fix conference buffer for 30ms conference and 20ms chans

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@5649 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/mod/applications/mod_conference/mod_conference.c

@@ -1720,7 +1720,7 @@ static void conference_loop_output(conference_member_t * member)
 						switch_set_flag_locked(member, MFLAG_FLUSH_BUFFER);
 					}
 					mux_used = 0;
-				} else if (mux_used > bytes * 2) {
+				} else if (mux_used > bytes * 4) {
 					/* getting behind, clear the buffer */
 					switch_set_flag_locked(member, MFLAG_FLUSH_BUFFER);
 				}