Originally Posted by Merlin803
What setting do you use for "Format"? I believe I read that if you set it to 4K HDR that it will improperly display non HDR content?
Here's a bit of a clarification and recommendation regarding what "Format" to choose with your ATV 4K. FYI, I've had an ATV 4K since day one (literally), and am also a beta tester . . . .
There are a few SDR apps which do not correctly tell the ATV 4K to "downshift" to SDR. In those cases, you will see the ATV 4K applying an HDR effect on top of SDR content if your "Format" is set to some flavor of HDR. As far as I know - (and I've looked for this) - no one has compiled a list of offending apps, and some may have already been fixed. HBOGO used to be one of those apps, and it actually had a positive effect on shows such as "GOT" - but they have since rev'd the app, so it no longer has this issue.
Popular apps such as iTunes, Vudu, Netflix, Prime, MoviesAnywhere, and most others DO NOT have this problem.
You will find others in this thread, or in the "AppleTV Owners" thread, who will recommend that the "Format" be set to 4K SDR. This will ensure that the ATV 4K will not apply an HDR effect over SDR content in case you are using an app that doesn't properly send the "downshift" signal. Truth be told, there are not that many apps out there that haven't been fixed, so it's becoming less and less of a concern.
Personally, I have the "Format" set to 4K Dolby Vision 60Hz, with "Match Content" set to "On" for both "Dynamic Range" and "Frame Rate". I don't use any apps with the above issue, so my ATV 4K will properly "downshift" to SDR, and "upshift" to HDR10/DV as necessary - and also playback content at the studio intended frame rate.
One of the reasons why I do it this way is because the Aerial Screen Saver videos are all mastered in 4K Dolby Vision, and look incredible when the "Format" is set to the same. They will not playback in Dolby Vision if the "Format" is set to SDR. Also, I generally don't use any other apps except for the one's I already listed above, so I won't encounter this issue anyway.
[ To properly setup the screensaver, open "Settings" then General / Screen Saver. Choose the "Type" as Aerial (default), and also choose "Download New Video" = "Daily". There is a recently available series of ISS videos that are really cool - in addition to all the fantastic night time cityscapes, etc. ]
ISS = International Space Station lol