Audio file separator

separator.py

"""
Audio file separator 
This script splits an audio file into a given length of video files.
1. Split an input file into a given length of .wav files
2. Combine the .wav file with a given video file using FFmpeg
You can use this script to prepare for audio psychological experiments. 

(c) T.Mizumoto
"""

import pathlib
import subprocess
import argparse
import pydub
import pydub.utils
import numpy


if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "file",
        help="Input audio file"
    )
    parser.add_argument(
        "--videofile", default="noaudio.mp4",
        help="A silent video file to combine with audio chunks."
    )
    parser.add_argument(
        "--chunk_length", default=60, type=int,
        help="duration of the audio file"
    )
    args = parser.parse_args()

    # parse audio file
    input_file = pathlib.Path(args.file)
    sound = pydub.AudioSegment.from_file(file=args.file)
    samples = numpy.array(sound.get_array_of_samples())
    nsamples = len(samples)

    chunk_size = args.chunk_length * sound.frame_rate

    # prepare a folder to store the chunks
    folder = pathlib.Path(input_file.with_suffix(""))
    folder.mkdir(exist_ok=True)
  
    # Calculate start and end samples, splits, and converts into a video
    for index, start in enumerate(range(0, nsamples, chunk_size)):
        end = start + chunk_size
        print(start, end, sound[start:end])
        filename = folder / ("%05d.wav" % index)
        sound[start:end].export(filename, format="wav")
        
        subprocess.call(
            "ffmpeg -i %s -i %s -y %s.mp4" % (
                args.videofile, filename, filename.with_suffix("")
            ), shell=True
        )
        filename.unlink()