Wrong RGB information signal to external display

[The Green Nerd]

It seems (some/most) TV's won't detect that the output of the HDMI signal is Limited RGB, while the output is actually Full RGB. Colors are therefore saturated and have crushed blacks. Changing the HDMI setting of the TV to Full RGB, fixes the issue. I tested this with my Sony and LG. My TV also won't detect it as an game device. I guess this information is missing to from the signal?

Also a good measuring tool is at looking at settings --> Display --> Nightmode --> Look at the grey scale. The two left blocks should be a different color, if not = wrong RGB setting.

This occurs with both my official Steam Deck Dock, as my cheap dock.

p.s. seems I am not the only one: https://steamcommunity.com/app/1675200/discussions/0/3319737272513115983/ But strange that this bug is only noticed now.

To illustrate the issue I made some pictures:
TV set to Auto mode = Wrong, look at the two black blocks. One should be lighter.
https://steamcommunity.com/sharedfiles/filedetails/?id=2874279265
TV set to Full RGB = Correct, look at the two left black blocks. One is a bit brighter.
https://steamcommunity.com/sharedfiles/filedetails/?id=2874279369

I also made an Reddit (https://www.reddit.com/r/SteamDeck/comments/y3r3ys/change_your_rgbrange_setting_on_your_tv_always/) post for this, to help people with this issue. It seems more people thought it looked off when connected to the TV. But more people had issues determining the correct setting. If it's not possible to fix this by an update, maybe add a disclaimer?

[Ponchos]

Messaggio originale di v00d00m4n:

Can you also do script that does the opposite or expand this script with some toggle settings to do conversion in both direction (and preferably with debanding technique implemented in shader to prevent color banding) ?
Or maybe you can implement it as decky plugin as well?

Interesting. Can you provide a few games where this is the case, preferably with some sources showing evidence of the problem. I have never heard of this before.

I can probably update the shader to also do the inverse, though I don't know anything about debanding. If you create an issue on the github repo ill look into it.

[deaddoof]

Messaggio originale di quent.8:

I don't understand this discussion.

The GPU driver doesn't provide the option to change RGB range, it's not entirely up to Valve.

The ticket is here: https://gitlab.freedesktop.org/drm/amd/-/issues/476

It could be nice to get acknowledgement from Valve though.

The display pipeline is pretty programmable from start to finish. With Linux, Valve have even more access to the display controller internal unlike Windows and other OS.

This thread showcases quite a few problems. Ponchos and v00d00m4n talks about format matching between applications and display out. A easy common example to understand is displaying SDR content on HDR. Do you ever wonder why SDR content look pretty dark on a HDR TV?

HDR have 10 bit (1024) values and SDR have 8 (256) bit values. 0 is dark while 255 is light in RGB additive color space.

Let say you have a bright green with high values in high SDR 102, 255, 51 RGB.

When you super impose a 8 bit color onto a 10 bit color space, you end up compressing the intensity. It is much easier to translate the super impose color back to SDR for comparison.

102 * 256/1024 = 25 R

255* 256/1024 = 63 G

51* 256/1024 = 13 B

This resulting color looks darker. Put (102, 255, 51) and (25, 63, 13) in the same color picker for comparison. Hence, SDR content looks darker on HDR displays.

https://www.mikekohn.net/file_formats/yuv_rgb_converter.php

The other issue to TV display detection. GPU can talk to the TV to retrieve rgb color ranges. Well, the edid needs to be parsed which is a slightly different problem from color space mismatching. I said to upload your edid files for faster support. I guess I am the clown. Oh well.

[FramerateUK]

I'm using my Steam Deck with a BenQ projector at 1080p. What's odd, is that at some resolutions the RGB info does appear to be passed correctly to my projector and it switches the RGB setting correctly, but frustratingly at 1080/60 this doesn't seem to work.

1680x1050 and. 1920x1200 appear to pass the value correctly.

[Mozzie]

For those who have problems with this, you can try:

On your Steam deck go to Settings -> Display -> Adjust Display Colors -> swipe left to minimum

It's works for me

[okcomputing]

Unfortunately my monitor doesn't have a RGB range setting, so HDMI is just not usable for me.

[ShenmueGuy]

Has there been any update to this? Having this issue with my Samsung S95B where the blacks are crushed and colors are off. It gets fixed when I switch the HDMI black level to Normal.

However, I always have it on Auto for my other consoles (which work with auto) when connected to a multi-hdmi switcher. I hope valve fixes this because the signal doesn't have enough information for the TV to detect what the Steam Deck is sending.

Having to change it back and forth on the TV is annoying.

[Critney Spears]

Messaggio originale di Ponchos:

If they are flatpaks you must set the environment variables for the specific flatpak apps. See here https://blog.checkyo.tech/2022/06/20/steam-deck-how-to-apply-luts/

vkBasalt only works in vulkan. I could not get Final Fantasy XIII-2 to play along for example.

After endless googling and trying out things I came across this: https://github.com/safijari/Reshadeck

It (I guess?) runs a version of reshade through decky loader as a plugin and is pretty much always on, even in the main menu. I tried loading the RGBFullToLimited.fx shader, but it causes the deck to crash. Is it possible to rewrite the shader to work with reshadeck?

[D. Flame]

This still doesn't seem to be fixed. Steam Deck OLED in Desktop mode still looks horrendous.


EDIT:
I think I found a work around.

Boot into Gaming mode. Go into settings, then display, then disable HDR. Then boot into Desktop mode. This seems to fix the issue with over saturation for me. What is annoying is that you have to repeat this process every single time, because every time you leave desktop mode, it will turn forced HDR right back on.

[HOBaRT]

This appears to be at least partially converter chipset related.

Confirmed in the service menu of my OLED monitor that the signal is incorrectly tagged as Limited regardless of color mode with the official dock.

I noticed the same behavior on the Deck with an old Type-C HDMI dongle, so I tried it on my AMD framework as well.

Saw the same issue in both Linux and Windows, regardless of the color mode I selected in Windows.

Then I tried the official Framework 3rd gen HDMI card, and it output the proper signal as well as providing additional color output modes.

Tried the Framework card on the Deck, and it also worked and displayed Full RGB HDMI just fine.

So this seems like it's at least partially some issue with the dock's chipset and maybe other older chipsets.

Double checking, are there any known dock models that have proper HDMI color output?

[D. Flame]

Messaggio originale di HOBaRT:

This appears to be at least partially converter chipset related.

Confirmed in the service menu of my OLED monitor that the signal is incorrectly tagged as Limited regardless of color mode with the official dock.

I noticed the same behavior on the Deck with an old Type-C HDMI dongle, so I tried it on my AMD framework as well.

Saw the same issue in both Linux and Windows, regardless of the color mode I selected in Windows.

Then I tried the official Framework 3rd gen HDMI card, and it output the proper signal as well as providing additional color output modes.

Tried the Framework card on the Deck, and it also worked and displayed Full RGB HDMI just fine.

So this seems like it's at least partially some issue with the dock's chipset and maybe other older chipsets.

Double checking, are there any known dock models that have proper HDMI color output?

From what I have seen mentioned elsewhere, the issue is that the device outputs full RGB, like a computer would, but it doesn't included this information in the output, so receiving TVs assume that it is outputting the limited-RGB TV default standard instead, which leads to color mismatches.

Some TVs have the option to set an input to Full RGB or a PC setting, which can help the issue. Mine didn't. And so I had to use the work around where you disable HDR in game mode. Likely the only way to fix this is a patch from Valve, so that it broadcasts the proper color range,

[ShenmueGuy]

I hope this can be fixed with a patch

[TDurden84]

I'm using a USB Hub from Baseus for both my 4K tv and beamer and it works with this one. When using a noname USB Hub I also had the issue that the colors were far too dark.

[HOBaRT]

Messaggio originale di TDurden84:

I'm using a USB Hub from Baseus for both my 4K tv and beamer and it works with this one. When using a noname USB Hub I also had the issue that the colors were far too dark.

May I ask which exact model?

I'm kind of interested in buying several to see if I can determine which chipsets behave properly/which don't.

* The official Steam Deck Dock uses a Kinetic KTM5030 for its Type-C -> DP MST Hub -> DP++/HDMI conversion, and struggles with the issues mentioned above. It'll happily put out 4k30 12-bit with correct Full RGB at HDMI 1.4b, but any of the HDMI 2.0+ modes seem locked to limited. This is not a limitation of the Deck and seemingly happens with any device I attach to the Deck Dock.

* The Framework HDMI card nominally uses a Parade PS186 direct Type-C -> HDMI converter, and seems to work fine. Startech sells a Type-C hub with this same chipset explicitly advertising the PS186 for "iPad Pro and iPad Mini" compatibility.

* Cable Matters 8K DP -> HDMI cables, seemingly using a Synaptic VMM-7100. A pretty good converter, but still Limited color space at 4k60 with the latest CM firmware 7.02.120 (happens on Windows Nvidia too). 4k60 is kind of temperamental and sometimes won't display at all. But again, other modes including 4k120 do proper RGB, but I don't think the Steam Deck/Dock has enough bandwidth to push that. Need to try some of the other firmware versions people found.

[TDurden84]

Sorry for the late answer:
These 2 models work in 4K without issues:
* Baseus BS-OH047 (from Amazon)
* Baseus BS-OH101 (from Aliexpress)

[HOBaRT]

After further searching, I found a fairly cheap DP -> HDMI dongle that's actually available in the US, which outputs the proper color information:
"Plugable Active DisplayPort to HDMI adapter Supports HDMI displays up to 3840x2160 @ 60 Hz (4K) resolution"; currently $15.

Uses a Parade PS176 chip, and 4k60+seemingly all resolutions below that give me proper Full RGB using the official Steam Deck Dock.

4k60 HDR works on the Deck, but VRR doesn't (not unexpected, and personally I don't mind).

I'm reasonably happy with this solution for now.


For those who live in the EU, I'd say try a Delock PS186 dongle like the 66436 or 85929. Those would've been my first choice if they were available in the US.