Got my Vero 4k last week. Very nice bit of kit, except for this flickering and banding (looks similar to @lukcinek 's screenshots but hard to be sure) at 2160p 24Hz.
For reference I am connecting to an LG OLED B6 through a Denon X3300W. My main test clip is one I have ripped myself from my own 4k Bluray - the opening studio logos on Guardians of the Galaxy 2. The bright red “Marvel” logo shows both issues perfectly.
I can make the flicking go away (as others have reported) by switching the GUI to 2160 / 60Hz and disabling refresh rate switching (which if my understanding is correct is actually refresh rate AND resolution switching - might be worth making that clear in the hint text). Interestingly I still get bitstreamed audio so long as I don’t enable sync playback to display. So far I haven’t noticed any audio sync issues, although if I get too carried away seeking, the audio stops working until a stop / restart. In the real world rather than testing though this is unlikely to be an issue I think.
And I can make the banding go away by switching output from the Vero to 4:4:4 by modifying /sys/class/display/mode. (echo “2160p60hz444”>/sys/class/display/mode). I know it shouldn’t work and is outside of HDMI spec, but it does seem to work and removes the banding…
With these two changes, the Vero output appears near as damnit identical to playing the original disc on my Samsung UBD K8500, although the OCD part of me knows it is 60Hz rather than 24Hz
Whilst testing on the K8500, I noticed it only has four options for chroma sampling - 444, RGB Full, RGB Limited, and Auto (the default). It makes me wonder if “Auto” is defaulting to 444 (within HDMI spec for 24p, which I also have enabled on the K8500). Unfortunately it’s hard to tell for sure as neither my Denon nor LG give that level of detail on what is being input. If that is correct though, maybe the B6 (or the X3300W) don’t like receiving 4:2:0 or 4:2:2? Seems unlikely but…
Not sure if any of this helps anyone but thought I’d share, just in case. @sam_nazarko I’m happy to be a guinea pig for any potential improvements you have in mind. Or if you’d like to see the test clip I use just let me know.
Sorry for the massive post!