what Tero said, the screen will have something like a switcher unit that accepts the video signal. This will expect a source with a certain pixel dimension video (whoever maintains the screen will know). This is usually something like 1024 x 576, 1920×1080, etc. They may even have a template for you to fit to, as the aspect of the screen is non-standard so you kind of overlay a standard 16:9 image over the top (or similar).
I hope this is of help, I know it can get confusing!