Windows 11 and metadata exchange on Display Port to HDMI conversion HDR; is uni-directional Display Port to HDMI Required?

Question

Windows 11 and metadata exchange on Display Port to HDMI conversion HDR; is uni-directional Display Port to HDMI Required?

Anonymous

Windows 11 HDR on 2 monitors

Has anyone ever gotten Win 11 HDR to work on more than one monitor?

There are a lot of asks for help threads in the Microsoft Community forum with folks asking how to get HDR to work on Windows with multiple monitors (on my LG TV the visual difference is quite large, but thus far have not been able to get it to work on two duplicated outputs on my ASUS Phoenix NVIDIA GeForce RTX 3050 to the same LG TV PhysX right now are:

HDMI --> LG TV
DP (DisplayPort) --> Passive HDMI/DP cable --> Anthem AVM 70 Processor --> LG TV via HDMI ARC
(yes the AVM 70 is HDR 10 capable (and even Dolby Vision capable) - but not G-sync capable

It is notable in https://support.microsoft.com/en-us/windows/display-requirements-for-hdr-video-in-windows-192f362e-1245-e14d-3d3f-4b3fc606b80f that DP 1.4 is required. According to my research DP 1.4 is not uni-directional with a passive cable (yes, my cables are good quality); I have gotten native HDMI --> LG TV with DP disabled to work with HDR to the LG TV so either: (HDMI display only)

Win 11 HDR never works with Duplicated ports or
Requires an active cable for DP 1.4 to HDMI conversions to support uni-directional metadata (leading theory based on https://g.co/gemini/share/aaf60ae2f112 )
NVIDIA RTX cards afaik tend never to have multiple HDMI ports (don't ask me why but it sucks)

Windows HDR setup screen indicates my setup today is not HDR streaming capable but is HDR capable. The NVIDIA Control Panel says turn Windows HDR on lol.

My working theory is that Windows is trying to read the HDR metadate for an HDR 10+ Flag but this is not going to happen in a DP to HDMI passive cable setup (https://g.co/gemini/share/aaf60ae2f112) . I'm too lazy to write the code for this but if anyone has the code for this I would be interested in getting that (esp. if Python) I have been unable to verify in the windows HDR spec if uni-directional DP 1.4 is required.

I am posting this mainly to help other folks and will update once I get an uni-directional DP/HDMI)I cable I will update the thread; I am also interested to understand the theory here,

I was not planning to add a bunch of Sysinfo here as i already have HDR working on a single HDMI port on this system.

Locked Question. This question was migrated from the Microsoft Support Community. You can vote on whether it's helpful, but you can't add comments or replies or follow the question.

0 comments

Answer accepted by question author

Anonymous

HDR in Windows 11 is fragile, here is some background especially on using conversion from Display Port to HDMI.

After quite a bit of testing, here are my conclusions:

If you are going from Display Port (DP) --> HDMI a non-active cable, a plug adapter or other passive conversion won't work; a Unidirectional DP to HDMI cable is required.
If you have 2 inputs/outputs you would like to duplicate, even if both support HDR 10 (eg. both support Windows HDR when using in dedicated mode) , Windows 11 will not let you use HDR
for the sake of clarity when i say duplicate this is what I mean displayswitch.exe /clone
It is possible to get information from WMI on your system about HDMI, but not the HDR metadata using Get-WMIObject CIM_VideoControllerResolution from Powershell or Get-CimInstance -ClassName Win32_VideoController | Select-Object VideoModeDescription see:https://learn.microsoft.com/en-us/windows/win32/wmisdk/managed-reference-for-wmi-powershell-command-classes refuted in https://github.com/patrick-theprogrammer/WindowsDisplayManager/wiki/WindowsDisplayManager-Wiki#display
a handy command line dump is also available but again it seems like they forgot to include HDR in WIMI: wmic.exe path Win32_VideoController https://learn.microsoft.com/en-us/windows/win32/wmisdk/wmic

My overall conclusion is as follows:

HDR in Windows 11 was poorly tested with little or no diagnostics
HDR in Windows is not fully documented
HDR in Windows 11 was not fully tested outside very limited lab type setup
If you have a high quality TV or Monitor the HDR feature is visually stunning once you get to work
Back in the day when I worked at Microsoft they had testers dedicated to finding things like this but the fragile nature of this features demonstrate it is not well tested or crafted.

Given the number of questions about getting HDR to work in Windows 11 in many many forums both here and places like Reddit (Why HDR is so bad on W11? : r/Windows11) points to a significant gap between features, users and the ability of even technical savvy users to diagnose problems and ultimately get the feature to work. A tech article in in Microsoft Learn is really needed badly!

0 comments

1 additional answer

Answer 1

Hi, dansker1234

Welcome to the Microsoft Community

Thanks for your feedback. I read the information you provided.

The solution and additional information you provided are very detailed and I appreciate your enthusiasm in sharing them. This information will help other users who are troubled by the same problem.

I look forward to your continued updates to this thread. If you post subsequent updates, I will mark your answer as the answer, so that when other users search for "how to solve HDR problems with multiple monitors", your solution will be more searched for.

Best regards

Brian - Microsoft Community Support Specialist

Share via

Windows 11 and metadata exchange on Display Port to HDMI conversion HDR; is uni-directional Display Port to HDMI Required?

1 additional answer