Join 4GB GoPro chapter video files into a single file with ffmpeg

join_gopro_files.py

# Script to join GoPro video files, which are split at 4GB boundaries, into a single file
import os
import glob
import subprocess

# sleazy case-insensitive list of mp4 files in this dir
filepaths = glob.iglob("*.[mM][pP]4")
filenames = list(filter(lambda f: os.path.split(f)[1], filepaths))

# extract unique clip numbers from list of all files in this dir
clip_numbers = set()
for f in filenames:
    f_no_ext = os.path.splitext(f)[0]
    clip_numbers.add(f_no_ext[-4:])

for clip in clip_numbers:
    # create a text file listing the video files for each clip, in sorted order
    clip_files = sorted(list(filter(lambda f: clip in f, filenames)))
    with open("video_list.txt", "w") as vf:
        for f in clip_files:
            vf.write("file " + f + "\n")
    
    # execute fmpeg based on https://askubuntu.com/q/1342540 to join
    cmd = ["ffmpeg", 
           "-f", "concat", 
           "-safe", "0", 
           "-i", "video_list.txt",
           "-c", "copy",
           "GoPro" + clip + ".mp4"
           ]
    subprocess.check_call(cmd)