feat(player): support playback speeds up to 8x

close #1545

android/app/src/main/kotlin/com/edde746/plezy/exoplayer/ExoPlayerCore.kt

@@ -111,6 +111,8 @@ class ExoPlayerCore(private val activity: Activity) : Player.Listener {
     private const val WATCHDOG_TIMEOUT_MS = 8000L
     private const val DECODER_HANG_TIMEOUT_MS = 5000L
     private const val MAX_AUDIO_RECOVERY_ATTEMPTS = 2
+    private const val MIN_PLAYBACK_SPEED = 0.25f
+    private const val MAX_PLAYBACK_SPEED = 8f
     private const val FPS_SAMPLE_COUNT = 8
     private const val AUDIO_BOUNCE_TIMEOUT_MS = 1000L
 
@@ -3270,10 +3272,10 @@ class ExoPlayerCore(private val activity: Activity) : Player.Listener {
   }
 
   fun setPlaybackSpeed(speed: Float) {
-    val clampedSpeed = speed.coerceIn(0.25f, 4f)
+    val clampedSpeed = speed.coerceIn(MIN_PLAYBACK_SPEED, MAX_PLAYBACK_SPEED)
     exoPlayer?.setPlaybackSpeed(clampedSpeed)
     updateTunnelingState("speed changed")
-    delegate?.onPropertyChange("speed", speed.toDouble())
+    delegate?.onPropertyChange("speed", clampedSpeed.toDouble())
   }
 
   fun selectAudioTrack(trackId: String) {

android/app/src/test/kotlin/com/edde746/plezy/exoplayer/ExoPlayerPlaybackSpeedTest.kt

@@ -0,0 +1,55 @@
+package com.edde746.plezy.exoplayer
+
+import android.app.Activity
+import android.os.Looper
+import android.widget.FrameLayout
+import androidx.media3.exoplayer.ExoPlayer
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertTrue
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.robolectric.Robolectric
+import org.robolectric.RobolectricTestRunner
+import org.robolectric.Shadows.shadowOf
+import org.robolectric.annotation.Config
+
+@RunWith(RobolectricTestRunner::class)
+@Config(sdk = [28])
+class ExoPlayerPlaybackSpeedTest {
+
+  @Test
+  fun eightTimesPlaybackIsAppliedAndOutOfRangeRequestsReportTheClamp() {
+    val activity = Robolectric.buildActivity(Activity::class.java).setup().get()
+    activity.setContentView(FrameLayout(activity))
+    val core = ExoPlayerCore(activity)
+    val delegate = RecordingDelegate()
+    core.delegate = delegate
+
+    try {
+      assertTrue(core.initialize())
+      val player = core.getExoPlayer()
+
+      core.setPlaybackSpeed(8f)
+      assertEquals(8f, player.playbackParameters.speed, 0f)
+
+      core.setPlaybackSpeed(9f)
+      assertEquals(8f, player.playbackParameters.speed, 0f)
+      assertEquals(listOf(8.0, 8.0), delegate.reportedSpeeds)
+    } finally {
+      core.dispose()
+      shadowOf(Looper.getMainLooper()).idle()
+    }
+  }
+
+  private fun ExoPlayerCore.getExoPlayer(): ExoPlayer = javaClass.getDeclaredField("exoPlayer").apply { isAccessible = true }.get(this) as ExoPlayer
+
+  private class RecordingDelegate : ExoPlayerDelegate {
+    val reportedSpeeds = mutableListOf<Double>()
+
+    override fun onPropertyChange(name: String, value: Any?) {
+      if (name == "speed") reportedSpeeds += value as Double
+    }
+
+    override fun onEvent(name: String, data: Map<String, Any>?) = Unit
+  }
+}