YouTube XML Caption Format to SRT

youtube_xml_to_srt.py

#!/usr/bin/env python3
# -*- encoding:utf-8 -*-

# Install: pip install lxml
# Usage: python youtube_xml_to_srt.py INPUT_FILE.xml > OUTPUT_FILE.srt

import re
import sys
from decimal import Decimal
import html
from lxml import html as lxml_html

filename = sys.argv[1]
with open(filename, 'rb') as f:
    root = lxml_html.fromstring(f.read())

def extract_s_ms(value):
    if '.' in value:
        s, ms = value.split('.')
    else:
        s, ms = (value, 0)
    return Decimal(s), Decimal(ms)

def convert_to_h_m_s(value):
    rem_m, s = divmod(value, 60)
    h, m = divmod(rem_m, 60)
    return h, m, s

for (i, element) in enumerate(root):
    start_time_s, start_time_ms = extract_s_ms(element.attrib['start'])
    duration_s, duration_ms = extract_s_ms(element.attrib['dur'])

    end_time_s, end_time_ms = start_time_s + duration_s, start_time_ms + duration_ms

    s_h, s_m, s_s = convert_to_h_m_s(start_time_s)
    e_h, e_m, e_s = convert_to_h_m_s(end_time_s)

    text = html.unescape(element.text)
    print(f"""{i}
{s_h:02.2}:{s_m:02.2}:{s_s:02.2},{start_time_ms:03} --> {e_h:02.2}:{e_m:02.2}:{e_s:02.2},{end_time_ms:03}
{text}
""")