diff --git a/tools/chatgui-android/app/src/main/java/com/utun/chat/data/StreamPlayerEngine.kt b/tools/chatgui-android/app/src/main/java/com/utun/chat/data/StreamPlayerEngine.kt
index 11761a92..62566927 100644
--- a/tools/chatgui-android/app/src/main/java/com/utun/chat/data/StreamPlayerEngine.kt
+++ b/tools/chatgui-android/app/src/main/java/com/utun/chat/data/StreamPlayerEngine.kt
@@ -68,6 +68,7 @@ class StreamPlayerEngine(private val group: Long, private val source: Long, priv
     private val id = StreamController.nextId()
     private var requestedAtUs = 0L
     @Volatile private var running = false
+    private var stopped = false // Main: stop до start также запрещает запуск этого одноразового viewer.
     @Volatile var drainTimeoutMs = 2000L
         private set
     private var worker: Thread? = null
@@ -76,6 +77,8 @@ class StreamPlayerEngine(private val group: Long, private val source: Long, priv
     private val releaseCallbacks = mutableListOf<() -> Unit>()
 
     fun start(surface: Surface) {
+        check(Looper.myLooper() == Looper.getMainLooper()) { "Viewer start requires main" }
+        if (stopped) { LogManager.addLog("WARN", "stream", "viewer start after stop ignored id=$id"); return }
         if (worker != null) return
         if (CallController.blocksMedia()) {
             LogManager.addLog("WARN", "stream", "viewer blocked by call id=$id")
@@ -108,10 +111,18 @@ class StreamPlayerEngine(private val group: Long, private val source: Long, priv
                 if (!main.post { players.remove(this); mutableViewing.value = players.isNotEmpty() })
                     LogManager.addLog("ERROR", "stream", "viewer completion post rejected id=$id; registry retains owner")
             }
-        }, "stream-audio-$id").apply { start() }
+        }, "stream-audio-$id")
+        try { worker!!.start() } catch (e: Exception) {
+            running = false; stopped = true
+            synchronized(releaseLock) { released = true }
+            players.remove(this); mutableViewing.value = players.isNotEmpty(); mutableStatus.value = R.string.stream_failed
+            LogManager.addLog("ERROR", "stream", "viewer worker start failed id=$id; no native owners started: $e")
+        }
     }
     /** Surface/SurfaceTexture освобождаются callback только после остановки decoder и native DSP. */
     fun stop(onReleased: (() -> Unit)? = null) {
+        check(Looper.myLooper() == Looper.getMainLooper()) { "Viewer stop requires main" }
+        stopped = true
         running = false
         try { NativeLib.streamStop(id) } catch (e: Exception) {
             LogManager.addLog("ERROR", "stream", "viewer stop request failed id=$id; worker retains cleanup: $e")
@@ -120,7 +131,10 @@ class StreamPlayerEngine(private val group: Long, private val source: Long, priv
             val immediate = synchronized(releaseLock) {
                 if (worker == null || released) true else { releaseCallbacks.add(onReleased); false }
             }
-            if (immediate) onReleased()
+            if (immediate) try { onReleased() } catch (e: Exception) {
+                LogManager.addLog("ERROR", "stream", "late viewer release callback failed id=$id; caller retains ownership: $e")
+                throw e
+            }
         }
     }
 
diff --git a/tools/chatgui-android/video-tests/src/test/kotlin/com/utun/chat/data/StreamPlayerEngineLifecycleTest.kt b/tools/chatgui-android/video-tests/src/test/kotlin/com/utun/chat/data/StreamPlayerEngineLifecycleTest.kt
index c1ecb10c..c8991aa2 100644
--- a/tools/chatgui-android/video-tests/src/test/kotlin/com/utun/chat/data/StreamPlayerEngineLifecycleTest.kt
+++ b/tools/chatgui-android/video-tests/src/test/kotlin/com/utun/chat/data/StreamPlayerEngineLifecycleTest.kt
@@ -53,6 +53,7 @@ class StreamPlayerEngineLifecycleTest {
 
     @Test fun failedOpenStillCompletesCleanupAndTheReleaseCallback() {
         HostStreams.failures = setOf("open"); val viewer = viewer(); val released = AtomicInteger()
+        await("open refusal reported") { viewer.status.value == com.utun.chat.R.string.stream_failed }
         viewer.stop { released.incrementAndGet() }; await("failed open callback") { released.get() == 1 }
         assertTrue(HostStreams.signals.isEmpty())
     }
@@ -98,9 +99,25 @@ class StreamPlayerEngineLifecycleTest {
         val old = AudioTrack.created.single(); old.failures = setOf("release")
         first.stop(); await("first viewer released") { !StreamPlayerEngine.viewing.value }
         assertThrows(IllegalStateException::class.java) { StreamAudioMixer.awaitIdle() }
+        assertThrows(IllegalStateException::class.java) { StreamPlayerEngine.stopForCore() }
         val second = viewer(key = true, audio = true); await("second playback ready") { HostStreams.playbacks.isNotEmpty() }
         assertEquals(1, AudioTrack.created.size); assertFalse(old.released)
         old.failures = emptySet(); await("second output opens after old release") { AudioTrack.created.size == 2 }
         assertTrue(old.released); second.stop()
     }
+
+    @Test fun coreTeardownCannotPassAViewerWithUnacknowledgedNativeResources() {
+        val viewer = viewer(); await("viewer signal opened") { HostStreams.signals.size == 1 }
+        HostStreams.failures = setOf("signal close")
+        assertThrows(IllegalStateException::class.java) { StreamPlayerEngine.stopForCore() }
+        await("other native owners close") { HostStreams.playbacks.isEmpty() && HostStreams.ports.isEmpty() }
+        assertThrows(IllegalStateException::class.java) { StreamPlayerEngine.stopForCore() }
+        HostStreams.failures = emptySet(); await("viewer barrier released") { !StreamPlayerEngine.viewing.value }
+        StreamPlayerEngine.stopForCore()
+    }
+    @Test fun stopBeforeStartLeavesTheViewerPassive() {
+        val viewer = StreamPlayerEngine(1, 2, 3).also { viewers.add(it) }
+        viewer.stop(); val surface = Surface().also { surfaces.add(it) }; viewer.start(surface)
+        assertFalse(StreamPlayerEngine.viewing.value); assertTrue(HostStreams.ports.isEmpty())
+    }
 }