Embed lyrics directly in audio file tags

Lyrics from LRClib are now embedded in audio file tags (USLT for MP3,
lyrics for FLAC/OGG, ©lyr for M4A) in addition to the .lrc sidecar
file. Navidrome, Jellyfin, and Plex can read embedded lyrics but not
all support .lrc files.

Embedding is best-effort — if it fails, the .lrc file still exists.
Only adds to existing tags, never creates tags from scratch.

core/lyrics_client.py

@@ -111,8 +111,11 @@ class LyricsClient:
             with open(lrc_path, 'w', encoding='utf-8') as f:
                 f.write(lrc_content)
 
+            # Embed lyrics directly in audio file tags (Navidrome/Jellyfin read these)
+            self._embed_lyrics(audio_file_path, lrc_content)
+
             lyrics_type = "synced" if getattr(lyrics_data, 'synced_lyrics', None) else "plain"
-            logger.info(f"✅ Created {lyrics_type} LRC file: {os.path.basename(lrc_path)}")
+            logger.info(f"✅ Created {lyrics_type} LRC file + embedded: {os.path.basename(lrc_path)}")
             return True
 
         except Exception as e:
@@ -120,5 +123,40 @@ class LyricsClient:
             return False
 
 
+    def _embed_lyrics(self, audio_file_path: str, lyrics_text: str):
+        """Embed lyrics directly into audio file tags."""
+        try:
+            from mutagen import File as MutagenFile
+            from mutagen.flac import FLAC
+            from mutagen.oggvorbis import OggVorbis
+            from mutagen.mp4 import MP4
+            from mutagen.id3 import ID3, USLT
+
+            audio = MutagenFile(audio_file_path)
+            if audio is None:
+                return
+
+            if audio.tags is None:
+                return  # Don't create tags just for lyrics
+
+            if isinstance(audio.tags, ID3):
+                audio.tags.delall('USLT')
+                audio.tags.add(USLT(encoding=3, lang='eng', desc='', text=lyrics_text))
+                audio.save(v1=0, v2_version=4)
+            elif isinstance(audio, (FLAC, OggVorbis)) or type(audio).__name__ == 'OggOpus':
+                audio['lyrics'] = [lyrics_text]
+                if isinstance(audio, FLAC):
+                    audio.save(deleteid3=True)
+                else:
+                    audio.save()
+            elif isinstance(audio, MP4):
+                audio['\xa9lyr'] = [lyrics_text]
+                audio.save()
+
+            logger.debug(f"Embedded lyrics in: {os.path.basename(audio_file_path)}")
+        except Exception as e:
+            logger.warning(f"Could not embed lyrics in {os.path.basename(audio_file_path)}: {e}")
+
+
 # Global instance for easy import
 lyrics_client = LyricsClient()

web_server.py

@@ -19009,6 +19009,15 @@ def get_version_info():
         "title": "What's New in SoulSync",
         "subtitle": f"Version {SOULSYNC_VERSION} — Latest Changes",
         "sections": [
+            {
+                "title": "🎵 Embedded Lyrics in Audio Files",
+                "description": "Lyrics are now embedded directly in audio file tags alongside the .lrc sidecar file",
+                "features": [
+                    "• Lyrics embedded as USLT (MP3), lyrics (FLAC/OGG), or ©lyr (M4A) tags",
+                    "• Navidrome, Jellyfin, and Plex can now display lyrics without .lrc file support",
+                    "• .lrc sidecar files are still created for compatibility with other players"
+                ]
+            },
             {
                 "title": "🔧 Fix AcoustID False Positives for Non-English Tracks",
                 "description": "AcoustID no longer quarantines correct files when titles are in different languages",

webui/static/helper.js

@@ -3403,6 +3403,7 @@ function closeHelperSearch() {
 const WHATS_NEW = {
     '2.1': [
         // Newest features first
+        { title: 'Embedded Lyrics',                     desc: 'Lyrics now embedded directly in audio file tags — Navidrome, Jellyfin, and Plex can display them' },
         { title: 'Fix AcoustID False Positives',        desc: 'High-confidence fingerprints no longer quarantine correct files when titles are in different languages' },
         { title: 'Fix Junk Tags Surviving',            desc: 'Soulseek source tags are now wiped to disk immediately — no more album fragmentation from partial metadata' },
         { title: 'Watch All Preview Modal',           desc: 'Watch All Unwatched now opens a modal showing which artists will be added before confirming', page: 'library', selector: '#library-watchlist-all-btn' },