From ad3af474e9a8647e6a695b464380cb5d3189a47d Mon Sep 17 00:00:00 2001
From: edde746 <86283021+edde746@users.noreply.github.com>
Date: Mon, 27 Jul 2026 17:44:52 +0200
Subject: [PATCH] fix(android): emit playback-restart after every seek

Separate the playback-restart signal from the one-shot decoder-hang latch. A
seek flushes the codec without re-initializing it, so the claimed latch
swallowed the post-seek first frame and Watch Together guests sat in
correcting for the full settle timeout.
---
 .../edde746/plezy/exoplayer/ExoPlayerCore.kt  | 23 +++++--
 .../ExoPlayerFallbackTerminalTest.kt          | 67 +++++++++++++++++++
 2 files changed, 83 insertions(+), 7 deletions(-)

diff --git a/android/app/src/main/kotlin/com/edde746/plezy/exoplayer/ExoPlayerCore.kt b/android/app/src/main/kotlin/com/edde746/plezy/exoplayer/ExoPlayerCore.kt
index 29dbc1f1..7b3f501a 100644
--- a/android/app/src/main/kotlin/com/edde746/plezy/exoplayer/ExoPlayerCore.kt
+++ b/android/app/src/main/kotlin/com/edde746/plezy/exoplayer/ExoPlayerCore.kt
@@ -1035,12 +1035,15 @@ class ExoPlayerCore(private val activity: Activity) :
         emitTrackList()
 
         // Video becomes ready only when a frame renders. Audio-only media has
-        // no video callback, so STATE_READY is its renderer-ready boundary.
+        // no video callback, so re-entering STATE_READY (load, and the
+        // re-buffer that follows a seek) is its renderer-ready boundary.
         val hasVideoGroup = exoPlayer?.currentTracks?.groups?.any { it.type == C.TRACK_TYPE_VIDEO } == true
         if (hasVideoGroup) {
           startFrameWatchdog()
-        } else if (claimPlaybackOutputReady()) {
-          emitLog("debug", "audio", "Audio-only playback ready")
+        } else {
+          if (claimPlaybackOutputReady()) {
+            emitLog("debug", "audio", "Audio-only playback ready")
+          }
           stopFrameWatchdog()
           delegate?.onEvent("playback-restart", null)
         }
@@ -2708,15 +2711,21 @@ class ExoPlayerCore(private val activity: Activity) :
       val mediaGeneration = mediaGenerationAt(eventTime) ?: return
       if (mediaGeneration != currentMediaGeneration) return
       hasRenderedVideoFrameForMedia = true
-      if (!claimPlaybackOutputReady()) return
-      emitLog("debug", "decoder-hang", "First frame rendered — decoder OK")
-      logNativeDvFirstFrameIfNeeded()
-      logDolbyVisionPlaybackPathIfNeeded()
+      if (claimPlaybackOutputReady()) {
+        emitLog("debug", "decoder-hang", "First frame rendered — decoder OK")
+        logNativeDvFirstFrameIfNeeded()
+        logDolbyVisionPlaybackPathIfNeeded()
+      }
       // STATE_READY fires when the player has enough buffered to start, but
       // the first frame may not be on screen yet (decoder init + keyframe
       // decode). The MPV-parity `playback-restart` event consumers (Dart
       // first-frame detection, frame-rate matching) want the moment the
       // pixel actually hits the screen, which is here.
+      // The claim above is a one-shot decoder-hang latch and must not gate the
+      // event: ExoPlayer re-arms its first-frame state on every position reset,
+      // so this callback also fires after each seek. That is exactly MPV's
+      // MPV_EVENT_PLAYBACK_RESTART contract — first frame after load *and*
+      // after every seek — which the Dart consumers rely on.
       delegate?.onEvent("playback-restart", null)
     }
   }
diff --git a/android/app/src/test/kotlin/com/edde746/plezy/exoplayer/ExoPlayerFallbackTerminalTest.kt b/android/app/src/test/kotlin/com/edde746/plezy/exoplayer/ExoPlayerFallbackTerminalTest.kt
index 57b8396a..47218c36 100644
--- a/android/app/src/test/kotlin/com/edde746/plezy/exoplayer/ExoPlayerFallbackTerminalTest.kt
+++ b/android/app/src/test/kotlin/com/edde746/plezy/exoplayer/ExoPlayerFallbackTerminalTest.kt
@@ -147,6 +147,52 @@ class ExoPlayerFallbackTerminalTest {
     }
   }
 
+  @Test
+  fun videoPlaybackRestartRepeatsAfterSeekWithoutDecoderReinit() {
+    val core = ExoPlayerCore(Robolectric.buildActivity(Activity::class.java).setup().get())
+    val delegate = RecordingDelegate(handlesFallback = false)
+    core.delegate = delegate
+    setField(core, "currentMediaGeneration", 7)
+    val mediaItem = MediaItem.Builder()
+      .setMediaId("7")
+      .setUri("https://example.test/video.mkv")
+      .build()
+    val timeline = SinglePeriodTimeline(
+      1_000_000L,
+      true,
+      false,
+      false,
+      null,
+      mediaItem
+    )
+    val eventTime = AnalyticsListener.EventTime(
+      0L,
+      timeline,
+      0,
+      null,
+      0L,
+      timeline,
+      0,
+      null,
+      0L,
+      0L
+    )
+    val analytics = getField(core, "decoderHangListener") as AnalyticsListener
+
+    try {
+      analytics.onRenderedFirstFrame(eventTime, Any(), 0L)
+      analytics.onRenderedFirstFrame(eventTime, Any(), 0L)
+
+      assertEquals(
+        listOf("playback-restart", "playback-restart"),
+        delegate.events.map { it.first }
+      )
+      assertEquals(true, getField(core, "firstFrameRendered"))
+    } finally {
+      core.dispose()
+    }
+  }
+
   @Test
   fun audioOnlyReadyEmitsPlaybackRestartWithoutAFrameCallback() {
     val core = ExoPlayerCore(Robolectric.buildActivity(Activity::class.java).setup().get())
@@ -163,6 +209,27 @@ class ExoPlayerFallbackTerminalTest {
     }
   }
 
+  @Test
+  fun audioOnlyPlaybackRestartRepeatsOnReentryToReady() {
+    val core = ExoPlayerCore(Robolectric.buildActivity(Activity::class.java).setup().get())
+    val delegate = RecordingDelegate(handlesFallback = false)
+    core.delegate = delegate
+
+    try {
+      invokePlaybackState(core, Player.STATE_READY)
+      invokePlaybackState(core, Player.STATE_BUFFERING)
+      invokePlaybackState(core, Player.STATE_READY)
+
+      assertEquals(
+        listOf("playback-restart", "playback-restart"),
+        delegate.events.map { it.first }
+      )
+      assertEquals(true, getField(core, "firstFrameRendered"))
+    } finally {
+      core.dispose()
+    }
+  }
+
   @Test
   fun pausedTimeDoesNotConsumeTheFrameWatchdogTimeout() {
     val core = ExoPlayerCore(Robolectric.buildActivity(Activity::class.java).setup().get())