don't add rtpmap or mid attributes for deleted/silenced streams

fixes #686

Change-Id: Ie9a155072a8b6acb8edcf59a5dd164f78a503616
(cherry picked from commit 415af36ae6)

daemon/sdp.c

@@ -2085,6 +2085,9 @@ int sdp_replace(struct sdp_chopper *chop, GQueue *sessions, struct call_monologu
 
 			copy_up_to_end_of(chop, &sdp_media->s);
 
+			if (!sdp_media->port_num || !ps->selected_sfd)
+				goto next;
+
 			if (call_media->media_id.s) {
 				chopper_append_c(chop, "a=mid:");
 				chopper_append_str(chop, &call_media->media_id);
@@ -2102,9 +2105,6 @@ int sdp_replace(struct sdp_chopper *chop, GQueue *sessions, struct call_monologu
 				assert(j->data == ps_rtcp);
 			}
 
-			if (!sdp_media->port_num || !ps->selected_sfd)
-				goto next;
-
 			if (!flags->original_sendrecv) {
 				if (MEDIA_ARESET2(call_media, SEND, RECV))
 					chopper_append_c(chop, "a=sendrecv\r\n");

t/auto-daemon-tests.pl

@@ -465,6 +465,36 @@ a=candidate:ICEBASE 2 UDP 2130706430 203.0.113.1 PORT typ host
 a=candidate:ICEBASE 2 UDP 2130706174 2001:db8:4321::1 PORT typ host
 SDP
 
+# github issue #686
+
+new_call;
+
+offer('gh 686', { ICE => 'remove' }, <<SDP);
+v=0
+o=- 1545997027 1 IN IP4 198.51.100.1
+s=tester
+t=0 0
+c=IN IP4 198.51.100.1
+m=audio 0 RTP/AVP 8 101
+m=image 2000 udptl t38
+c=IN IP4 198.51.100.1
+a=T38FaxVersion:0
+a=T38FaxRateManagement:transferredTCF
+----------------------------------
+v=0
+o=- 1545997027 1 IN IP4 198.51.100.1
+s=tester
+t=0 0
+c=IN IP4 203.0.113.1
+m=audio 0 RTP/AVP 8 101
+m=image PORT udptl t38
+c=IN IP4 203.0.113.1
+a=T38FaxVersion:0
+a=T38FaxRateManagement:transferredTCF
+a=sendrecv
+SDP
+
+
 
 END {
 	if ($rtpe_pid) {