Python script to rapidly convert folders of flac audio files to mp3, preserving metadata and cover art

flac2mp3.py

# pip install fastprogress
# pip install pydub
from pydub import AudioSegment
from pydub.utils import mediainfo
from fastprogress import progress_bar

import os
import glob
from pathlib import Path
from concurrent.futures.process import ProcessPoolExecutor
import concurrent

def parallel(func, arr, max_workers):
    """
    Call `func` on every element of `arr` in parallel using `max_workers`.
    Adapted from fastai. Thanks!
    """
    if max_workers<2: _ = [func(o,i) for i,o in enumerate(arr)]
    else:
        with ProcessPoolExecutor(max_workers=max_workers) as ex:
            futures = [ex.submit(func,o,i) for i,o in enumerate(arr)]
            for f in progress_bar(concurrent.futures.as_completed(futures), total=len(arr)): pass

def proc_vid(v, i):
    video, pth_to, pth = v
    mp3_filename = pth_to/video.parent.relative_to(pth)/(video.stem + '.mp3')
    os.makedirs(mp3_filename.parent, exist_ok=True)
    cover_dir = None
    # Try to discover a cover image in the current album's folder
    # by looking for generic filenames.
    if os.path.isfile(video.parent/'cover.jpg'):
        cover_dir = video.parent/'cover.jpg'
    elif os.path.isfile(video.parent/'cover.png'):
        cover_dir = video.parent/'cover.jpg'
    elif os.path.isfile(video.parent/'Cover.jpg'):
        cover_dir = video.parent/'Cover.jpg'
    elif os.path.isfile(video.parent/'Cover.png'):
        cover_dir = video.parent/'Cover.png'
    elif os.path.isfile(video.parents[1]/'cover.jpg'):
        cover_dir = video.parents[1]/'cover.jpg'
    elif os.path.isfile(video.parents[1]/'cover.png'):
        cover_dir = video.parents[1]/'cover.jpg'
    elif os.path.isfile(video.parents[1]/'Cover.jpg'):
        cover_dir = video.parents[1]/'Cover.jpg'
    elif os.path.isfile(video.parents[1]/'Cover.png'):
        cover_dir = video.parents[1]/'Cover.png'

    k = AudioSegment.from_file(video, format='flac')
    if cover_dir is not None:
        k.export(str(mp3_filename), format='mp3', tags=mediainfo(str(video)).get('TAG', {}), cover=str(cover_dir))
    else:
        k.export(str(mp3_filename), format='mp3', tags=mediainfo(str(video)).get('TAG', {}))

def convert():
    folder_with_albums = './my_mixtape_archives/'  # Path with folders of flac files
    extension_list = ('**/*.flac',)

    dirs = os.listdir(folder_with_albums)

    for ost in dirs:
        if ost.endswith('-mp3'): continue
        print("\nConverting ", ost, '\n')
        pth = Path(folder_with_albums)/ost
        
        i = 0
        pth_to = Path(pth.name + '-mp3')
        os.makedirs(pth_to, exist_ok=True)

        for extension in extension_list:
            videos = [(f, pth_to, pth) for f in pth.glob(extension)]
            if len(videos) > 0:
  
                parallel(proc_vid, videos, max_workers=os.cpu_count())
                break

    print('\n\n')

if __name__ == "__main__":
    convert()

So i tried this, i ran it, it prints to me what flac files its supposedly converting, but then i don't see anything created?

It should appear in the same folder of the flac folder but with an "-mp3" appended to the end of the folder name. For example, if you had an album './my_mixtape_archives/album1/', the converted output should be in './my_mixtape_archives/album1-mp3/'

Yeah for some reason nothing was being created and i thought maybe it was an admin right for creating folders and i tried it on my desktop, c: drive, etc... nothing, but i did change it to this and it worked:

def convert(mp3folder):

dirs = Path(mp3folder).glob('**/*.flac')
for ost in dirs:
    print("\nConverting ", ost, '\n')
    flac_audio = AudioSegment.from_file(ost, "flac")
    flac_audio.export(os.path.splitext(ost)[0] + ".mp3", format="mp3", bitrate="320k", tags=mediainfo(str(ost)).get('TAG', {}))

print('\n\n')

if name == "main":
convert('mp3folder')

maybe if someone else is having trouble they could use that...also, was this written for linux? maybe that's my problem.

Oh yeah, this kept the mp3's in the same folder as the flac... i kept it this way because when i grab folders from itunes it won't grab the flac's anyway so at least it just grabs what i want it to grab being in the same folder.

Ahh glad you came right. This code I tested actually for windows, and how pydub's internals might have also changed in the last three years, so this script probably is slightly out of date. If I were to make a new one for 2022 it would probably use ffmpeg instead of pydub. Glad you came right though :)