feat(music): embed plain lyrics and save timed lyrics from Song.synced_lyrics

docs/dev/service-architecture.md

@@ -197,9 +197,11 @@ Each subclass adds its own required fields on top of `id_` and `service`:
 
     A `Song` also takes optional metadata keywords that the tagger and the naming templates
     read: `album_artist`, `release_type`, `total_tracks`, `total_discs`, `genre`,
-    `explicit`, `isrc`, `upc`, `copyright`, `label`, `lyrics`, `lyrics_suffix`, and
+    `explicit`, `isrc`, `upc`, `copyright`, `label`, `lyrics`, `synced_lyrics`,
-    `artwork_url`. Read the class for the current list. With `lyrics_suffix` (`".lrc"`,
+    `lyrics_suffix`, and `artwork_url`. Read the class for the current list. Give `lyrics` as
-    `".ttml"`), unshackle also saves `lyrics` beside the final audio file under that suffix.
+    plain text: the tagger embeds it as is. With `synced_lyrics` (timed LRC or TTML) and
+    `lyrics_suffix` (`".lrc"`, `".ttml"`), unshackle also saves the timed lyrics beside the
+    final audio file under that suffix.
     You can set these fields in `get_tracks()` too, and a remote client gets them back.
 
     The tagger also falls back to `Song.data` for fields the constructor did not get, such

docs/guide/output-and-naming.md

@@ -269,9 +269,9 @@ unshackle writes lyrics when the service supplies them: a `LYRICS` Vorbis commen
 `USLT` frame for MP3, and a `©lyr` atom for M4A. Ogg uses the same `LYRICS` field as
 FLAC. unshackle does not write synchronized lyrics (`SYLT`).
 
-A service can also ask for a lyrics file beside the audio, for example
+The embedded lyrics are plain text. A service can also save timed lyrics in a file beside
-`08.Get.Lucky.lrc` next to `08.Get.Lucky.m4a`. A music player reads the timed lines from
+the audio, for example `08.Get.Lucky.lrc` next to `08.Get.Lucky.m4a`. A music player reads
-it. The file also comes back to the client from a remote server.
+the timed lines from that file. The file also comes back to the client from a remote server.
 
 A metadata fault does not stop the run. The file is already in place, so unshackle writes a
 warning and continues.

tests/core/test_load_tracks_enrich.py

@@ -46,6 +46,6 @@ def test_a_song_takes_only_the_language():
 
 def test_a_song_takes_the_lyrics_set_in_get_tracks():
     song = Song(id_="song-0001", service=SERVICE, name="Track 1", artist="A", album="B", track=1, disc=1)
-    info = {"name": "Track 1", "lyrics": "[00:01.00]Line", "lyrics_suffix": ".lrc"}
+    info = {"name": "Track 1", "lyrics": "Line", "synced_lyrics": "[00:01.00]Line", "lyrics_suffix": ".lrc"}
     load_tracks(refreshing_service(info), song)
-    assert (song.lyrics, song.lyrics_suffix) == ("[00:01.00]Line", ".lrc")
+    assert (song.lyrics, song.synced_lyrics, song.lyrics_suffix) == ("Line", "[00:01.00]Line", ".lrc")

unshackle/commands/dl.py

@@ -3867,9 +3867,9 @@ class dl:
                             )
                         if include_sample:
                             self.write_sample(final_path, title, media_info)
-                        if isinstance(title, Song) and title.lyrics and title.lyrics_suffix:
+                        if isinstance(title, Song) and title.synced_lyrics and title.lyrics_suffix:
                             lyrics_path = final_path.with_suffix(title.lyrics_suffix)
-                            lyrics_path.write_text(f"{title.lyrics}\n", encoding="utf-8")
+                            lyrics_path.write_text(f"{title.synced_lyrics}\n", encoding="utf-8")
                             sidecar_files.setdefault(muxed_path, []).append(lyrics_path)
                             self.log.info(f"Saved lyrics to {lyrics_path.name}")
 

unshackle/core/remote_service.py

@@ -654,6 +654,7 @@ def build_title(info: Dict[str, Any], service_tag: str, fallback_id: str) -> Tit
             label=info.get("label"),
             lyrics=info.get("lyrics"),
             artwork_url=info.get("artwork_url"),
+            synced_lyrics=info.get("synced_lyrics"),
             lyrics_suffix=info.get("lyrics_suffix"),
         )
     else:

unshackle/core/titles/music.py

@@ -28,6 +28,7 @@ SONG_FIELDS = (
     "copyright",
     "label",
     "lyrics",
+    "synced_lyrics",
     "lyrics_suffix",
     "artwork_url",
 )
@@ -59,9 +60,13 @@ class Song(Title):
         label: Optional[str] = None,
         lyrics: Optional[str] = None,
         artwork_url: Optional[str] = None,
+        synced_lyrics: Optional[str] = None,
         lyrics_suffix: Optional[str] = None,
     ) -> None:
-        """`lyrics_suffix` (".lrc", ".ttml") also saves `lyrics` beside the audio file with that suffix."""
+        """`lyrics` is the plain text the tagger embeds.
+
+        `synced_lyrics` (timed LRC or TTML) is saved beside the audio file with `lyrics_suffix` (".lrc", ".ttml").
+        """
         super().__init__(id_, service, language, data)
 
         if not name:
@@ -113,6 +118,8 @@ class Song(Title):
             raise TypeError(f"Expected lyrics to be a str, not {lyrics!r}")
         if artwork_url is not None and not isinstance(artwork_url, str):
             raise TypeError(f"Expected artwork_url to be a str, not {artwork_url!r}")
+        if synced_lyrics is not None and not isinstance(synced_lyrics, str):
+            raise TypeError(f"Expected synced_lyrics to be a str, not {synced_lyrics!r}")
         if lyrics_suffix is not None and not (isinstance(lyrics_suffix, str) and lyrics_suffix.startswith(".")):
             raise TypeError(f"Expected lyrics_suffix to be a str starting with '.', not {lyrics_suffix!r}")
 
@@ -160,6 +167,7 @@ class Song(Title):
         self.label = label
         self.lyrics = lyrics
         self.artwork_url = artwork_url
+        self.synced_lyrics = synced_lyrics.strip() if synced_lyrics else None
         self.lyrics_suffix = lyrics_suffix
 
     def __str__(self) -> str: