diff --git a/libs/gst/control/dparam_smooth.h b/libs/gst/control/dparam_smooth.h
index 967e956cf4..4eecd88b22 100644
--- a/libs/gst/control/dparam_smooth.h
+++ b/libs/gst/control/dparam_smooth.h
@@ -59,6 +59,8 @@ struct _GstDParamSmoothClass {
 	/* signal callbacks */
 };
 
+GType gst_dpsmooth_get_type (void);
+
 GstDParam* gst_dpsmooth_new (GType type);
 
 G_END_DECLS
diff --git a/libs/gst/control/unitconvert.h b/libs/gst/control/unitconvert.h
index 3acea459d0..1f23ade3c2 100644
--- a/libs/gst/control/unitconvert.h
+++ b/libs/gst/control/unitconvert.h
@@ -54,6 +54,8 @@ struct _GstUnitConvertClass {
 	/* signal callbacks */
 };
 
+GType gst_unitconv_get_type (void);
+
 GstUnitConvert* gst_unitconv_new (void);
 void _gst_unitconv_initialize (void);