Python script to rip music from YouTube. Includes MP3 metadata, normalizes loudness, and embeds album art

yt-rip.py

#!/usr/bin/env python3

import json
import math
import os
import sys

import PIL.Image    as img
import pyloudnorm   as pl
import soundfile    as sf
import yt_dlp       as yt

# What we want to do:
#   1. Accept a video or playlist URL       DONE
#   2. Extract audio                        DONE
#   3. Normalize audio                      DONE
#   4. Embed mp3 metadata                   DONE
#   5. Embed album art                      DONE
#   5. Save as <ARTIST> - <TITLE>.mp3       DONE

# Audio normalizer
class NormalizerPP(yt.postprocessor.PostProcessor):
    def __init__(self, loudness):
        yt.postprocessor.PostProcessor.__init__(self)
        self._loudness = loudness

    def run(self, info):
        fp = os.path.join(info['__finaldir'], info['filepath'])
        data, rate = sf.read(fp)
        meter = pl.Meter(rate)
        loudness = meter.integrated_loudness(data)
    
        self.to_screen(
            f'Normalizing loudness from {loudness} to {self._loudness}')

        corrected = pl.normalize.loudness(data, loudness, self._loudness)

        sf.write(fp, corrected, rate)

        return [], info

# Create square album art
class AlbumArtPP(yt.postprocessor.PostProcessor):
    def run(self, info):
        # Find thumbnail path
        thumb_name = next(
                (t['filepath'] for t in info['thumbnails'] if 'filepath' in t),
            None)
        if thumb_name == None:
            self.to_screen('No thumbnail could be found')
            return [], info

        # Open thumbnail
        fp = os.path.join(info['__finaldir'], thumb_name)
        im = img.open(fp)

        # Center crop
        leftcrop = math.ceil((im.width - im.height) / 2)
        im = im.crop((leftcrop, 0, im.width - leftcrop, im.height))
        self.to_screen(f'Resized to {im.height}x{im.height}')

        # Save
        im.save(fp)

        return [], info

class RenamePP(yt.postprocessor.PostProcessor):
    def run(self, info):
        newpath = info['filepath']
        if 'track' in info and 'artist' in info:
            track = info['track']
            artist = info['artist']
            ext = os.path.splitext(info['filepath'])[1]
            newpath = f'{artist} - {track}{ext}'
        else:
            self.to_screen('No metadata')
            return [], info

        # Remove path delimiters from name
        newpath = newpath.replace('/', '-')
        newpath = newpath.replace('\\', '-')
        # Remove windows-unfriendly characters from name
        newpath = newpath.replace('?', '')

        self.to_screen(f'Renaming to {newpath}')
        if not os.path.exists(newpath):
            os.rename(
                os.path.join(info['__finaldir'], info['filepath']),
                os.path.join(info['__finaldir'], newpath)
            )
            info['filepath'] = newpath
        else:
            self.to_screen('File already exists, skipping')        
        
        return [], info

if __name__ == '__main__':
    if len(sys.argv) != 2:
        print(f'Usage: {sys.argv[0]} <URL>')
        exit(1)

    ytdl_opts = {
        'format': 'bestaudio',
        'writethumbnail': 'True',
    }
    with yt.YoutubeDL(ytdl_opts) as ytdl:
        ytdl.add_post_processor(yt.postprocessor.FFmpegExtractAudioPP(
            preferredcodec='wav'
        ))
        ytdl.add_post_processor(NormalizerPP(-15))
        ytdl.add_post_processor(yt.postprocessor.FFmpegExtractAudioPP(
            ytdl, 'mp3'
        ))
        ytdl.add_post_processor(yt.postprocessor.FFmpegMetadataPP(
            ytdl
        ))
        ytdl.add_post_processor(AlbumArtPP())
        ytdl.add_post_processor(yt.postprocessor.EmbedThumbnailPP(
            ytdl
        ))
        ytdl.add_post_processor(RenamePP())
        ytdl.download([sys.argv[1]])
        # info = ytdl.extract_info(sys.argv[1])
        # print(json.dumps(ytdl.sanitize_info(info), indent=4, sort_keys=True))