Tvheadend

Hi, as the title says I need help with setting up a port forwarding rule in my Fritzbox in order to reroute port 9983 to 554 so more SAT>IP clients can communicate with Tvheadend SAT>IP server.

As testing setup I'm using VLC as SAT>IP client entering the URL from Tvheadend. Until now VLC cannot open the stream, probably because of port 9983 which has to be 554 for VLC.

rtsp://192.168.0.205:9983/?freq=410&msys=dvbc&sr=6900&mtype=256qam&pids=0,16,17,20,2000,2001,2101,2011

I cannot install Tvheadend as root, so I need port forwarding.
This is an example of how it looks like in my Fritzbox.

192.168.0.205 is the device where Tvheadend is installed.

Thanks!