Ensuring a flicker free gaming experience

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Ensuring a flicker free gaming experience

Post by link » 07 Oct 2017, 23:46

Hi, wondering if anyone can help. I'm looking for a flicker free and temporal dither free gaming experience. Firstly I understand flicker can be caused by PWM. So removing that is a easy one. Where it gets complicated is that is it true that at 60 HZ refresh rate there is flicker regardless? Here are a couple of sites that talk about this not sure if I understand it correctly. Do we need 800hz displays?! https://www.nature.com/articles/srep07861
http://www.conradbiologic.com/articles/ ... ckerI.html

Secondly temporal dithering from what I understand can introduce flickering. So if a true 8 bit panel is used that would mean no temporal dithering? But aside from the panel being used I hear that the graphics cards can enable dithering by default. Not only ATI chips and Intel integrated chips but that even nvidia geforce chips from 900 series and onwards enable dithering. I hear specifically the Playstation 4 and Xbox have dithering on by default. The Nintendo switch is a question mark since it uses older nvidia Tegra and maxwell based chip.

My questions then are, is there anyway to ensure temporal dithering is off and avoid any flicker? Is there any type of display be it oled to lcd to plasma or projector combined with a source be it a gaming console or PC setup that would ensure a flicker free experience.

Speaking of oled and plasma since they are self emitting displays that don't use back lights would that negate any flicker or dithering problems? I hear plasmas heavily dither and flicker using pwm but I suspect they aren't a issue since it probably happens at a high enough hz.

Thanks for any help.

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Re: Ensuring a flicker free gaming experience

Post by Sparky » 08 Oct 2017, 04:26

Your best bet is a high refresh rate monitor with a constantly on backlight(any blur reduction features turned off). If you're really that sensitive, you'll want to make sure the backlight dimming doesn't cause PWM artifacts. Inversion artifacts can also cause flicker. You probably don't need to worry too much about temporal dithering, if anything that should look more like white noise than flicker, and it's not easy to avoid it.

If possible, see the monitor in operation before buying it.

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Re: Ensuring a flicker free gaming experience

Post by RealNC » 08 Oct 2017, 09:36

Dithering is used on all panels, 8-bit or not. However, as Sparky said, dithering doesn't flicker.

Inversion artifacts can flicker. This is more prominent on TN panels. IPS panels have much less issues with that.

Other than that, if the monitor is "flicker-free" (marking term for non-PWM), and you're not using blur reduction (like ULMB, LightBoost, etc.) and your panel is not prone to inversion issues, then there't not going to be any flicker, either at 60H or any other refresh rate.
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Re: Ensuring a flicker free gaming experience

Post by Chief Blur Buster » 08 Oct 2017, 14:17

link wrote:Speaking of oled and plasma since they are self emitting displays that don't use back lights would that negate any flicker or dithering problems? I hear plasmas heavily dither and flicker using pwm but I suspect they aren't a issue since it probably happens at a high enough hz.
Refresh rate is not necessarily a source of flicker
On plain continuous-illumination (PWM-free LCDs), a static image doesn't flicker at all. That said, lowness of a refresh rate causes stutter which is a form of an edge-flickering artifact that bothers many people -- e.g. http://www.testufo.com even on iPhones and iPads at the 30fps or 15fps UFO, the UFO will look like it's vibrating (edge flicker). That's simply stutter, but the flickeriness of stutter can bother some people immensely. The only good solution to that is extremely high frame rates at high refresh rates (e.g. 120 frames per second plus)

First, determine what your flicker tolerance level is
Are you saying you're not bothered by plasma? Flicker isn't always harmful, depending on the person -- a precise one-flash-per-refresh is used by strobe backlights such as ULMB. While many peoples' human eyes have strain from flicker, we have other people who get eyestrain from motion blurring. This is a situation where certain people don't mind things like plasma flicker or CRT flicker (At sufficiently high frequencies, above any painfully-low flicker threshold). You should be aware that newer gaming monitors have an optional mode (e.g. "ULMB") that intentionally uses a special synchronized flicker to emulate a CRT or plasma -- to eliminate LCD motion blur -- see Motion Blur Reduction FAQ.

PWM dimming versus intentional blur reduction (ULMB is a special synchronized PWM)
Sometimes it gets complicated. There are people here who get eyestrain from PWM dimming, but doesn't get eyestrain from ULMB (NVIDIA Ultra Low Motion Blur). This is probably because that the pleasant clarity of motion of strobing (proper one-flash-per-refresh PWM at sufficiently high refresh rates)

Do you get eyestrain/pain from flicker?
Ask yourself, not just ask others. Are you currently getting eye pain? And you know it's definitely coming from PWM rather than a different cause? While a lot of cases are genuine, the "chasing the wild goose" effect sometimes happens -- sometimes the strain actually came from a different source (e.g. too bright, or too much blue, or discomfort from stutter, etc).

Are you sensitive to temporal dithering?
DLP, plasma and LCD FRC (6bit, etc) all use forms of temporal dithering in different ways, and are at very different levels of visibilities on different panels. Also, FRC artifacts should not be confused with inversion artifacts (e.g. horizontal/vertical line/checkerboard pattern flicker effects) as that's a different cause of LCD flicker that's completely different from temporal dithering. If you're annoyed by inverison flicker, get an IPS LCD instead of TN LCD -- you may get more motion blur but you will get less inversion/FRC/whatever LCD-related flicker artifacts. One of those 165Hz IPS G-SYNC LCDs could be just what the doctor ordered.

Towards Holy Grail
If you want as completely flicker-free motion experience, you want to get as high framerates as possible. Doubling your framerates will halve your display motion blur, and to get less motion blur than 60fps@60Hz, you will need a 120Hz or higher monitor. Obtaining a variable refresh rate monitor and getting a powerful GPU (to keep frame rates triple digit), will eliminate the edge-flickering-effects of stutter. For people ultra-sensitive to flicker and stutter, this is my recommendation: 240Hz G-SYNC or FreeSync.

For options, see Official List of Best Gaming Monitors.
The good news is that many modern monitors are flicker-free PWM-free in non-strobed mode. You've got a high Hz. You've got variable refresh rate. And you've got completely optional blur reduction (ULMB modes). By having a lot of options, you can have multiple modes that satisfy your problems.
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Re: Ensuring a flicker free gaming experience

Post by link » 08 Oct 2017, 14:19

Okay thanks guys. So, what do you think about the two articles that I linked above, do you think that they are just BS?

Also, what do you guys think about the Samsung C24FG70? Would it suffer from inversion issues? This monitor is a VA panel, I hear TN panels only suffer from this issue. If this is not a good monitor, could you guys please point me in the right direction towards a flicker-free, inversion-free, true 8-bit gaming monitor primarily for gaming console use? Preferable size would be from 23" to 27".

On a side note, would plasma technology or O-LED technology be a better option for flicker?

Thanks for all the help.

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Re: Ensuring a flicker free gaming experience

Post by Chief Blur Buster » 08 Oct 2017, 14:35

link wrote:Okay thanks guys. So, what do you think about the two articles that I linked above, do you think that they are just BS?
They're accurate but those do not help with "which monitor should I get" shopping.

Not bullshit, but it's apples versus oranges. It's like trying to diagnose a broken bone using a thermometer. Or educating me about baseball by telling me hockey rules. Or trying to fix a car using a cake icing bowl. Wrong tool for the wrong job. Ask yourself: Are you bothered by flicker? Are you seeing banding/line artifacts? Is a flicker artifact annoying you? :)

That said, the Nature "possible to perceive up to 500Hz" is quite correct.
And it is possible to perceive up to 10,000Hz indirectly via phantom array effects.

Image
(From lighting industry research but also applicable to display PWM-dimming too)

Also, great demos of seeing artifacts caused by Hertz limitations:
http://www.testufo.com/mousearrow
http://www.testufo.com/persistence

These problems don't even disappear at 500Hz. Yet. It's still human-beneficial to keep raising monitor Hz, even despite the "diminishing points of returns".

We tested a prototype 480Hz LCD, and we were still able to tell apart 60Hz vs 120Hz vs 240Hz vs 480Hz.

One of the 4 different ways we were able to tell them apart:
Image

Today, there's no jack-of-all-trades screen that passes everybody 100% perfectly. There will always (at this moment) be screens that some humans are happier than others, and a different screen that the other humans are happier with. What I'm trying to say, there's currently no single-screen that satisfies everyone.

Example1: The most completely flicker-free screens with best colors, will often have more motion blur for example.
Example2: The fastest screens with least motion blur often have worse colors, so you have to trade-off or pick-your-poison or compromise.
Example3: Stutter sensitivity versus color sensitivity versus brightness sensitivity versus flicker sensitivity versus motion blur sensitivity. No monitor can solve all the above, all simultaneously, all at the same time, perfectly. So a different model might solve 3 out of 5 of the above.

Therefore, I cannot recommend anyone a single "perfect" screen that will satisfy their eyes. That perfect screen, just, simply does not exist. In fact, 8% of human population is color blind, and a bigger than 8% of population while not color blind are "less picky than usual about colors" -- being more, for example, bothered by flicker. Other humans, however, are not bothered by flicker at all, and totally prefer seeing less motion blur (closer to plasma or CRT quality).

That said, unsynchronized PWM for dimming is quite evil and is unnecessary. (That's to avoid dissing properly synchronized one-pulse-per-refresh PWM that's used for motion blur reduction, ala plasmas & CRTs). That said, synchronized strobing is currently a workaround (fairly good, if strobing at sufficiently high refresh rate, just like a high-Hz CRT or plasma) since simultaneously "blurless+flickerfree" requires currently unobtainium Hertz to have perfectly sharp blurfree motion clarity without the use of properly synchronized strobe as a means of motion-blur-reduction.

The workaround of doing the (usually) beneficial blur-reducing flicker is how NVIDIA ULMB / LightBoost, as well as BenQ/Zowie DyAc and ASUS ELMB works. So there's bad unsynchronized PWM-dimming and good blur-reduction PWM (but some people still get eye strain from the latter). It really depends. The good news is you can turn on/off ULMB (or whatever mode) as a user preference. When you turn off ULMB, you're in a completely flicker-free mode on modern newer gaming monitors but you have the problem of lots of motion blur. When you turn on ULMB, you have flicker (like a 120Hz CRT, so it's not bad) but the motion blur is gone. Sometimes one or the other is the lesser of evil for a specific individual.

Anyway:

So the important question is to ask yourself: What current problems are you having with current monitor technology? Are you seeing a specific artifact that is currently bothering your eyes? I'd be happy to help out here; just need more information in the correct apples-versus-apples ballpark -- tell me problems you're seeing these days, today, that you see in SCREENs (nothing else, please) and I can help diagnose a possible solution of a screen that might help your problem you see with a specific screen. What currently bothers you today about displays? I'll try my best to help find you the most ideal display that pleases your eyes the most.

There are many sources of flicker artifacts and other display motion artifacts.
  • Inversion flicker artifacts (Fine texture artifacts flickering in solid colors; lines, plaid, crosshatch, etc)
    http://www.testufo.com/inversion
    http://www.lagom.nl/lcd-test/inversion.php
    http://www.techmind.org/lcd/index.html#inversion
    This is a bigger problem with TN panels than IPS panels
    -
  • FRC flicker artifacts (noise similar to an analog TV channel with no signal).
    Usually fainter flicker than inversion artifacts. Using higher Hz will make this harder to notice than plasma/DLP dithering. Solution is 120Hz+
    -
  • PWM-dimming flicker artifacts (serrated-edge artifacts during motion), http://www.testufo.com/ghosting and has a PWM-dimming pursuit camera photograph at LCD Motion Blur 101
    Image
    -
  • Stutter artifacts (low-frame-rate motion can look very edge-flickery), http://www.testufo.com/stutter (try out all of them)
    Stutter sensitive people should consider G-SYNC and FreeSync
    -
  • Blur artifacts tied to frame rate limitations on flicker-free displays (common sample-and-hold LCDs), http://www.testufo.com
    Image
    -
  • Color artifacts, viewing angle artifacts, etc.
    -
  • Solid-screen inconsistency artifacts (IPS glow, VA gamma nonuniformities, etc)
    -
  • Other artifacts you see
You're welcome!
Apologies I have to ask for more information (from the correct ballpark) to try and help solve the problems you have with today's screens.

Generic Desktop Monitor Recommendation for flicker-sensitive people who's also bothered by stutter
Generic advice is to get a 144Hz or 240Hz LCD monitor with VRR capability and a powerful GPU, if you want to have the smoothest flickerfree images with the least motion blur without resorting to strobing. However, this makes some grave assumptions (e.g. that you weren't sensitive to minor LCD inversion artifacts common to TN panels)
-- Modern LCDs have a PWM-free dimming mode, so no flicker worry
-- Variable refresh rate capability will further minimize stutter (and the erratic edge-flicker effects that stutters can produce).
-- Higher framerates will eliminate edge-flicker-effects of stutter
-- Higher framerates will minimize motion blur

However, this means TN, which has somewhat poorer colors and viewing angles, and the potential appearance of possible inversion artifacts (a slight fainter flicker that appears sometimes on certain TN panels). The problem is, I'm not sure what kind of flicker artifact you're currently sensitive to, as FRC is not the only source of flicker. If you're also sensitive to inversion artifacts and you can tolerate other IPS quirks such as IPS glow, then the next generic recommendations fall through to getting a 165Hz IPS monitor. You will get more motion blurring, but still far less motion blurring and stutter visibility (less edge-flicker effects) than 60Hz.

Options: Available Desktop Monitors: 240Hz TN and 165Hz IPS

However, if you can express your problems with today's screens, I'd love to hear them out, and can try to give a recommendation. And if you're getting a screen for desktop use or television use, etc.
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Re: Ensuring a flicker free gaming experience

Post by Sparky » 08 Oct 2017, 17:03

link wrote:Okay thanks guys. So, what do you think about the two articles that I linked above, do you think that they are just BS?
Not BS, but they're not answering the question I think you're asking. If you're looking at a static image, you care about flicker fusion threshold which for most people is somewhere in the 75~100hz range. When you're looking at a moving image, or moving your eyes across a stationary image, you have the choice either stroboscopic artifacts or motion blur. To get rid of both, you need some truly absurd refresh rates, which we won't be seeing for quite some time, even 500hz won't get rid of all motion artifacts. Something as simple as moving the mouse cursor across the screen with neither motion blur nor stroboscopic stepping would take a refresh of several khz.
On a side note, would plasma technology or O-LED technology be a better option for flicker?

Nope. All the OLED desktop displays you see are just OLED backlit LCDs, and have all the same flicker characteristics of LCDs backlit with inorganic LEDs, and good luck finding a CCFL backlit panel theses days. Actual LED matrix displays have so far only made it to cell phones. And plasma is a low persistence technology, so you will get stroboscopic artifacts, assuming you can even find one.

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Re: Ensuring a flicker free gaming experience

Post by Chief Blur Buster » 09 Oct 2017, 16:10

Sparky wrote:Nope. All the OLED desktop displays you see are just OLED backlit LCDs, and have all the same flicker characteristics of LCDs backlit with inorganic LEDs, and good luck finding a CCFL backlit panel theses days. Actual LED matrix displays have so far only made it to cell phones. And plasma is a low persistence technology, so you will get stroboscopic artifacts, assuming you can even find one.
Unless, of course, he's looking for a television (HDTV) instead of a desktop monitor.
(I'll wait for link to answer that question)

The Samsung C24FG70 is a pretty good desktop monitor that meets "Better Than 60Hz" requirements.
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Re: Ensuring a flicker free gaming experience

Post by link » 10 Oct 2017, 14:58

First of all guys I really want to thank everyone in this thread, I really do appreciate you guys clearing up and putting my mind at ease about a lot of this. I wasn't even aware about PWM, dithering and inversion etc till I randomly came across it on the web with sites holding flicker responsible for eyestrain and headaches. I even came across stuff believe it or not saying flicker even if you can't see it, subliminally your brain can and it causes health issues puts strain on your nervous system etc. Some people even said it causes hypnosis lol. I was born with a eye condition so got a little worried but thanks everyone for clearing up my misconceptions. Ultimately I'm just looking for a display whichever kind it maybe that's easiest on eyes. Take whatever preventative measures I can to ensure there isn't any or minimize negative impact on health.

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Re: Ensuring a flicker free gaming experience

Post by link » 10 Oct 2017, 15:27

Chief Blur Buster wrote: Are you saying you're not bothered by plasma?
Are you saying you're not bothered by plasma?
No, I am particularly bothered by Plasmas. I have a Panasonic ST50. Though I have come to learn that plasmas use PWM and so I became concerned. I am just in search for a display whether it be OLED, Plasma, LCD or even a projector if it mean easiest on eyes as I already was born with an eye condition and I do not want to exacerbate it.

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