pass a media file with mode 'parse_file'")
        mi_parse = MediaInfo.parse(Path(mode_input)).menu_tracks[0].to_data()
    else:
        raise ValueError("'mode' must be equal to 'chapter_data' or 'parse_file'")

    # parse file with mediainfo
    chapter_starting_index = list(mi_parse.keys()).index("chapters_pos_end") + 1
    chapter_timestamps = list(mi_parse.keys())[chapter_starting_index:]

    # create chapters
    new_chapter_file = ""
    for ch_num, ct in enumerate(chapter_timestamps, start=1):
        # format timestamps
        chap_timestamps_list = ct.replace("_", ":").split(":")
        chap_timestamps = "{}:{}:{}".format(
            chap_timestamps_list[0],
            chap_timestamps_list[1],
            chap_timestamps_list[2][:2] + "." + chap_timestamps_list[2][2:],
        )

        # format chapter numbers
        chapter_number = str(ch_num).zfill(2)

        # create chapter lines
        chapter_line1 = "CHAPTER{}={}".format(chapter_number, chap_timestamps)
        chapter_line2 = "CHAPTER{}NAME=Chapter {}".format(
            chapter_number, chapter_number
        )

        # update chapter file
        new_chapter_file = (
            new_chapter_file + chapter_line1 + "\n" + chapter_line2 + "\n"
        )

    return new_chapter_file.rstrip()