ryans

I updated my post with links to better videos that I recorded. The recordings are done with a 1st gen iphone SE not the 2020 version. All the tests were done with ditherig running on an intel g4560 using the IGP so the flickering shouldn't be from the OS.

The lagom and blurbuster pixel inversion tests do show pixel inversion issues at certain settings on my monitor. But at the setting that I recorded the updated videos at, I could not see any pixel inversion with the naked eye.

Here's a microscope video I recorded of two patterns at one monitor setting that showed visible pixel inversion and one setting that didn't.

https://www.youtube.com/watch?v=-8gyeFWmAOE

I don't know what to make of it. I don't really see much difference between the visible and non visible tests. The subpixel flickering in all the videos seems to be occurring at 30hz, half of the 60hz display frequency of the monitor and the phones. The iphone SE first gen did not show any pixel inversion issues to the naked eye when using both the blurbusters and lagom test.

I paid about $20 for the microscope on amazon.

edit: It actually seems that there is indeed very minor pixel inversion issues with the p24h-10 monitor. They were only visible when I went full screen and carefully cycled through each pixel inversion setting. It wasn't visible when only viewing the initial image with all 12 examples shown at once. It seems to cycle around 2a, 2b, 4b and 7a when changing monitor settings. The 7a being subtle enough that is only visible when viewed full screen. I tried full screen with the iphone SE 1st gen and wasn't able to see anything with the naked eye.

edit 2: Interestingly the pixel walk goes away at maximum setting, which are the setting that I recorded the original microscope dithering videos. the screen is too bright at max setting but I guess I'll just try compensating by wearing my maui jim sunglasses since they also help increase the contrast and reduce ips glow.

  • KM likes this.
    5 days later

    Results from my tests: (slo-mo camera and @chahahc's microscope model)

    All my screens have a pixel flicker (exactly like the one in the original post in this thread). Nothing that I tried reduced it.

    Setups that I tested:

    • Dell 2408 WFP (external monitor). Both in Windows 10 and latest Ubuntu Linux. Tried YCbCr option on and off. Tried "Text content" option on and off.
    • Lenovo IdeaPad 320 laptop (built-in display). Tried restarting ditherig.exe, tried a lower-than-native and higher-than-native res.
    • iPhone SE (1st gen)
    • Samsung Syncmaster 710N (very old external monitor). Tried at native res. Also tried at max res (provided by my HDMI-VGA adapter), which actually increased the pixel flicker.

    The only setup in this list that had a less strong pixel flicker was the Dell 2408 WFP external monitor. Which makes sense, as this is the monitor that gives me least eye strain.

    At this point I think I'm seeing "LCD inversion" artefacts and not TD. This probably means I won't find any software solution, and I should just look for a higher-quality (and/or pricier) display.

    • KM likes this.

    It could be interesting to boot an OS/GPU driver combination that lets you reliably activate and deactivate GPU-side temporal dithering to see if switching it on and off causes any observable change in the pixel flicker.
    For example, Nvidia has an official Unix application, NVIDIA X Server settings, that lets you do this with Nvidia GPUs.

      KM It could be interesting to boot an OS/GPU driver combination that lets you reliably activate and deactivate GPU-side temporal dithering to see if switching it on and off causes any observable change in the pixel flicker.

      Indeed. I did that now.

      ditherig.exe set to "Dithering off": https://share.icloud.com/photos/056qVnI9n2n3S-uiHrjCGCrpg

      ditherig.exe set to "Spatio-temporal 1": https://share.icloud.com/photos/041v9WasX11htkpGqO9zFMM-A

      I don't see any difference between these 2 videos.

      And I know ditherig.exe is working because, when it's set to "Dithering off", I see banding in my wallpaper.

      KM For example, Nvidia has an official Unix application, NVIDIA X Server settings, that lets you do this with Nvidia GPUs.

      Yes, I tried that, but that app barely had any options. And certainly none related to dithering. I think the reason is because I'm on a laptop (i.e. "switchable graphics" between intel and nvidia).

      • glvn replied to this.

            KM It could be interesting to boot an OS/GPU driver combination that lets you reliably activate and deactivate GPU-side temporal dithering to see if switching it on and off causes any observable change in the pixel flicker.

            I know certain AMD GPUs under Linux allow you to easily toggle dithering (verified with my lossless capture setup). Unfortunatly I'm not @logixoul and don't have the same high-speed camera setup. 😃

                I don't think ditherig does anything to help anymore in Win10/11; it doesn't help that much nor in 8.1 in versions past 1.7

                9 days later

                logixoul

                And I know ditherig.exe is working because, when it's set to "Dithering off", I see banding in my wallpaper.

                Could you share a file with your wallpaper (as a verified sample) ? Of course if it is not personal 🙂

                    Just load up a greyscale gradient from 0 to 255 at 100% zoom. If you have banding on a non-8-bit panel with dithering off, then the app works.

                    JTL

                    Which AMD GPUs are you referring to?

                    • JTL replied to this.
                        4 days later
                        9 days later
                        a year later

                        Adding to what a couple of others have said, I believe this is pixel inversion, not temporal dithering. One clue is that it happens on all colors except for pure white. For many screens that I've tested (but not all screens), pixel inversion is worst at fairly light colors (such as #A0A0A0) but is difficult to detect at pure white.

                        In fact, I think it would be very difficult to design a test like this that measures temporal dithering because you somehow have to control for pixel inversion. Perhaps the best you could do would be to test a series of consecutive colors, like #A0A0A0 through #AFAFAF and try to determine whether certain colors in that range flicker more than other colors in that range. Assuming a 6-bit panel, if roughly 3/4 of those colors flicker more than the other colors, then the additional flickering would likely be due to temporal dithering.

                        You guys ever check if this happens more at 60hz vs 75hz vs 120hz vs 144hz, etc?

                        I have a few different monitors with those refresh rates to check but don't really have the tools to outside of a regular phone camera.

                          Elever I've only tested a handful of devices, but the pixel inversion frequency that I saw was 60 hz regardless of how I set the refresh rate.

                            Elever If you feel bad about the old monitor (1) Just buy a new (2) 6bit + FRC panels do not buy. Only honest 8/10bit (3) Turn off responce time (backlight blinking). Ultra Low Motion Blur (ULMB), Extreme Low Motion Blur (ELMB), Dynamic Accuracy (DyAc), OverDrive, AIM Stabilizer, Visual Response Boost (VRB). (4) Enable FreeSync Premium (G-SYNC for Nvidia) (5) At 144Hz, the eyes get tired faster (especially if "black frame insertion" is enabled)

                              7 months later

                              KM For example, Nvidia has an official Unix application, NVIDIA X Server settings, that lets you do this with Nvidia GPUs.

                              Hi. I'm coming back to this old thread because I'm currently using a laptop with Intel+AMD "switchable graphics" (so, not NVidia). Any way to reliably disable GPU-created TD on such a setup for my external display/projector? I'm certainly willing to install Linux, VMs or whatever else needed.

                                dev