Normal
Merged filter before sending SETUP request reserves pair of UDP ports (create sockets without SO_REUSEADDR option). If any of ports are used by someone else, it simply choose next pair of ports (by default, filter starts on port 50000 and goes up to 65535, but min and max ports can be configured in RTSP url). UDP ports are reserved without SO_REUSEADDR option on socket, so it's not able to access them.
