Turn a Raspberry Pi, a Webcam and a TV into a video call device

Yes, you need to run that in a terminal into the Host OS of the device. Keep in mind the caveat about overheating

Perfect, thank you very much !
Then, my grand parents probably have latency issues with their network.
By any chance, is there any way of reducing the image quality encoded?

Hi Paul, Jitsi does seem to have a video quality setting in the menu at the bottom right, “Manage Video Quality”. However, this setting doesn’t appear to have any effect with my setup, and as previously mentioned, the behavior of Jitsi’s platform is out of our control. You might try setting it to “low bandwidth”, and see if that improves things.