In which situations do Temporal Dithering occurs?

Moe3224

I have different scenarios and want to know if dithering is taking place:

(1) GPU Dithering: YES | MONITOR: 8-bit : (Y/N)

(2) GPU Dithering: NO | MONITOR: 8-bit : (Y/N)

(3) GPU Dithering: NO | MONITOR: 8-bit + FRC : (Y/N)

In other words, I bought a new LG monitor that has 8-bit+FRC. If a PC/Laptop GPU's dithering is disabled, will the monitor still force the GPU for dithering or it will only display 8-bit colors?

If I buy a monitor that is 8-bit only (NO FRC) and my PC/Laptop GPU's dithering is enabled, will the 8-bit monitor be forced to display 10-bit color by dithering or it will only display 8-bit color with no dithering.

@Seagull I tagged you in this post because you might have an answer for me

JTL

Hello

To answer your questions, based on my research, some GPUs appear to have dithering enabled by default regardless of drivers and OS, and some do not.

FRC is dependent on the internal monitor driving circuitry.

Based on the above:

(1) GPU Dithering: YES | MONITOR: 8-bit : (Y/N)

Yes.

(2) GPU Dithering: NO | MONITOR: 8-bit : (Y/N)

Assuming the GPU isn't awful and trying to dither everything: No.

(3) GPU Dithering: NO | MONITOR: 8-bit + FRC : (Y/N)

I assume it relates to the monitor circuitry.

Testing for FRC in monitors is harder due to the difficulty of obtaining high-speed recording equipment.

Moe3224

Thanks for the explanation JTL , here is what's happening with me:

I bought a 4k LG monitor, I did some research and found out that this monitor's display supports 8-bit+FRC.

I tested two laptops on this monitor:

Lenovo Thinkpad (GPU: Intel Graphics Card)
MacBook Air M1

I am using the same monitor's settings on both above laptops. I can use the Lenovo for 7 hrs+ without feeling any eye strain and no symptoms shows up.

On the other hand, I can feel instant eye strain and headache when I connect the MacBook Air m1 to this monitor.

What I understood from your explanation is that GPU with enabled temporal dithering will toggle dithering no matter what type of display your monitor is (real 8-bit and 8-bit + FRC). If the GPU's temporal dithering is disabled, dithering might be used depending on the FRC of the monitor.

Can you please clarify what you mean by monitor circuitry? Is there a chance of dithering when GPU's dithering is OFF but the monitor supports FRC?

JTL

Moe3224 Can you please clarify what you mean by monitor circuitry? Is there a chance of dithering when GPU's dithering is OFF but the monitor supports FRC?

In theory, feeding a color signal "below" the depth of the FRC stage (i.e an 8-bit signal on an 8-bit+FRC monitor) should not have temporal dithering, but if the monitor is doing something internally to cause dithering that can still be an issue.