diff --git a/spa/include/spa/pod/filter.h b/spa/include/spa/pod/filter.h
index d5fe18d24..6e238c2e6 100644
--- a/spa/include/spa/pod/filter.h
+++ b/spa/include/spa/pod/filter.h
@@ -294,7 +294,7 @@ SPA_API_POD_FILTER int spa_pod_filter_part(struct spa_pod_builder *b,
 						res = spa_pod_filter_prop(b, p1, p2);
 					else if (SPA_FLAG_IS_SET(p1->flags, SPA_POD_PROP_FLAG_MANDATORY))
 						res = -EINVAL;
-					else
+					else if (!SPA_FLAG_IS_SET(p1->flags, SPA_POD_PROP_FLAG_DROP))
 						spa_pod_builder_raw_padded(b, p1, SPA_POD_PROP_SIZE(p1));
 					if (res < 0)
 						break;
@@ -307,7 +307,7 @@ SPA_API_POD_FILTER int spa_pod_filter_part(struct spa_pod_builder *b,
 							continue;
 						if (SPA_FLAG_IS_SET(p2->flags, SPA_POD_PROP_FLAG_MANDATORY))
 							res = -EINVAL;
-						else
+						else if (!SPA_FLAG_IS_SET(p2->flags, SPA_POD_PROP_FLAG_DROP))
 							spa_pod_builder_raw_padded(b, p2, SPA_POD_PROP_SIZE(p2));
 						if (res < 0)
 							break;
diff --git a/spa/include/spa/pod/pod.h b/spa/include/spa/pod/pod.h
index 91c4d57ce..e20990cc6 100644
--- a/spa/include/spa/pod/pod.h
+++ b/spa/include/spa/pod/pod.h
@@ -201,8 +201,11 @@ struct spa_pod_prop {
 							 *	  Int : n_items,
 							 *	  (String : key,
 							 *	   String : value)*)) */
-#define SPA_POD_PROP_FLAG_MANDATORY	(1u<<3)		/**< is mandatory */
+#define SPA_POD_PROP_FLAG_MANDATORY	(1u<<3)		/**< is mandatory, when filtering, both sides
+							  *  need this property or filtering fails. */
 #define SPA_POD_PROP_FLAG_DONT_FIXATE	(1u<<4)		/**< choices need no fixation */
+#define SPA_POD_PROP_FLAG_DROP		(1u<<5)		/**< drop property, when filtering, both sides
+                                                          *  need the property or it will be dropped. */
 	uint32_t flags;			/**< flags for property */
 	struct spa_pod value;
 	/* value follows */