diff --git a/audio/ukmedia_volume_control.cpp b/audio/ukmedia_volume_control.cpp
index 9ad4680..8398527 100644
--- a/audio/ukmedia_volume_control.cpp
+++ b/audio/ukmedia_volume_control.cpp
@@ -1527,6 +1527,10 @@ void UkmediaVolumeControl::sourceOutputCb(pa_context *c, const pa_source_output_
         decOutstanding(w);
         return;
     }
+
+    if (i->source == PA_ID_INVALID)
+        return;
+
     if (i->name)
         qDebug() << "sourceOutputCb" << i->name << i->source <<eol ;
     if (!w->sourceOutputVector.contains(i->index)) {
diff --git a/audio/ukmedia_volume_control.h b/audio/ukmedia_volume_control.h
index d0ea47f..46d69fc 100644
--- a/audio/ukmedia_volume_control.h
+++ b/audio/ukmedia_volume_control.h
@@ -22,7 +22,7 @@
 
 #define NOISE_REDUCE_SOURCE "noiseReduceSource"
 #define PANGUW_SINK "alsa_output.platform-raoliang-sndcard.analog-stereo"
-
+#define PA_ID_INVALID  ((uint32_t)0xffffffff)
 #define DECAY_STEP .04
 
 static int n_outstanding = 0;