Index: chan_sip.c
===================================================================
RCS file: /usr/cvsroot/asterisk/channels/chan_sip.c,v
retrieving revision 1.466
diff -u -r1.466 chan_sip.c
--- chan_sip.c	31 Jul 2004 04:04:05 -0000	1.466
+++ chan_sip.c	6 Aug 2004 08:51:52 -0000
@@ -2203,6 +2203,7 @@
 			if (f->subclass != p->owner->nativeformats) {
 				ast_log(LOG_DEBUG, "Oooh, format changed to %d\n", f->subclass);
 				p->owner->nativeformats = f->subclass;
+                p->owner->readformat = p->owner->writeformat = ast_best_codec(p->owner->nativeformats);
 				ast_set_read_format(p->owner, p->owner->readformat);
 				ast_set_write_format(p->owner, p->owner->writeformat);
 			}