diff --git a/ext/mad/gstmad.c b/ext/mad/gstmad.c
index f8fe497d32..2b50b8eed0 100644
--- a/ext/mad/gstmad.c
+++ b/ext/mad/gstmad.c
@@ -1000,6 +1000,7 @@ gst_mad_chain (GstPad *pad, GstBuffer *buffer)
   gboolean new_pts = FALSE;
 
   mad = GST_MAD (gst_pad_get_parent (pad));
+  g_assert (GST_IS_MAD (mad));
 
   /* handle events */
   if (GST_IS_EVENT (buffer))