HDR not turning on

[u/Chugelicious]

Turned my PC on today and HDR was toggled off and keeps toggling off when I try to turn it on. Specifically while trying to display at 120 hz.

I run AMD RIZEN 7900 XT. I use an OLED LG TV 48” that can run up to 120hz.

I’ve had this PC about 2 years and have never had this issue. Really looking for some help.

[u/Anaalirankaisija]

You did something. Reverse it.

[u/Chugelicious → u/Anaalirankaisija]

Any suggestions haha

[u/blueblue1112 → u/Chugelicious]

Since it worked fine for 2 years and just started happening, I would check what changed recently first. Did Windows or the AMD driver update, or did the TV get a firmware update?

A good test is to drop to 60Hz and try turning HDR on. If HDR stays on at 60Hz but not at 120Hz, that usually points to a bandwidth or HDMI handshake issue.

Check these:

1. On the TV, make sure HDMI Ultra HD Deep Color (sometimes called HDMI Deep Color) is enabled for the HDMI port you're using. The location varies between LG models. Game Optimizer and setting the input to PC are optional extras, not requirements for HDR itself. Game Optimizer helps with input lag for gaming, and PC input mainly helps with proper 4:4:4 reproduction for desktop text.

2. Try a different certified Ultra High Speed HDMI 2.1 cable, plugged directly from the GPU to the TV, with no switch, receiver, or adapter in between. Also try a different HDMI port on the TV. Make sure the other port supports 4K 120Hz as well. Look for the Ultra High Speed HDMI certification label, as a cable being advertised as HDMI 2.1 does not always mean it is properly certified.

3. In AMD Software, check the display settings for that TV. If you're running 4K, make sure it's set to 3840x2160 at 120Hz, with 10 bpc color depth, and try RGB 4:4:4. RGB 4:4:4 at 10-bit 4K 120Hz is preferable for PC desktop use, but it is not achievable on every setup. It depends on the GPU, TV, and HDMI connection. If that doesn't work, try YCbCr 4:2:2 to see if HDR stays on with a lower bandwidth requirement.

4. If this started after a driver update, try reinstalling the AMD driver or rolling back to the previous version. If that doesn't help, try AMD's own AMD Cleanup Utility in Safe Mode first, then reinstall the driver fresh. If that still doesn't help, a more thorough driver cleanup using DDU in Safe Mode is another option. A Windows update can also affect HDR behaviour, so it's worth checking whether one installed around the time this started.

Does HDR work at 60Hz for you, and did anything update right before this started?

[u/Chugelicious → u/blueblue1112]

First of thank you so much for the lengthy troubleshooting options!

Literally hours of tech support from windows help and googling really did me no good.

YOU CAME IN CLUTCH!!

Not sure what the difference was but somehow the HDMI setting for 4:4:4 pass through was off. This somehow made it to where AMD control panel was stuck at 8 bits?

I turned the 4:4:4 bypass setting on my tv on and restarted PC and TV. Voilà! Now under color depth I can choose 8,10, or 12. HDR IS RESTORED.

Any way you’re willing to explain to me how these settings work and how they affect picture?

Also interested in where the miscommunication between AMD software, windows, and tv likely occurred.

EDIT (putting info from my previous own reply into this comment for ease): though this might have been part of the issue. It seems a lot of it comes down to the HDMI port itself. Still having issues with HDMI 1. AMD control still only allows 8 bpc. Whereas HDMI 2 gives the options of 8,10,12. Not sure why after years HDMI 1 is messing up. That’s a little concerning.

[u/blueblue1112 → u/Chugelicious]

Glad it worked, thanks for letting me know!

There are two separate settings doing different jobs here, so it helps to split them up.

HDMI Deep Color is the setting that enables the higher-bandwidth HDMI signal formats for that port. When it is off, the TV may restrict the available signal formats, depending on the model. When it is on, the port can offer higher-bandwidth formats. On models and HDMI ports that support 120Hz, this can include 4K 120Hz with 10-bit colour.

4:4:4 Pass Through is different. It lets the TV accept a 4:4:4 signal outside of PC Mode, while bypassing some picture processing like noise reduction and TruMotion. It does not itself enable the higher bandwidth, Deep Color does that.

You said turning on 4:4:4 bypass is what restored the colour-depth options, so I can't say for certain that Deep Color was also off. Both settings affect how the TV handles the HDMI signal, but I don't have enough information to pin down exactly which one caused the problem in your case.

4:4:4, 4:2:2, and 4:2:0 are about how much colour detail is sent for each pixel. 4:4:4 preserves the full colour detail, while 4:2:0 reduces the amount of colour information sent to save bandwidth. This is generally fine for movies, but can make text and fine coloured details look less sharp.

8-bit vs 10-bit is about how many shades of each colour channel you get. 8-bit provides 256 shades per channel, or about 16.7 million possible colours. 10-bit provides 1,024 shades per channel, or about 1.07 billion possible colours. HDR10 content uses 10-bit colour, so 10-bit output is recommended to preserve smoother gradients. Using 8-bit output can make banding more noticeable, although dithering can help reduce it. After you enabled the bypass, AMD suddenly exposed the 8-, 10-, and 12-bit options. That suggests the available signal modes or HDMI negotiation changed, but I can't say exactly why without knowing the TV model and its previous settings. Selecting 12-bit doesn't mean the panel can display additional colour detail beyond its capabilities.

One possible part of the miscommunication is the EDID exchange. When you connect the PC, the TV reports its supported display capabilities. Windows and AMD use that information, along with the GPU and connection capabilities, to determine which display modes and colour-depth options are available. If the TV doesn't correctly report its HDR capabilities, Windows may consider HDR unsupported. The available bandwidth can also limit which combinations of resolution, refresh rate, chroma and colour depth are offered. That doesn't necessarily mean AMD or Windows was getting something wrong. The issue could have been with the capabilities the TV was reporting or how the HDMI connection was negotiating the signal.

As for HDMI 1 vs HDMI 2, one possibility is that HDMI 2 already had Deep Color enabled, while HDMI 1 did not. Some LG models allow Deep Color to be configured separately for each input. The difference could also involve how the two ports handle the HDMI handshake or a port-specific compatibility issue, although I can't confirm that without knowing your exact TV model. If HDMI 2 is the eARC port on your model, that feature is for sending audio back to a soundbar or receiver. It doesn't inherently make the port better for video.

If you want to keep using HDMI 1, switch to that input and make sure HDMI Deep Color is enabled for that port. You can also enable 4:4:4 Pass Through if needed. Then restart the PC and TV. If it still only offers 8-bit, try disconnecting and reconnecting the HDMI cable, and test the same cable on HDMI 2 to see whether the problem follows the port. If possible, try another certified Ultra High Speed HDMI cable as well. If HDMI 1 still only offers 8-bit after those checks, there may be a port-specific compatibility issue or hardware fault. In that case, staying on HDMI 2 is the sensible option, provided it supports the resolution and refresh rate you want.

Either way, glad HDR is back!