Python script to extract each track in a .MKV file

split_mkv.py

# requires ffmpeg-python and click
import click
import ffmpeg
import os.path

def extract_track(filepath, track_index, output_path):
	file = ffmpeg.input(filepath)
	output = ffmpeg.output(file[f"{track_index}"], output_path)
	ffmpeg.run(output)

@click.command()
@click.option("--file", "filepath", type=click.Path(exists=True), required=True)
@click.option("--video", "video_format", default="mp4", help="Format to use for video tracks")
@click.option("--audio", "audio_format", default="mp3", help="Format to use for audio tracks")
@click.option("--format", "filename_formatting", default="{filename} - {title}", help="Filename formatting for output files", required=False)
@click.option("--directory", "output_directory", help="Directory to store output files", required=False)
def main(filepath: str, video_format: str, audio_format: str, filename_formatting: str, output_directory: str):
	"""
	Split a MKV file into each stream to representative files.
	"""

	codec_map = {
		"video": video_format,
		"audio": audio_format,
	}
	
	directory, filename = os.path.split(filepath) # remove filepath
	filename, _ = os.path.splitext(filename) # remove extension
	
	if output_directory is not None: # override directory if other directory is specified
		directory = output_directory
	
	for stream in ffmpeg.probe(filepath).get("streams", []):
		index = stream.get("index", None)
		codec = stream.get("codec_type", None)
		assert index is not None, "Stream index is None"
		assert codec in codec_map, f"Unsupported codec {codec}"

		title = stream.get("tags", {}).get("title", codec) # use codec name if no title
		extension = codec_map[codec]

		output_filepath = os.path.join(directory, filename_formatting.format(**{
			"filename": filename,
			"title": title,
			"index": index,
			"codec": codec,
		}))
		output_filepath += f".{extension}"

		extract_track(filepath, index, output_filepath)

if __name__ == "__main__":
	main()