YouTube VTT cleaning script

clean_vtt.py

#!/usr/bin/env python3

# Forked and improved version of https://github.com/anandiamy/Batch-Single-Clean-Youtube-Vtt/blob/main/single_clean.py

# Remove duplicated lines from a .vtt file generated by youtube-dl when
# downloading auto-subs from a Youtube video using the --write-auto-sub option
# This script only prints the lines so save the edited subs as:
#
# python this_script.py original_sub.vtt new_sub.vtt

import re
import sys
import html

# a subtitle is a timestamp line followed by one or more lines of text

# Find a line starting with a time stamp: 00:13:23 ...
TIMESTAMP_PATTERN = re.compile(r'^\d\d:\d\d:\d\d', re.M)

# Matches inline YouTube timestamps like:
# <00:00:01.680>
INLINE_TIMESTAMP_PATTERN = re.compile(r'<\d\d:\d\d:\d\d\.\d{3}>')

# Matches caption formatting tags like:
# <c> and </c>
CAPTION_TAG_PATTERN = re.compile(r'</?c>')

def clean_vtt_line(line):
    """Remove YouTube inline timestamps and caption formatting tags."""
    line = INLINE_TIMESTAMP_PATTERN.sub('', line)
    line = CAPTION_TAG_PATTERN.sub('', line)
    line = html.unescape(line)
    return line

def print_subtitle(output_file, timestamp, text, previous_text):
    deduped = [line for line in text if line == '\n' or line not in previous_text]
    if len([line for line in deduped if line.strip()]) == 0:
        return
    output_file.write(timestamp)
    for t in deduped:
        output_file.write(t)

def clean_vtt_content(input_file, output_file):
    with open(input_file, 'r', encoding='utf-8') as f:
        subtitle_timestamp = ''
        subtitle_text = []
        last_subtitle_text = []
        for line in f:
            line = clean_vtt_line(line)
            if re.findall(TIMESTAMP_PATTERN, line):
                print_subtitle(output_file, subtitle_timestamp, subtitle_text, last_subtitle_text)
                last_subtitle_text = subtitle_text
                subtitle_timestamp = line
                subtitle_text = []
                continue
            subtitle_text.append(line)
        print_subtitle(output_file, subtitle_timestamp, subtitle_text, last_subtitle_text)

if __name__ == "__main__":
    try:
        input_file = sys.argv[1]
        output_file = sys.argv[2]
        
        with open(output_file, 'w', encoding='utf-8') as out_f:
            clean_vtt_content(input_file, out_f)
        print(f"File successfully cleaned and saved to {output_file}")
    except FileNotFoundError:
        print("Error: Input file not found")
    except Exception as e:
        print(f"An error occurred: {str(e)}")