Problem with Adaptive\GSync and Black Frame Insertion

Talk about NVIDIA G-SYNC, a variable refresh rate (VRR) technology. G-SYNC eliminates stutters, tearing, and reduces input lag. List of G-SYNC Monitors.
mamenewb100
Posts: 6
Joined: 24 Feb 2021, 22:02

Problem with Adaptive\GSync and Black Frame Insertion

Post by mamenewb100 » 24 Feb 2021, 23:17

Hello, First post in here. Everybody seems stumped on this. I've narrowed down my problem being directly related to the use of Adaptive Sync\Nvidia Gsync on my Omen 27i 165Hz monitor (set at 120Hz to double 60Hz) in combination with Black Frame Insertion in emulation programs like RetroArch.

The issue is after literally only running a game for minutes, I get what looks like Burn-in left on the monitor for about 20 minutes after playing. I've researched this and found the correct term is 'Image Retention'. This is known to be a temporary effect on some LCD monitors from being on one screen too long. However as I said this happens literally within ONE MINUTE. But it ONLY happens when Adaptive Sync is enabled on my monitor along with Black Frame Insertion. Another strange thing that happens is when I change the response time on my monitor it actually gets BRIGHTER, when normally it does not effect brightness at all. Adaptive Sync works fine in any other game. And when I have Adaptive Sync OFF and Black Frame Insertion ON I also have no Image Retention problems but then of course I get flickering because it's not syncing up with the frames properly.


I'm wondering if this is a known problem or my monitor is possibly faulty. I tend to doubt it since I haven't really noticed any problems other then what I mentioned above. I've attached images to give you an example. Thanks! Any help would be awesome.
Attachments
sf2t.jpg
sf2t.jpg (1.55 MiB) Viewed 7102 times
20210224_191325[1].jpg
20210224_191325[1].jpg (1.88 MiB) Viewed 7102 times

User avatar
RealNC
Site Admin
Posts: 3737
Joined: 24 Dec 2013, 18:32
Contact:

Re: Problem with Adaptive\GSync and Black Frame Insertion

Post by RealNC » 25 Feb 2021, 01:52

It's a known problem. I also got this when I tried BFI in RetroArch (IPS panel here,) and I've seen other people mention it too.

I don't know if it's dangerous for the panel or not.
SteamGitHubStack Overflow
The views and opinions expressed in my posts are my own and do not necessarily reflect the official policy or position of Blur Busters.

mamenewb100
Posts: 6
Joined: 24 Feb 2021, 22:02

Re: Problem with Adaptive\GSync and Black Frame Insertion

Post by mamenewb100 » 25 Feb 2021, 07:20

Thanks for the response. Found very little info on this in a search. It's a bummer because black frame insertion does pretty much eliminate blur and makes all games look better. Unfortunately the image retention is bad enough that you can see it while playing any game and kind of defeats the purpose of using it.

There is something about the way that BFI is implemented that developers of Adaptive Sync technologies did not anticipate. Or maybe it just isn't compatible with the way these technologies work. I've heard of ways to reduce motion blur even at Native refresh rates but involves the use of technology built-in to certain monitors but mine is only G-Sync compatible and has no such option. Oh well. I can only hope a solution or update happens in the future if enough people make others aware of the problem.

User avatar
Chief Blur Buster
Site Admin
Posts: 11647
Joined: 05 Dec 2013, 15:44
Location: Toronto / Hamilton, Ontario, Canada
Contact:

Re: Problem with Adaptive\GSync and Black Frame Insertion

Post by Chief Blur Buster » 26 Feb 2021, 04:53

This is the best explanation thread:

Why Image Retention / Burn-In Sometimes Occur On LCDs

I am crossposting it here.

You can make it immune by running an odd-divisor BFI. You need a 180Hz or 300Hz display to do it though. Most 240 Hz monitors can do 180 Hz BFI. Besides, BFI looks better at 180 Hz than at 120 Hz.
Chief Blur Buster wrote:
22 Sep 2020, 21:38
Image Retention ("Temporary Burn-In")
From Temporary Static Electricity Buildup In Pixels


Flicker patterns such as:
- Emulator black-frame insertion
- 3D-glasses software
- Certain motion tests (including but not just TestUFO's Sync Track)
- Anything that does exactly a half-Hz or quarter-Hz flicker with no dropped frames for a sustained period

Can create temporary LCD image retention. It's a static-electricity behavior when a flicker goes in sync with the positive-negative voltage inversion algorithm, and creates this inversion-related image retention.

This is temporary and you just display video full-screen, or some other thing that really exercise the whole screen -- e.g.
This gets rid of the per-pixel static electricity buildups.

You also get the same problem in anything that flickers pixels in-phase with the positive-negative voltages of the LCD inversion algorithm.

https://www.google.com/search?q=techmind+LCD+inversion

Voltages inverts to try to balance the electricity buildup in the panel, but flicker patterns that go in sync with this, can cause a voltage unbalance = static electricity build up, as an LCD pixels can accidentally behave as capacitors.

The layered nature of an LCD unfortunately creates unavoidable capacitance effects that interfere with operation.

Image

Modern LCDs try to avoid this by using spatial and temporal alternating voltage (positive voltage, then negative voltage, then positive voltage, then negative voltage, and so on)

Image

It's often in a chessboard pattern spatially, which sometimes produces an inversion artifact. Normally this is invisible when the positive voltages are perfectly balanced with negative voltages. But the voltage balancing is not always perfect, so you see this:

Image

However, this is also done temporally -- the voltages swap (like an inverted chessboard) at the next refresh cycle.

Now, if you flicker perfectly (at half Hz), then pixels that gets the "higher voltage" (different brightnesses = different voltages) are always getting negative voltages or always getting positive voltages = static electricity buildup = image retention.
  • The chessboard artifact is the quirk from spatial component of the inversion algorithm.
  • The image retention is the quirk from temporal component of the inversion algorithm.
Not all screens use the same inversion pattern / inversion algorithm, so some LCDs don't get image retention easily, while others do. In an ideal world, we would be now using error-diffusion temporal dithering or some randomized dithered inversion algorithm, to be fully immune to all material. But in the real world, the panel makers don't do that, and just settle for simple patterned inversion algorithms which are easier to do at high refresh rates (complex invisible inversion processing can be costly). Historically, this is why inversion patterns often have showed up more commonly on high-Hz monitors -- for example, the early ASUS VG278HE (one of the first-ever 27 inch 144Hz monitors) was particularly known for its chessboard artifact during 3D glasses operation.

Thusly, I am not surprised that the world's first panels of a specific refresh rate has some "inversion-related quirks". Every single 240Hz 1ms IPS panel currently has this pixel-as-capacitors quirk at the moment, that only shows up with sustained exact-Hz flicker patterns. As time passes, I'm sure this will improve, with improved inversion algorithms.

Since the pixels have inadvertently behaved like capacitors because of the layered nature of an LCD worked against proper pixel operation. Now you got to drain the charge -- the built-up static electricity stored in the pixel.

Draining the pixel static electricity charge is best done by playing highly active video material. If you want to erase image retention faster, use full screen random-color flashing (fully randomized colors).

HOW TO FIX FIX: Play highly active fullscreen video or animation.
Play pixel fixer software https://www.youtube.com/watch?v=39HUG7QrQi8 (play at 2X speed, it's too slow)
Or simulated analog TV noise https://www.shadertoy.com/view/tdXXRM -- this usually erases image retention faster.
I prefer simulated analog TV noise as a quick burn-in eraser.
Make sure to click the full screen button

While a technology quirk, it is not an RMA defect at all.

Emulator/RetroArch BFI: Use an odd divisible Hz such as 180 Hz or 300 Hz

Doing this techniques is 100% immune to these problems.

If you want to keep using emulator BFI, use the new 180Hz BFI feature now found in some emulators, a 3-cycle flicker pattern never produces image retention on majority of monitors -- RetroArch is building this feature in now.

NOTE: Some old LCDs had inversion-algorithms bugs (firmware bugs or hardware bugs) that caused burn-in even with stationary images, especially at certain picture settings. Also, certain manoevers such as overclocking an LCD may cause inversion algorithms to fail, creating a more image-retention-sensitive LCD. You will immediately know if image retention occurs with stationary images instaed of moving images.
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

Image
Forum Rules wrote:  1. Rule #1: Be Nice. This is published forum rule #1. Even To Newbies & People You Disagree With!
  2. Please report rule violations If you see a post that violates forum rules, then report the post.
  3. ALWAYS respect indie testers here. See how indies are bootstrapping Blur Busters research!

mamenewb100
Posts: 6
Joined: 24 Feb 2021, 22:02

Re: Problem with Adaptive\GSync and Black Frame Insertion

Post by mamenewb100 » 26 Feb 2021, 20:26

Really great writeup. Thanks! That seems to make sense since I do not experience the screen retention with BFI when GSync is not enabled. Because it needs to be an exact doubling of refresh rate for the issue to occur. I was looking at a 240Hz Display but figured it would overkill. Could still return this monitor even though I love it for everything else... Aargh. Why does technology have to be so complicated. :D

STOPchris
Posts: 129
Joined: 13 Jan 2020, 18:23

Re: Problem with Adaptive\GSync and Black Frame Insertion

Post by STOPchris » 26 Feb 2021, 22:25

I stopped using BFI when TN panels were first coming out with it. The reason for me to stop using it is the lag, most monitors have artifacts with it on, and headaches. Count yourself lucky, the Acer monitors tend to have this issue while NOT using BFI as well.

mamenewb100
Posts: 6
Joined: 24 Feb 2021, 22:02

Re: Problem with Adaptive\GSync and Black Frame Insertion

Post by mamenewb100 » 27 Feb 2021, 12:16

STOPchris wrote:
26 Feb 2021, 22:25
I stopped using BFI when TN panels were first coming out with it. The reason for me to stop using it is the lag, most monitors have artifacts with it on, and headaches. Count yourself lucky, the Acer monitors tend to have this issue while NOT using BFI as well.
I had great success using BFI on CRT monitors. Not so much on IPS LCD monitors. Some games flicker even with GSync ON and some work flawless. Only reason why I'm bothering is because low refresh rates are just not fast enough to get smooth motion on a 5ms response monitor. Overclocking the response just causes inverse ghosting. You are saying BFI causes more input lag? Because I thought it was less?

Anyways I'll probably give up on the idea of BFI unless there is a way to overclock my refresh rate from 165Hz to 180Hz. I think the monitor is already a 144Hz that was overclocked to 165Hz from the factory though. Would be worth a shot just for the sake of Science. ;)

mamenewb100
Posts: 6
Joined: 24 Feb 2021, 22:02

Re: Problem with Adaptive\GSync and Black Frame Insertion

Post by mamenewb100 » 27 Feb 2021, 12:57

In case you're wondering why I used BFI on a CRT.. it's because I had a 480p 60Hz CRT Monitor and needed BFI for 120Hz to downscale the display to Native 240p Arcade Resolutions. Kind of a backwards technology hack. But it worked flawlessly. ;)

STOPchris
Posts: 129
Joined: 13 Jan 2020, 18:23

Re: Problem with Adaptive\GSync and Black Frame Insertion

Post by STOPchris » 27 Feb 2021, 14:10

mamenewb100 wrote:
27 Feb 2021, 12:57
In case you're wondering why I used BFI on a CRT.. it's because I had a 480p 60Hz CRT Monitor and needed BFI for 120Hz to downscale the display to Native 240p Arcade Resolutions. Kind of a backwards technology hack. But it worked flawlessly. ;)
I have always found that a good 240Hz monitor is overall better than BFI.

mamenewb100
Posts: 6
Joined: 24 Feb 2021, 22:02

Re: Problem with Adaptive\GSync and Black Frame Insertion

Post by mamenewb100 » 27 Feb 2021, 22:25

STOPchris wrote:
27 Feb 2021, 14:10
mamenewb100 wrote:
27 Feb 2021, 12:57
In case you're wondering why I used BFI on a CRT.. it's because I had a 480p 60Hz CRT Monitor and needed BFI for 120Hz to downscale the display to Native 240p Arcade Resolutions. Kind of a backwards technology hack. But it worked flawlessly. ;)
I have always found that a good 240Hz monitor is overall better than BFI.
I'm not in disagreement that having a fast refresh in anything is better. BFI is pointless on PC games since you can use pure framerates to eliminate any blur or ghosting. But that's not how emulated hardware works. Most of the old emulated hardware I run ran at 60Hz or less with only 60FPS max. 60 Hz is not smooth on modern IPS monitors. No option for unlimited FPS to match your refresh rate, unlike every new computer game. So you only get 60Hz refresh speed, even if your monitor is capable of 1000Hz. If you ran a 60FPS emulated game at 240FPS, the audio and video would run at 4 times the speed it's supposed to. Fast Pixel Response times are the ONLY way to overcome low refresh rates without using tricks like BFI. See what I mean?

When I get my hands on a true Sub-1ms IPS display in the future, I certainly won't bother with any gimmicks that aren't necessary.

Post Reply