Concatenate a few video files into one with ffmpeg

concat.py

"""
Concatenate a few video files into one with ffmpeg
Use a wild card
"""

import subprocess
import glob
import re

to_concat = 'robocar*'

def natural_key(string_):
    """See http://www.codinghorror.com/blog/archives/001018.html"""
    return [int(s) if s.isdigit() else s for s in re.split(r'(\d+)', string_)]

files = glob.glob(to_concat)
files = sorted(files, key=natural_key)

with open('tmplist.txt', 'w') as out_fh:
    for fn in files:
        line = "file '%s'\n" % fn
        out_fh.write(line)

cmd = 'ffmpeg -f concat -safe 0 -i tmplist.txt -c copy output.mp4'
subprocess.check_call(cmd, shell=True)