PSA: GSYNC/VRR ON C9 OLED IS AFFECTING PICTURE QUALITY

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.
vmd12
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PSA: GSYNC/VRR ON C9 OLED IS AFFECTING PICTURE QUALITY

Post by vmd12 » 16 Mar 2020, 22:42

Try Call of Duty: Modern Warfare (2019). Go to HDR Calibration. The first test is Black Point. It asks us to move the slider until the logo at the middle is barely visible. With gsync/vrr enabled in nvidia control panel, even when the slider is moved all the way to the left, the logo at the middle is still very much visible. With gsync/vrr disabled, the logo disappears and we need to move the slider a few notches to the right to make the logo visible again. So my guess is gsync/vrr is raising the brightness of some near-black value (IRE5/IRE10). Please share this on Twitter to LG & Nvidia and some pro calibrators/reviewers so we can get this fixed soon.

P.S. Please read my post carefully before suggesting changing my tv settings. All settings are the same between 2 scenarios (gsync off vs gsync on) so the culprit here is gsync and gsync only.

Update: LG liked my tweet so that could mean they're aware of this and hopefully working for a fix.

Dmoney405
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Re: PSA: GSYNC/VRR ON C9 OLED IS AFFECTING PICTURE QUALITY

Post by Dmoney405 » 17 Mar 2020, 11:52

That's cool to know. I was thinking seriously of getting the c10s when they come out this year. I wonder if they will have the issue as well.

I'm curious if it lessens or worsens with refresh rate indicating some kind of white frame insertion, which I would have no clue why they would want that. Another thing may be that it is auto setting a game mode since the only thing you would ever need VRR for is gaming so they assume you would want faster response time as well. Since OLEDs have a bit of pixel delay coming from black (off) to white. By forcing the blacks to gray you can get a better pixel response time in dark scenes giving you less input lag and ghosting. So if you are using a normal mode with deep blacks and it forces a game mode you could see a large gamma shift. This can probably be tested if they have a documented game mode that reduces input lag. Swap from your usual mode to game mode without enabling VRR and see if if it does the same thing. Make sure it's documented for that purpose though, having a mode say GAME at the top could simply be just for color correction and not for latency of any kind and would not be a good test.

This is just a theory and is probably wrong but that's what I look into if I had one to play around with. If this is the case then I doubt you can fix it without firmware but it's just cool to try and figure out what's going on behind the scenes.

vmd12
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Re: PSA: GSYNC/VRR ON C9 OLED IS AFFECTING PICTURE QUALITY

Post by vmd12 » 17 Mar 2020, 13:22

Dmoney405 wrote:
17 Mar 2020, 11:52
Swap from your usual mode to game mode without enabling VRR and see if if it does the same thing.
I did. Everything in my original post was tested in game mode, regardless of whether vrr is enabled or not. So everything is the same, except vrr on/off.

Dmoney405
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Re: PSA: GSYNC/VRR ON C9 OLED IS AFFECTING PICTURE QUALITY

Post by Dmoney405 » 17 Mar 2020, 14:45

vmd12 wrote:
17 Mar 2020, 13:22
Dmoney405 wrote:
17 Mar 2020, 11:52
Swap from your usual mode to game mode without enabling VRR and see if if it does the same thing.
I did. Everything in my original post was tested in game mode, regardless of whether vrr is enabled or not. So everything is the same, except vrr on/off.
Okay, what about Truemotion and OLED motion? The LG has a BFI when Truemotion is set to user and OLED motion is on. Since asus is the only company that I know of that is using BFI+VRR at the same time I am under the assumption that LG does not allow both to be running simultaneously. Since BFI will significantly dim the screen this may heavily wash out the scene if it were calibrated with BFI in mind and it was suddenly disabled. So i'd take a look there just out of curiosity.

vmd12
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Re: PSA: GSYNC/VRR ON C9 OLED IS AFFECTING PICTURE QUALITY

Post by vmd12 » 17 Mar 2020, 14:52

Dmoney405 wrote:
17 Mar 2020, 14:45
vmd12 wrote:
17 Mar 2020, 13:22
Dmoney405 wrote:
17 Mar 2020, 11:52
Swap from your usual mode to game mode without enabling VRR and see if if it does the same thing.
I did. Everything in my original post was tested in game mode, regardless of whether vrr is enabled or not. So everything is the same, except vrr on/off.
Okay, what about Truemotion and OLED motion? The LG has a BFI when Truemotion is set to user and OLED motion is on. Since asus is the only company that I know of that is using BFI+VRR at the same time I am under the assumption that LG does not allow both to be running simultaneously. Since BFI will significantly dim the screen this may heavily wash out the scene if it were calibrated with BFI in mind and it was suddenly disabled. So i'd take a look there just out of curiosity.
Anything motion related is turned off. I never touch those settings.

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Re: PSA: GSYNC/VRR ON C9 OLED IS AFFECTING PICTURE QUALITY

Post by Chief Blur Buster » 17 Mar 2020, 15:33

Dmoney405 wrote:
17 Mar 2020, 14:45
Okay, what about Truemotion and OLED motion? The LG has a BFI when Truemotion is set to user and OLED motion is on. Since asus is the only company that I know of that is using BFI+VRR at the same time I am under the assumption that LG does not allow both to be running simultaneously. Since BFI will significantly dim the screen this may heavily wash out the scene if it were calibrated with BFI in mind and it was suddenly disabled. So i'd take a look there just out of curiosity.
OLED BFI doesn't wash out colors -- but it does reduce brightness. But if you were decreasing brightness to begin with in non-BFI, you may get (sometimes) indistinguishable image quality.

The mechanism of OLED strobing is completely different from LCD strobing. There's a method to add rolling-strobe to OLEDs that adds zero lag (+0ms for TOP, +0ms for CENTER, +0ms for BOTTOM), but not all OLEDs strobe in the same algorithm.

(Terminology Note: I tend to use "BFI" and "strobing" synonymously though sometimes they are labels of two different strobe algorithms, but I've seen the same technique use both labels, and BFI is not necessarily 50%:50% ON:OFF. Also, BFI is not always necessarily global, it can be rolling-shutter-style based in a rolling scan. It can be arbitrary percentages on some displays like 37%:63% or 92%:8% or whatever, while on others it is more granular such as 75%:25% or only limited to 50%:50%). Right now, on LG displays it is, alas, limited to 50%:50% though I hear newer panels coming out can do 25%:75% and 75%:25% too, at least at 60Hz refresh rate.
vmd12 wrote:
17 Mar 2020, 14:52
Anything motion related is turned off. I never touch those settings.
PSA for other readers:

Not all motion settings are interpolation related.
Not all motion settings add lag (BFI typically doesn't, but interpolation does).
Not all kinds of frame rate amplification technology is inherently bad.

Hollywood Filmmaker Mode (24p purist setting) is good for movies, but certain other motion settings do benefit gaming (especially at 120fps). Understanding and using motion settings correctly is key. Also OLED strobing is more lagless than LCD strobing, because it is rolling-window based. Right tool for right job. Readers, do not boilerplate-reject all motion settings you do not understand, and not all motion settings are laggy fake interpolation. Some are, but not all of them.

Read between lines when others on the Internet tell you "Don't Touch Motion Settings, They Add Lag" -- more qualification and context is required. On some displays there isn't good motion settings, but on yet other displays, some motion settings are very good for some things and does not create "fake frames" at all. Future displays will have even better motion settings.

Cheers,
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       To support Blur Busters:
       • Official List of Best Gaming Monitors
       • List of G-SYNC Monitors
       • List of FreeSync Monitors
       • List of Ultrawide Monitors

Dmoney405
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Re: PSA: GSYNC/VRR ON C9 OLED IS AFFECTING PICTURE QUALITY

Post by Dmoney405 » 17 Mar 2020, 17:17

Chief Blur Buster wrote:
17 Mar 2020, 15:33
OLED BFI doesn't wash out colors -- but it does reduce brightness. But if you were decreasing brightness to begin with in non-BFI, you may get (sometimes) indistinguishable image quality.
I don't mean that BFI will wash out colors, my theory was that calibrating your screen while BFI is enabled may require you to increase the gamma or brightness to achieve a neutral scene since it darkens the image, then once the setting is disabled it may wash out colors because the screen will now be brighter after disabling it which may no longer be a normal gamma curve with the same calibration in effect. Since the CoD brightness slider is essentially a gamma curve I thought it was an unlikely possibility.

I thought most people use the motion things on OLEDs because they stutter when they display 24fps media. I don't have one, just stuff I've read so I could be super wrong.

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Re: PSA: GSYNC/VRR ON C9 OLED IS AFFECTING PICTURE QUALITY

Post by Chief Blur Buster » 17 Mar 2020, 19:27

Dmoney405 wrote:
17 Mar 2020, 17:17
I thought most people use the motion things on OLEDs because they stutter when they display 24fps media. I don't have one, just stuff I've read so I could be super wrong.
There are different ways motion can be enhanced.
Different settings are strobe-based instead of interpolation-based.

For strobe-based, it behaves like LightBoost or ULMB.
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

       To support Blur Busters:
       • Official List of Best Gaming Monitors
       • List of G-SYNC Monitors
       • List of FreeSync Monitors
       • List of Ultrawide Monitors

vmd12
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Re: PSA: GSYNC/VRR ON C9 OLED IS AFFECTING PICTURE QUALITY

Post by vmd12 » 17 Mar 2020, 21:42

Chief Blur Buster wrote:
17 Mar 2020, 19:27
Dmoney405 wrote:
17 Mar 2020, 17:17
I thought most people use the motion things on OLEDs because they stutter when they display 24fps media. I don't have one, just stuff I've read so I could be super wrong.
There are different ways motion can be enhanced.
Different settings are strobe-based instead of interpolation-based.

For strobe-based, it behaves like LightBoost or ULMB.
You have any input for my original post? Regarding gsync brightening near black?

vmd12
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Re: PSA: GSYNC/VRR ON C9 OLED IS AFFECTING PICTURE QUALITY

Post by vmd12 » 17 Mar 2020, 22:01

I have tested another game: Control (2019). This game is in SDR and has a brightness calibration screen kinda similar to Modern Warfare: https://i.ytimg.com/vi/PkdYTkmU4AQ/maxresdefault.jpg.

Similar as my previous finding. With gsync/vrr enabled, the value must be reduced 37 for the logo at the middle to be barely visible. With gsync/vrr enabled, the value should only be 41, again strongly suggesting that gsync/vrr is wrongly brightening near-black values.

If you own any game that has this kind of brightness calibration, I encourage you to try the test above and see for yourself. All games are most likely affected, regardless of whether it is in sdr or hdr.

I’m exchanging emails with nvidia as well, hoping they can see the similar problem on their side and either work on a fix by themselves or work with LG on a firmware update.

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