Crosspost, because people are asking about combining LightBoost with G-Sync:
Originally Posted by Pocatello;1040297646
What is best right now for FPS gaming? Lightboost or G-sync?
-- If you get variable framerates; use G-Sync
-- If you get constant 120fps@120Hz: use LightBoost (blur eliminating strobe backlight).
G-Sync is still limited by 144Hz motion blur; it would take G-Sync at 400fps@400Hz to achieve flickerfree LightBoost CRT motion clarity (2.5ms sample-and-hold length), based on existing motion blur math formulas directly co-relating strobe length with motion blur. So frame durations would have to match today's LightBoost strobe lengths. Using 2.5ms means frames have to last only 1/400th of a second, and that would require 400fps@400Hz using nVidia G-Sync. If you want the clarity of LightBoost=10%, you need about 700fps@700Hz (1.4ms frame duration length) and upwards. That's not feasible. So we still need strobing, at least until we have a 1000Hz LCD (to have flickerfree CRT motion clarity). It's surprising how human eyes still sees indirect display-induced motion blur (sample-and-hold effect), even at 240Hz, 480Hz, and beyond (as we witness human eyes can tell apart LightBoost=10% (~1 to 1.4ms frame duration) versus LightBoost=100% (~2.5ms frame duration) during motion tests such as www.testufo.com/photo#photo=toronto-map.png&pps=1440
...) Display motion blur is directly proportional to visible frame duration times.
LightBoost (blur eliminating strobe backlight) is great at triple-digit framerates. However, we already know LightBoost becomes terrible at lower framerates, and can become very stuttery at less than triple-digit framerates. G-Sync stays smooth during varying framerates; LightBoost does not. The solution is to Combine LightBoost AND G-Sync
. This solves the problem. However, new problems occurs with variable-rate strobing. Fortunately, I've come up with a successful solution.
I've found a way to combine the two. John Carmack did say it was possible in his twitch.tv video, but it didn't appear that anyone came up with a novel idea of blending PWM-free with LightBoost strobing, an enhancement that I have just come up:
I have quickly invented a new idea of combining PWM-free with LightBoost, while having G-Sync:New Section Added to "Electronics Hacking: Creating a Strobe Backlight"
To the best of my knowledge, no patents exist on this, and not even John Carmack appears to have mentioned this in his twitch.tv video when he mentioned combining LightBoost with G-Sync. So I'm declaring it as my idea of a further improvement to nVidia G-Sync:
From: New Section in "Electronics Hacking: Creating a Strobe Backlight"
With nVidia’s G-Sync announcement, variable refresh rate displays are now a reality today. Refresh rates can now dynamically vary with frame rates, and it is highly likely that nVidia has several patents on this already. If you are a monitor manufacturer, contact nVidia to license this technology, as they deserve kudos for this step towards tomorrow’s perfect Holodeck display.
However, one additional idea that Mark Rejhon of Blur Busters has come up with is a new creative PWM-free-to-strobing dynamic backlight curve manipulation algorithm, that allows variable-rate backlight strobing, without creating flicker at lower frame rates.
It is obvious to a scientist/engineer/vision researcher that to maintain constant perceived brightness during variable-rate strobing, you must keep strobing duty cycle percentages constant when varying the strobe rate. This requires careful and precise strobe-length control during variable refresh rate, as the display now refreshes dynamically on demand rather than at discrete scheduled intervals. However, a problem occurs at lower framerates: Strobing will cause uncomfortable flicker at lower refresh rates.
Mark Rejhon has invented a solution: Dynamic shaping of the strobe curve from PWM-free mode at low framerates, all the way to square-wave strobing at high framerates. The monitor backlight runs in PWM-free mode during low refresh rates (e.g. 30fps@30Hz, 45fps@45Hz), and gradually become soft gaussian/sinewave undulations in backlight brightness (bright-dim-bright-dim) at 60fps@60Hz, with the curves becoming sharper (fullbright-off-fullbright-off) as you head higher in framerates, towards 120fps@120Hz. At the monitor’s maximum framerate, the strobing more resembles a square wave with large totally-black-gaps between strobes.
10fps@10Hz — PWM-free backlight
30fps@30Hz — PWM-free backlight
45fps@45Hz — PWM-free backlight
60fps@60Hz — Minor backlight brightness undulations (bright / dim / bright / dim)
80fps@80Hz — Sharper backlight brightness undulations (very bright / very dim)
100fps@100Hz — Starts to resemble rounded-square-wave (fullbright / fulloff)
120fps@120Hz and up — Nearly square-wave strobing like original LightBoost
This would be a dynamically variable continuum all the way in bewteen too, much like automobile CVT instead of discrete gears in automobile transmissions. You avoid flicker at lower frame rates, and you get full strobing benefits at higher frame rates.
Simpler algorithm variations are also possible (e.g. keeping a square wave, and using only pulsewidth / pulseheight manipulation to achieve the blending effect, but without curve-softening). This is included as part of my general idea of blending from PWM-free at lower refresh rates, to strobing at higher refresh rates. The trigger framerates may be different from the example above (or may even be adjustable via a user flicker-threshold setting), but the concept is the same.
If nVidia or any monitor manufacturer uses this idea (if no patent application dated before October 19, 2013 covers my invention), please give Mark Rejhon / Blur Busters appropriate due credit. It is realized nVidia has several patents, but none appears to be covering this additional improvement being suggested during combining strobing and variable refresh rates. As of this writing, research is being done on any prior art, to determine whether anyone dynamically considered blending from PWM-free to square-wave strobing. If anyone else already came up with this idea, already documented in a patent application prior to October 19, 2013, please let me know & due credit will be given here.
(For those living under a rock, LightBoost (for 2D) is a strobe backlight that eliminates motion blur in a CRT-style fashion. It eliminates crosstalk for 3D, but also eliminates motion blur (For 2D too). LightBoost is now more popular for 2D. Just google "lightboost". See the "It's like a CRT" testimonials
, the LightBoost media coverage
(AnandTech, ArsTechnica, TFTCentral, etc), the improved Battlefield 3 scores
from LightBoost, the photos of 60Hz vs 120Hz vs LightBoost
, the science behind strobe backlights
, and the LightBoost instructions
for existing LightBoost-compatible 120Hz monitors
. It is truly an amazing technology that allows LCD to have less motion blur than plasma/CRT
. John Carmack uses a LightBoost monitor, and Valve Software talked about strobing solutions too
. Now you're no longer living under a rock!)Edited by Mark Rejhon - 10/19/13 at 2:16am