Full Quantization Range (0-255) not available with Displayport->HDMI adapter

[MGill2]

Hi Wanner,

Sure, here is a picture that illustrates the issue.

In the picture you can see 3 captures of a typical Facebook post. The first is just a screen grab of the Facebook post, the second is a capture of how it's rendered when RGB limited range is in effect. This was taken from my monitor when it was output to the external monitor with the Thunderbolt 3-to-DisplayPort cable. For comparison the third capture shows the rendered page on the same monitor from the native HDMI port with RGB full range turned on. Sorry for the low quality but I had to take actual pictures of my monitor to show how it's actually rendered.

As you can see the text bubbles and some drop shadows completely disappear and show up as pure white due to the fact that the RGB values for the gray color are R: 239 G: 241 B: 243 (also shown in the picture) which fall above the 235 RGB value of the limited range. This may be fine for watching videos which are limited range as-is but it's inadequate for actual PC usage like graphics editing, web design etc that require accurate color reproduction. This is a serious issue and I can't see why Intel don't just allow to set the RGB range for external monitors on Intel graphics chips.

[idata]

Hello matang,

Thank you for your response. I will do further research about this issue.Besides, have you tried using other USB Type-C to HDMI or DP-to-HDMI adapters?Wanner G.

[MGill2]

Thanks Wanner.

I don't have any other adapters.

For reference these are the adapters I used:

Vantec Vlink USB-C to HDMI 2.0 4K/60Hz Video Converter (CB-CU300HD20)

https://www.amazon.com/Vantec-Vlink-USB-C-Converter-CB-CU300HD20/dp/B074XBWR69 https://www.amazon.com/Vantec-Vlink-USB-C-Converter-CB-CU300HD20/dp/B074XBWR69

Cable Matters USB C to DisplayPort Cable (USB-C to DisplayPort Cable/USB C to DP Cable)

https://www.amazon.com/gp/product/B06XTZZYKX Amazon.com: Cable Matters USB C to DisplayPort Cable (USB-C to DisplayPort Cable/USB C to DP Cable) Supporting 4K 60Hz W…

The second one I believe isn't even considered an adapter, it's just a cable that transfers the native DisplayPort output from the USB-C (Thunderbolt 3) port to a DisplayPort connector.

They both produce the same result with RGB limited range. I'm not sure why DisplayPort would output RGB limited range when it is mainly used for PC monitors that should support RGB full range.

Thanks again, please update me with the results of your research.

[idata]

Hello matang,

Thank you for your reply.

I would like to add that we created a new thread to continue working with you to address this issue. Since every system configuration is different, we think that it is better to have a separate thread.

Please fill out the following information and attach the reports.

/thread/77761 Required information for reporting Graphics issues

-Intel SSU report (Intel® System Support Utility).

-DxDiag* report.

-DispDiag.

Wanner G.

Intel Customer Support Technician

Under Contract to Intel Corporation

[idata]

Hello matang,

Please provide the information requested above. We will be glad to assist you.Wanner G.Intel Customer Support TechnicianUnder Contract to Intel Corporation

[MGill2]

Hello ,

I sent the information to you in an email last Friday since I'm reluctant to post sensitive system information in a public forum. I'll be happy to send this to you any other way as long as it's private.

Thanks,

Matan

[idata]

Hello matang,

I did not receive your email. I will send you an email so that you can reply at your earliest convenience. However, keep in mind that we will be posting any update via our Intel® Communities. Wanner G.Intel Customer Support TechnicianUnder Contract to Intel Corporation

[RonaldM_Intel · Accepted solution]

Hello everyone,

We apologize for the long delay on updates for this one.

Our development team has confirmed that the Quantization range option will only show on HDMI connections. In previous drivers such as 15.45 branch, the option was showing on DP and USB Type-C connections, but internally it wasn't really working, hence on newer drivers this was corrected.

We are evaluating ways to make this option appear and work correctly on DP and USB Type-C connections but can't make any promises at this point.

I'll provide further updates as they become available.

Best Regards,

Ronald M.

[Dmitry]

Dear Intel, I am having the same issue as the topic starter except I am using a Dell DP to HDMI 2.0 adapter. The driver (26.20.100.7373) won't let me choose the Quantization range and it internally defaults to Limited RGB which I can tell by switching Quantization Range in my TV as the picture looks good only with Limited range selected.

Update: quantization range while still not selectable - works fine on the older driver 15.45. Full range is applied by default.