I'm confused by the projector support - I thought the native aspect ratio of HD and 4K was 16:9 so a wider ratio just has black bars top and bottom. This certainly fills my screen from side to side. Not sure I understand how an 18:9 ratio would display films better.
My projector is natively 4096 x 2160. That's the technical 4K resolution. Home "UHD" 4K is 3840 x 2160 pixels 16x9 ratio.
Most movies and TV shows are in a wider format than 16x9, and this format known as cinemascope or anamorphic is roughly a ratio of 2.35:1 or "21x9" as it is known in computer land.
This basically means you have black bars at the top and bottom of your movie on a normal shaped TV/screen.
SOME people actually have a projection screen that is in that wider format of 21x9.
Then they use some features of their projector to do one of two things.
1. They "zoom" the picture so that they fill up their wider screen with the wider image of the movie they are watching, essentially pushing the 'black bars' off the top and bottom of their screen. Or...
2. When projecting a 16x9 standard image on their wider screen, they actually have black bars on the left and right of their picture because their screen is too wide. When. they want to watch a movie in that wider format, they enable a special mode on their projector that takes the video signal and stretches it vertically to make it 33% taller than it needs to be. It makes the image look all thin and stretched tall.
This basically makes the projector's image sensor use ALL the available pixels to project the image and NOT waste the pixels projecting the black bars. This does involve duplicating and stretching some of the movie's pixels although good projectors do a great job of this.
THEN, a lens is slid in front of the projector's main lens which then stretches the image in the other direction to make it WIDER to fill the wider screen, and returning the image to it's normal appearance rather than looking stretched.
The benefit? You get a larger image that fills the screen without having to move the projector or use more zoom, AND you get the benefit of using all of the available pixels to render the light/colour image rather than wasting them on black bars. This is the setup I have.
Of course, the Apple TV interface doesn't have black bars at the top and bottom of it as it is presented in 16x9 ratio. So this new mode will essentially render the AppleTV interface with black bars at the top and bottom with the interface occupying around 3840 x 1608 pixels (of the available 2160 vertical pixels).