Potential correlation between video timings and flicker

machala

So after studying the issue for so long I just encountered something that helped me understand what's going on and II might have the final answer. It may not be the answer to all of the issues but I believe most of them yes.

Sadly I do not offer a simple solution.

So what are my findings about: the issues with modern HW and its output are all about not having proper screen refresh timing between the graphics card and the screen itself. Timing and timing algorithms are quite a complex subject and there are many standards. NVidia offers you a chance to set it, you can also completely set your own values from scratch.

Thanks to my recent experience I know that incorrect timing values not only cause exactly the usual symptoms, but they may also cause gradual damage to the display as it interferes with pixel inversion and causes imbalance of pixel usage in one direction (you can look up what pixel inversion is) which further worsens the flickering that the incorrect timing is doing.

I will later write more proof of why this is my conclusion, for now I can only say that thee is no simple solution.

Overall it is not just about the GPU or just about the display. It is about both and most probably also about the rest of the PC as it may have interactions with how the timing is executed. Therefore it is about the COMBINATION of all these components that causes this flickering. Of course, good pixel inversion on the display is the base, but this is the final answer why GPU plays its (significant) role too.

Additionally as timing standards have changed over time this also explains why old monitors usually have more issues with modern HW. You simply need to exchange both, which most of the audience here (including me) are not willing to do as they have their "good" monitors.

And to add more: as the quality of HW is getting lower and lower the pixel inversion is not taken care of very well.

And one extra potential answer: why do different OSes have different impact? I have seen that different colors make this imbalance more visible.

Definitely I KNOW now this is not our imagination nor any serious health condition. It is simply flickering, very subtle, some part of display and some sub pixels only, but it is flickering.

JTL

machala Mind if I rename this "Potential correlation between video timings and eyestrain"?

arturpanteleev

machala any serious health condition

but most people are not suffered from this…and only we are(a very small minority). How could your theory explain this?

machala

JTL Not at all of course. I fully realize the title is stupid 🙂

It's just after what I discovered I was really happy to finally understand what's going on, hence the title 🙂

But I would be more for "Potential correlation between video timings and screen flickering (=eye strain)" title. But here the word potential could be left out, it is capable of causing flickering, I've seen it.

There are some cases where temporal dithering is the issue (like recent Macs with certain color settings I've seen here), some specific applications like Google Chrome might be the same case (temporal dithering). But now I am very sure the vast majority of other issues discribed here is caused by this effect I describe here.

ryans

machala But now I am very sure the vast majority of other issues discribed here is caused by this effect I describe here.

Whenever you get the chance, would love to learn more, for my own research (and suffering).

machala

OK, so let me tell you the full story, it is not that long anyway.

Recently I came across an old game that is currently on offer, game that I played in the 90s, bought it to bring back some good old memories. After running the game on my laptop I immediately noticed the picture of the game itself was not stable, but what is more: after shutting the game down I noticed my laptop's screen was not "stable" either - not that bad as the game, but still it was not the "perfect" screen I've been using for the past years.

However I could not believe it could really "damage" the screen - OK, so it's using temporal dithering I thought (as we all usually say here) and well, what could it do to the screen? But the screen was not OK and I was again testing the game several times to see if I am just imagining things (which as I later learned was making it only worse).

However it was weird that such a game run in an emulator would be using temporal dithering. I have always thought that video timing could have some impact so after many years I finally started looking into NVidia timing settings and tried some of the other timing algorithms. And to my surprise the screen started flickering and it was getting worse and worse. And it stayed like that even after removing the new timing and reverting all the changes back - obviously what happened was that some subpixels did not have their inversion properly timed and parts of the image started to be burned into the screen matrix and most of the screen was heavily flickering. Although the screen looked severely damagedit started to recover slowly as the pixels were no longer stressed by one polarity only. Burned in images disappeared and flickering was getting better. When it reached only tiny, almost unnoticeable flickering that mataches exactly the symptoms I usually get from screens. it was exactly that picture, that feeling. This is the state the screen is in now. I can see it's not alright, but noticeable flickering is gone.

Additionally it confirms that the game above running in full screen definitely impacted the screen due to incorrect timing - every fullscreen application is capable of setting refresh rate from scratch. The effect was very similar to what I saw with changed nvidia settings, of course with much smaller effect. And what I saw in that game was again exactly what I am used to when recent video cards are "unacceptable" for me. The picture is somehow unstable. It's like the picture is there and not there at the same time.

ryans

machala so after many years I finally started looking into NVidia timing settings and tried some of the other timing algorithms

Thanks for sharing! Is this some NVIDIA settings? I don't use NVIDIA but a screenshot could be useful 🙂

machala Burned in images disappeared and flickering was getting better.

Just wondering, is this an IPS or TN or OLED panel?

machala

ryans

It is an IPS laptop panel.

I can't show you a screenshot as I don't want to initiate creation of this custom resolution again (for obvious reasons) - unfortunately this part of the NVidia control panel behaves a little bit strange.

It is in NVCP, Change resolution, under the resolution list click on customize and then create your own resolution. This allows you to build a custom profile for resolution, refresh rate as well as related timing.

However I can't say changing timing here solves the issue on setups where you have the problem, I tried on other systems and it does not fix it for me, but trying different algorithms does change the "feeling". Perhaps if we knew exact meaning of the numbers we could set it up manually… or some part of the timing is just built-in and you can't change it. But the point of the whole post is that I now see this timing as the main source of all the issues I am experiencing. You need to see it to be able to say that I guess.

Hazard

Coincidence or not, I'm testing in the last days a similar theory. In my quest to find something bearable for my eyes, I have bought a new laptop (TN), and the screen seems bearable so far (5 days of testing). But the refresh rate is terribly low (60Hz, also because the screen response time is quite bad) so I was trying to raise the refresh rate with the CRU software.

Turns out, I have modified a 1080p profile in the software that have the wrong polarity (positive for Vertical instead of negative), the screen worked fine but in the next minutes and hours I started to have the same feeling that I have with any other screen I have (all IPS, except for the new laptop). After looking into the settings I realize the difference between the stock settings and the custom profile, so I tried to fix it. I felt relieved a few moments later but was not enough.

Then I replicated all the stock settings except for the refresh rate into a new custom resolution. I have been using it in the last 2 days, I would test for more time before posting here, but after seeing this topic I could not resist.

Also, I applied the laptop settings to my monitor (Gigabyte G24F) about 12h ago, it's working fine and seems easy on my eyes than before, but still not good as the TN laptop. I'll continue testing for a few days more, but if this is not all placebo effect, I would risk saying that those reference numbers are really helping but not perfect, maybe because they are just from a random laptop that is not perfect on my eyes either.

If you are willing to try, please back up your files and settings

*Please turn off Freesync/Gsync before doing this, otherwise it may fail. You can turn it back on after you're done.*

This can be easily done through the AMD driver (if you have an AMD graphic card/APU): Open the "AMD Radeon Software" > Click on the gear icon at the top right > Click on Display > Scroll down until "Display specs" and expand it > Save you original parameters in case something goes too wrong > On the right side, click on "Create New" next to "Custom resolutions" > Enter the new parameters and save it.

Through CRU (Custom Resolution Utility - Please check the developer's website for more details and double-check everything, something may go wrong, be aware of the issues you may cause): Open the app > Choose the monitor you want to try (active) > just below on "Detailed resolutions" click on the "add" button > Choose "Manual" on Timming > Fill up with the desired parameters > Click Ok (2x) > Restart the video driver or the PC

My "good" parameters:

https://imgur.com/BwmFVAa

ryans

Hazard So you can manually set the "polarity"?

Hazard

ryans

Yes, kind of, I think. So far so good, the experiment still holds up, it looks easier on the eyes and no issues with my external monitor that I applied the settings to.

karut

Hazard what would be the equivalent settings for a resolution of 2560*1440?

Hazard

karut

Unfortunately, I can't answer that, as my "good sample" is 1080p native. But maybe if this theory holds up through other users testing it, then someone with a different resolution (from a good setup) may share their good parameters too. Even for 1080p, it might have something better out there.

Deepak

Hazard

I have an Asus G752VT laptop (i7-6700HQ, GTX 970M Nvidia GFX) from 2016 with a 17.3inch 75hz IPS screen that I am totally comfortable with.
Then, I bought this Asus EyeCare Monitor VA24DQ which is a 24" FHD 75hz monitor.
So the monitor has the same resolution and refresh rate as my laptop, but here I get dizzy and headachey in 1-2hrs of usage.

So how would I go about replicating my perfectly fine laptop display config onto my external Asus monitor?
I just need to install the CRU utility and go from there?
Is it straight forward?

tfouto

Deepak What OS do you use?

Hazard

Deepak

Yes, you would have to copy the same parameters I show in my screenshot from your good setup and then create & apply a new custom resolution with those same settings on your external monitor.

If the Nvidia software doesn't have an option for this, I suggest you the CRU software.

*Please turn off Freesync/Gsync before doing this, otherwise it may fail. You can turn it back on after you're done.*

Deepak

tfouto
MS Windows 10 Home 10.0.19044 Build 19044

Deepak

Hazard
Thanks for the instructions.
I tried copying the info from my good laptop screen to the external Asus monitor.
I still get quite dizzy tho unfortunately (even with the polarity changed to +/-, and the other settings).

karut

arturpanteleev Doesnt that apply to all theories on this board? Probably some variation in brain function that only affects a small population (lower threshold in processing flicker as movement, inability to compensate for it), maybe in combination with some binocular vision dysfunction. Perhaps think of it like the also relatively small group of those idiopathic epilepsy whose nerves are more easily "overexcited" and an even smaller subgroups of those affected are sensitive to flicker as a trigger for a seizure.

alexdonskih

arturpanteleev To be honest I don't think that only a very small minority is affected. In fact I strongly believe that the problem is more major, but many people just don't realize it as a problem. For example I can explain the huge popularity of OS dark themes with nothing than the fact that dark theme reduces flickering (true for PWM on AMOLED for example). Lots of people have never used older Windows (Even older builds of Windows 10) and they have never experienced non-flickering displays and OS. So they accept as a fact that their eyes get tired quickly from computer and practice that bullshit techniques like 20-20-20, enable nigh shift, wear yellow glasses etc. I have been staring at computer screens for hours since the beginning of 2000-s and have never ever experienced any kind of eye strain until I have updated to latest Windows 10 and to MacOS Monterey on my Macbook last year.

Hazard

Deepak

Thanks for testing, this can be somewhat of a placebo in fact, or help/make it worse a little.