diff --git a/gst/audiofx/audiodynamic.c b/gst/audiofx/audiodynamic.c
index f8d77a3736..2fdf7b3908 100644
--- a/gst/audiofx/audiodynamic.c
+++ b/gst/audiofx/audiodynamic.c
@@ -185,6 +185,9 @@ gst_audio_dynamic_set_process_function (GstAudioDynamic * filter)
 {
   gint func_index;
 
+  if (GST_AUDIO_FILTER_FORMAT (filter) == GST_AUDIO_FORMAT_UNKNOWN)
+    return FALSE;
+
   func_index = (filter->mode == MODE_COMPRESSOR) ? 0 : 4;
   func_index += (filter->characteristics == CHARACTERISTICS_HARD_KNEE) ? 0 : 2;
   func_index +=