G-Sync and ULMB at the same time is in fact possible!

Ask about motion blur reduction in gaming monitors. Includes ULMB (Ultra Low Motion Blur), NVIDIA LightBoost, ASUS ELMB, BenQ/Zowie DyAc, Turbo240, ToastyX Strobelight, etc.
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Re: G-Sync and ULMB at the same time is in fact possible!

Post by Chief Blur Buster » 12 Jul 2017, 15:40

masterotaku wrote:And holy shit! This monitor is a lot brighter in Lightboost mode. It has a Lightboost option in 3D, but for some unknown reason it doesn't change strobe length at all, so it just acts as brightness and there isn't any reason to use anything other than 100%. I'm a bit mad about this, because I wanted lower motion blur.
So the adjustments LightBoost 10% through 100% just acts as brightness, and doesn't adjust strobe length / motion clarity? No difference in TestUFO Panning Map Test at very high speeds?

How does LightBoost compare to ULMB specifically for PG278QR, including strobe crosstalk? There's a new test dedicated URL for crosstalk now: www.testufo.com/crosstalk
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Falkentyne
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Re: G-Sync and ULMB at the same time is in fact possible!

Post by Falkentyne » 12 Jul 2017, 16:08

Sounds like a bug on 3d capable ULMB monitors. Wouldn't be surprised as Lightboost was probably just left for compatibility reasons.

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Re: G-Sync and ULMB at the same time is in fact possible!

Post by masterotaku » 16 Jul 2017, 10:23

Chief Blur Buster wrote: So the adjustments LightBoost 10% through 100% just acts as brightness, and doesn't adjust strobe length / motion clarity? No difference in TestUFO Panning Map Test at very high speeds?
Exactly. There isn't any difference in motion blur. And the slider is in the same OSD position as the brightness slider in ULMB mode (inside the "Color" section and not "Image", where ULMB pulse width is). I tried to bug the monitor into letting me enter the ULMB pulse width slider in Lightboost mode, and I could (letting the monitor switch modes with the OSD open and being inside an slider), but it's always at maximum and I can't change it.
Chief Blur Buster wrote:How does LightBoost compare to ULMB specifically for PG278QR, including strobe crosstalk? There's a new test dedicated URL for crosstalk now: http://www.testufo.com/crosstalk
Mmmm, I'd say ULMB is a bit better regarding crosstalk. There's less at the top than in Lightboost mode. And it's better about motion blur too, obviously. By the way, using Chrome in fullscreen triggers 3D Vision for me :p.
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Re: G-Sync and ULMB at the same time is in fact possible!

Post by Chief Blur Buster » 17 Jul 2017, 10:49

masterotaku wrote:Mmmm, I'd say ULMB is a bit better regarding crosstalk. There's less at the top than in Lightboost mode. And it's better about motion blur too, obviously. By the way, using Chrome in fullscreen triggers 3D Vision for me :p.
That's unusual about ULMB having less strobe crosstalk than LightBoost.

Usually, it's been LightBoost that has less strobe crosstalk.

In exchange for doing slightly poorer colors. Some (not all) of the implementations seem to compress the greyscale dynamic range. Lowering contrast ratio (raising black levels, decreasing white levels) can often reduce the number of LCD GtG pairs that are incomplete between strobe flashes. That's one of the reasons why LightBoost traditionally had poorer colors than ULMB, but often less strobe crosstalk.
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Re: G-Sync and ULMB at the same time is in fact possible!

Post by masterotaku » 24 Jul 2017, 03:26

Chief Blur Buster wrote: That's unusual about ULMB having less strobe crosstalk than LightBoost.

Usually, it's been LightBoost that has less strobe crosstalk.
Oh, wait. It makes sense because I use a low ULMB pulse width value (usually between 37 and 45). If I put it to 100, crosstalk is more or less equal to Lightboost. Sad that I can't reduce strobe length in Lighboost :( .
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Re: G-Sync and ULMB at the same time is in fact possible!

Post by masterotaku » 01 Aug 2017, 15:16

Another discovery :lol: !

In my monitor, Asus PG278QR, I can create custom resolutions at 99Hz, 119Hz and 121Hz (edit: also valid at 84-86Hz) that still use ULMB, and can be used in 3D Vision (if their refresh rate is the only one available at the resolution you create).

That way, 3D Vision will use ULMB instead of Lightboost.

Pros:

- Capable of lower motion blur (or even no strobing if you want, which means unplayable crosstalk). This was the main goal and the only reason you have to used this trick.


Cons:

- Eyes are reversed, which is solved by wearing the glasses upside down. Uncomfortable, but not unbearable.
- A red text warning may appear. This can be avoided by modifying the "nvstres.dll" and "nvstres64.dll" files from the drivers, using "resourcehacker" (http://angusj.com/resourcehacker/#download) and this (http://www.avsforum.com/forum/68-digita ... st22791252) to use as substitute of the bmp number 201.
- There is significantly more ghosting/crosstalk than in Lightboost. Where previously there was nothing or almost nothing, it's now at mildly-average annoying levels.


I tried Tekken 7 and Dark Souls 3. It's nice seeing highly detailed textures moving at <1ms strobing (pretty dark, to be honest. The glasses eat part of the light and also divide the Hz by 2, one per eye) instead of the forced 2.4ms I had to use before, but the severely increased 3D crosstalk makes it an inferior mode. Lightboost for 3D in this monitor is just too near perfection, and a proper strobe length option for it would be ideal.

PS: I also tried to combine 3D + strobing + G-Sync this way, but even if the monitor said that G-Sync was enabled, the refresh rate was fixed while playing.
Last edited by masterotaku on 01 Aug 2017, 15:28, edited 1 time in total.
CPU: Intel Core i7 7700K @ 4.9GHz
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Re: G-Sync and ULMB at the same time is in fact possible!

Post by Chief Blur Buster » 01 Aug 2017, 15:25

masterotaku wrote:- Eyes are reversed, which is solved by wearing the glasses upside down. Uncomfortable, but not unbearable.
- A red text warning may appear. This can be avoided by modifying the "nvstres.dll" and "nvstres64.dll" files from the drivers, using "resourcehacker" (http://angusj.com/resourcehacker/#download) and this (http://www.avsforum.com/forum/68-digita ... st22791252) to use as substitute of the bmp number 201.
- There is significantly more ghosting/crosstalk than in Lightboost. Where previously there was nothing or almost nothing, it's now at mildly-average annoying levels.
Fascinating tests.

One thing that may improve things is opening up your monitor -- and hacking the backlight to allow overrideable LightBoost/ULMB strobe lengths & phase. Basically, adding an Ardiuno or a simple 555 timer to the backlight strobe circuit -- essentially a delay line + overriden pulse length adjustable.

I've played with backlights that are programmed in the Arduino IDE on Arduino-style controllers backlights before (and in fact, I'm beginning to play with them again, keep tuned for a new article!).

One upon a time, in 2012, Blur Busters was originally called http://www.scanningbacklight.com (redirects to Blur Busters now) -- it was actually the raison d'etre of launching Blur Busters (our first ever post in 2012). Certainly I put that project on the shelf once I realized LightBoost became available. However, now, I've just gotten my hands on the source code to a strobe/scanning backlight for a generic LCD panel. It's loaded right here in Ardunio 1.8.2 IDE development environment, with fully tweakable timings for every backlight LED, as a piggyback add-on to a modified LCD panel.

Blur Busters will indeed, very well, briefly visit a returns-to-the-roots article about this topic matter -- Arduino-controlled scanning backlight with full spectrum of customization. :D More to be revealed -- it's one of our next articles in the pipeline (next major article after an article written by spacediver)! Hint, hint.

Adjusting strobe length can adjust motion blur (persistence), in a brightness-versus-clarity tradeoff. (Briefer strobes = darker picture).

Adjustable strobe phase can adjust the timing of the flash to reduce strobe crosstalk. (You'll may also need to adjust shutter delay on the 3D glasses to compensate, to stay in sync with strobe phase).
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Re: G-Sync and ULMB at the same time is in fact possible!

Post by masterotaku » 01 Aug 2017, 15:32

I don't feel confident about doing that and also wouldn't know where to start (I know others did it with other monitors, I saw it in this website years ago). I also don't want to risk breaking a monitor this expensive :( .

I edited my previous post to add that 84, 85 and 86 Hz are also valid (edit: and their crosstalk is more bearable. But this is 40 something Hz per eye :p). I knew about 85Hz more than a year ago, but I could only do it in GZDoom which let me use any refresh rate in 3D.
Last edited by masterotaku on 01 Aug 2017, 15:40, edited 1 time in total.
CPU: Intel Core i7 7700K @ 4.9GHz
GPU: Gainward Phoenix 1080 GLH
RAM: GSkill Ripjaws Z 3866MHz CL19
Motherboard: Gigabyte Gaming M5 Z270
Monitor: Asus PG278QR

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Re: G-Sync and ULMB at the same time is in fact possible!

Post by Chief Blur Buster » 01 Aug 2017, 15:36

<SNEAK PREVIEW ALERT>
It's possible to obtain a modified backlight motherboard that can be added to a monitor, to improve its strobing capabilities.

Basically, connect a few ribbon connectors -- like buying replacement monitor motherboards used to add 120Hz overclocking capabilities or add features (e.g. the old VG248QE GSYNC upgrade). This is easier than building from scratch.

I'm in contact with somebody capable of creating a "backlight driver modification board" to add custom strobe capabilities.

- Overrides the monitor's default strobe logic (And annoying manufacturer limits) with external adjustments.
- Any refresh rate (yes, 50/60Hz single strobe if you want!)
- Any pulse length
- Any pulse phase (per LED, or all LED).
- Overvoltage boost for brighter strobes at shorter pulses.
- Switchable global-strobe and scanning-strobe.
- Possibly variable-rate strobe.
- This might be open source. Possibly open-sourcing this codebase so other programmers can attempt their own custom strobe code to attempt to reduce strobe crosstalk further, or reduce motion blur, etc.

Right now, designed for only a couple panels but it should be flexible to cover more common panels. Obviously, it would be at mercy to the monitor's quality of overdrive lookup tables and won't necessarily be as good as ULMB/LightBoost for all panels (in terms of strobe crosstalk & afterimages) but you'll have a far wider range of adjustability.

It would certainly work best on 1ms GtG TN monitors that also does large vertical totals (less ghosting via putting most of GtG in VBI), see Electronics Hacking: Creating a Strobe Backlight as an explanation why large vertical totals create less strobe crosstalk (by speeding up scanout to create more VBI time for GtG settlement time). Basically GPU-side scanout speedup (large VT), rather than monitor-side scanout speedup (monitor logic, like LightBoost/ULMB), and a compatible panel that merrily scans out faster if the video cable is transmitting at higher dotclocks.

The question is -- is there demand? We'll find out...

Regardless, a board is running here in a panel, the source code is tweakable in Arduino IDE, and the possibilities are endless!

Keep tuned for an upcoming major article... very soon! It's within one of our next few major articles (other than upcoming display reviews & input lag articles).

EDIT: It's up now -- http://www.zisworks.com/shop
</SNEAK PREVIEW ALERT>
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Re: G-Sync and ULMB at the same time is in fact possible!

Post by lexlazootin » 02 Aug 2017, 07:11

Does it plug into the board or replace it? ZisWorks gave me a update to his board for backlight stobing, without Overdrive it's defiantly not as good as it could of been :(

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