--- chan_mgcp.c-orig	2012-05-14 21:44:27.000000000 +0200
+++ chan_mgcp.c	2013-02-28 12:53:37.377076390 +0100
@@ -1990,8 +1990,9 @@
 		ast_log(LOG_WARNING, "Unable to lookup host in c= line, '%s'\n", c);
 		return -1;
 	}
-	if (sscanf(m, "audio %30d RTP/AVP %n", &portno, &len) != 1) {
-		ast_log(LOG_WARNING, "Unable to determine port number for RTP in '%s'\n", m);
+	len = 0;
+	if (sscanf(m, "audio %30d RTP/AVP %n", &portno, &len) != 1 || !len) {
+		ast_log(LOG_WARNING, "Unable to determine port number or codecs for RTP in '%s'\n", m);
 		return -1;
 	}
 	sin.sin_family = AF_INET;