Do you mean as found in BI's built-in "Help", under "Administration" => "HTTP Interface" => "RTSP server" ?
- rtsp:/yourip:81/cam1
- rtsp:/yourip:81/index (all camera group)
- rtsp:/yourip:81/@index (all camera group cycle)
NOTE: of course, use 2 "/" after "rtsp:", as forum software won't allow 2 to be displayed consecutively here.