A utility that automatically compresses timestamps for mkv chapter xml files from 23.976fps sources that have been converted to 24fps (only affects ChapterTimeStart as other timestamps can be removed)

23.975fps-to-24fps-chapters.pyw

import os, sys
import tkinter as tk
import xml.etree.ElementTree as ET

try:
    from tkinterdnd2 import TkinterDnD, DND_FILES
except ImportError:
    print('Please install tkinterdnd2: pip install tkinterdnd2')
    sys.exit(1)

r"""
Description:
  - A utility that automatically compresses timestamps for mkv chapter xml files from 23.976fps sources that have been converted to 24fps
  - This only affects ChapterTimeStart (other time stamps are not required and can be safely removed) and will overwrite the xml file(s)
Author:
  - natyusha
Requirements:
  - programs : python 3.7+
  - pip      : tkinterdnd2 (pip install tkinterdnd2)
Usage:
  - Run the script and drag chapter xml file(s) into the window
"""

def parse_time(time_str):
    """Convert Matroska timestamp (HH:MM:SS.nnnnnnnnn) to milliseconds"""
    time_parts = time_str.split(':')
    hours = int(time_parts[0])
    minutes = int(time_parts[1])
    seconds = float(time_parts[2])
    total_ms = (hours * 3600 + minutes * 60 + seconds) * 1000
    return total_ms

def format_time(ms):
    """Convert milliseconds back to Matroska timestamp format (HH:MM:SS.nnnnnnnnn), rounded to 3 decimal places"""
    seconds = ms / 1000
    hours = int(seconds // 3600)
    seconds %= 3600
    minutes = int(seconds // 60)
    seconds = seconds % 60
    seconds = round(seconds, 3)                          # round seconds to 3 decimal places
    return f'{hours:02d}:{minutes:02d}:{seconds:012.9f}' # format with 9 decimal places, padding with zeros

def convert_chapters(input_file, console):
    """Apply 23.976fps to 24fps conversion to ChapterTimeStart timestamps"""
    scale_factor = 23.976 / 24 # Approximately 0.999 (999 / 1000)

    try:
        # parse the XML file
        tree = ET.parse(input_file)
        root = tree.getroot()

        # process all ChapterTimeStart elements
        for chapter in root.findall('.//ChapterTimeStart'):
            time_ms = parse_time(chapter.text)
            scaled_ms = time_ms * scale_factor
            chapter.text = format_time(scaled_ms)

        # overwrite the original file
        tree.write(input_file, encoding='utf-8', xml_declaration=True)
        console.insert(tk.END, f'Success: Timestamps converted in:\n{os.path.basename(input_file)}\n')
        console.see(tk.END)
        return True

    except ET.ParseError:
        console.insert(tk.END, f'Error: Failed to parse XML file:\n{input_file}\n')
        console.see(tk.END)
    except FileNotFoundError:
        console.insert(tk.END, f'Error: File not found:\n{input_file}\n')
        console.see(tk.END)
    except Exception as e:
        console.insert(tk.END, f'Error: An error occurred:\n{e}\n')
        console.see(tk.END)
    return False

def on_drop(event, console):
    """Handle drag-and-drop for multiple files"""
    # get the dropped file path
    file_paths = event.data
    # handle TkinterDnD2 formatting (braced or space-separated paths)
    if file_paths.startswith('{') and file_paths.endswith('}'):
        file_paths = file_paths[1:-1].split('} {')
    else:
        file_paths = file_paths.split()

    # process each file
    for file_path in file_paths:
        if os.path.isfile(file_path) and file_path.lower().endswith('.xml'):
            convert_chapters(file_path, console)
        else:
            console.insert(tk.END, f'Error: Not a valid XML chapter file:\n{file_path}\n')
            console.see(tk.END)

def create_gui():
    """Create the GUI window for drag-and-drop with a console"""
    root = TkinterDnD.Tk()  # use TkinterDnD2.Tk for drag-and-drop support
    root.title('23.976fps to 24fps Chapters')
    root.geometry('500x200')
    root.resizable(False, False)

    # create a label to indicate drag-and-drop area
    label = tk.Label(
        root,
        text='Drag and Drop a Chapter XML File Here',
        font='TkHeadingFont',
        justify='center',
        borderwidth=2,
        relief='groove',
        padx=10,
        pady=10
    )
    label.pack(expand=False, fill='both', padx=10, pady=10)

    # create a scrollable console for messages
    console = tk.Text(
        root,
        font='TkFixedFont',
        wrap='word',
        state='normal'
    )
    console.pack(expand=True, fill='both', padx=10, pady=10)

    # add scrollbar to the console
    scrollbar = tk.Scrollbar(root, orient='vertical', command=console.yview)
    scrollbar.pack(side='right', fill='y')
    console['yscrollcommand'] = scrollbar.set

    # bind drag-and-drop events to the root window
    root.drop_target_register(DND_FILES)
    root.dnd_bind('<<Drop>>', lambda event: on_drop(event, console))

    root.mainloop()

def main():
    create_gui()


if __name__ == '__main__':
    main()