Apple TV 4K (set up) questions

[Phooey]

Hi, just upgraded to the latest 4th gen 4k ATV from the 3rd gen. I have switched Match Dynamic Range and Match Frame Rate on but am confused as to which setting I should use on HDMI output!? My options are YCbCr, RGB High, or RGB Low. I *think* it was originally on YCbCr but can't remember.. and now I have fiddled about with it and left it on RGB High! Any recommendations much appreciated

Cheers

[VEX]

Just set one up for a client over a HD over IP matrix and found the best setting is YCbCr, 4K 25fps.

But this might be unique to his settings and system.