If set to 1080p HDR - will Apple TV 4K downscale to a 720p HDR TV set but still output HDR?

Hi deanoxxm,

Thanks for reaching out to Apple Support Communities. It sounds like you have a question about the Apple TV 4K. We're happy to help.

Apple TV 4K technical specifications for video output can be found here: Apple TV 4K - Tech Specs

You can adjust video and audio settings using the help of the guide page here: Adjust video and audio settings on Apple TV

Details for the frame rate are found at the bottom of the article here: About frame rate and dynamic range matching on Apple TV

It states the following:

1. "Apple TV matches the frame rate of content encoded at 60, 50, 30, 25, and 24fps. Frame rates match the refresh rate appropriate for your region, for example 29.97fps for NTSC. 25fps and 30fps content uses frame rate doubling to display at 50Hz and 60Hz when available, matching its original appearance while preserving a fluid user interface."

If needed, you can view helpful set up details and requirements here: Set up your Apple TV

Cheers!