--- a/res/res_rtp_multicast.c
+++ b/res/res_rtp_multicast.c
@@ -141,6 +141,9 @@ struct ast_multicast_rtp_options *ast_mu
 	struct ast_multicast_rtp_options *mcast_options;
 	char *pos;
 
+	if (!options) {
+		options = "";
+	}
 	mcast_options = ast_calloc(1, sizeof(*mcast_options)
 			+ strlen(type)
 			+ strlen(options) + 2);