PICARD-1355: Allow changing NAT album title by script

picard/album.py

@@ -624,9 +624,11 @@ class NatAlbum(Album):
 
     def update(self, update_tracks=True):
         self.enable_update_metadata_images(False)
+        old_album_title = self.metadata["album"]
         self.metadata["album"] = config.setting["nat_name"]
         for track in self.tracks:
-            track.metadata["album"] = self.metadata["album"]
+            if old_album_title == track.metadata["album"]:
+                track.metadata["album"] = self.metadata["album"]
             for file in track.linked_files:
                 track.update_file_metadata(file)
         self.enable_update_metadata_images(True)

picard/track.py

@@ -278,7 +278,7 @@ class NonAlbumTrack(Track):
         self.metadata.copy(self.album.metadata)
         self.metadata["title"] = "[loading track information]"
         self.loaded = False
-        self.tagger.nats.update(True)
+        self.album.update(True)
         mblogin = False
         inc = ["artist-credits", "artists", "aliases"]
         if config.setting["track_ars"]:
@@ -322,7 +322,11 @@ class NonAlbumTrack(Track):
         if self.callback:
             self.callback()
             self.callback = None
-        self.tagger.nats.update(True)
+        self.album.update(True)
+
+    def _customize_metadata(self):
+        super()._customize_metadata()
+        self.metadata['album'] = self.album.metadata['album']
 
     def run_when_loaded(self, func):
         if self.loaded: