Is it possible to get 10-bit or more color depth through VGA?

Hello!
Probably cannot be done, at least with my hardware, but I wanted to ask just in case. I have read about professional graphics cards of the 90's that could give 10-bit per color channel to get better image for image editing. There was no DVI or HDMI or DP back then, they gave this on analog VGA monitors. So I wonder if there is any modern card that can give more than 8-bit per color channel through analog VGA connection. Probably a professional Quadro card can. Do you need a special monitor, or any monitor with VGA input will do? Is there any hack to force a consumer level card (such as my GeForce GTX 1050 Ti) to output more than 8-bit per color channel through VGA (through a DP to VGA adapter I have connected to the DP output)? How? Do I need a special monitor, or any monitor with VGA input (such as my Sony 19" TV) is OK?

Thank you very much.

PS: I didn't know which section was appropriate to post it. If it should be at another section, move it as appropriate.

If I understand your question correctly, I don't think it can be done in quite the way you are asking.
VGA has a colour gamut of 18-bit depth (6-bit red+6-bit green+6-bit blue), which is mapped onto hardware registers to give the exact colour. VGA is backward compatible with a couple of other standards, so the exact mapping of colours depends on the mode in use. The analogue Red, Green, Blue channels are 0.7 Volt maximum, and cannot be changed.
The colour gamut supported by the VGA standard might not be displayable on the monitor, depending on the monitor's LCD technology. The monitor technologies can be Twisted Nematic Effect (TN-effect), In-Plane Switching (IPS) or Vertical Alignment (VA). The TN-effect panels were the cheapest to manufacture, but their colour gamut was the lowest. So, if you want more colours out of VGA, then perhaps check the LCD technology of your TV/display device. Eizo used to make VGA monitors with a higher colour gamut, but when I last checked their website, they seemed no longer stock the VGA standard. But I only looked briefly, so I may have missed something.

VGA (and SVGA) signals are of the analog type so, the number of colors that a videocard can output through SVGA is determined by the RAMDAC that it uses. Back in the early 1990s I was using Borland Turbo Assembler (TASM) to write my own graphics related programs and demos (for DOS, on an i486 DX2/66 machine). The code you had to write to gain access to the advanced video modes and specialized hardware capabilities of cards such as my Tseng Labs ET4000 (Opti2 Local Bus) with the (optional) upgraded RAMDAC was all hardware-specific, it varied heavily depending what card you had installed in your PC. It was a fun part of my PC hobby for sure, but took a lot of time and effort to learn. I actually still have the book that I had bought from the bookstore back then, it's this one:

I just thought since VGA is analog, maybe we could improve color fidelity by using 10-bit instead of 8-bit per channel. Of course the DAC must also support it and it might work for an analog (CRT) monitor. To work on an LCD monitor is another story... At least in most monitors you can improve image if you go at Control Panel, Color Management, Advanced, Calibrate Display (couldn't see any improvement on my Sony TV but I have seen on many other monitors). After calibrating the display you are also asked to adjust Clear Type. Do it for better looking text.

PS: I have noticed that the default color values produce too vivid colors on my Sony TV. I go at nVidia Control Panel, Display, Adjust Desktop Color Settings and reduce Digital Vibrance from 50% to 40% to get more natural colors. I just share this in case you have a similar problem. This usually happens when using a TV as monitor. The colors are too vivid. Just reduce Digital Vibrance to make them better. When using HDMI I prefer RGB instead of YCbCr to get the full dynamic range and better colors. It might be my idea, but I think colors do look better in RGB, so I stick to it, unless I use 4K resolution which goes at YCbCr automatically.

spapakons said:

using a TV as monitor

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I find that reading text on my Sony Bravia XR-55X90J in dark mode has helped me to reduce eyestrain and the stress symptoms that result from working with various software and surfing on the internet up to 14 hours per day, much more heavily than the review on rtings.com had been able to suggest. Use your own eyes... de gustibus et coloribus non disputandum est.

I don't like dark mode, it reminds me of the 80's (MS DOS). I don't have any eye strain issue, I was just wondering if I can see a couple of 10-bit MKV videos I have any better on my monitor. I guess not, so I stick with standard 8-bit per color channel.

The Wikipedia article doesn't list the higher resolutions available in some VGA setups, so I wonder whether some makers might use a DAC with greater than a 6 bit depth.

But if you're not seeing excessive banding on your VGA monitor, it may not be worth worrying about.

The original IBM VGA had 256KB RAM and could show the CGA mode 320x200 with 4 colors (2-bit), the EGA modes 320x200 with 16 colors (4-bit) and 640x350 with 16 colors selectable from a 64-color palette (6-bit). It could also show the VGA mode 320x200 with 256 (8-bit) colors selectable from a 6-bit per color channel (18-bit total) palette. This is 262144 colors or 256K colors. It could also show the standard VGA mode of 640x480 with 16 colors. All Windows from 95 and newer can show that standard VGA mode 640x480 with 16 colors without graphics drivers. Newer VGA clones with more RAM (called Super VGA or SVGA) could also show 800x600 and 1024x768 with the number of colors depending on the amount of RAM. Valid color values for Windows were 256 (8-bit), 16384 or 16K colors (15-bit), 65536 or 64K colors (16-bit) and 16M (8-bit per color channel or 24-bit total). 10-bit per color channel or 30-bit total is even more colors, about 1 billion.

spapakons said:

16384 or 16K colors (15-bit)

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"15-bit color depth" is actually 32768 colors, or 32K colors.

hdmi said:

"15-bit color depth" is actually 32768 colors, or 32K colors.

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I might remember wrong, anyway. The point is that all modern graphics adapters and monitor support at least 8-bit per channel or 24-bit color (16 million) total. This is as good as it gets without going to higher values such as 10-bit per color channel. Old laptop screens were limited to 6-bit per channel (18-bit total, 256K colors), but I believe more modern models can do 8-bit per channel (24-bit total or 16M colors) without any issue. My original question was if I could cheat and get more than 16M colors on unsupported hardware, probably not.

A new idea: I know we can emulate larger resolutions than the monitor's native, this in nVidia is called Super Resoution and is enabled in 3D settings, DSR factor (Digital Super Resolution). This allows us to set 1920x1200, for example, and then the GPU downscales it to the native 1440x900 for example. Of course you are still watching the movie at the native resolution of 1440x900 but it looks slightly better because it actually plays in 1920x1200 and is resized to 1440x900 by the GPU (I think it does a much better scaling than the media player). Much like a large photo file resized to a smaller size looks better than if the photo was is the smaller size in the first place. So can we do something similar with colors? Is there any driver or hack or application than can play a 10-bit per color channel movie at 10-bit and then convert to 8-bit to display at our conventional monitor? Probably what I am asking is already done by media players when playing 10-bit video on a standard screen, but I still ask just in case.

spapakons said:

media players

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Just use MPC-HC as the player, with madVR as the renderer. To set this up in breeze, download and install K-Lite Codec Pack Full, then check if a separate upadate installer is out, and, if yes, download and install it too, to update to the latest version. Codec Guide: K-Lite Codec Pack - For Windows 11 / 10 / 8.1 / 7
With madVR you can get better scaling results than pretty much anything that exists, and much better than the hardware capabilities can allow. For both scaling the pixel resolution and color scaling.

I already use MPC-HC with MadVR. I don't use DSR when watching movies, I wouldn't see the difference anyway. The primary use of DSR is in gaming so you can see larger area of the map or game screen that your native resolution allows. Enabling 1920x1200 for example shows more on screen than playing on the native 1440x900 resolution. Also when you want to take a screenshot of a website that shows more in larger resolution than in your native. There are many photos that look better in larger resolutions than resized on your native. Using DSR in a fast paced movie you wouldn't be able to tell the difference. I can hardly tell the difference from 720p to 1080p in fast scenes.

spapakons said:

I already use MPC-HC with MadVR.

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In that case, the only way that I can think of (aside from experimenting with settings everywhere also including all the various settings of the actual TV itself, and also assuming that you already have chosen the highest possible quality of .mkv files available for playback) that would help to improve on picture quality would be to take the plunge and buy a better TV.