make_camhd_srt_subtitles.py

import argparse
import logging
import datetime
from os import path

parser = argparse.ArgumentParser(description='Generate .str file for a set of image files')

parser.add_argument('input', metavar='inputfiles', nargs='+',
                    help='Image files to process')

parser.add_argument('--output', dest='srtfile', nargs='?', default='subtitles.srt', help='Name of output .srt file')

args = parser.parse_args()

images_per_sec = 10.0
dt = datetime.timedelta(seconds=(1.0/images_per_sec))

with open(args.srtfile, 'w') as srt:
    count = 1
    this_time = datetime.datetime(1,1,1)

    for f in args.input:
        srt.write("%d\n" % count)

        next_time = this_time + dt
        srt.write("%02d:%02d:%02d,%03d --> %02d:%02d:%02d,%03d\n" %
                  (this_time.hour, this_time.minute, this_time.second, this_time.microsecond/1000,
                   next_time.hour, next_time.minute, next_time.second, next_time.microsecond/1000))

        # Write the actual subtitle
        srt.write("%s\n" % path.basename(f) )

        # Blank line between entries
        srt.write("\n")

        this_time = next_time
        count = count + 1


## To add subtitles to an existing file (makes a new copy)
#  ffmpeg -i input.mp4 -i subtitles.srt -scodec mov_text subtitled.mp4
#
# This '-scodec mov_text' converts the .srt file to mov_text, which I guess
# the mp4 version of subtitle data.  Not necessary if using a different
# container (?)