add network-dependent stream quality

Combine max bitrate and transcode format into one StreamQuality and store a separate value per network mode (Wi-Fi vs mobile data). NetworkMonitor reports metered vs unmetered via ConnectivityManager, SourceRepository selects and exposes the active quality, and PlaybackController reloads the window at the current position when it changes, so a network switch re-issues stream URLs with the new settings. Reset Coil's singleton in SubtracksApp.onCreate alongside Koin, since ArtworkSeedCache's background scope can call get() across Robolectric tests and poison the next Application.

app/src/main/AndroidManifest.xml

@@ -1,6 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
 
+    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
     <uses-permission android:name="android.permission.FOREGROUND_SERVICE_MEDIA_PLAYBACK" />

app/src/main/kotlin/com/subtracks/SubtracksApp.kt

@@ -3,6 +3,7 @@ package com.subtracks
 import android.app.Application
 import coil3.ImageLoader
 import coil3.SingletonImageLoader
+import coil3.annotation.DelicateCoilApi
 import coil3.network.okhttp.OkHttpNetworkFetcherFactory
 import com.subtracks.data.repo.ArtworkSeedStore
 import com.subtracks.di.appModule
@@ -14,9 +15,11 @@ import org.koin.core.context.stopKoin
 class SubtracksApp : Application() {
     private val http = OkHttpClient()
 
+    @OptIn(DelicateCoilApi::class)
     override fun onCreate() {
         super.onCreate()
         stopKoin()
+        SingletonImageLoader.reset()
         val koin =
             startKoin {
                 modules(appModule(this@SubtracksApp, http))

app/src/main/kotlin/com/subtracks/data/net/NetworkMonitor.kt

@@ -0,0 +1,48 @@
+package com.subtracks.data.net
+
+import android.content.Context
+import android.net.ConnectivityManager
+import android.net.Network
+import android.net.NetworkCapabilities
+import kotlinx.coroutines.channels.awaitClose
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.callbackFlow
+import kotlinx.coroutines.flow.conflate
+import kotlinx.coroutines.flow.distinctUntilChanged
+
+enum class NetworkMode(
+    val key: String,
+) {
+    Wifi("wifi"),
+    Mobile("mobile"),
+}
+
+class NetworkMonitor(
+    context: Context,
+) {
+    private val connectivity = context.applicationContext.getSystemService(ConnectivityManager::class.java)
+
+    val mode: Flow<NetworkMode> =
+        callbackFlow {
+            val callback =
+                object : ConnectivityManager.NetworkCallback() {
+                    override fun onAvailable(network: Network) = push()
+
+                    override fun onLost(network: Network) = push()
+
+                    override fun onCapabilitiesChanged(
+                        network: Network,
+                        capabilities: NetworkCapabilities,
+                    ) = push()
+
+                    private fun push() {
+                        this@callbackFlow.trySend(current())
+                    }
+                }
+            val registered = runCatching { connectivity?.registerDefaultNetworkCallback(callback) }.isSuccess
+            this@callbackFlow.trySend(current())
+            awaitClose { if (registered) runCatching { connectivity?.unregisterNetworkCallback(callback) } }
+        }.distinctUntilChanged().conflate()
+
+    private fun current(): NetworkMode = if (connectivity?.isActiveNetworkMetered == true) NetworkMode.Mobile else NetworkMode.Wifi
+}

app/src/main/kotlin/com/subtracks/data/prefs/UserPreferences.kt

@@ -4,9 +4,9 @@ import android.content.Context
 import androidx.datastore.core.DataStore
 import androidx.datastore.preferences.core.Preferences
 import androidx.datastore.preferences.core.edit
-import androidx.datastore.preferences.core.intPreferencesKey
 import androidx.datastore.preferences.core.stringPreferencesKey
 import androidx.datastore.preferences.preferencesDataStore
+import com.subtracks.data.net.NetworkMode
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.map
 
@@ -34,6 +34,11 @@ data class ListQuery(
     val starred: StarredFilter = StarredFilter.Any,
 )
 
+data class StreamQuality(
+    val maxBitrate: Int = 0,
+    val format: String? = null,
+)
+
 private val Context.preferences: DataStore<Preferences> by preferencesDataStore("user_prefs")
 
 class UserPreferences(
@@ -48,24 +53,32 @@ class UserPreferences(
         store.edit { prefs -> prefs[listQueryKey(tab)] = encode(query) }
     }
 
-    val maxBitrate: Flow<Int> = store.data.map { prefs -> prefs[MAX_BITRATE] ?: 0 }
+    fun streamQuality(mode: NetworkMode): Flow<StreamQuality> =
+        store.data.map { prefs -> decodeStreamQuality(prefs[streamQualityKey(mode)]) }
 
-    suspend fun setMaxBitrate(kbps: Int) {
+    suspend fun setStreamQuality(
-        store.edit { prefs -> prefs[MAX_BITRATE] = kbps }
+        mode: NetworkMode,
+        quality: StreamQuality,
+    ) {
+        store.edit { prefs -> prefs[streamQualityKey(mode)] = encode(quality) }
     }
 
-    val streamFormat: Flow<String?> = store.data.map { prefs -> prefs[STREAM_FORMAT] }
+    private fun streamQualityKey(mode: NetworkMode) = stringPreferencesKey("stream_quality_${mode.key}")
-
-    suspend fun setStreamFormat(format: String?) {
-        store.edit { prefs ->
-            if (format.isNullOrEmpty()) prefs.remove(STREAM_FORMAT) else prefs[STREAM_FORMAT] = format
-        }
-    }
 
     private fun listQueryKey(tab: LibraryListTab) = stringPreferencesKey("list_query_${tab.key}")
 
     private fun encode(query: ListQuery) = "${query.sort}|${if (query.descending) 1 else 0}|${query.starred.ordinal}"
 
+    private fun encode(quality: StreamQuality) = "${quality.maxBitrate}|${quality.format.orEmpty()}"
+
+    private fun decodeStreamQuality(stored: String?): StreamQuality {
+        val parts = stored?.split("|") ?: return StreamQuality()
+        return StreamQuality(
+            maxBitrate = parts.getOrNull(0)?.toIntOrNull() ?: 0,
+            format = parts.getOrNull(1)?.takeIf { it.isNotEmpty() },
+        )
+    }
+
     private fun decode(
         stored: String?,
         defaultSort: String,
@@ -78,11 +91,6 @@ class UserPreferences(
             starred = StarredFilter.entries.getOrElse(parts[2].toIntOrNull() ?: 0) { StarredFilter.Any },
         )
     }
-
-    private companion object {
-        val MAX_BITRATE = intPreferencesKey("max_bitrate")
-        val STREAM_FORMAT = stringPreferencesKey("stream_format")
-    }
 }
 
 fun createUserPreferences(context: Context): UserPreferences = UserPreferences(context.preferences)

app/src/main/kotlin/com/subtracks/data/repo/SourceRepository.kt

@@ -5,6 +5,8 @@ import com.subtracks.data.model.CoverArtRef
 import com.subtracks.data.model.Source
 import com.subtracks.data.model.SubsonicConfig
 import com.subtracks.data.model.SubsonicSource
+import com.subtracks.data.net.NetworkMode
+import com.subtracks.data.prefs.StreamQuality
 import com.subtracks.data.prefs.UserPreferences
 import com.subtracks.data.source.MusicSource
 import com.subtracks.data.source.subsonic.SubsonicClient
@@ -13,8 +15,10 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.cancel
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.combine
-import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.flowOf
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
 import okhttp3.HttpUrl.Companion.toHttpUrl
@@ -25,6 +29,7 @@ class SourceRepository(
     private val db: SubtracksDatabase,
     private val http: OkHttpClient,
     private val prefs: UserPreferences,
+    networkMode: Flow<NetworkMode> = flowOf(NetworkMode.Wifi),
     private val showMessage: (String) -> Unit = {},
 ) {
     private val scope = CoroutineScope(SupervisorJob() + Dispatchers.Default)
@@ -33,15 +38,20 @@ class SourceRepository(
     private var active: SubsonicMusicSource? = null
     private var activeSourceId: Long? = null
 
+    private val _quality = MutableStateFlow(StreamQuality())
+    val quality: StateFlow<StreamQuality> = _quality
+
     init {
         scope.launch {
             combine(
                 db.sourcesDao().activeSubsonicConfig(),
-                prefs.maxBitrate,
+                networkMode,
-                prefs.streamFormat,
+                prefs.streamQuality(NetworkMode.Wifi),
-            ) { config, maxBitrate, streamFormat -> Triple(config, maxBitrate, streamFormat) }
+                prefs.streamQuality(NetworkMode.Mobile),
-                .collect { (config, maxBitrate, streamFormat) ->
+            ) { config, mode, wifi, mobile -> config to (if (mode == NetworkMode.Wifi) wifi else mobile) }
-                    active = config?.toMusicSource(maxBitrate, streamFormat)
+                .collect { (config, quality) ->
+                    active = config?.toMusicSource(quality)
+                    _quality.value = quality
                     val sourceChanged = config?.id != activeSourceId
                     activeSourceId = config?.id
                     if (sourceChanged && config != null && config.useTokenAuth) {
@@ -129,7 +139,7 @@ class SourceRepository(
 
     suspend fun activeMusicSource(): MusicSource? {
         val config = db.sourcesDao().activeSubsonicConfigOnce() ?: return null
-        return config.toMusicSource(prefs.maxBitrate.first(), prefs.streamFormat.first())
+        return config.toMusicSource(quality.value)
     }
 
     private fun SubsonicConfig.toClient(): SubsonicClient =
@@ -141,15 +151,12 @@ class SourceRepository(
             onTokenAuthUnsupported = { disableTokenAuth(id) },
         )
 
-    private fun SubsonicConfig.toMusicSource(
+    private fun SubsonicConfig.toMusicSource(quality: StreamQuality): SubsonicMusicSource =
-        maxBitrate: Int,
-        streamFormat: String?,
-    ): SubsonicMusicSource =
         SubsonicMusicSource(
             id = id,
             client = toClient(),
-            maxBitrate = maxBitrate,
+            maxBitrate = quality.maxBitrate,
-            streamFormat = streamFormat,
+            streamFormat = quality.format,
         )
 
     private fun disableTokenAuth(sourceId: Long) {

app/src/main/kotlin/com/subtracks/di/AppModule.kt

@@ -5,6 +5,7 @@ import android.os.Handler
 import android.os.Looper
 import android.widget.Toast
 import com.subtracks.data.db.createAndroidDatabase
+import com.subtracks.data.net.NetworkMonitor
 import com.subtracks.data.prefs.createUserPreferences
 import com.subtracks.data.repo.ArtworkSeedRepository
 import com.subtracks.data.repo.ArtworkSeedStore
@@ -38,7 +39,8 @@ fun appModule(
     single { createAndroidDatabase(context) }
     single { http }
     single { createUserPreferences(context) }
-    single { SourceRepository(get(), get(), get(), showMessage = toast) }
+    single { NetworkMonitor(context.applicationContext) }
+    single { SourceRepository(get(), get(), get(), networkMode = get<NetworkMonitor>().mode, showMessage = toast) }
     single { LibraryRepository(get(), get(), toast) }
     single<ArtworkSeedStore> { ArtworkSeedRepository(get()) }
     single { SyncManager(get(), get(), get()) }

app/src/main/kotlin/com/subtracks/playback/PlaybackController.kt

@@ -16,6 +16,7 @@ import kotlinx.coroutines.cancel
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.drop
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.sync.Mutex
 import kotlinx.coroutines.sync.withLock
@@ -133,6 +134,9 @@ class PlaybackController(
                 if (queueSourceId != null && sourceId != null && sourceId != queueSourceId) stop()
             }
         }
+        scope.launch {
+            sourceRepository.quality.drop(1).collect { reloadQuality() }
+        }
     }
 
     fun close() {
@@ -699,6 +703,17 @@ class PlaybackController(
         refresh(position)
     }
 
+    private suspend fun reloadQuality() =
+        startLock.withLock {
+            val player = player ?: return@withLock
+            val snapshot = snapshot ?: return@withLock
+            if (snapshot.size == 0L) return@withLock
+            val sourceId = queueSourceId
+            if (sourceId == null || sourceRepository.activeSourceIdOnce() != sourceId) return@withLock
+            val position = currentPosition() ?: return@withLock
+            loadWindow(position, autoplay = player.playWhenReady && !player.isEnded, startPositionMs = player.currentPositionMs)
+        }
+
     private fun jumpTo(target: Long) {
         scope.launch {
             startLock.withLock {

app/src/main/kotlin/com/subtracks/ui/settings/SettingsScreen.kt

@@ -13,6 +13,8 @@ import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.rememberLazyListState
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.verticalScroll
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.rounded.ArrowBack
 import androidx.compose.material.icons.rounded.Add
@@ -42,13 +44,14 @@ import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import com.subtracks.data.model.Source
+import com.subtracks.data.prefs.StreamQuality
 import com.subtracks.ui.components.rememberViewportFill
 import org.koin.compose.viewmodel.koinViewModel
 
 private val bitrateOptions = listOf(0, 24, 32, 64, 96, 128, 192, 256, 320)
 private val streamFormats = listOf(null, "mp3", "opus", "ogg", "webm", "aac", "flac")
 
-private enum class SettingsDialog { Bitrate, Format }
+private enum class SettingsDialog { WifiQuality, MobileQuality }
 
 @Composable
 fun SettingsRoute(
@@ -58,17 +61,17 @@ fun SettingsRoute(
 ) {
     val sources by viewModel.sources.collectAsStateWithLifecycle()
     val activeSourceId by viewModel.activeSourceId.collectAsStateWithLifecycle()
-    val maxBitrate by viewModel.maxBitrate.collectAsStateWithLifecycle()
+    val wifiQuality by viewModel.wifiQuality.collectAsStateWithLifecycle()
-    val streamFormat by viewModel.streamFormat.collectAsStateWithLifecycle()
+    val mobileQuality by viewModel.mobileQuality.collectAsStateWithLifecycle()
     SettingsScreen(
         sources = sources,
         activeSourceId = activeSourceId,
-        maxBitrate = maxBitrate,
+        wifiQuality = wifiQuality,
-        streamFormat = streamFormat,
+        mobileQuality = mobileQuality,
         onSelectSource = viewModel::selectSource,
         onDeleteSource = viewModel::deleteSource,
-        onMaxBitrateChange = viewModel::setMaxBitrate,
+        onWifiQualityChange = viewModel::setWifiQuality,
-        onStreamFormatChange = viewModel::setStreamFormat,
+        onMobileQualityChange = viewModel::setMobileQuality,
         onAddServer = onAddServer,
         onBack = onBack,
     )
@@ -79,12 +82,12 @@ fun SettingsRoute(
 fun SettingsScreen(
     sources: List<Source>,
     activeSourceId: Long?,
-    maxBitrate: Int,
+    wifiQuality: StreamQuality,
-    streamFormat: String?,
+    mobileQuality: StreamQuality,
     onSelectSource: (Long) -> Unit,
     onDeleteSource: (Long) -> Unit,
-    onMaxBitrateChange: (Int) -> Unit,
+    onWifiQualityChange: (StreamQuality) -> Unit,
-    onStreamFormatChange: (String?) -> Unit,
+    onMobileQualityChange: (StreamQuality) -> Unit,
     onAddServer: () -> Unit,
     onBack: () -> Unit,
     modifier: Modifier = Modifier,
@@ -147,17 +150,17 @@ fun SettingsScreen(
             item { SectionHeader("Network") }
             item {
                 ListItem(
-                    headlineContent = { Text("Maximum bitrate") },
+                    headlineContent = { Text("Wi-Fi") },
-                    supportingContent = { Text(bitrateLabel(maxBitrate)) },
+                    supportingContent = { Text(qualityLabel(wifiQuality)) },
-                    modifier = Modifier.clickable { dialog = SettingsDialog.Bitrate },
+                    modifier = Modifier.clickable { dialog = SettingsDialog.WifiQuality },
                     colors = ListItemDefaults.colors(containerColor = Color.Transparent),
                 )
             }
             item {
                 ListItem(
-                    headlineContent = { Text("Preferred stream format") },
+                    headlineContent = { Text("Mobile data") },
-                    supportingContent = { Text(streamFormat ?: "Use server default") },
+                    supportingContent = { Text(qualityLabel(mobileQuality)) },
-                    modifier = Modifier.clickable { dialog = SettingsDialog.Format },
+                    modifier = Modifier.clickable { dialog = SettingsDialog.MobileQuality },
                     colors = ListItemDefaults.colors(containerColor = Color.Transparent),
                 )
             }
@@ -166,28 +169,20 @@ fun SettingsScreen(
     }
 
     when (dialog) {
-        SettingsDialog.Bitrate -> {
+        SettingsDialog.WifiQuality -> {
-            ChoiceDialog(
+            QualityDialog(
-                title = "Maximum bitrate",
+                title = "Wi-Fi",
-                options = bitrateOptions.map { it to bitrateLabel(it) },
+                quality = wifiQuality,
-                selected = maxBitrate,
+                onSelect = onWifiQualityChange,
-                onSelect = { value ->
-                    onMaxBitrateChange(value)
-                    dialog = null
-                },
                 onDismiss = { dialog = null },
             )
         }
 
-        SettingsDialog.Format -> {
+        SettingsDialog.MobileQuality -> {
-            ChoiceDialog(
+            QualityDialog(
-                title = "Preferred stream format",
+                title = "Mobile data",
-                options = streamFormats.map { it to (it ?: "Use server default") },
+                quality = mobileQuality,
-                selected = streamFormat,
+                onSelect = onMobileQualityChange,
-                onSelect = { value ->
-                    onStreamFormatChange(value)
-                    dialog = null
-                },
                 onDismiss = { dialog = null },
             )
         }
@@ -198,21 +193,51 @@ fun SettingsScreen(
     }
 }
 
+private fun qualityLabel(quality: StreamQuality): String = "${bitrateLabel(quality.maxBitrate)} · ${quality.format ?: "Server default"}"
+
 private fun bitrateLabel(kbps: Int): String = if (kbps == 0) "Unlimited" else "${kbps}kbps"
 
 @Composable
-private fun <T> ChoiceDialog(
+private fun QualityDialog(
     title: String,
-    options: List<Pair<T, String>>,
+    quality: StreamQuality,
-    selected: T,
+    onSelect: (StreamQuality) -> Unit,
-    onSelect: (T) -> Unit,
     onDismiss: () -> Unit,
 ) {
     AlertDialog(
         onDismissRequest = onDismiss,
         title = { Text(title) },
         text = {
-            Column {
+            Column(modifier = Modifier.verticalScroll(rememberScrollState())) {
+                ChoiceGroup(
+                    header = "Maximum bitrate",
+                    options = bitrateOptions.map { it to bitrateLabel(it) },
+                    selected = quality.maxBitrate,
+                    onSelect = { onSelect(quality.copy(maxBitrate = it)) },
+                )
+                Spacer(Modifier.height(16.dp))
+                ChoiceGroup(
+                    header = "Preferred format",
+                    options = streamFormats.map { it to (it ?: "Use server default") },
+                    selected = quality.format,
+                    onSelect = { onSelect(quality.copy(format = it)) },
+                )
+            }
+        },
+        confirmButton = {
+            TextButton(onClick = onDismiss) { Text("Done") }
+        },
+    )
+}
+
+@Composable
+private fun <T> ChoiceGroup(
+    header: String,
+    options: List<Pair<T, String>>,
+    selected: T,
+    onSelect: (T) -> Unit,
+) {
+    Text(header, style = MaterialTheme.typography.titleSmall, color = MaterialTheme.colorScheme.primary)
     options.forEach { (value, label) ->
         Row(
             verticalAlignment = Alignment.CenterVertically,
@@ -224,12 +249,6 @@ private fun <T> ChoiceDialog(
         }
     }
 }
-        },
-        confirmButton = {
-            TextButton(onClick = onDismiss) { Text("Cancel") }
-        },
-    )
-}
 
 @Composable
 private fun SectionHeader(text: String) {

app/src/main/kotlin/com/subtracks/ui/settings/SettingsViewModel.kt

@@ -3,6 +3,8 @@ package com.subtracks.ui.settings
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import com.subtracks.data.model.Source
+import com.subtracks.data.net.NetworkMode
+import com.subtracks.data.prefs.StreamQuality
 import com.subtracks.data.prefs.UserPreferences
 import com.subtracks.data.repo.SourceRepository
 import kotlinx.coroutines.flow.SharingStarted
@@ -20,13 +22,15 @@ class SettingsViewModel(
     val activeSourceId: StateFlow<Long?> =
         sourceRepository.activeSourceId().stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), null)
 
-    val maxBitrate: StateFlow<Int> =
+    val wifiQuality: StateFlow<StreamQuality> =
-        userPreferences.maxBitrate
+        userPreferences
-            .stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), 0)
+            .streamQuality(NetworkMode.Wifi)
+            .stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), StreamQuality())
 
-    val streamFormat: StateFlow<String?> =
+    val mobileQuality: StateFlow<StreamQuality> =
-        userPreferences.streamFormat
+        userPreferences
-            .stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), null)
+            .streamQuality(NetworkMode.Mobile)
+            .stateIn(viewModelScope, SharingStarted.WhileSubscribed(5_000), StreamQuality())
 
     fun selectSource(id: Long) {
         viewModelScope.launch { sourceRepository.selectSource(id) }
@@ -36,11 +40,11 @@ class SettingsViewModel(
         viewModelScope.launch { sourceRepository.deleteSource(id) }
     }
 
-    fun setMaxBitrate(kbps: Int) {
+    fun setWifiQuality(quality: StreamQuality) {
-        viewModelScope.launch { userPreferences.setMaxBitrate(kbps) }
+        viewModelScope.launch { userPreferences.setStreamQuality(NetworkMode.Wifi, quality) }
     }
 
-    fun setStreamFormat(format: String?) {
+    fun setMobileQuality(quality: StreamQuality) {
-        viewModelScope.launch { userPreferences.setStreamFormat(format) }
+        viewModelScope.launch { userPreferences.setStreamQuality(NetworkMode.Mobile, quality) }
     }
 }

app/src/test/kotlin/com/subtracks/data/prefs/UserPreferencesTest.kt

@@ -2,6 +2,7 @@ package com.subtracks.data.prefs
 
 import androidx.datastore.preferences.core.PreferenceDataStoreFactory
 import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.subtracks.data.net.NetworkMode
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.test.runTest
@@ -35,6 +36,25 @@ class UserPreferencesTest {
                 prefs.listQuery(LibraryListTab.Artists).first(),
             )
 
+            file.delete()
+        }
+
+    @Test
+    fun streamQualityRoundTripsPerNetworkMode() =
+        runTest {
+            val file = File.createTempFile("user-prefs", ".preferences_pb").apply { delete() }
+            val store = PreferenceDataStoreFactory.create(scope = backgroundScope) { file }
+            val prefs = UserPreferences(store)
+
+            assertEquals(StreamQuality(), prefs.streamQuality(NetworkMode.Wifi).first())
+            assertEquals(StreamQuality(), prefs.streamQuality(NetworkMode.Mobile).first())
+
+            prefs.setStreamQuality(NetworkMode.Wifi, StreamQuality(320, null))
+            prefs.setStreamQuality(NetworkMode.Mobile, StreamQuality(96, "opus"))
+
+            assertEquals(StreamQuality(320, null), prefs.streamQuality(NetworkMode.Wifi).first())
+            assertEquals(StreamQuality(96, "opus"), prefs.streamQuality(NetworkMode.Mobile).first())
+
             file.delete()
         }
 }

app/src/test/kotlin/com/subtracks/playback/PlaybackControllerTest.kt

@@ -11,6 +11,9 @@ import com.subtracks.data.model.QueueEntry
 import com.subtracks.data.model.QueueKind
 import com.subtracks.data.model.Song
 import com.subtracks.data.model.Source
+import com.subtracks.data.net.NetworkMode
+import com.subtracks.data.prefs.StreamQuality
+import com.subtracks.data.prefs.UserPreferences
 import com.subtracks.data.prefs.fakeUserPreferences
 import com.subtracks.data.repo.QueueRepository
 import com.subtracks.data.repo.SourceRepository
@@ -35,6 +38,7 @@ class PlaybackControllerTest {
     private val dispatcher = Executors.newSingleThreadExecutor().asCoroutineDispatcher()
 
     private lateinit var db: SubtracksDatabase
+    private lateinit var prefs: UserPreferences
     private lateinit var sources: SourceRepository
     private lateinit var queues: QueueRepository
     private lateinit var handle: FakePlayerHandle
@@ -48,7 +52,8 @@ class PlaybackControllerTest {
                 .inMemoryDatabaseBuilder(context, SubtracksDatabase::class.java)
                 .setDriver(BundledSQLiteDriver())
                 .build()
-        sources = SourceRepository(db, OkHttpClient(), fakeUserPreferences())
+        prefs = fakeUserPreferences()
+        sources = SourceRepository(db, OkHttpClient(), prefs)
         queues = QueueRepository(db)
         handle = FakePlayerHandle()
         controller = PlaybackController(sources, queues, FakePlayerConnection(handle), dispatcher = dispatcher)
@@ -1015,6 +1020,25 @@ class PlaybackControllerTest {
             assertEquals(paused, controller.positionMs.value)
         }
 
+    @Test
+    fun changingStreamQualityReloadsTheCurrentItemAtTheSamePosition() {
+        seedAlbum(60, sourceId = 1)
+        runBlocking { prefs.setStreamQuality(NetworkMode.Wifi, StreamQuality(64, null)) }
+        await { sources.quality.value == StreamQuality(64, null) }
+
+        controller.playAlbum(1, "al1", 10)
+        await { handle.operations.contains("play") }
+        handle.positionMs = 42_000L
+        val windows = handle.operations.count { it.startsWith("setWindow") }
+
+        runBlocking { prefs.setStreamQuality(NetworkMode.Wifi, StreamQuality(128, "opus")) }
+        await { handle.operations.count { it.startsWith("setWindow") } > windows }
+
+        assertEquals("s11", handle.currentItem?.id)
+        assertEquals(42_000L, handle.positionMs)
+        assertEquals(listOf("prepare", "play"), handle.operations.takeLast(2))
+    }
+
     private fun seedAlbum(
         count: Int,
         sourceId: Long,

app/src/test/kotlin/com/subtracks/ui/AppScreenshotTest.kt

@@ -36,6 +36,7 @@ import com.subtracks.data.model.Playlist
 import com.subtracks.data.model.Song
 import com.subtracks.data.model.SongListItem
 import com.subtracks.data.model.Source
+import com.subtracks.data.prefs.StreamQuality
 import com.subtracks.playback.PlaybackState
 import com.subtracks.playback.QueueItem
 import com.subtracks.playback.RepeatMode
@@ -303,12 +304,12 @@ class AppScreenshotTest {
                 SettingsScreen(
                     sources = Fixtures.sources,
                     activeSourceId = 1,
-                    maxBitrate = 0,
+                    wifiQuality = StreamQuality(),
-                    streamFormat = null,
+                    mobileQuality = StreamQuality(192, "mp3"),
                     onSelectSource = {},
                     onDeleteSource = {},
-                    onMaxBitrateChange = {},
+                    onWifiQualityChange = {},
-                    onStreamFormatChange = {},
+                    onMobileQualityChange = {},
                     onAddServer = {},
                     onBack = {},
                 )

docs/architecture.md

@@ -86,7 +86,7 @@ The queue lives in SQL, not memory. `queue_entries` is an ordered list of *refer
 
 Because the resolver reports *which entry* a position falls in, `PlaybackState` also carries the current queue context (`kind` and `refId`). That is what scopes the playing-track indicator in the album and playlist lists: a song that appears in both only lights up in the list the queue was actually started from.
 
-Stream URLs come from `SourceRepository.streamUri`, which asks the active `SubsonicSource` for a freshly salted `stream` URL; because the URL changes every request, artwork is attached to the media item by identity (the `CoverArtRef` cache key) rather than by URL.
+Stream URLs come from `SourceRepository.streamUri`, which asks the active `SubsonicSource` for a freshly salted `stream` URL; because the URL changes every request, artwork is attached to the media item by identity (the `CoverArtRef` cache key) rather than by URL. The active source carries the stream quality (a max bitrate plus an optional transcode format) for the current network: `NetworkMonitor` reports Wi-Fi vs mobile (metered) and `UserPreferences` stores a separate `StreamQuality` per mode, so `SourceRepository` rebuilds the source when either the mode or a quality changes. `PlaybackController` observes that effective quality and reloads the window around the current position, preserving play/pause and the playback position, so a Wi-Fi↔mobile transition re-issues the stream URLs with the new settings (a no-op when the two modes share a quality).
 
 The window is also the queue the media notification and Android Auto can browse — a deliberate trade-off, since the alternative is holding an entire large library in memory. The queue view resolves positions lazily too: it loads the queue around the cursor in chunks and extends by a chunk when you scroll near either end, so it never materializes the whole queue. Dragging uses `sh.calvin.reorderable`, which floats the lifted row and reorders the loaded list live (animating with `animateItem`), so editing is what a drag needs: the view reorders its loaded list while dragging and commits one move on drop. `queue_entries` is rewritten to edit: removing a position splits its entry into up to two ranges, and moving one turns the moved track into an explicit song entry inserted at the target index, so an edit costs a couple of rows rather than a copy of the queue. When the edit falls inside the player's window the controller mirrors it with `removeMediaItem`/`moveMediaItem` so playback is not interrupted; removing the playing track, or a move that crosses the window boundary, reloads the window around the cursor. The controller keeps the pre-edit entries and cursor, so the queue view can offer a one-step undo. Timed lyrics/gapless format preferences, scrobbling, downloads and adding to the queue from the library are not wired yet.