I have installed the Unifi TV onto my Mi Box S, and it loads fine on all TVs, except for my own TV. My TV is a 24inch Toshiba (model 24PB1E).
After loading the Unifi TV app, it works for like 10 seconds, then the video goes blank, but I can still hear the audio. The menus work and I can switch to different channels, but the video will be blank. When this happens, I can't watch any video at all on the Mi Box S even if I switch to YouTube, BBC Player, Kodi, VLC, etc. Only way I can fix this is to reboot, and not use the Play TV app.
Funnily enough, I tried the Unifi TV app with my Mi Box S with other TVs and there was no problem.