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fix(audio): apply normalization immediately from YouTube response, reset stale cross-track gain #3905

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fix(audio): apply normalization immediately from YouTube response, reset stale cross-track gain #3905

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29d0896
fix(audio): apply normalization immediately and fix UI freeze
kairosci Jun 5, 2026
c918658
fix(audio): apply normalization immediately by bypassing main thread
kairosci Jun 5, 2026
ae0f217
fix(audio): apply track-specific normalization to secondary ExoPlayer…
kairosci Jun 6, 2026
da648fa
fix(audio): prevent normalization of pre-buffered tracks from affecti…
kairosci Jun 6, 2026
e7fbada
fix(audio): reset normalization state when track format is missing
kairosci Jun 7, 2026
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77 changes: 65 additions & 12 deletions app/src/main/kotlin/com/metrolist/music/playback/MusicService.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -406,10 +406,20 @@ class MusicService :
@Volatile
private var loudnessLevelCached: LoudnessLevel = LoudnessLevel.BALANCED

@Volatile
private var cachedNormalizationGainMb: Int? = null

@Volatile
private var cachedNormalizationEnabled: Boolean = false

@Volatile private var discordRpcEnabled = false
@Volatile
private var cachedMeasuredLufs: Double? = null

@Volatile
private var cachedMeasuredLufsMediaId: String? = null

@Volatile
private var discordRpcEnabled = false
private val screenOffHandler = Handler(Looper.getMainLooper())
private val screenOffTimeout = Runnable {
Timber.tag("DiscordSvc").i("screenOffTimeout: isPlaying=%s, isReady=%s",
Expand Down Expand Up @@ -2113,6 +2123,42 @@ class MusicService :
)
}

private fun applyNormalizationFromLoudnessData(
mediaId: String,
loudnessDb: Double?,
perceptualLoudnessDb: Double?,
) {
Handler(Looper.getMainLooper()).post {
val measuredLufs = perceptualLoudnessDb
?: loudnessDb?.let { it + LoudnessLevel.AGGRESSIVE.targetLufs }

cachedMeasuredLufs = measuredLufs
cachedMeasuredLufsMediaId = mediaId

if (!normalizationEnabledCached) {
playerNormalizationProcessors.values.forEach { it.enabled = false }
return@post
}

val targetLufs = loudnessLevelCached.targetLufs
if (measuredLufs != null) {
val loudnessDelta = measuredLufs - targetLufs
val targetGain = (-loudnessDelta * 100.0).toInt()
val clampedGain = targetGain.coerceIn(MIN_GAIN_MB, MAX_GAIN_MB)

cachedNormalizationGainMb = clampedGain
cachedNormalizationEnabled = true

if (isCrossfading) return@post

playerNormalizationProcessors.values.forEach {
it.setTargetGain(clampedGain)
it.enabled = true
}
}
}
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}

private fun applyCachedAudioNormalizationNow() {
if (isCrossfading) return
try {
Expand Down Expand Up @@ -2144,16 +2190,21 @@ class MusicService :
val normalizeAudio = normalizationEnabledCached

if (normalizeAudio && currentMediaId != null) {
val format = withContext(Dispatchers.IO) {
database.format(currentMediaId).first()
}

val targetLufs = loudnessLevelCached.targetLufs

Timber.tag(TAG).d("Audio normalization enabled: $normalizeAudio")

val measuredLufs: Double? = format?.perceptualLoudnessDb
?: format?.loudnessDb?.let { it + LoudnessLevel.AGGRESSIVE.targetLufs }
var isFormatNull = false
val measuredLufs: Double? = if (cachedMeasuredLufsMediaId == currentMediaId) {
cachedMeasuredLufs
} else {
null
} ?: run {
val format = withContext(Dispatchers.IO) {
database.format(currentMediaId).first()
}
isFormatNull = format == null
format?.perceptualLoudnessDb
?: format?.loudnessDb?.let { it + LoudnessLevel.AGGRESSIVE.targetLufs }
}

withContext(Dispatchers.Main) {
if (!isActive || requestGeneration != loudnessSetupGeneration) return@withContext
Expand All @@ -2162,8 +2213,8 @@ class MusicService :

when {
measuredLufs != null -> {
val loudnessDb = measuredLufs - targetLufs
val targetGain = (-loudnessDb * 100.0).toInt()
val loudnessDelta = measuredLufs - targetLufs
val targetGain = (-loudnessDelta * 100.0).toInt()
val clampedGain = targetGain.coerceIn(MIN_GAIN_MB, MAX_GAIN_MB)

cachedNormalizationGainMb = clampedGain
Expand All @@ -2173,10 +2224,11 @@ class MusicService :
it.enabled = true
}
}
format == null -> {
isFormatNull -> {
Timber.tag(TAG).d("Loudness row not ready yet; keeping cached normalization state")
}
else -> {
Timber.tag(TAG).d("Loudness data not available; resetting to neutral")
cachedNormalizationGainMb = null
cachedNormalizationEnabled = false
playerNormalizationProcessors.values.forEach { it.enabled = false }
Expand Down Expand Up @@ -3554,6 +3606,7 @@ class MusicService :
),
)
}
applyNormalizationFromLoudnessData(mediaId, loudnessDb, perceptualLoudnessDb)
scope.launch(Dispatchers.IO) { recoverSong(mediaId, nonNullPlayback) }

// Clear bypass flag now that we've fetched fresh stream
Expand Down
84 changes: 38 additions & 46 deletions app/src/main/kotlin/com/metrolist/music/playback/audio/VolumeNormalizationAudioProcessor.kt
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@ class VolumeNormalizationAudioProcessor : AudioProcessor {
}
}

private var buffer: ByteBuffer = EMPTY_BUFFER
private var outputBuffer: ByteBuffer = EMPTY_BUFFER
private var inputEnded = false

Expand Down Expand Up @@ -83,66 +84,55 @@ class VolumeNormalizationAudioProcessor : AudioProcessor {
inputBuffer.order(ByteOrder.LITTLE_ENDIAN)
out.order(ByteOrder.LITTLE_ENDIAN)

when (encoding) {
C.ENCODING_PCM_16BIT -> {
repeat(sampleCount) {
val sample = inputBuffer.getShort()
val processed = if (applyGain) {
(sample * gain.linearGain)
if (!applyGain) {
out.put(inputBuffer)
} else {
when (encoding) {
C.ENCODING_PCM_16BIT -> {
repeat(sampleCount) {
val sample = inputBuffer.getShort()
val processed = (sample * gain.linearGain)
.coerceIn(-32768.0, 32767.0)
.toInt()
.toShort()
} else {
sample
out.putShort(processed)
}
out.putShort(processed)
}
}

C.ENCODING_PCM_24BIT -> {
repeat(sampleCount) {
val b0 = inputBuffer.get().toInt() and 0xFF
val b1 = inputBuffer.get().toInt() and 0xFF
val b2 = inputBuffer.get().toInt()
val sample = (b2 shl 16) or (b1 shl 8) or b0
C.ENCODING_PCM_24BIT -> {
repeat(sampleCount) {
val b0 = inputBuffer.get().toInt() and 0xFF
val b1 = inputBuffer.get().toInt() and 0xFF
val b2 = inputBuffer.get().toInt()
val sample = (b2 shl 16) or (b1 shl 8) or b0

val processed = if (applyGain) {
(sample * gain.linearGain)
val processed = (sample * gain.linearGain)
.coerceIn(-8388608.0, 8388607.0)
.toInt()
} else {
sample

out.put((processed and 0xFF).toByte())
out.put(((processed shr 8) and 0xFF).toByte())
out.put(((processed shr 16) and 0xFF).toByte())
}
out.put((processed and 0xFF).toByte())
out.put(((processed shr 8) and 0xFF).toByte())
out.put(((processed shr 16) and 0xFF).toByte())
}
}

C.ENCODING_PCM_32BIT -> {
repeat(sampleCount) {
val sample = inputBuffer.getInt()
val processed = if (applyGain) {
(sample * gain.linearGain)
C.ENCODING_PCM_32BIT -> {
repeat(sampleCount) {
val sample = inputBuffer.getInt()
val processed = (sample * gain.linearGain)
.coerceIn(-2147483648.0, 2147483647.0)
.toLong()
.toInt()
} else {
sample
out.putInt(processed)
}
out.putInt(processed)
}
}

C.ENCODING_PCM_FLOAT -> {
repeat(sampleCount) {
val sample = inputBuffer.getFloat()
val processed = if (applyGain) {
(sample * gain.linearGain.toFloat()).coerceIn(-1.0f, 1.0f)
} else {
sample
C.ENCODING_PCM_FLOAT -> {
repeat(sampleCount) {
val sample = inputBuffer.getFloat()
val processed = (sample * gain.linearGain.toFloat()).coerceIn(-1.0f, 1.0f)
out.putFloat(processed)
}
out.putFloat(processed)
}
}
}
Expand All @@ -155,9 +145,9 @@ class VolumeNormalizationAudioProcessor : AudioProcessor {
}

override fun getOutput(): ByteBuffer {
val buffer = outputBuffer
val buf = outputBuffer
outputBuffer = EMPTY_BUFFER
return buffer
return buf
}

override fun isEnded(): Boolean {
Expand All @@ -173,6 +163,7 @@ class VolumeNormalizationAudioProcessor : AudioProcessor {
@Deprecated("Deprecated in AudioProcessor")
override fun reset() {
flush()
buffer = EMPTY_BUFFER
sampleRate = 0
channelCount = 0
encoding = C.ENCODING_INVALID
Expand All @@ -182,11 +173,12 @@ class VolumeNormalizationAudioProcessor : AudioProcessor {
}

private fun replaceOutputBuffer(size: Int): ByteBuffer {
if (outputBuffer.capacity() < size) {
outputBuffer = ByteBuffer.allocateDirect(size).order(ByteOrder.nativeOrder())
if (buffer.capacity() < size) {
buffer = ByteBuffer.allocateDirect(size).order(ByteOrder.nativeOrder())
} else {
outputBuffer.clear()
buffer.clear()
}
outputBuffer = buffer
return outputBuffer
}

Expand Down
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