bahamutfan wrote: ↑31 May 2026, 07:05
I noticed a strange observation where if I use a capture card to pipe in a video game console and apply motion interpolation, the input lag varies greatly at different PC monitor refresh rates (using a 5080).
60 Hz content —> 2x interpolation —> output to PC monitor set to 240 Hz
results in a lot less input lag than:
60 Hz content —> 2x interpolation —> output to PC monitor set to 120 Hz
results in a lot more input lag
This is normal. In a VSYNC ON frame queue of 3 frame depth:
3/120 = 25ms
3/240 = 12.5ms
So depending on your output frame queue size, you're lopping off a gigantic amount of latency, even if you're only outputting 120fps at 240Hz. Higher refresh rates will reduce latency even further, so get the highest output Hz you can afford, if you're doing interactive stuff using Vint as the video processor.
So for a 1000Hz LCD:
3/1000 = 3ms
Or a 720Hz OLED:
3/720 = 4.16ms
Even literally moving from 120Hz to 720Hz, you reduce output latency by more than 20ms for a computer using a 3 framebuffer queue that isn't flushing out fast. Sometimes this happens if you're heavily layered (e.g. Browser compositor -> Windows compositor -> Driver sync technology -> Display sync technology) if some stages create unexpected backpressures.
You'll have less lag if it's managing to keep only 1 or 2 framebuffer in the queue, but you still have less lag.
Accessibility Feature for the win!
Sometimes it's a "looks nice", and sometimes it's "I don't see a big deal".
Low frame rates can induce worse motion sickness than latency does, so some gamers still have to use interpolation as an ergonomic accessibility feature. Like it or not, it's an Accessibility Feature for some... You may not care, but there are those with nearly-hospitalizing migraines from using screens too long. Often it's caused by other things (flicker, etc) but sometimes low frame rates is one of the known medical triggers in certain niche cases.
After all, when you use giant size OLEDs -- there are times where OLED GtG means 60fps OLED often looks like 40fps-45fps LCD, and that's... bad for some who are extremely sensitive to flicker (since low frame rates = edge flicker effect = as seen at
www.testufo.com). No other poison-solution except to interpolate, and... boom.
Many consumers still use TV interpolation with game consoles, and it's possible (with these clever tricks) to have lower Vint latency than a typical TV interpolation latency. Even if you can only interpolate to 120fps or 240fps, still having even higher output Hz is still beneficial (e.g. 720 Hz or 1000 Hz). While Vint is not as good as DLSS5 framegen, it is closer to that quality than an average TV interpolator, so Vint can be a superior video processor to an average television's existing interpolation both in quality AND latency (with the extreme-Hz-output trick).
Engineers and software authors often overlook the accessibility nature of interpolation as much as we hate AI slop. I don't like interpolation. But I liked DLSS framegen on Cyberpunk 2077. It reduced my motion nausea (in addition to turning off "Accessibility" -> "Additive Camera Motions" -> turn off bobbing during walk -> solved MY motion sickness). The two tweaks (no head bob + add frame gen) turned Cyberpunk 2077 into a magically enjoyable ergonomic experience on my 240Hz OLED as I could framegen RTX ON to 200fps+, with zero motion sickness in me. It's not useable for esports, but perfectly fine for a solo epic for many (including me).
It depends hugely between different people. Triggers can weirdly vary between people.
You have people who prefer low frame rates only, or high frame rates only, or weird "framerate no-go zones" regions that needs to be blur-busted (BFI) or interpolated (framegen), or things like that. It varies from individual to individual.
Other times you have the framerate uncanny region where only 24fps or 200fps is comfortable but 40-60fps is motion sickening on some large immersive displays. I even get less motionsick in "Comfortable"-rated VR games than some content on a large desktop 45" ultrawide, if my framerates is mid-region like that, and head bob is enabled. So multiple motionsickness triggers.
Typically, this is because 24fps is far below the flicker fusion threshold and feels like a Hollywood movie (so head bob doesn't trigger as much motion sickness as it can at higher frame rates). For me on OLED, intermediate frame rates like ~30fps to ~70fps on OLED is often the "almost smooth but not comfortably so" region (this can begin to trigger motion sickness) if I'm playing interactive content instead of watching a movie.
Intermediate frame rates still has a bit of coarseness/motionblur that is an ergonomic trigger, and head bob in FPS games creates some minor motion sickness in me, and still even persists at 200fps. So I try to turn off head bob in all my FPS games on top of keeping frame rates high, to keep it quite ergonomically enjoyable in win-win.
Anyway... Motion blur is also a nausea trigger. Low frame rates = motion blur. And I fix motion blur.
Rheoretical question.
"How did I ****ing start Blur Busters?"
Yes.
Sometimes I have to toot the accessibility horn (I'm born deaf, by the way) that the mainstream is not realizing, especially when most display engineers and software developers overlook things. And things like how I convinced NVIDIA to support 60fps GSYNC; I take my Blur Busters very seriously on multiple fronts. Users should have the choice. It's great someone just posted Vint is actually useful for interactive content.
Just like hearing people don't know what a deaf person's life is like, many people don't realize how necessary (sometimes) interpolation becomes a medically accessibility feature. I hate interpolation, but when it becomes so low-lag and almost indistinguishable from native, it becomes an actual option even to myself (like NVIDIA's DLSS during CP2077). Yes, 2% of the time I get distracted from the DLSS framegen artifacts that do occur, but a mere 2% is better than being motionsick more than 50% of the time. This isn't Grandpa's Sony TV Motionflow interpolation from yesteryore.
It looks like an accessibility feature, it quacks like an accessibility feature, it IS an accesibility feature.
I'll keep RobinHooding this little known front, thank you.
Moral of Story: Users need choice. And, if you're using a PC-based video processor, higher output Hz massively reduces latency even for unchanged low frame rates.
Glad to hear Vint is at least usable to at least one person for interactive content! It's obviously better to have more native framegen (built into game) than blackbox approaches, as there's way fewer artifacts, but if you have no other choice for specific situations (like a 30fps-locked or 60fps-locked game)...
