Will Steam OS Allow Full Range RGB over HDMI

[Kor]

Just finished setting up the beta on my loungeroom machine. Once thing Nvidia have been guilty of for years now is not including user friendly driver method for enabling full range (0-255) RGB over HDMI, even when the display or receiver has full support for it.

On Windows this requires a hand full of registry changes which the community have put into a tool since Nvidia seemingly can't be assed to address such a simple issue/requirement. On Steam OS and Linux in general I'm not aware of any method to perform the same action. Will there be some form of OS interface level flag to enable full range RGB? It would be rather silly not to include it since most PC games live in the full range world and crushing out certain details in the picture would be a pretty big bummer.

[BONKERS]

This is a necrobump but this is an EXTREMELY important issue.

Getting correct levels, Chroma and everything on an HDTV over HDMI is an absolute train wreck and a complete nightmare.

If SteamOS doesn't fix this issue, i'm going to lose my mind

[powerarmour]

At least on Intel HDMI outputs, you can use the following command :-

xrandr --output <HDMI> --set "Broadcast RGB" "Full"

(replace <HDMI> with the appropriate output device, verify by running xrandr, i.e HDMI3)

From here :-

https://wiki.archlinux.org/index.php/Intel_Graphics#Weathered_colors_.28colorspace_problem.29

[istvan_v]

From the nVidia X config options documentation:

Option "ColorSpace" "string"
This option sets the color space for all or a subset of the connected flat panels.

The option string is a semicolon-separated list of device specific options. Each option can optionally be prepended with a display device name and a GPU specifier.

"<dpy-0>: <tok>; <dpy-1>: <tok>; ..."
Possible arguments:

"RGB": sets color space to RGB. RGB color space supports two valid color ranges; full and limited. By default, full color range is set when the color space is RGB.

"YCbCr444": sets color space to YCbCr 4:4:4. YCbCr supports only limited color range. It is not possible to set this color space if the GPU or display is not capable of limited range.

If the ColorSpace option is not specified, or is incorrectly specified, then the color space is set to RGB by default.

Examples:

Option "ColorSpace" "YCbCr444"
set the color space to YCbCr 4:4:4 on all flat panels.

Option "ColorSpace" "GPU-0.DFP-0: YCbCr444"
set the color space to YCbCr 4:4:4 on DFP-0 of GPU-0.

Option "ColorRange" "string"
This option sets the color range for all or a subset of the connected flat panels.

The option string is a semicolon-separated list of device specific options. Each option can optionally be prepended with a display device name and a GPU specifier.

"<dpy-0>: <tok>; <dpy-1>: <tok>; ..."
The set of legal ColorRange values depends upon the selected color space.

Possible arguments:

"Full": sets color range to full range. By default, full color range is set when the color space is RGB.

"Limited": sets color range to limited range. YUV supports only limited color range. Consequently, limited range is selected by the driver when color space is set to YUV, and can not be changed.

If the ColorRange option is not specified, or is incorrectly specified, then an appropriate default value is selected based on the selected color space.

Examples:

Option "ColorRange" "Limited"
set the color range to limited on all flat panels.

Option "ColorRange" "GPU-0.DFP-0: Limited"
set the color range to limited on DFP-0 of GPU-0.

[istvan_v]

By the way, these options are also available in nvidia-settings (on the "Controls" tab for the monitor), if you do not like editing configuration files. Also, since full range RGB is the default, you might not actually need to change anything.

[powerarmour]

Would be nice if BPM had a toggle for this though, especially for the Intel fix as above as it doesn't default to full range RGB unlike the Nvidia driver.

[wh1sper_123]

Originally posted by powerarmour:

Would be nice if BPM had a toggle for this though, especially for the Intel fix as above as it doesn't default to full range RGB unlike the Nvidia driver.

+1

[Kor]

Originally posted by istvan_v:

From the nVidia X config options documentation:

Option "ColorSpace" "string"
This option sets the color space for all or a subset of the connected flat panels.

The option string is a semicolon-separated list of device specific options. Each option can optionally be prepended with a display device name and a GPU specifier.

"<dpy-0>: <tok>; <dpy-1>: <tok>; ..."
Possible arguments:

"RGB": sets color space to RGB. RGB color space supports two valid color ranges; full and limited. By default, full color range is set when the color space is RGB.

"YCbCr444": sets color space to YCbCr 4:4:4. YCbCr supports only limited color range. It is not possible to set this color space if the GPU or display is not capable of limited range.

If the ColorSpace option is not specified, or is incorrectly specified, then the color space is set to RGB by default.

Examples:

Option "ColorSpace" "YCbCr444"
set the color space to YCbCr 4:4:4 on all flat panels.

Option "ColorSpace" "GPU-0.DFP-0: YCbCr444"
set the color space to YCbCr 4:4:4 on DFP-0 of GPU-0.

Option "ColorRange" "string"
This option sets the color range for all or a subset of the connected flat panels.

The option string is a semicolon-separated list of device specific options. Each option can optionally be prepended with a display device name and a GPU specifier.

"<dpy-0>: <tok>; <dpy-1>: <tok>; ..."
The set of legal ColorRange values depends upon the selected color space.

Possible arguments:

"Full": sets color range to full range. By default, full color range is set when the color space is RGB.

"Limited": sets color range to limited range. YUV supports only limited color range. Consequently, limited range is selected by the driver when color space is set to YUV, and can not be changed.

If the ColorRange option is not specified, or is incorrectly specified, then an appropriate default value is selected based on the selected color space.

Examples:

Option "ColorRange" "Limited"
set the color range to limited on all flat panels.

Option "ColorRange" "GPU-0.DFP-0: Limited"
set the color range to limited on DFP-0 of GPU-0.

It's probably worth mentioning that I went through this stuff when first trying to correct the problem. It would seem that the custom driver included with SteamOS doesn't take into account changes made to the X config. It totally picks up when you're working from the gnome desktop environment however the range switches back to limited once you change over to the big picture front end (and subsequently all games seem to run in limited).