Index: channels/chan_sip.c
===================================================================
--- channels/chan_sip.c	(revision 42669)
+++ channels/chan_sip.c	(working copy)
@@ -5999,7 +5999,7 @@
 	if (option_debug > 2)
 		ast_log(LOG_DEBUG, "-- Done with adding codecs to SDP\n");
 
-	if(!ast_internal_timing_enabled(p->owner))
+	if(!p->owner || !ast_internal_timing_enabled(p->owner))
 		ast_build_string(&a_audio_next, &a_audio_left, "a=silenceSupp:off - - - -\r\n");
 
 	if ((m_audio_left < 2) || (m_video_left < 2) || (a_audio_left == 0) || (a_video_left == 0))