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[bobkatz]

Hi guys. I've got a new Vizio 65" P series, which is a fabulous monitor. So of course I'm playing with pushing the envelope, and i'm coming into limits of my video card. Definitely I need 60 Hz refresh or above or I can't get motion to look smooth enough. I don't mind having 8 bit out of MadVR because the dithering in MadVR is so good.

1080p Blu Rays look great through MadVR! I should quit while I'm ahead :-). With this NVidia 1050Ti I can do 1080p 120 Hz 8 bit RGB Full, which suits me. MadVR is set to think the set wants to see 16-235 levels, which means that it will pass through the full range without range conversion. In other words, BTB and WTW will make it through the chain. I calibrated and produced a 3D LUT and again, things look great and maybe I should quit while I'm ahead. :-)

But I'm fascinated with the prospect of 4k doubling and how great it looks with MadVR, except: It appears that my GPU will not do RGB when set to 4k resolution if the refresh is above 30 Hz. It switches to YC and "limited". Maybe I should give up on being able to reproduce BTB and WTW... Is it true that YC communication does not have a BTB or WTW? Does YC stop the equivalent of below 16 and above 235? Is it possible my card can run RGB Full at 60 Hz 4k but currently the control panel is not permitting it to do that? (wishful thinking)

So I'm seeing the blacks are getting a bit crushed when I use the LUT that I created for RGB full and try to watch 4k. Do you think if I recalibrate in 4k, using YC communication, forget about BTB and WTW.... that I'll be able to get nice looking results?

Thanks in advance,

Bob

[Hendrik]

BTB/WTW aren't particularly useful when you send RGB anyway, but thats more of a philosophical debate then anything. I don't think anyone can prove a visual difference either way, since with proper calibration BTB/WTW are supposed to be invisible. But it makes no difference to the resolution/refresh rate combination that is possible, anyway.

On a PC, especially with madVR, you lose quite a bit of quality when you send sub-sampled YCbCr instead of RGB, so that should be avoided.

For 60Hz RGB at 4K - you need a full HDMI 2.0 chain to be able to do that. Your GPU can definitely do it, so make sure you connected to a port on the TV thats full HDMI 2.0, and if you have an AV-Receiver in between make sure its also HDMI 2.0 capable - and to top it all off, you need a High-Speed HDMI cable. Some TVs sometimes need some special options set to allow HDMI 2.0 unlimited input for some reason that eludes me, might be worth checking if there is something like that for your model.

One thing to note is that 60Hz RGB at 4K is limited to 8-bit only over HDMI for bandwidth reasons, so you might need to specifically set 8-bit in the NVIDIA control panel to be able to see that resolution combination.

[bobkatz]

Thanks, Hendrik! I think that HDMI 2.0 then is my bottleneck and not the video card. The TV can do it, but I'm certain my KVM switch cannot! I'll wait till I feel rich enough to buy a new KVM switch.

Best wishes,


Bob

BTB/WTW aren't particularly useful when you send RGB anyway, but thats more of a philosophical debate then anything. I don't think anyone can prove a visual difference either way, since with proper calibration BTB/WTW are supposed to be invisible. But it makes no difference to the resolution/refresh rate combination that is possible, anyway.

On a PC, especially with madVR, you lose quite a bit of quality when you send sub-sampled YCbCr instead of RGB, so that should be avoided.

For 60Hz RGB at 4K - you need a full HDMI 2.0 chain to be able to do that. Your GPU can definitely do it, so make sure you connected to a port on the TV thats full HDMI 2.0, and if you have an AV-Receiver in between make sure its also HDMI 2.0 capable - and to top it all off, you need a High-Speed HDMI cable. Some TVs sometimes need some special options set to allow HDMI 2.0 unlimited input for some reason that eludes me, might be worth checking if there is something like that for your model.

One thing to note is that 60Hz RGB at 4K is limited to 8-bit only over HDMI for bandwidth reasons, so you might need to specifically set 8-bit in the NVIDIA control panel to be able to see that resolution combination.