Difficulty getting HDR display output to work

In the 4.15 preview livestream, it was mentioned that it’s going to be adding support for HDR displays. Using settings that work on my PS4 Pro for HDR, I connected my Samsung KS8000 TV to my GTX 1080, which should support HDR just fine, and gave the console commands an attempt. I then set in the Nvidia Control Panel for it to use YCbCr422, as it’s the only option for HDMI 2.0b that supports 10bpc.

No matter how I mix and match all of the following console variables, I can’t get anything looking even remotely correct:

r.HDR.Display.ColorGamut 1-4
r.HDR.Display.OutputDevice 3-6

These are, as far as I’m aware, the only ways to actually configure the HDR mode and not just use LDR anyway (at least according to the console variables help file the engine generated for me).

r.HDR.UI.CompositeMode also seems to affect more than just the UI, it also turns up or down the contrast of the entire scene. Similarly, r.HDR.UI.Level impacts the scene as well.

In dark areas, there’s also severe color banding when in HDR mode, which leads me to believe the engine isn’t actually sending out the HDR signal to the display in the first place.

If there’s anything I’m missing that I need to configure or set up properly, I’ll be more than happy to give it a try.

Hi Daniel,

I seem to be the only other person on the planet looking into how to get this to work. (answerHub cross post - https://answers.unrealengine.com/questions/567055/how-to-use-hdr-output.html )

The Release notes were a bit brief but I’ve tried what you have and have a working configuration as far as HITMAN is concerned (HDR enabled PC game) but can’t get UE4 to write out the correct meta data into the HDMI stream to my LG OLED E6 panel.

I hope someone can help us -

For me the r.hdr.enableHDRoutput just makes everything gamma’ed up or washed out but doesn’t trigger anything on the panel. I’m running the panel as a primary/solo display via HDMI 2.0 lead from a 1080 under Windows 10. Running the UE4 project as a compiled binary with -dx11 and full screen parameters. Am I missing something in regards to “Exclusive Fullscreen” as apposed to -fullscreen maybe ?

Anyway, good luck to us and I’ve subscribed for any news…

Here’s the scoop I worked out by reading the code.

r.FullScreenMode 0

r.HDR.EnableHDROutput 1

r.HDR.Display.OutputDevice 5

start with -fullscreen on the command line parameters.

You may or may not need your TV in YCbCr420 mode. It theoretically shouldn’t require it, but it might.

Seconded. I’ve also found the key to be enabling non-borderless fullscreen (in my case, with a command like “r.SetRes 2560x1440f”) before enabling HDR with “r.HDR.EnableHDROutput 1” and “r.HDR.Display.OutputDevice 5” (or 6).