A simple Python script for splitting an audio file using ffmpeg and a set list.

split-audio.py

#!/usr/bin/env python3
"""
Split an audio file based on the timestamps in a file containing set information.

Expected format for the setfile is:

    HH:MM:SS Track #1
    HH:MM:SS Track #2
    HH:MM:SS Track #3

    Note: "HH:MM:SS" is the timestamp in the file where the given track starts.

Artist and album information can be given to the script as well and metadata
will automatically be filled out for the generated files.
"""
import argparse
import itertools
import os
import subprocess
import sys


DEFAULT_ARTIST = 'Unknown Artist'
DEFAULT_ALBUM = 'Unknown Album'


def get_metadata(track_num, track, artist, album):
    """
    Builds metadata args for basic tagging.
    """
    metadata = {
        'title': track,
        'artist': artist,
        'album_artist': artist,
        'album': album,
        'track': track_num,
    }

    return itertools.chain(*[('-metadata', f'{k}={v}') for k, v in metadata.items()])


def main(args):
    lines = [l.strip() for l in args.setfile]
    num_tracks = len(lines)

    for track_num, line in enumerate(lines, start=1):
        start, track = line.split(maxsplit=1)
        _, ext = os.path.splitext(args.infile)
        command = ['ffmpeg', '-i', args.infile, '-acodec', 'copy', '-ss', start]

        if track_num < num_tracks:
            end, _ = lines[track_num].split(maxsplit=1)
            command.extend(['-to', end])

        command.extend(get_metadata(track_num, track, args.artist, args.album))
        command.append(f'{args.outdir}/{track_num:02d}-{track}{ext}')

        try:
            ret = subprocess.run(command, check=True, capture_output=True)
        except subprocess.CalledProcessError as cpe:
            error = cpe.stderr.decode("utf-8")
            print(f'Error:\n{error}', file=sys.stderr)
            return cpe.returncode

    return 0


if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('--infile', '-i', required=True,
            help='The audio file to split')
    parser.add_argument('--outdir', '-o', required=True,
            help='The directory to write split files to')
    parser.add_argument('--setfile', '-s', type=argparse.FileType('r'), required=True,
            help='The file containing set information')
    parser.add_argument('--artist', default=DEFAULT_ARTIST,
            help='The artist to use in the generated metadata')
    parser.add_argument('--album', default=DEFAULT_ALBUM,
            help='The album name to use in the generated metadata')
    args = parser.parse_args()

    if not os.path.exists(args.outdir):
        os.mkdir(os.path.expanduser(args.outdir))

    raise SystemExit(main(args))