CAC-1170 won't do 4:4:4 at 4K

10 replies

9 Feb 2017

Hello,

I'm running Fedora 25 on Lenovo T460p with Intel HD Graphics 530 in processor and NVIDIA GeForce® 940MX. When I use CAC-1170 I'm able to get 3840x2160 at 30 HZ and even at 60 HZ but definitely not with 4:4:4 color sampling. However when I use Lenovo reduction I'm able to get 3840x2160 @30 HZ with 4:4:4 sampling.

Any idea why CAC-1170 won't do 4:4:4 even @30 HZ?

Thanks!

10 Feb 2017

When running in 3840x2160 at 60Hz in 4:4:4 the BPC needs to be at 8Bit BPC otherwise the signal will get too big …

HDMI2.0 has 18Gbps of bandwidth …

Resolution	Refresh Rate	Bits Per Color	Chroma Sampling	Bandwidth GBPS
3840x2160	60	8	4:4:4	17,82
3840x2160	60	10	4:4:4	22,28
3840x2160	60	12	4:4:4	26,73
3840x2160	60	16	4:4:4	35,64

Please also check if your screen can do 4:4:4 at 4K 60 Hz, not all screens can do that ...

28 Feb 2017 ♥ 1

I have not found anyone that could successfully do 3840×2160@60Hz in 4:4:4 mode using Intel HD graphics over DP>HDMI 2.0.
https://communities.intel.com/thread/111370
https://communities.intel.com/thread/111279

15 Mar 2017

My previous post is wrong, it can work.
What TV are you using?

15 Mar 2017

Hello, 40" Samsung UE40KU6072

15 Mar 2017

Please check if your TV has the "HDMI UHD Color" setting. It enables UHD 60Hz 4:4:4. Unfortunately I remember reading the the 6070 series doesn't have this option.

15 Mar 2017

They do have and I had it enabled. I also used the right HDMI port as only one was supposed to handle 4k @60Hz

15 Mar 2017

Anyway I have returned the adapter already as I was not able to make it work for me :-(

16 Mar 2017

Sorry to hear that can you recall what linux graphics driver version you were using ?

16 Mar 2017

Hello, sure.

This is what my package manager has to say:

Name : xorg-x11-drv-nouveau
Arch : x86_64
Epoch : 1
Version : 1.0.13
Release : 1.fc25
Size : 213 k
Repo : @System
From repo : anaconda
Summary : Xorg X11 nouveau video driver for NVIDIA graphics chipsets
URL : http://www.x.org
License : MIT
Description : X.Org X11 nouveau video driver.

16 Mar 2017

Hi Preichl,

Thanks a lot.
Running on Nvidia Kepler based graphics would indeed be a challenge to say the least. If the Notebook can also run on the Intel Graphics only, so with Nvidia Graphics Disabled completely, it should be able to work. The Intel 530 Graphics can do it, which would only leave you needing a decnt linux driver for HD 530 ...