Shift all the times in SRT subtitles by a constant amount

move_subs.py

#!/usr/bin/env python
# A little script to move the times in SRT subtitle files to
# align properly with your video.

import datetime
import re

time_re = re.compile(r'(\d\d):(\d\d):(\d\d),(\d\d\d)')

def next(i): # for python 2.5
   return i.next()

def moveTime(time, delta):
    t = datetime.datetime(2000,1,1, *map(int, time)) + delta
    return t.strftime('%H:%M:%S') + ',%03d' % t.microsecond

def time_line(line, delta):
    a, b = time_re.findall(line)
    return ' --> '.join(moveTime(x, delta) for x in (a,b))

def process_block(i, delta):
    print next(i), # number
    print time_line(next(i), delta)
    
    s = next(i)
    while s and s.strip():
        print s,
        s = next(i)
    print

def process_file(lines, delta):
    i = iter(lines)
    try:
        while True:
           process_block(i, delta)
    except StopIteration:
        pass

if __name__ == '__main__':
    import sys
    delta = datetime.timedelta(seconds=int(sys.argv[1]))
    process_file(sys.stdin, delta)