Untested pre/post-processors (ID3 + correct info dict), v0.0.1

id3pp.py

@@ -0,0 +1,62 @@
+from mutagen import mp3, id3
+from yt_dlp.postprocessor import PostProcessor
+
+
+ENC_UTF8 = 3
+
+
+def add_tags(file: mp3.MP3, info: dict[str, str | int]) -> None:
+
+    file['TIT2'] = id3.TIT2(encoding=ENC_UTF8, text=info['track'])
+    file['TPE1'] = id3.TPE1(encoding=ENC_UTF8, text=info['artist'])
+    if 'album' in info:
+        file['TALB'] = id3.TALB(encoding=ENC_UTF8, text=info['album'])
+    if 'release_year' in info:
+        file['TDRC'] = id3.TDRC(encoding=ENC_UTF8, text=str(info['release_year']))
+    if 'track_number' in info:
+        file['TRCK'] = id3.TRCK(encoding=ENC_UTF8, text=str(info['track_number']))
+
+
+class InfoYouTubePP(PostProcessor):
+    '''Generates YT Music fields in info if necessary.
+    Must be run before downloading and post-processing with
+    FFmpegExtractAudioPP and ID3YouTubePP, so use only with
+    when<="before_dl" ("pre_process" also suits, see yt_dlp.utils.POSTPROCESS_WHEN)
+    for correct file path and ID3 tags'''
+
+    def run(self, information):
+
+        if not 'track' in information:
+            information['track'] = information['title']
+        if not 'artist' in information:
+            information['artist'] = information['channel'].removesuffix(' - Topic')
+
+        if not 'album' in information:
+            try:
+                information['album'] = information['playlist'].removeprefix('Album \u2013 ')
+            except KeyError:
+                pass
+
+        if not 'track_number' in information:
+            try:
+                information['track_number'] = information['playlist_index']
+            except KeyError:
+                pass
+        # here was some code for disc_number,
+        # but it is even not in mutagen ID3 fields list
+
+        return [], information
+
+
+class ID3YouTubePP(PostProcessor):
+    '''Inserts ID3 tags after InfoYouTubePP and FFmpegExtractAudioPP,
+    triggers searching and parsing lyrics from Genius'''
+
+    def run(self, information):
+
+        add_tags(
+            mp3.MP3(information['filepath']),
+            information,
+        )
+
+        return [], information