diff --git a/gst-libs/gst/pbutils/gstaudiovisualizer.c b/gst-libs/gst/pbutils/gstaudiovisualizer.c
index d339d66..f894407 100644
--- a/gst-libs/gst/pbutils/gstaudiovisualizer.c
+++ b/gst-libs/gst/pbutils/gstaudiovisualizer.c
@@ -811,8 +811,9 @@
   gst_structure_fixate_field_nearest_int (structure, "width", 320);
   gst_structure_fixate_field_nearest_int (structure, "height", 200);
   gst_structure_fixate_field_nearest_fraction (structure, "framerate", 25, 1);
-  gst_structure_fixate_field_nearest_fraction (structure, "pixel-aspect-ratio",
-      1, 1);
+  if (gst_structure_has_field (structure, "pixel-aspect-ratio"))
+    gst_structure_fixate_field_nearest_fraction (structure,
+        "pixel-aspect-ratio", 1, 1);
 
   target = gst_caps_fixate (target);