<IMPORTANT: This post was written in year 2019>
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>
</IMPORTANT: This post was written in year 2019>
Updated information:
Chief Blur Buster wrote: ↑05 Dec 2023, 20:44
Updated 2023 Information
motionsofclarity wrote: ↑29 Nov 2023, 10:01
Sorry for necroing, but I'm sitting in front of a Corsair 27QHD240 right now kind of new to blur busting.
- You Cannot Read Street Name Labels On This Animation On ANY OLED without BFI <-- TRY THIS!
I can actually read this fine, even the small roads, but it does hurt my eyes a bit - or it's very fatiguing I'm not sure how to put it. I guess ULMB 2 would greatly improve on this?
That is an old post you replied to. I wrote that before 240Hz OLEDs existed.
Now 240Hz OLEDs let you barely read the street name labels. But it's still not as clear as the "Paused" setting. Full blur reduction means fast-motion is exactly as perfectly clear as stationary.
As a rule of thumb, you can go up to roughly (2xHz) pixels per second before you start seeing noticeable blur around text, and you can just about barely read text up to about (4xHz). Beyond that, it's just a blurry mess.
Assuming GtG=0 (essentially) and framerate=Hz:
Clear text on OLED without BFI:
480pps at 240Hz OLED
720pps at 360Hz OLED
960pps at 480Hz OLED
Barely readable text OLED without BFI:
~960pps at 240Hz OLED
~1440pps at 360Hz OLED
~1920pps at 480Hz OLED
Blurry text on OLED without BFI:
>960pps at 240Hz OLED
>1440pps at 360Hz OLED
>1920pps at 480Hz OLED
This is because Blur Busters Law dictates 1ms of pixel visibility time translates to 1 pixel of motion blur per 1000 pixels/sec
- Pixel visibility time = frametime on sample and hold
- Pixel visibility time = pulsewidth on BFI/strobed.
Why Twice Motion Speed In Pixels/Sec versus Refresh Rate?
- It's actually surprisingly simple blur mathematics that Blur Busters has discovered, for perceptuals.
- At frame rate half the refresh rate, there's approximately 2 pixels of motion blur, which perceptually shows up to the eyes as half pixelwidth of motion blur at leading edge (the midpoint of a 1-pixel blur gradient), and half pixelwidth of motion blur at trailing edge (the midpoint of a 1-pixel blur gradient).
- That's why things look so clear until motionspeeds more than twice the OLED refresh rate.
Be noted, LCDs have it worse due to slow GtG. OLEDs are fantastic for strobeless blur reduction, via brute framerate-based approach of reducing display motion blur. As long as your GPU can spray the needed frame rate.
But, now that OLEDs are 240Hz+, they are absurdly fantastic blur reduction alternatives, if you hate strobing, and if you can spray the needed frame rate, or if you use add external BFI injection (e.g. the
Blur Busters Approved Retrotink 4K)