mp4tomp3.py

"""Script used to extract audio tracks from MP4 videos to MP3
   with ffmpeg. The script processes multiple files simultaneously.

Examples:

    # To extract the audio track from my-video.mp4
    # and write it in my-videos.mp3:
    python3 mp4tomp3.py my-video.mp4

    # the script accepts multiple arguments
    python3 mp4tomp3.py my-video1.mp4 my-video2.mp4

    # pass a directory to the script to convert all MP4 videos
    # contained in this directory (not recursive)
    python3 mp4tomp3.py my-directory/

"""
import argparse
import multiprocessing
from pathlib import Path
import subprocess
import sys


def convert_mp4(mp4):
    mp3 = str(mp4)[:-4] + ".mp3"
    command = ["ffmpeg", "-i", mp4, mp3]
    subprocess.run(command)


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "-p",
        "--processes",
        help="Specifies  the number of conversions to run simultaneously (default is %(default)s)",
        default=multiprocessing.cpu_count(),
    )
    parser.add_argument(
        "PATH", help="MP4 file to convert or directory containing MP4 files to convert", nargs='+'
    )
    args = parser.parse_args()

    # gather all the files to be converted
    tasks = set()
    for path in args.PATH:
        path = Path(path).resolve()
        if not path.exists():
            print("Error: path does not exists: ", path, file=sys.stderr)
            sys.exit(1)

        if path.is_dir():
            for mp4 in path.glob("*.mp4"):
                tasks.add(mp4)
        else:
            tasks.add(path)
    # execute the conversion in a pool of processes
    with multiprocessing.Pool(args.processes) as pool:
        pool.map(convert_mp4, tasks)


if __name__ == "__main__":
    main()