fix(subtitles): fix external subtitles

android/src/main/java/dev/zoriya/omni/OmniPlayer.kt

@@ -13,6 +13,7 @@ import androidx.media3.common.AudioAttributes
 import androidx.media3.common.C
 import androidx.media3.common.MediaItem
 import androidx.media3.common.MediaMetadata
+import androidx.media3.common.MimeTypes
 import androidx.media3.common.Player
 import androidx.media3.datasource.DefaultDataSource
 import androidx.media3.datasource.DefaultHttpDataSource
@@ -187,6 +188,19 @@ class OmniPlayer(
         super.dispose()
     }
 
+    private fun inferSubtitleMimeType(link: String): String? {
+        val ext = link.toUri().lastPathSegment?.substringAfterLast('.', "")?.lowercase()
+        return when (ext) {
+            "vtt", "webvtt" -> MimeTypes.TEXT_VTT
+            "srt" -> MimeTypes.APPLICATION_SUBRIP
+            "ass", "ssa" -> MimeTypes.TEXT_SSA
+            "ttml", "dfxp", "xml" -> MimeTypes.APPLICATION_TTML
+            "sup" -> MimeTypes.APPLICATION_PGS
+            "sub" -> MimeTypes.APPLICATION_VOBSUB
+            else -> null
+        }
+    }
+
     private fun buildMediaItem(
         src: com.margelo.nitro.omni.VideoSrc,
         metadata: com.margelo.nitro.omni.Metadata?,
@@ -212,7 +226,10 @@ class OmniPlayer(
                     .setId(subtitle.id)
                     .setLanguage(subtitle.language)
                     .setLabel(subtitle.label)
-                    .setMimeType(subtitle.mimeType)
+                    // exoplayer requires a mime type to pick a subtitle parser.
+                    // fall back to inferring it from the link's extension so
+                    // consumers don't have to provide one.
+                    .setMimeType(subtitle.mimeType ?: inferSubtitleMimeType(subtitle.link))
                     .build()
             })
             .setRequestMetadata(

android/src/main/java/dev/zoriya/omni/VlcPlayer.kt

@@ -46,6 +46,7 @@ import org.videolan.libvlc.MediaPlayer
 import org.videolan.libvlc.interfaces.IMedia
 import org.videolan.libvlc.interfaces.IMedia.VideoTrack
 import org.videolan.libvlc.interfaces.IVLCVout
+import java.security.MessageDigest
 
 @SuppressLint("UnsafeOptInUsageError")
 class VlcPlayer(ctx: Context) :
@@ -387,6 +388,20 @@ class VlcPlayer(ctx: Context) :
         }
     }
 
+    // vlc keys each slave's tracks by the md5 of its uri ("<md5(uri)>/spu/<n>")
+    private fun subtitleSlaveForTrackId(trackId: String): MediaItem.SubtitleConfiguration? {
+        val hash = trackId.substringBefore("/spu/", "")
+        if (hash.isEmpty()) return null
+        return mediaItems.getOrNull(currentMediaItemIndex)
+            ?.localConfiguration?.subtitleConfigurations
+            ?.firstOrNull { md5(it.uri.toString()) == hash }
+    }
+
+    private fun md5(value: String): String =
+        MessageDigest.getInstance("MD5")
+            .digest(value.toByteArray())
+            .joinToString("") { "%02x".format(it.toInt() and 0xFF) }
+
     // vlc doesn't allow arbitrary headers :c
     private fun applyRequestHeaders(media: Media, extras: Bundle?) {
         if (extras == null) return
@@ -599,10 +614,12 @@ class VlcPlayer(ctx: Context) :
             }
 
         player.getTracks(IMedia.Track.Type.Text)?.forEach { track ->
+            // external subs don't have label/language, match them back to surface them
+            val slave = subtitleSlaveForTrackId(track.id)
             val format = Format.Builder()
                 .setId(track.id)
-                .setLabel(track.name)
-                .setLanguage(track.language)
+                .setLabel(slave?.label ?: track.name)
+                .setLanguage(slave?.language ?: track.language)
                 .setSampleMimeType("text/x-unknown")
                 .build()
             val group = TrackGroup("vlc-sub-${track.id}", format)