2016-12-27, 14:17
The issues with 2160p50 and 2160p59.94 couldn't be related to 4:2:0 vs 4:2:2 / 4:4:4 compatibility could they? I know some displays only accept 4:2:0 at this resolution and frame rate, as they are still using the lower bandwith HDMI 1.4 physical hardware which can just about handle 4:2:0 at 2160p50 and 59.94, rather than the higher bandwith (optional) modes which add support for 4:2:2 and 4:4:4 at these frame rates.
AIUI this is one major reason that a 4:2:0 mode was added to the HDMI 2.0 spec, and meeting it is enough to be considered HDMI 2.0. (And given that pretty much all consumer video is, and will remain, 4:2:0, the only major issues is for UIs and Photo-type display applications, until you need 12 bit for HDR. Not sure if 10 bit is supported or not)
AIUI this is one major reason that a 4:2:0 mode was added to the HDMI 2.0 spec, and meeting it is enough to be considered HDMI 2.0. (And given that pretty much all consumer video is, and will remain, 4:2:0, the only major issues is for UIs and Photo-type display applications, until you need 12 bit for HDR. Not sure if 10 bit is supported or not)