Video input from UDP

Hi everyone,
I am trying to get inside QGC an UDP stream obtained with a broadcast software like VLC or OBS. This because I’m not able to read directly the desired HDMI input from QGC (as pointed here), and so I’m trying to stream this input over UDP.

Unfortunately, I was not able to read a network stream sent from either of the two software. I’m not sure at which address QGC is listening, since I can only specify the port. I tried streaming to localhost (127.0.0.1) as well as to the multicast addreess 224.0.0.1 as suggested here but with no luck.
The video window of QGC says “waiting for video”, while the consol log an error on the VideoReceiver:

[E] at …/VideoStreaming/VideoReceiver.cc:572 - “Failed because video sink is not set”

I’m using QGC on Windows, and I tried version 4.0 as well as 3.5 with the same result.
Can someone tell me how to make it work?

Thank you!
Giulio