Hacked ASUS VG279QM modified to single-strobe 60 fps capped VRR for emulators

Advanced display talk, display hackers, advanced game programmers, scientists, display researchers, display manufacturers, vision researchers & Advanced Display Articles on Blur Busters. The masters on Blur Busters.
User avatar
Chief Blur Buster
Site Admin
Posts: 9272
Joined: 05 Dec 2013, 15:44
Location: Toronto / Hamilton, Ontario, Canada
Contact:

Re: Hacked ASUS VG279QM modified to single-strobe 60 fps capped VRR for emulators

Post by Chief Blur Buster » 12 Jul 2021, 17:01

Yes, that's a quite reasonable algorithm -- instantaneous strobe phase accuracy is not as critical as flicker prevention algorithms.

You can slew phase "after the fact", so free floating strobe phase that slowly flywheels around to "catch up" with the frame rate, is a very adequate flicker-prevention strategy for strobed VRR.
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

elexor
Posts: 126
Joined: 07 Jan 2020, 04:53

Re: Hacked ASUS VG279QM modified to single-strobe 60 fps capped VRR for emulators

Post by elexor » 14 Jul 2021, 08:28

Chief Blur Buster wrote:
12 Jul 2021, 17:01
You can slew phase "after the fact", so free floating strobe phase that slowly flywheels around to "catch up" with the frame rate, is a very adequate flicker-prevention strategy for strobed VRR.
If i freewheel really fast it will just bang up against my reference signal re-introducing the jitter i just filtered out. What I want is a way to slow down freewheeling as it gets closer to the reference signal. I can't seem to get my head around how to do that every attempt so far has failed. any ideas? or is it not possible?

often you will have a scene change or camera change that will throw it far out of phase. just want it to return close enough then slow freewheeling can take over again.

edit: figured it out for the most part.

Code: Select all

  if (leftSlewLocked && rightSlewLocked) {leftSlew = -(phaseDiff * 0.01); rightSlew = ( (frameTime - phaseDiff) * 0.01 ); leftSlewLocked = false; rightSlewLocked = false;}
  if (phaseDiff > (frameTime / 2) && slewLock == false) {slewPhase = rightSlew; slewLock = true; rightSlewLocked = true;}
  if (phaseDiff < (frameTime / 2) && slewLock == true) {slewPhase = leftSlew; slewLock = false; leftSlewLocked = true;}
pretty crappy code but it works. requires phase much quicker after camera cuts in cemu mariokart 8 without introducing jitter.
can even adapt to the super erratic retroarch vrr frametimes.
not sure why retroarch frametime consistency sucks when the content is fixed framerate predominantly. did they just not care because it's hidden by sample and hold?

User avatar
Chief Blur Buster
Site Admin
Posts: 9272
Joined: 05 Dec 2013, 15:44
Location: Toronto / Hamilton, Ontario, Canada
Contact:

Re: Hacked ASUS VG279QM modified to single-strobe 60 fps capped VRR for emulators

Post by Chief Blur Buster » 17 Jul 2021, 17:23

It's pretty neat to see DIY strobed VRR outperforming manufacturer strobed VRR. This is better than first-generation ASUS ELMB-SYNC.
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

elexor
Posts: 126
Joined: 07 Jan 2020, 04:53

Re: Hacked ASUS VG279QM modified to single-strobe 60 fps capped VRR for emulators

Post by elexor » 18 Jul 2021, 09:19

Chief Blur Buster wrote:
17 Jul 2021, 17:23
It's pretty neat to see DIY strobed VRR outperforming manufacturer strobed VRR. This is better than first-generation ASUS ELMB-SYNC.
Biggest hurdles are stuff out of my control like nvidia lfc and some games just have the most horrible vrr fracepacing i don't think you can do much with them. some games have excellent frame pacing with their internal limiters.

i once seen 60hz with frametimes like this :shock: |-|-|---|-|-|---|-|-|---

pretty sure my ref signal is showing vbp because crosstalk is lowest right before it.

Also wanted to ask you if a pll is better suited to dejittering and phase locking vbp. I still struggle with heavier filters causing too much group delay.

elexor
Posts: 126
Joined: 07 Jan 2020, 04:53

Re: Hacked ASUS VG279QM modified to single-strobe 60 fps capped VRR for emulators

Post by elexor » 25 Jul 2021, 09:37

So I have been trying out an AMD videocard and boy their LFC is so much better it actually respects the freesync range and only kicks in when below the minimum range. it also returns to the correct refresh rate fast. is much better behaved in general.

edit: would also like to mention this is with vrr via hdmi. since this amd card does not have displayport.

Post Reply