Implement normalization gain for music tracks

playback/core/src/main/kotlin/mediastream/normalizationGainElement.kt

@@ -0,0 +1,13 @@
+package org.jellyfin.playback.core.mediastream
+
+import org.jellyfin.playback.core.element.ElementKey
+import org.jellyfin.playback.core.element.element
+import org.jellyfin.playback.core.queue.QueueEntry
+
+private val normalizationGainKey = ElementKey<Float>("NormalizationGain")
+
+/**
+ * Get or set the normalization gain for this [QueueEntry]. A supported backend will use this to
+ * apply a gain to the audio output. The normalization gain must target a loudness of -23LUFS.
+ */
+var QueueEntry.normalizationGain by element(normalizationGainKey)

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

@@ -0,0 +1,37 @@
+package org.jellyfin.playback.exoplayer
+
+import android.media.audiofx.LoudnessEnhancer
+import timber.log.Timber
+
+class ExoPlayerAudioPipeline {
+ private var loudnessEnhancer: LoudnessEnhancer? = null
+ var normalizationGain: Float? = null
+ set(value) {
+ Timber.d("Normalization gain changed to $value")
+ field = value
+ applyGain()
+ }
+
+ fun setAudioSessionId(audioSessionId: Int) {
+ Timber.d("Audio session id changed to $audioSessionId")
+
+ // Re-creare loudness enhancer for normalization gain
+ loudnessEnhancer?.release()
+ loudnessEnhancer = LoudnessEnhancer(audioSessionId)
+
+ // Re-apply current normalization gain
+ applyGain()
+ }
+
+ private fun applyGain() {
+ val targetGain = normalizationGain
+ // Convert to millibels
+ ?.times(100f)
+ // Round to integer
+ ?.toInt()
+
+ Timber.d("Applying gain (targetGain=$targetGain)")
+ loudnessEnhancer?.setEnabled(targetGain != null)
+ loudnessEnhancer?.setTargetGain(targetGain ?: 0)
+ }
+}

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

@@ -24,6 +24,7 @@ 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.mediastream.mediaStream
+import org.jellyfin.playback.core.mediastream.normalizationGain
 import org.jellyfin.playback.core.model.PlayState
 import org.jellyfin.playback.core.model.PositionInfo
 import org.jellyfin.playback.core.queue.QueueEntry
@@ -48,6 +49,7 @@ class ExoPlayerBackend(
 
  private var currentStream: PlayableMediaStream? = null
  private var subtitleView: SubtitleView? = null
+ private var audioPipeline = ExoPlayerAudioPipeline()
 
  private val exoPlayer by lazy {
  ExoPlayer.Builder(context)
@@ -58,24 +60,32 @@ class ExoPlayerBackend(
  .setTrackSelector(DefaultTrackSelector(context).apply {
  setParameters(buildUponParameters().apply {
  setTunnelingEnabled(true)
- setAudioOffloadPreferences(TrackSelectionParameters.AudioOffloadPreferences.DEFAULT.buildUpon().apply {
- setAudioOffloadMode(TrackSelectionParameters.AudioOffloadPreferences.AUDIO_OFFLOAD_MODE_ENABLED)
- }.build())
+ setAudioOffloadPreferences(
+ TrackSelectionParameters.AudioOffloadPreferences.DEFAULT.buildUpon().apply {
+ setAudioOffloadMode(TrackSelectionParameters.AudioOffloadPreferences.AUDIO_OFFLOAD_MODE_ENABLED)
+ }.build()
+ )
  })
  })
  .setMediaSourceFactory(DefaultMediaSourceFactory(
  context,
  DefaultExtractorsFactory().apply {
- val isLowRamDevice = context.getSystemService<ActivityManager>()?.isLowRamDevice == true
- setTsExtractorTimestampSearchBytes(when (isLowRamDevice) {
- true -> TS_SEARCH_BYTES_LM
- false -> TS_SEARCH_BYTES_HM
- })
+ val isLowRamDevice =
+ context.getSystemService<ActivityManager>()?.isLowRamDevice == true
+ setTsExtractorTimestampSearchBytes(
+ when (isLowRamDevice) {
+ true -> TS_SEARCH_BYTES_LM
+ false -> TS_SEARCH_BYTES_HM
+ }
+ )
  }
  ))
  .setPauseAtEndOfMediaItems(true)
  .build()
- .also { player -> player.addListener(PlayerListener()) }
+ .also { player ->
+ player.addListener(PlayerListener())
+ audioPipeline.setAudioSessionId(player.audioSessionId)
+ }
  }
 
  inner class PlayerListener : Player.Listener {
@@ -109,6 +119,15 @@ class ExoPlayerBackend(
  listener?.onMediaStreamEnd(requireNotNull(currentStream))
  }
  }
+
+ override fun onAudioSessionIdChanged(audioSessionId: Int) {
+ audioPipeline.setAudioSessionId(audioSessionId)
+ }
+
+ override fun onMediaItemTransition(mediaItem: MediaItem?, reason: Int) {
+ val queueEntry = mediaItem?.localConfiguration?.tag as? QueueEntry
+ audioPipeline.normalizationGain = queueEntry?.normalizationGain
+ }
  }
 
  override fun supportsStream(
@@ -132,7 +151,7 @@ class ExoPlayerBackend(
  override fun prepareItem(item: QueueEntry) {
  val stream = requireNotNull(item.mediaStream)
  val mediaItem = MediaItem.Builder().apply {
- setTag(stream)
+ setTag(item)
  setMediaId(stream.hashCode().toString())
  setUri(stream.url)
  }.build()
@@ -153,7 +172,9 @@ class ExoPlayerBackend(
 
  var streamIsPrepared = false
  repeat(exoPlayer.mediaItemCount) { index ->
- streamIsPrepared = streamIsPrepared || exoPlayer.getMediaItemAt(index).mediaId == stream.hashCode().toString()
+ streamIsPrepared =
+ streamIsPrepared || exoPlayer.getMediaItemAt(index).mediaId == stream.hashCode()
+ .toString()
  }
 
  if (!streamIsPrepared) prepareItem(item)

playback/jellyfin/src/main/kotlin/queue/createBaseItemQueueEntry.kt

@@ -1,5 +1,6 @@
 package org.jellyfin.playback.jellyfin.queue
 
+import org.jellyfin.playback.core.mediastream.normalizationGain
 import org.jellyfin.playback.core.queue.QueueEntry
 import org.jellyfin.playback.core.queue.QueueEntryMetadata
 import org.jellyfin.playback.core.queue.metadata
@@ -44,6 +45,7 @@ fun createBaseItemQueueEntry(api: ApiClient, baseItem: BaseItemDto): QueueEntry
  genre = baseItem.genres?.joinToString(", "),
  )
  entry.baseItem = baseItem
+ entry.normalizationGain = baseItem.normalizationGain
  return entry
 }