[ie] Add new fields with proper support for multiple values

yt_dlp/YoutubeDL.py

@@ -1735,6 +1735,7 @@ def __extract_info(self, url, ie, download, extra_info, process):
                 '_type': 'compat_list',
                 'entries': ie_result,
             }
+        self.fix_deprecated_fields(ie_result)
         if extra_info.get('original_url'):
             ie_result.setdefault('original_url', extra_info['original_url'])
         self.add_default_extra_info(ie_result, ie, url)
@@ -1744,6 +1745,18 @@ def __extract_info(self, url, ie, download, extra_info, process):
         else:
             return ie_result
 
+    def fix_deprecated_fields(self, ie_result):
+        deprecated_multivalue_fields = {
+            'artist': 'artist_list',
+            'composer': 'composer_list',
+            'album_artist': 'album_artist_list',
+            'genre': 'genre_list',
+        }
+        for deprecated_field, new_field in deprecated_multivalue_fields.items():
+            if deprecated_field not in ie_result:
+                continue
+            ie_result[new_field] = re.split(r', ?', ie_result[deprecated_field])
+
     def add_default_extra_info(self, ie_result, ie, url):
         if url is not None:
             self.add_extra_info(ie_result, {
@@ -3918,10 +3931,9 @@ def print_debug_header(self):
 
         # These imports can be slow. So import them only as needed
         from .extractor.extractors import _LAZY_LOADER
-        from .extractor.extractors import (
-            _PLUGIN_CLASSES as plugin_ies,
+        from .extractor.extractors import _PLUGIN_CLASSES as plugin_ies
+        from .extractor.extractors import \
             _PLUGIN_OVERRIDES as plugin_ie_overrides
-        )
 
         def get_encoding(stream):
             ret = str(getattr(stream, 'encoding', 'missing (%s)' % type(stream).__name__))

yt_dlp/__init__.py

@@ -670,6 +670,11 @@ def get_postprocessors(opts):
             'add_metadata': opts.addmetadata,
             'add_infojson': opts.embed_infojson,
         }
+    # MutagenMetadata must run after FFmpegMetadata
+    if opts.addmetadata:
+        yield {
+            'key': 'MutagenMetadata',
+        }
     # Deprecated
     # This should be above EmbedThumbnail since sponskrub removes the thumbnail attachment
     # but must be below EmbedSubtitle and FFmpegMetadata

yt_dlp/extractor/common.py

@@ -422,16 +422,24 @@ class InfoExtractor:
     track_number:   Number of the track within an album or a disc, as an integer.
     track_id:       Id of the track (useful in case of custom indexing, e.g. 6.iii),
                     as a unicode string.
-    artist:         Artist(s) of the track.
-    genre:          Genre(s) of the track.
+    artist_list:    List of artists of the track.
+    composer_list:  List of composers of the piece
+    genre_list:     List of genres of the track.
     album:          Title of the album the track belongs to.
     album_type:     Type of the album (e.g. "Demo", "Full-length", "Split", "Compilation", etc).
-    album_artist:   List of all artists appeared on the album (e.g.
-                    "Ash Borer / Fell Voices" or "Various Artists", useful for splits
-                    and compilations).
+    album_artist_list: List of all artists appeared on the album. E.g.
+                    ["Ash Borer", "Fell Voices"] or ["Various Artists"].
+                    Useful for splits and compilations.
     disc_number:    Number of the disc or other physical medium the track belongs to,
                     as an integer.
-    composer:       Composer of the piece
+    composer:       Deprecated; use "composer_list" instead.
+                    Composer(s) of the piece, comma-separated.
+    artist:         Deprecated; use "artist_list" instead.
+                    Artist(s) of the track, comma-separated.
+    genre:          Deprecated; use "genre_list" instead.
+                    Genre(s) of the track, comma-separated.
+    album_artist:   Deprecated; use "album_artist_list" instead.
+                    All artists appeared on the album, comma-separated.
 
     The following fields should only be set for clips that should be cut from the original video:
 

yt_dlp/postprocessor/__init__.py

@@ -30,6 +30,7 @@
 )
 from .modify_chapters import ModifyChaptersPP
 from .movefilesafterdownload import MoveFilesAfterDownloadPP
+from .mutagenmetadata import MutagenMetadataPP
 from .sponskrub import SponSkrubPP
 from .sponsorblock import SponsorBlockPP
 from .xattrpp import XAttrMetadataPP

yt_dlp/postprocessor/ffmpeg.py

@@ -738,9 +738,10 @@ def _get_metadata_opts(self, info):
 
         def add(meta_list, info_list=None):
             value = next((
-                str(info[key]) for key in [f'{meta_prefix}_'] + list(variadic(info_list or meta_list))
+                info[key] for key in [f'{meta_prefix}_'] + list(variadic(info_list or meta_list))
                 if info.get(key) is not None), None)
             if value not in ('', None):
+                value = ', '.join(map(str, variadic(value)))
                 value = value.replace('\0', '')  # nul character cannot be passed in command line
                 metadata['common'].update({meta_f: value for meta_f in variadic(meta_list)})
 
@@ -754,10 +755,11 @@ def add(meta_list, info_list=None):
         add(('description', 'synopsis'), 'description')
         add(('purl', 'comment'), 'webpage_url')
         add('track', 'track_number')
-        add('artist', ('artist', 'creator', 'uploader', 'uploader_id'))
-        add('genre')
+        add('artist', ('artist_list', 'creator', 'uploader', 'uploader_id'))
+        add('composer', 'composer_list')
+        add('genre', 'genre_list')
         add('album')
-        add('album_artist')
+        add('album_artist', 'album_artist_list')
         add('disc', 'disc_number')
         add('show', 'series')
         add('season_number')

yt_dlp/postprocessor/mutagenmetadata.py

@@ -0,0 +1,42 @@
+from .common import PostProcessor
+from ..dependencies import mutagen
+
+if mutagen:
+    from mutagen.easymp4 import EasyMP4
+    from mutagen.flac import FLAC
+    from mutagen.mp3 import EasyMP3
+    from mutagen.musepack import Musepack
+    from mutagen.oggopus import OggOpus
+    from mutagen.oggvorbis import OggVorbis
+
+
+class MutagenMetadataPP(PostProcessor):
+    def __init__(self, downloader):
+        PostProcessor.__init__(self, downloader)
+
+    @PostProcessor._restrict_to(images=False)
+    def run(self, information):
+        extension = information['ext']
+        ret = [], information
+        if not mutagen:
+            if extension in ['mp3', 'm4a', 'ogg', 'opus', 'flac', '.mpc']:
+                self.report_warning('module mutagen was not found. Tags with multiple values (e.g. artist, album artist and genre) may be set incorrectly. Please install using `python -m pip install mutagen`')
+            return ret
+        tag_mapping = {
+            'artist': 'artist_list',
+            'albumartist': 'album_artist_list',
+            'genre': 'genre_list',
+            'composer': 'composer_list'
+        }
+        supported_formats = [EasyMP3, EasyMP4, OggVorbis, OggOpus, FLAC, Musepack]
+        file = mutagen.File(information['filepath'], supported_formats)
+        if not file:
+            return ret
+        if isinstance(file, EasyMP4):
+            file.RegisterTextKey('composer', '\251wrt')
+        for tag_key, info_key in tag_mapping.items():
+            value = information.get(info_key)
+            if value:
+                file[tag_key] = value
+        file.save()
+        return ret