Converting an audio library to mp3

1 minute read

Over the years I had accumulated a number of audio recordings done with Audacity with a mix of formats and quality. I had these stored on a Synology NAS in a deeply nested structure and I wanted to standardise the format to 320kbps mp3 files so I wrote the following script to do so.

The script does the following:

Traverses a directory tree recursively (using python’s os.walk)
Guesses the file type using the filetype package (some files had a format that did not match the extension)
If file is OGG, Flac or Wav it triggers ffmpeg to convert it to 320k mp3.
On success it removes the old file

To set it up, create a file flac_to_mp3.py with contents:

#!/usr/bin/env python

import os
import sys
import filetype

print('FLAC to MP3 Script')

if len(sys.argv) > 1:
    folder = sys.argv[1]
    print('Will scan folder ' + folder)
    for dirpath, dnames, fnames in os.walk(folder):
        for f in fnames:
            sys.stdout.write('.')
            sys.stdout.flush()
            file_path = os.path.join(dirpath, f)
            file_kind = filetype.guess(file_path)
            if file_kind is None:
                continue
            elif file_kind.mime == "audio/x-flac" \
                    or file_kind.mime == "audio/x-wav" \
                    or file_kind.mime == "audio/ogg":
                print('\nConverting: ' + file_kind.mime + ' - ' + file_path)
                destination_file = os.path.splitext(file_path)[0] + '.mp3'
                os.system("ffmpeg -i \"{0}\" -ab 320k -map_metadata 0 -y -id3v2_version 3 \"{1}\"" \
                    .format(file_path, destination_file))
                os.remove(file_path)
else:
    print('Usage: ./flac_to_mp3.py /path/to/folder')