How do OLEDs with/without BFI compare to gaming monitors?

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blurbustingbunny
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How do OLEDs with/without BFI compare to gaming monitors?

Post by blurbustingbunny » 23 Apr 2019, 14:55

Do you think that the motion clarity with BFI enabled on the upcoming Alienware OLED monitor will be "good enough" for competitive gaming if the input lag is low?

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Re: How do OLEDs with/without BFI compare to gaming monitors

Post by Chief Blur Buster » 23 Apr 2019, 23:33

The mathematics of motion blur is actually surprisingly simple -- for situations where GtG is an insignificant percentage of a refresh cycle.

It follows Blur Busters Law of 1ms of frame visibility time = 1 pixel of motion blur per 1000 pixels/second.

Here are diagrams:

Image

Image

This means:
- A non-strobed OLED has identical motion blur to a fast non-strobed TN LCD (a model with excellent overdrive tuning).
- An OLED with a 50%:50% on:off BFI will reduce motion blur by 50% (half original motion blur)
- An OLED with a 25%:75% on:off BFI will reduce motion blur by 75% (quarter original motion blur)

Typically, most OLED BFI is only in 50% granularity (8ms persistence steps), though the new 2019 LG OLEDs can do BFI in 25% granularity at 60Hz and 50% granularity at 120Hz (4ms persistence steps)

Except for the virtual reality OLEDs (Oculus Rift 2ms persistence), no OLEDs currently can match the short pulse length of a strobe backlight just yet, though I'd expect that a 2020 or 2021 LG OLED would thus be able to do so.
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blurbustingbunny
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Re: How do OLEDs with/without BFI compare to gaming monitors

Post by blurbustingbunny » 24 Apr 2019, 18:10

So if someone were sensitive to backlight strobing, an OLED without BFI but with low input lag would be about as good or better (due to image quality) than a fast TN gaming monitor without strobing?

Vega
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Re: How do OLEDs with/without BFI compare to gaming monitors

Post by Vega » 26 Apr 2019, 00:21

I've tested this on my LG C8 OLED versus my 165 Hz 1440p TN. With the OLED set to 1080p 120 Hz, the OLED pixels are so fast (sample and hold in this case) that I can see each individual frame. It doesn't "appear" as smooth as say the TN panel set to 1080p/120 Hz because even a fast TN will "smear" the images together. OLED doesn't blur one frame to the next.

To me seeing as OLED pixels are so dark fast, if kept sample and hold, the refresh rate even needs to be higher than LCD to get that silky smooth fast refresh feeling.

I dream of the day we get both VRR working in conjunction with BFI. I think NVIDIA may have given up in that realm since we haven't heard anything for quite a while on that topic.

Stitch7
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Re: How do OLEDs with/without BFI compare to gaming monitors

Post by Stitch7 » 30 Apr 2019, 14:24

What exactly is "Ultra-Hz"?

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Re: How do OLEDs with/without BFI compare to gaming monitors

Post by dhaine » 30 Apr 2019, 15:12

Chief Blur Buster wrote:T

Typically, most OLED BFI is only in 50% granularity (8ms persistence steps), though the new 2019 LG OLEDs can do BFI in 25% granularity at 60Hz and 50% granularity at 120Hz (4ms persistence steps)
Unfortunately, it seems the 2019 models does not have the new BFI as seen in CES. Due to last minutes issues (or so I heard), they switched BFI mode to be the same as 2018 models.

Reviews should pop soon to confirm

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Re: How do OLEDs with/without BFI compare to gaming monitors

Post by Chief Blur Buster » 30 Apr 2019, 18:29

Vega wrote:I dream of the day we get both VRR working in conjunction with BFI. I think NVIDIA may have given up in that realm since we haven't heard anything for quite a while on that topic.
I think we'll see ultra-Hz (plus frame rate amplification technology) before this happens.

Who needs VRR and strobing when we have ultra-Hz as the method of blur reduction instead?
Stitch7 wrote:What exactly is "Ultra-Hz"?
Ultra high refresh rates -- as in 1000Hz true display refresh rate.
See Blur Busters Law: The Amazing Journey To Future 1000 Hz Displays
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       To support Blur Busters:
       • Official List of Best Gaming Monitors
       • List of G-SYNC Monitors
       • List of FreeSync Monitors
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Re: How do OLEDs with/without BFI compare to gaming monitors

Post by Vega » 01 May 2019, 01:49

dhaine wrote:
Chief Blur Buster wrote:T

Typically, most OLED BFI is only in 50% granularity (8ms persistence steps), though the new 2019 LG OLEDs can do BFI in 25% granularity at 60Hz and 50% granularity at 120Hz (4ms persistence steps)
Unfortunately, it seems the 2019 models does not have the new BFI as seen in CES. Due to last minutes issues (or so I heard), they switched BFI mode to be the same as 2018 models.

Reviews should pop soon to confirm
Ya unfortunately they stole that back-plane bandwidth that allowed for 120 Hz BFI (4K 240Hz back-plane) and used it to get rid of some sort of "flashing" problem. I imagine since the Alienware is using the same panel it may also have that worthless 60 Hz BFI limitation. :(

If they take too long on the Alienware it will leave them in a bit of a predicament. DP 1.4 port is its key selling feature and the Alienware may not be out until HDMI 2.1 GPUs come out anyway.

masneb
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Re: How do OLEDs with/without BFI compare to gaming monitors

Post by masneb » 01 May 2019, 03:01

I'm actually curious why anyone thinks OLED needs BFI in the first place in the case of gaming. ULMB covers up pixel transition time. OLED has almost no pixel transition time and as such, there is no smearing between pixel states. Putting aside what the pixels are transferring from-to-from again, sometimes even with ULMB the 'snap shot' when the monitor turns on isn't in a complete state anyway for TN. BFI is simply there for all the normal people who can't tolerate the 'jarring' clarity low response times deliver for OLED and movies/TV. Thats great for cinema, but not what you want for gaming.

OLED is almost instantaneous, I have a C865PUA and don't have any problems without BFI. 'Seeing' the frame rate is a good thing (as a FPS player), that means you can actually take in every bit of what is showing up on the screen. Comparing my VG248QE vs my PG258Q, even though the PG258Q is faster refresh wise, the lower refresh of the 248 basically functions like BFI/ULMB, where it gives the pixels more time to reach their final states before the next refresh comes in so it doesn't smear. While that's fine and dandy, it also isn't as smooth when it comes to motion. So it's a trade off between fluidity and picture clarity. Depending on what's going on with the 258Q sometimes you get that feeling of seeing the framerate as well and I don't find that disjointing at all.

OLED hits all the right places. More Hz is always better, but even 240hz will do. This sort of reminds me of the outcry people had when 48fps HFR came out for films and everyone hated it because you could actually see what was going on in the picture during fight scenes instead of it turning into a ghastly mess. Watching the Hobbit in a HFR theater and being able to keep track of three simultaneous fight scenes happening at the same time was something I'll never forget.

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Re: How do OLEDs with/without BFI compare to gaming monitors

Post by Chief Blur Buster » 01 May 2019, 15:36

masneb wrote:I'm actually curious why anyone thinks OLED needs BFI in the first place in the case of gaming. ULMB covers up pixel transition time. OLED has almost no pixel transition time and as such, there is no smearing between pixel states. Putting aside what the pixels are transferring from-to-from again, sometimes even with ULMB the 'snap shot' when the monitor turns on isn't in a complete state anyway for TN.
0ms GtG still has lots of motion blur

There are two different pixel response numbers.
- GtG response and MPRT response.
- GtG is pixel transition time = Grey To Grey
- MPRT is pixel visibility time = Moving Picture Response Time
- MPRT can only be shortened by BFI or higher Hz).
- MPRT is the bigger cause of motion blur.
- OLED has fast GtG response.
- OLED has slow MPRT unless it uses strobing/BFI.

Please see:
FAQ: Why Does Some OLEDs Have Motion Blur?

To better understand why there are two different pixel response benchmarks (GtG versus MPRT), see
Blur Busters Law: The Amazing Journey To Future 1000Hz Displays
(View this on a desktop computer, because the animations work properly in a desktop web browser)

MPRT Motion blur is based on pixel visibility time, not pixel transition time. As you track eyes on moving objects, your eyes are in a different position at the end of a refresh cycle than at the beginning of a refresh cycle. The longer a pixel stays visible for (even if it's long finished transitioning), the more opportunity it smears across your retinas. OLED still has long pixel visibility time because it's a sample-and-hold technology. On most OLEDs, the OLED pixels continuously shine. 60Hz OLEDs without BFI have a pixel visibility time of 1/60sec translating to 16.7ms of motion blur -- 16.7 pixels of motion blur per 1000 pixels/sec.

See-For-Yourself Animations:
- TestUFO Animation: Eye Tracking Motion Blur
- TestUFO Animation: Black Frame Insertion
- TestUFO Animation: Persistence Of Vision
- You Cannot Read Street Name Labels On This Animation On ANY OLED without BFI <-- TRY THIS!

Now, before you dispute this information, I may have to remind some newbies about my credentials here on motion blur research to silent the doubters of this reply. Even long before Blur Busters, I've been mythbusting the famous "Humans Can't Tell Apart 30fps vs 60fps" myth since 1993 (screenshot).

It is a Blur Busters Prime Directive to provide correct information for questions like yours, like why OLEDs have motion blur. Stick around long enough, and false information about motion blur gets shot down pretty quickly around here with scientific facts. We exist to do that.

Credentials On Motion Blur
1. We're called "Blur Busters". This is 100% our business; display motion blur.
2. I have a peer-reviewed conference paper on motion blur measurement method, co-authored with NIST.gov, NOKIA and Keltek. Pursuit Camera Paper. Multiple websites including TFTCentral, PCMonitors, RTINGS, TomHardware, etc, have used my invention -- See Reviewers Using Pursuit Camera
3. Did you know that Oculus Rift VR headset uses a form of black frame insertion (pixel pulsing)? Did you know that Blur Busters had a contract with Oculus Kickstarter that convinced their journey to adding black frame insertion to OLED?

Sometimes Motion Blur Is Good And Artistic. But...
Yes, motion blur is sometimes good! But that's not the debate at hand. While motion blur is useful when done correctly, and is desired -- it is not often desirable in video games. And sometimes motion blur causes headaches and nausea for some of us. That's also why we exist, too. From time to time, display manufacturers pay me (expenses paid) to fly me down there to teach them about display motion blur.

There's Only Two Main Ways To Reduce Display Motion Blur
Even for 0ms GtG pixel response, there are only two ways to reduce MPRT motion blur
(A) Shorten per-frame pixel visibility time via turning off pixels. (strobing, pulsing, black frame, phosphor, etc) - diagram
(B) Shorten per-frame pixel visibility time via adding more frames. (higher framerate at higher Hz) - diagram

Otherwise you have eye tracking motion blur (animation proof) with your eyes-movement-past-pixels blurring those continuously-visible pixels across your retinas. That motion blur is unfixable even with perfect 0ms GtG as you now realize and understand by now; and in many use cases with games, you do want to minimize motion blur that is forced upon your eyes above-and-beyond natural human limitations. Many want VR to look like real life, you want game motion to look like real life, etc.

Headaches From Motion Blur. Motion Sickness Caused By Motion Blur
Display motion blur in VR causes motion sickness. A very large percentage of people (~50%) got motion sickness during head turning in non-strobed VR because that forces extra motion blur above-and-beyond natural human vision. A non-strobed OLED causes motion sickness. So the industry had to add black frame insertion to fix motion sickness in virtual reality.

Now, this also applies to desktop displays to a certain extent too. Not as big a percentage, but still a huge percentage -- that's why Blur Busters is popular among high-Hz gamers now with half a million viewers of TestUFO per month.

Yes, not everyone is sensitive to motion blur, especially with a smaller display. And many prefer motion blur. That's good too. Options. But some of us gets headaches from motion blur, and we want to turn that off to optimize display motion more exactly equal real life motion, where all motion blur is just the human brain's natural motion blur, and not any extra motion blur enforced upon our eyes by the display because of an artificial humankind invention of a frame rate (the human invention of emulating motion via static imagery, and its attendant problem of pixel visibility time).

Also, 48fps cinematic HFR only halves motion blur of 24fps. You should go see one of those newer 120fps HFR cinema movies, they have only 1/5th the motion blur of 24fps. For example, the upcoming Gemini Man movie. And 120fps HFR is not even the final frontier (See 1000fps UltraHFR, though that's cinematography of the 2030s). I actually don't mind 24fps movies when viewed on a TV across the room, though when strapped to my head, you definitely want framerate=Hz strobed (for display blur elimination).

Some are sensitive to blur, some are sensitive to flicker, some are sensitive to color quality, some of us are motion-videophiles and value fixing motion blur for game use cases. This is sacrosanct to respect everyones preference, full stop. Not all of us are sensitive to the same thing, and sometime certain use cases amplify the problems (e.g. VR or large-size screens). The fact is, 60Hz OLED big-FOV (aka not across the room) is still very bad at motion blur without BFI. Nothing changes that fact even with 0ms GtG. GtG is fast but MPRT is slow.

You Cannot Read This Below Moving Text On An OLED That Has No BFI
The ability to read tiny scrolling text CRT-clarity on an OLED is only achieved via a pulsed OLED (2ms or less) -- it's not possible with a non-pulsed OLED that's not running at ultra-high-Hz (e.g. 500fps at 500Hz+). Just try, Not possible on an OLED without shortening MPRT / pixel visibility time one way or another. Remember, in virtual reality = head turning equals screen panning equals extra display motion blur (above and beyond natural human blurring) = major disconnect between real and VR when you're trying to match reality on a screen. So, BFI needed to make a screen match closer to reality for many use cases such as desktop gaming & VR & fast-scrolling etc.

No display that can do 0ms GtG will ever be zero-blur unless it also has ultrashort pixel visibility time one way or another, via (A) or (B).

Now you understand. Use cases. Right Tool For Right Job.

That's Why.

</Mic Drop>
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

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