diff --git a/tools/chatgui-android/app/src/debug/AndroidManifest.xml b/tools/chatgui-android/app/src/debug/AndroidManifest.xml
new file mode 100644
index 00000000..32a234df
--- /dev/null
+++ b/tools/chatgui-android/app/src/debug/AndroidManifest.xml
@@ -0,0 +1,4 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <instrumentation android:name="com.utun.chat.data.CallVideoProbe"
+        android:targetPackage="com.utun.chat" android:label="Call video codec probe" />
+</manifest>
diff --git a/tools/chatgui-android/app/src/debug/java/com/utun/chat/data/CallVideoProbe.kt b/tools/chatgui-android/app/src/debug/java/com/utun/chat/data/CallVideoProbe.kt
new file mode 100644
index 00000000..8d4ea2b5
--- /dev/null
+++ b/tools/chatgui-android/app/src/debug/java/com/utun/chat/data/CallVideoProbe.kt
@@ -0,0 +1,19 @@
+package com.utun.chat.data
+
+import android.app.Instrumentation
+import android.os.Bundle
+
+/** Запускается только явно через adb am instrument; камера и реальные звонки не затрагиваются. */
+class CallVideoProbe : Instrumentation() {
+    override fun onCreate(arguments: Bundle?) { super.onCreate(arguments); start() }
+    override fun onStart() {
+        try {
+            val codecs = CallVideoCodec.probe()
+            check(codecs.isNotEmpty()) { "No conforming encoder/decoder pair" }
+            finish(0, Bundle().apply { putString("codecs", codecs.toString()) })
+        } catch (e: Exception) {
+            android.util.Log.e("CallVideoProbe", "probe failed", e)
+            finish(1, Bundle().apply { putString("error", e.toString()) })
+        }
+    }
+}