diff --git a/tools/chatgui-android/app/src/main/java/com/utun/chat/data/StreamCaptureEngine.kt b/tools/chatgui-android/app/src/main/java/com/utun/chat/data/StreamCaptureEngine.kt
index ffe3a3cc..69bd42f9 100644
--- a/tools/chatgui-android/app/src/main/java/com/utun/chat/data/StreamCaptureEngine.kt
+++ b/tools/chatgui-android/app/src/main/java/com/utun/chat/data/StreamCaptureEngine.kt
@@ -84,7 +84,8 @@ class StreamCaptureEngine(
         }
         check(NativeLib.streamOpen(id, group, width = size.width, height = size.height, rotation = rotation, audio = microphone))
         originNs = System.nanoTime()
-        encoder = MediaCodec.createByCodecName(info.name).also { codec ->
+        encoder = MediaCodec.createByCodecName(info.name)
+        encoder!!.also { codec ->
             codec.setCallback(object : MediaCodec.Callback() {
                 override fun onInputBufferAvailable(codec: MediaCodec, index: Int) {}
                 override fun onError(codec: MediaCodec, error: MediaCodec.CodecException) { failed("encoder: ${error.diagnosticInfo}") }
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 98269070..f48e64c9 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
@@ -61,13 +61,19 @@ class StreamPlayerEngine(private val group: Long, private val source: Long, priv
         var endDrainUntil = 0L
 
         fun resetVideo() {
-            try { decoder?.stop(); decoder?.release() }
+            try { decoder?.stop() }
             catch (e: Exception) { LogManager.addLog("WARN", "video", "decoder reset id=$id: ${e.message}") }
+            try { decoder?.release() }
+            catch (e: Exception) { LogManager.addLog("WARN", "video", "decoder release id=$id: ${e.message}") }
             decoder = null; videos.clear(); videoBytes = 0; waitingKey = true
             mutableStatus.value = R.string.stream_waiting_key
         }
         fun resetAudio() {
-            track?.pause(); track?.flush(); track?.release(); track = null
+            try { track?.pause(); track?.flush() }
+            catch (e: Exception) { LogManager.addLog("WARN", "stream", "audio reset id=$id: ${e.message}") }
+            try { track?.release() }
+            catch (e: Exception) { LogManager.addLog("WARN", "stream", "audio release id=$id: ${e.message}") }
+            track = null
             if (opus != 0L) NativeLib.streamOpusClose(opus)
             opus = 0; audioBase = -1; written = 0; lastHead = -1; audios.clear()
         }
@@ -85,6 +91,19 @@ class StreamPlayerEngine(private val group: Long, private val source: Long, priv
             }
             return if (videoBase >= 0) videoBase + (now - videoStartNs) / 1000 else 0
         }
+        fun writePcm(t: AudioTrack, pcm: ShortArray) {
+            val deadline = System.nanoTime() + 100_000_000
+            var offset = 0
+            while (running && offset < pcm.size) {
+                val count = t.write(pcm, offset, pcm.size - offset, AudioTrack.WRITE_NON_BLOCKING)
+                check(count >= 0) { "AudioTrack write=$count" }
+                if (count > 0) { offset += count; written += count }
+                else {
+                    check(System.nanoTime() < deadline) { "AudioTrack stalled for 100ms" }
+                    Thread.sleep(2)
+                }
+            }
+        }
         try {
             check(NativeLib.streamOpen(id, group, source)) { "Viewer open refused" }
             val openDeadline = System.nanoTime() + 10_000_000_000
@@ -159,10 +178,10 @@ class StreamPlayerEngine(private val group: Long, private val source: Long, priv
                             } else if (missing >= 0) {
                                 repeat(missing) {
                                     val conceal = NativeLib.streamOpusDecode(opus, byteArrayOf()) ?: error("Opus PLC failed")
-                                    check(t.write(conceal, 0, conceal.size, AudioTrack.WRITE_BLOCKING) == conceal.size); written += conceal.size
+                                    writePcm(t, conceal)
                                 }
                                 val pcm = NativeLib.streamOpusDecode(opus, f.data) ?: error("Opus decode failed")
-                                check(t.write(pcm, 0, pcm.size, AudioTrack.WRITE_BLOCKING) == pcm.size); written += pcm.size
+                                writePcm(t, pcm)
                             } else LogManager.addLog("DEBUG", "stream", "late audio discarded id=$id pts=${f.pts}")
                         }
                     }
@@ -178,7 +197,8 @@ class StreamPlayerEngine(private val group: Long, private val source: Long, priv
                                 setByteBuffer("csd-1", ByteBuffer.wrap(nals.first { it.first == 8 }.second))
                                 setInteger(MediaFormat.KEY_ROTATION, frame.rotation); setInteger(MediaFormat.KEY_MAX_INPUT_SIZE, H264AnnexB.MAX_FRAME)
                             }
-                            decoder = MediaCodec.createDecoderByType(MediaFormat.MIMETYPE_VIDEO_AVC).also { it.configure(format, surface, null, 0); it.start() }
+                            decoder = MediaCodec.createDecoderByType(MediaFormat.MIMETYPE_VIDEO_AVC)
+                            decoder!!.configure(format, surface, null, 0); decoder!!.start()
                             LogManager.addLog("INFO", "video", "decoder started id=$id ${frame.width}x${frame.height} rotation=${frame.rotation}")
                         }
                         val index = decoder!!.dequeueInputBuffer(0)
@@ -220,8 +240,10 @@ class StreamPlayerEngine(private val group: Long, private val source: Long, priv
             if (running) { mutableStatus.value = R.string.stream_failed; LogManager.addLog("ERROR", "stream", "viewer failed id=$id: ${e.message}") }
         } finally {
             NativeLib.streamStop(id)
-            try { decoder?.stop(); decoder?.release() } catch (e: Exception) { LogManager.addLog("WARN", "video", "decoder release id=$id: ${e.message}") }
-            try { track?.stop(); track?.release() } catch (e: Exception) { LogManager.addLog("WARN", "stream", "audio release id=$id: ${e.message}") }
+            try { decoder?.stop() } catch (e: Exception) { LogManager.addLog("WARN", "video", "decoder stop id=$id: ${e.message}") }
+            try { decoder?.release() } catch (e: Exception) { LogManager.addLog("WARN", "video", "decoder release id=$id: ${e.message}") }
+            try { track?.stop() } catch (e: Exception) { LogManager.addLog("WARN", "stream", "audio stop id=$id: ${e.message}") }
+            try { track?.release() } catch (e: Exception) { LogManager.addLog("WARN", "stream", "audio release id=$id: ${e.message}") }
             if (opus != 0L) NativeLib.streamOpusClose(opus)
             val deadline = System.nanoTime() + 500_000_000
             while (!ended && NativeLib.isReady() && System.nanoTime() < deadline) {