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Drivers & Software

cryobry
Adept I
‎01-14-2022 05:05 PM

Cannot change pixel format at 60hz on Vega 8

Windows 11

Latest beta and whql drivers.

When my refresh rate is set to 60hz I cannot select Full RGB 4:4:4 output to my monitor, it is stuck on YCbCr 4:2:0 and I cannot change it (this is at 8-bit, so no bandwidth issues). I know that that this is either an AMD driver or Windows issue because I can get perfect 4:4:4 output using madVR or JRVR video renderers (even at 10-bit->the full HDMI 2.0 spec). But in the desktop I cannot change it at all and it leaves the display colors looking strange.

I know I cannot get 4:4:4 at 10-bit 60hz on HDMI 2.0, I don't care about 10-bit for the desktop, I just want to be able to select full RGB 4:4:4 at 8-bit so my desktop colors don't look so odd! The colors at 30hz 4:4:4 look perfect in 8-bit and 10-bit (hdr) modes.

Samsung 5 2500U laptop -> HDMI 2.0 port -> HDMI 2.0 cable -> Hisense U6GR 4K HDR TV

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4 Replies
elstaci
MVP
‎01-14-2022 05:49 PM

What is the HDMI version for your laptop HDMI Video output port?

 

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cryobry
In response to elstaci
Adept I
‎01-14-2022 08:53 PM

I believe it is HDMI 2.0b. The laptop is here: https://www.samsung.com/us/support/downloads/?model=N0052400&modelCode=NP550XTA-K01US

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elstaci
In response to cryobry
MVP
‎01-14-2022 09:06 PM

I found these two pages from your Laptop manual. The first page concerns connecting an External Monitor:

Screenshot 2022-01-13 123521.pngScreenshot 2022-01-14 220214.png

I really not that familiar with Color settings and using 8 or 10 bit color. Maybe someone else more knowledgeable can help you out.

By any chance do you know if your own Laptop screen can be configured to run it that way you want?

EDIT: See if this Tech site for HDMI is of any help: https://www.the-home-cinema-guide.com/hdmi-cable-connector-explained.html

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cryobry
In response to elstaci
Adept I
‎01-15-2022 09:20 PM

Unfortunately changing from extended to clone to single display mode had no effect, I am still not able to change the pixel format at 60hz. My cable is HDMI 2.0 certified and like I mentioned I can get 10-bit 4:4:4 rgb output at 30hz when using a low-level renderer (madVR or JRVR) which indicates that it isn't a bandwidth issue At the very least I should be able to get 8-bit 4:4:4 regardless of the cable capabilities.

I think I might know what is going on. There is a widespread "yellow tint" problem with Windows 11 and after some testing I think I know what is happening. Windows 11 cannot seem to change to RGB pixel format without also simultaneously switching on HDR (which would exceed the bandwidth limits of HDMI 2.0) so it refuses to do so. Microsoft needs to release a fix that allows HDMI 2.0 displays to switch to RGB without also turning on HDR or else we will all be stuck in YCbCr 4:2:0 (yellow tinted) on all of our modern displays that expect full RGB at 8-bit.