Add initial subtitle implementation

app/src/main/java/org/jellyfin/androidtv/ui/playback/rewrite/PlaybackRewriteFragment.kt

@@ -4,6 +4,7 @@ import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
+import android.widget.FrameLayout
 import androidx.fragment.app.Fragment
 import androidx.lifecycle.Lifecycle
 import androidx.lifecycle.lifecycleScope
@@ -15,6 +16,7 @@ import org.jellyfin.androidtv.ui.ScreensaverViewModel
 import org.jellyfin.androidtv.ui.playback.VideoQueueManager
 import org.jellyfin.playback.core.PlaybackManager
 import org.jellyfin.playback.core.model.PlayState
+import org.jellyfin.playback.core.ui.PlayerSubtitleView
 import org.jellyfin.playback.core.ui.PlayerSurfaceView
 import org.jellyfin.sdk.api.client.ApiClient
 import org.koin.android.ext.android.inject
@@ -74,9 +76,15 @@ class PlaybackRewriteFragment : Fragment() {
 	}
 
 	override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
-		val view = PlayerSurfaceView(requireContext())
-		view.playbackManager = playbackManager
-		return view
+		return FrameLayout(requireContext()).apply {
+			addView(PlayerSurfaceView(requireContext()).also { view ->
+				view.playbackManager = playbackManager
+			})
+
+			addView(PlayerSubtitleView(requireContext()).also { view ->
+				view.playbackManager = playbackManager
+			})
+		}
 	}
 
 	override fun onPause() {

playback/core/src/main/kotlin/backend/BackendService.kt

@@ -1,9 +1,10 @@
 package org.jellyfin.playback.core.backend
 
-import android.view.SurfaceView
 import androidx.core.view.doOnDetach
 import org.jellyfin.playback.core.mediastream.PlayableMediaStream
 import org.jellyfin.playback.core.model.PlayState
+import org.jellyfin.playback.core.ui.PlayerSubtitleView
+import org.jellyfin.playback.core.ui.PlayerSurfaceView
 
 /**
  * Service keeping track of the current playback backend and its related surface view.
@@ -13,34 +14,57 @@ class BackendService {
 	val backend get() = _backend
 
 	private var listeners = mutableListOf<PlayerBackendEventListener>()
-	private var _surfaceView: SurfaceView? = null
+	private var _surfaceView: PlayerSurfaceView? = null
+	private var _subtitleView: PlayerSubtitleView? = null
 
 	fun switchBackend(backend: PlayerBackend) {
 		_backend?.stop()
 		_backend?.setListener(null)
-		_backend?.setSurface(null)
+		_backend?.setSurfaceView(null)
+		_backend?.setSubtitleView(null)
 
 		_backend = backend.apply {
-			_surfaceView?.let(::setSurface)
+			_surfaceView?.let(::setSurfaceView)
+			_subtitleView?.let(::setSubtitleView)
 			setListener(BackendEventListener())
 		}
 	}
 
-	fun attachSurfaceView(surfaceView: SurfaceView) {
+	fun attachSurfaceView(surfaceView: PlayerSurfaceView) {
 		// Remove existing surface view
 		if (_surfaceView != null) {
-			_backend?.setSurface(null)
+			_backend?.setSurfaceView(null)
 		}
 
 		// Apply new surface view
 		_surfaceView = surfaceView.apply {
-			_backend?.setSurface(surfaceView)
+			_backend?.setSurfaceView(surfaceView)
 
 			// Automatically detach
 			doOnDetach {
 				if (surfaceView == _surfaceView) {
 					_surfaceView = null
-					_backend?.setSurface(null)
+					_backend?.setSurfaceView(null)
+				}
+			}
+		}
+	}
+
+	fun attachSubtitleView(subtitleView: PlayerSubtitleView) {
+		// Remove existing surface view
+		if (_subtitleView != null) {
+			_backend?.setSubtitleView(null)
+		}
+
+		// Apply new surface view
+		_subtitleView = subtitleView.apply {
+			_backend?.setSubtitleView(subtitleView)
+
+			// Automatically detach
+			doOnDetach {
+				if (subtitleView == _subtitleView) {
+					_subtitleView = null
+					_backend?.setSubtitleView(null)
 				}
 			}
 		}

playback/core/src/main/kotlin/backend/PlayerBackend.kt

@@ -1,10 +1,11 @@
 package org.jellyfin.playback.core.backend
 
-import android.view.SurfaceView
 import org.jellyfin.playback.core.mediastream.MediaStream
 import org.jellyfin.playback.core.mediastream.PlayableMediaStream
 import org.jellyfin.playback.core.model.PositionInfo
 import org.jellyfin.playback.core.support.PlaySupportReport
+import org.jellyfin.playback.core.ui.PlayerSubtitleView
+import org.jellyfin.playback.core.ui.PlayerSurfaceView
 import kotlin.time.Duration
 
 /**
@@ -16,7 +17,8 @@ interface PlayerBackend {
 	fun supportsStream(stream: MediaStream): PlaySupportReport
 
 	// UI
-	fun setSurface(surfaceView: SurfaceView?)
+	fun setSurfaceView(surfaceView: PlayerSurfaceView?)
+	fun setSubtitleView(surfaceView: PlayerSubtitleView?)
 
 	// Data retrieval
 

playback/core/src/main/kotlin/ui/PlayerSubtitleView.kt

@@ -0,0 +1,28 @@
+package org.jellyfin.playback.core.ui
+
+import android.content.Context
+import android.util.AttributeSet
+import android.widget.FrameLayout
+import org.jellyfin.playback.core.PlaybackManager
+
+/**
+ * A view that is used to display the subtitle output of the playing media.
+ * The [playbackManager] must be set when the view is initialized.
+ */
+class PlayerSubtitleView @JvmOverloads constructor(
+	context: Context,
+	attrs: AttributeSet? = null,
+	defStyleAttr: Int = 0,
+	defStyleRes: Int = 0,
+) : FrameLayout(context, attrs, defStyleAttr, defStyleRes) {
+	lateinit var playbackManager: PlaybackManager
+
+	override fun onAttachedToWindow() {
+		super.onAttachedToWindow()
+
+		if (!isInEditMode) {
+			playbackManager.backendService.attachSubtitleView(this)
+		}
+	}
+}
+

playback/core/src/main/kotlin/ui/PlayerSurfaceView.kt

@@ -27,7 +27,7 @@ class PlayerSurfaceView @JvmOverloads constructor(
 		super.onAttachedToWindow()
 
 		if (!isInEditMode) {
-			playbackManager.backendService.attachSurfaceView(surface)
+			playbackManager.backendService.attachSurfaceView(this)
 		}
 	}
 }

playback/exoplayer/build.gradle.kts

@@ -36,6 +36,7 @@ dependencies {
 	implementation(libs.androidx.media3.exoplayer)
 	implementation(libs.androidx.media3.exoplayer.hls)
 	implementation(libs.jellyfin.androidx.media3.ffmpeg.decoder)
+	implementation(libs.androidx.media3.ui)
 
 	// Logging
 	implementation(libs.timber)

playback/exoplayer/src/main/kotlin/ExoPlayerBackend.kt

@@ -2,7 +2,7 @@ package org.jellyfin.playback.exoplayer
 
 import android.app.ActivityManager
 import android.content.Context
-import android.view.SurfaceView
+import android.view.ViewGroup
 import androidx.annotation.OptIn
 import androidx.core.content.getSystemService
 import androidx.media3.common.C
@@ -11,19 +11,23 @@ import androidx.media3.common.PlaybackException
 import androidx.media3.common.Player
 import androidx.media3.common.TrackSelectionParameters
 import androidx.media3.common.VideoSize
+import androidx.media3.common.text.CueGroup
 import androidx.media3.common.util.UnstableApi
 import androidx.media3.exoplayer.DefaultRenderersFactory
 import androidx.media3.exoplayer.ExoPlayer
 import androidx.media3.exoplayer.source.DefaultMediaSourceFactory
 import androidx.media3.exoplayer.trackselection.DefaultTrackSelector
 import androidx.media3.extractor.DefaultExtractorsFactory
 import androidx.media3.extractor.ts.TsExtractor
+import androidx.media3.ui.SubtitleView
 import org.jellyfin.playback.core.backend.BasePlayerBackend
 import org.jellyfin.playback.core.mediastream.MediaStream
 import org.jellyfin.playback.core.mediastream.PlayableMediaStream
 import org.jellyfin.playback.core.model.PlayState
 import org.jellyfin.playback.core.model.PositionInfo
 import org.jellyfin.playback.core.support.PlaySupportReport
+import org.jellyfin.playback.core.ui.PlayerSubtitleView
+import org.jellyfin.playback.core.ui.PlayerSurfaceView
 import org.jellyfin.playback.exoplayer.support.getPlaySupportReport
 import org.jellyfin.playback.exoplayer.support.toFormat
 import timber.log.Timber
@@ -41,6 +45,7 @@ class ExoPlayerBackend(
 	}
 
 	private var currentStream: PlayableMediaStream? = null
+	private var subtitleView: SubtitleView? = null
 
 	private val exoPlayer by lazy {
 		ExoPlayer.Builder(context)
@@ -89,6 +94,10 @@ class ExoPlayerBackend(
 			listener?.onVideoSizeChange(size.width, size.height)
 		}
 
+		override fun onCues(cueGroup: CueGroup) {
+			subtitleView?.setCues(cueGroup.cues)
+		}
+
 		override fun onPlaybackStateChanged(playbackState: Int) {
 			onIsPlayingChanged(exoPlayer.isPlaying)
 		}
@@ -104,8 +113,18 @@ class ExoPlayerBackend(
 		stream: MediaStream
 	): PlaySupportReport = exoPlayer.getPlaySupportReport(stream.toFormat())
 
-	override fun setSurface(surfaceView: SurfaceView?) {
-		exoPlayer.setVideoSurfaceView(surfaceView)
+	override fun setSurfaceView(surfaceView: PlayerSurfaceView?) {
+		exoPlayer.setVideoSurfaceView(surfaceView?.surface)
+	}
+
+	override fun setSubtitleView(surfaceView: PlayerSubtitleView?) {
+		if (surfaceView != null) {
+			if (subtitleView == null) subtitleView = SubtitleView(surfaceView.context)
+			surfaceView.addView(subtitleView)
+		} else {
+			(subtitleView?.parent as? ViewGroup)?.removeView(subtitleView)
+			subtitleView = null
+		}
 	}
 
 	override fun prepareStream(stream: PlayableMediaStream) {