address playback review findings

- treat flac/wav/alac as lossless and ignore the bitrate for them, so the declared length never drops below the real encoded size and truncates a lossless transcode
- read the effective stream quality once per media item and use it for both the URL and the clip, closing the window where they disagreed
- honour a bounded DataSpec length in KnownLengthDataSource and reject non-positive length fragments
- drop MetadataDurationPlayer: clipping already gives the timeline the real duration, and the forwarder could publish a wrong metadata duration for direct play
- drop the dead PlaybackState.error/lastError now that errors are toast-only, and tighten the floor test to assert the exact value

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

@@ -86,10 +86,11 @@ class SourceRepository(
 
     fun streamUri(
         songId: String,
-        durationMs: Long? = null,
+        durationMs: Long?,
+        quality: StreamQuality,
     ): String? {
         val uri = active?.streamUri(songId)?.toString() ?: return null
-        val length = declaredStreamLength(durationMs, quality.value) ?: return uri
+        val length = declaredStreamLength(durationMs, quality) ?: return uri
         return uri + streamLengthSuffix(length)
     }
 

app/src/main/kotlin/com/subtracks/data/source/StreamLength.kt

@@ -6,7 +6,9 @@ internal const val STREAM_LENGTH_FRAGMENT = "streamLength"
 
 private const val MIN_TRANSCODE_BPS = 64_000L
 private const val UNCAPPED_BPS = 2_000_000L
+private const val LOSSLESS_CEILING_BPS = 9_216_000L
 private const val OVERHEAD_BYTES = 256L * 1024L
+private val LOSSLESS_FORMATS = setOf("flac", "wav", "alac")
 
 fun declaredStreamLength(
     durationMs: Long?,
@@ -14,7 +16,12 @@ fun declaredStreamLength(
 ): Long? {
     if (durationMs == null || durationMs <= 0) return null
     if (!quality.transcodes) return null
-    val bps = if (quality.maxBitrate > 0) maxOf(quality.maxBitrate * 1000L, MIN_TRANSCODE_BPS) else UNCAPPED_BPS
+    val bps =
+        when {
+            quality.format?.lowercase() in LOSSLESS_FORMATS -> LOSSLESS_CEILING_BPS
+            quality.maxBitrate > 0 -> maxOf(quality.maxBitrate * 1000L, MIN_TRANSCODE_BPS)
+            else -> UNCAPPED_BPS
+        }
     return durationMs / 1000 * bps / 8 * 5 / 4 + OVERHEAD_BYTES
 }
 
@@ -23,5 +30,5 @@ internal fun streamLengthSuffix(length: Long): String = "#$STREAM_LENGTH_FRAGMEN
 internal fun declaredLengthFromFragment(fragment: String?): Long? {
     val marker = "$STREAM_LENGTH_FRAGMENT="
     if (fragment == null || !fragment.startsWith(marker)) return null
-    return fragment.substring(marker.length).toLongOrNull()
+    return fragment.substring(marker.length).toLongOrNull()?.takeIf { it > 0 }
 }

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

@@ -15,6 +15,7 @@ internal class KnownLengthDataSource(
     override fun open(dataSpec: DataSpec): Long {
         val length = delegate.open(dataSpec)
         if (length != C.LENGTH_UNSET.toLong()) return length
+        if (dataSpec.length != C.LENGTH_UNSET.toLong()) return dataSpec.length
         val declared = declaredLengthFromFragment(dataSpec.uri.fragment) ?: return length
         return (declared - dataSpec.position).coerceAtLeast(0)
     }

app/src/main/kotlin/com/subtracks/playback/Media3PlayerHandle.kt

@@ -143,13 +143,14 @@ class Media3PlayerHandle(
                         item.durationMs?.let { putLong(EXTRA_DURATION_MS, it) }
                     },
                 ).build()
+        val quality = sourceRepository.quality.value
         val builder =
             MediaItem
                 .Builder()
                 .setMediaId(item.id)
-                .setUri(sourceRepository.streamUri(item.id, item.durationMs))
+                .setUri(sourceRepository.streamUri(item.id, item.durationMs, quality))
                 .setMediaMetadata(metadata)
-        if (sourceRepository.quality.value.transcodes) {
+        if (quality.transcodes) {
             item.durationMs?.takeIf { it > 0 }?.let { duration ->
                 builder.setClippingConfiguration(
                     ClippingConfiguration.Builder().setEndPositionMs(duration).build(),

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

@@ -45,7 +45,6 @@ data class PlaybackState(
     val item: QueueItem? = null,
     val context: QueueContext? = null,
     val position: Long? = null,
-    val error: String? = null,
     val isBuffering: Boolean = false,
     val isPlaying: Boolean = false,
     val durationMs: Long = 0,
@@ -119,7 +118,6 @@ class PlaybackController(
     private val startLock = Mutex()
 
     private var snapshot: QueueSnapshot? = null
-    private var lastError: String? = null
     private var queueSourceId: Long? = null
     private var windowStart = 0L
     private var windowEnd = -1L
@@ -226,7 +224,6 @@ class PlaybackController(
             windowJob?.cancel()
             windowStart = 0
             windowEnd = -1
-            lastError = null
             lastEdit = null
             endedHandled = false
             val previous = snapshot
@@ -602,7 +599,6 @@ class PlaybackController(
         windowJob?.cancel()
         windowStart = 0
         windowEnd = -1
-        lastError = null
         lastEdit = null
         endedHandled = false
         val modes = queueRepository.modes()
@@ -676,7 +672,6 @@ class PlaybackController(
         bufferingJob = null
         showBuffering = false
         snapshot = null
-        lastError = null
         queueSourceId = null
         windowStart = 0
         windowEnd = -1
@@ -858,7 +853,6 @@ class PlaybackController(
     private val playerListener =
         object : PlayerHandle.Listener {
             override fun onTransition() {
-                lastError = null
                 endedHandled = false
                 if (updating) return
                 scope.launch { onPositionChanged() }
@@ -870,7 +864,6 @@ class PlaybackController(
             }
 
             override fun onError(message: String) {
-                lastError = message
                 showMessage(message)
                 refresh()
             }
@@ -939,7 +932,6 @@ class PlaybackController(
                 item = player.currentItem,
                 context = contextAt(position),
                 position = position,
-                error = lastError,
                 isBuffering = showBuffering,
                 isPlaying = player.playWhenReady && !player.isIdle && !player.isEnded,
                 durationMs = durationMs,

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

@@ -7,8 +7,6 @@ import android.util.Log
 import androidx.annotation.OptIn
 import androidx.media3.common.AudioAttributes
 import androidx.media3.common.C
-import androidx.media3.common.ForwardingPlayer
-import androidx.media3.common.Player
 import androidx.media3.common.util.ExperimentalApi
 import androidx.media3.common.util.UnstableApi
 import androidx.media3.datasource.okhttp.OkHttpDataSource
@@ -47,7 +45,6 @@ class PlaybackService : MediaSessionService() {
                             KnownLengthDataSourceFactory(OkHttpDataSource.Factory(streamingClient())),
                         ),
                 ).build()
-        val player = MetadataDurationPlayer(exoPlayer)
         val loader =
             CoverArtBitmapLoader(
                 applicationContext,
@@ -57,7 +54,7 @@ class PlaybackService : MediaSessionService() {
         artworkLoader = loader
         session =
             MediaSession
-                .Builder(this, player)
+                .Builder(this, exoPlayer)
                 .setSessionActivity(
                     PendingIntent.getActivity(
                         this,
@@ -106,10 +103,3 @@ class PlaybackService : MediaSessionService() {
         super.onDestroy()
     }
 }
-
-@OptIn(UnstableApi::class)
-private class MetadataDurationPlayer(
-    player: Player,
-) : ForwardingPlayer(player) {
-    override fun getDuration(): Long = currentMediaItem?.mediaMetadata?.durationMs?.takeIf { it > 0 } ?: super.getDuration()
-}

app/src/test/kotlin/com/subtracks/data/source/StreamLengthTest.kt

@@ -27,9 +27,16 @@ class StreamLengthTest {
 
     @Test
     fun aTinyBitrateStillClearsTheEncodersFloor() {
-        val length = declaredStreamLength(180_000, StreamQuality(24, "mp3"))!!
+        assertEquals(2_062_144L, declaredStreamLength(180_000, StreamQuality(24, "mp3")))
+    }
 
-        assertTrue(length >= 180 * 32_000 / 8)
+    @Test
+    fun losslessFormatsIgnoreTheBitrateAndAllowForTheLargestStream() {
+        val cdQuality = declaredStreamLength(320_000, StreamQuality(64, "flac"))!!
+        val highBitrate = declaredStreamLength(320_000, StreamQuality(320, "flac"))!!
+
+        assertEquals(cdQuality, highBitrate)
+        assertTrue(cdQuality >= 320 * 1_411_200 / 8)
     }
 
     @Test

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

@@ -280,28 +280,6 @@ class PlaybackControllerTest {
         await { !controller.state.value.isBuffering }
     }
 
-    @Test
-    fun playbackFailuresAreSurfacedUntilTheNextTrack() {
-        seedAlbum(3, sourceId = 1)
-
-        controller.playAlbum(1, "al1", 0)
-        await {
-            controller.state.value.item
-                ?.id == "s1"
-        }
-
-        handle.fail("ERROR_CODE_IO_UNSPECIFIED")
-        await { controller.state.value.error == "ERROR_CODE_IO_UNSPECIFIED" }
-
-        handle.advanceTo(handle.currentIndex + 1)
-        await {
-            controller.state.value.item
-                ?.id == "s2"
-        }
-
-        assertEquals(null, controller.state.value.error)
-    }
-
     @Test
     fun playbackErrorsAreShownAsAToast() {
         seedAlbum(3, sourceId = 1)