[Velocitization Effect] Adjusting to different refresh rates?

[Dalek]

If I spent a few days looking at a 144hz screen (or 360hz), then go back to 60hz, the 60hz screen now looks like 30fps, but after a few days of using 60hz it eventually starts to look like 60fps again.

1. Is there a specific term for this effect?

2. How do you get used to using a high refresh rate screen whilst using lower refresh rate devices such as a phone or TV for example? Does it take days or weeks to get used to using different refresh rate screens without it being jarring?

3. When I watched videos on a 360hz screen, it felt like the frame rate was lower than usual and seemed to have a stutter effect? is this a normal effect of going from 60hz to a higher refresh rate?

[Chief Blur Buster]

3. When I watched videos on a 360hz screen, it felt like the frame rate was lower than usual and seemed to have a stutter effect? is this a normal effect of going from 60hz to a higher refresh rate?

Many players aren't framepacing well. 60fps ideally should repeat in a 6:6:6:6:6:6:6 sequence (6 repeat refreshes of each frame, for 6x60 = 360). but may erratically do 6:5:6:7:6:5:7. Switch to 24Hz mode (for movies) or 60Hz mode (for videos) to force players to framepace better.

You can use ultra-accurately-framepacing players to try and solve this, but you have to experiment. Some GPUs play better with SMPlayer, others with MediaPlayer Classic, etc. VLC doesn't seem to, for example, framepace as well as, say, MediaPlayer Classic. To play my 480fps experimental videos on an early experimental 480Hz monitor, I had to use MediaPlayer Classic to play a 480fps .mp4 capture.

If I spent a few days looking at a 144hz screen (or 360hz), then go back to 60hz, the 60hz screen now looks like 30fps, but after a few days of using 60hz it eventually starts to look like 60fps again.

1. Is there a specific term for this effect?

There is none yet, but the nearest term I can find is:
"Velocitization"

Maybe I can popularize this term in the refresh rate context.

It's a more common word in vehicular contexts. Like a driver on an expressway going 100kph* for a long time, and then slowing down. Suddenly the 50kph ramp speed limit, feels like only 25kph. It's trained in driving courses in many parts of the world to be careful about the effect. If you don't pay attention, you could be complacent and go too fast on a ramp because you slowed down to what you thought was 50kph, but is really still 75kph and too fast for the offramp curve. Big safety problem. That's why many trucks tip over, due to velocitization; they did not slow down during the curves of an interchange or offramp. And very dangerous for bus drivers (you don't want to tip over all the passengers or children) so compensating for velocitization is a big part of safety training.

*(Blame me, I'm Canadian. That's 60mph to those of you south of the 49th parallel)

Slower speeds feel unusually slow for a while. It takes a moment for slower speeds to feel normal again if you've been driving at freeway speeds all day long.

Merriam-Webster specifically refers to automobiles, but Wiktonary makes it more generic; and potentially applicable to getting used to high refresh rates.

So this applies to using 240Hz for a long time, then suddenly going to 60Hz, and noticing it much more than usual.

While not the first to suggest it, Blur Busters was the world's first website to heavily popularize the term, "strobe backlight" and "backlight strobing" before manufacturers ran with it in a widespread way. Even NVIDIA didn't quite fully use that phrase. Now all manufacturers use the terminology, to refer to a motion blur reduction mode.

High refresh rates benefit high velocity motion on screen. Also higher refresh rate do have higher-velocity scanout (faster sequential refreshing of pixels). So the "velocit" prefix is reasonably appropriate. So we can, very justifiably, to appropriate an existing sensible word to a brand new context that this word was never used for -- but should.

So, yeah, here you go: Velocitization. Maybe this new term will stick. Run with it. Blog/tweet/youtube it and use this term. Let's make it the standard terminology.

I, too, get refresh rate velocitization. The sensation that lower refresh rates suddenly feel lower than they are, after having been using high refresh rates for a long time.

2. How do you get used to using a high refresh rate screen whilst using lower refresh rate devices such as a phone or TV for example? Does it take days or weeks to get used to using different refresh rate screens without it being jarring?

Switch between refresh rates often -- use a TV or iPad or other big display in between -- and the veolicitization effect will fade quicker between uses.

After using high Hz for many years, my veolocitization effect is relatively fairly brief, so I am no longer bothered as much by going back to 60Hz, even if I'd rather stay at 240Hz.

[Dalek]

WOW, this was an amazing read! Thank you so much Chief!

This makes total sense why I felt like 35mph was 30mph doing driving lessons after doing high speeds. I never learned about velocitization at all (sadly) during my lessons.

I was also watching videos in VLC so this makes sense as to why it didn't framepace properly. It felt like I was imagining it because the effect was quite subtle.

So this leads me to more questions

1. If framepacing is an issue with videos and films at high refresh rate displays, and switching to 60hz is the solution; does that mean there isn't a high refresh rate that doesn't have framepace issues? Is there not a refresh rate that's perfect for films, videos, gaming, and desktop usage?

2. Would frame pacing with videos and films be an issue at 1000hz for example?

3. Slightly off topic, but kind of related - if you were to be running at 1000hz but the game runs at 60fps, or 500fps, would that also not introduce a huge amount of double image effect? or would the content be smooth?

[Chief Blur Buster]

1. If framepacing is an issue with videos and films at high refresh rate displays, and switching to 60hz is the solution; does that mean there isn't a high refresh rate that doesn't have framepace issues? Is there not a refresh rate that's perfect for films, videos, gaming, and desktop usage?

There's no one-size-fits-all. Enabling VRR is usually the best workaround, with caveats.
VRR means refresh rate varies to match frame rate. Very few video players supports VRR, but SMPlayer can when running in full screen exclusive Direct3D mode, to play video files at their native frame rate, causing the monitor to match the frame rate. VLC does not support VRR, sadly.

Now, as a general rule of thumb for motion-videophiles:

Videophile Films/Videos: Use 24Hz for film and 60Hz for video
Use same refresh rate or low multiple (2x or 3x). At 48Hz, the player can simply snap-to-grid along a one-dimensional grid of refresh cycles (1/48sec = 20.8 milliseconds). It's easier for a video to round-off more accurately to 1/48sec = 20.8ms. So 5ms framepacing error is completely hidden by the rounding-off effect. But at 360Hz, your refresh cycles are 1/360sec=2.78ms. Now 5ms framepacing error becomes visible stutter for your movies, like a random-version of a 3:2 pulldown effect. Stick to low multiples of the frame rate, or even use a zero multiple (best for videophiles). One compromise is 120Hz for both film/video (divisible by 24 and 60) but it needs to framepace much better than 8.3ms. If you're a videophile, just use 24p and 60p instead, unless you've got a perfect-framepacing 120Hz-capable video player that won't create accidental pulldown effects (different-frame-repeats).
Use 24Hz/48Hz/72Hz for films. Use 50Hz/60Hz or 100Hz/120Hz for videos. Or use a VRR-compatible player

Videophile Gaming: Use VRR / G-SYNC / FreeSync
If you're quality/stutter-priority instead of latency-priority (VSYNC OFF is less laggy), Variable Refresh Rate is best most of the time for most games. Just remember to tweak it correctly.
....Newest drivers will be very happy with VRR as long as you set "Vertical Sync"="Use Application Setting" for the global part of NVCP. This will automatically use GSYNC+VSYNC ON when you set VSYNC OFF in newer games (2023 tip), due to the way some drivers now override tearing during VRR.
....Universal VRR workaround: VSYNC ON in NVCP, VSYNC OFF in game menu. Many older drivers or older games, especially pre-VRR games, you need to configure drivers to "VSYNC ON" and in-game menu to "VSYNC OFF". This is because older pre-VRR game engines stutter less in VRR when using their asynchronous framepacing branch/loop for VSYNC OFF. But you don't want tearing during VRR. It's an annoying tweak for first-time VRR users, and Jorim did a fantastic GSYNC 101 that is still mostly the "VRR bible" even 10 years later, even as graphics drivers have improved to automatically use "VSYNC ON"(driver)+"VSYNC OFF"(game) concurrently whenever in-game menus are set to "VSYNC OFF" while G-SYNC/FreeSync is enabled, but alas, this is not always automatic.
....Cap 3% below refresh rate, or use NVIDIA Reflex to cap for you. This prevents the motionfeel/lagfeel changes whenever framerates exit VRR ranges. For esports player who want to use VRR, ultrafast refresh cycles (360Hz-540Hz) allows near-zero disadvantages to VRR, when framerates can fully fluctuate inside a VRR range. Buying more refresh rate than you need, means you don't always need to cap your game anymore (unless you want to). So esports players who haven't bought a monitor yet but want to use VRR in esports, should always buy the biggest refresh rate range they can afford. This allows essentially lagless uncapped VRR with none of yesteryear VRR latency compromises, and enjoying the full framerate the game can blast at you. In 2015 videophile VRR wasn't esports latency. But in 2023, you can finally now get videophile VRR during esports, if you do it strategically and carefully (purchase more refresh rate range than your planned framerate range, so you don't have to cap or worry about VRR lag).

Desktop Use: Use Maximum Hz
Modern Windows on fast GPUs generally have no problems smoothscrolling at 540fps 540Hz on today's latest gaming monitors, nor 1000fps 1000Hz in lab tests (Windows 10 supports up to 512Hz, and Windows 11 supports up to 1000Hz). Use smooth scrolling software and browser extensions, to enjoy CRT-clarity smooth scrolling via brute framerate-based motion blur reduction. Or simply enable strobing, if you are very picky about motion blur. Also, not everyone can handle smooth scrolling (e.g. motion sickness), but I absolutely love it. If you're a motion-videophile, you definitely want to get the smoothest TestUFO-smooth window dragging, map panning, and text scrolling. More Hz = closer to CRT motion clarity for sample and hold displays. Doubling Hz halves display motion blur, assuming GtG=0.

2. Would frame pacing with videos and films be an issue at 1000hz for example?

Yes. So player software needs to be upgraded. VLC source code needs to be upgraded to use something better than timers for framepacing frames.

As a motion-videophile, I tend to slightly prefer strobless blur reduction (at slightly higher MPRTs) over strobe-based motion blur reduction if I can run at 240fps. Which is why I am a giant fan of 240Hz OLEDs over 360Hz LCDs. Even 240fps 240Hz OLED is clearer motion than most 360fps 360Hz LCD. Even with the very few 360Hz LCDs that has slightly clearer motion, it is at the cost of GPU power. If I can only do 240fps, it's always clearer on all 240Hz OLEDs than the world's fastest 360Hz LCD. So, that's why I now usually game on a Corsair Xeneon Flex ultrawide OLED, which is now my office display (I use MacType for Windows to make text a bit clearer, when in Visual Studio). And fire it up, enable DLSS framegen, and play System Shock at over 200 frames per second. QD-OLEDs have better HDR color, but WOLED is better for mixed use (office use, etc) with 3-year burnin warranty.

GtG is a MAJOR throttler for refresh rate differences. 120-vs-240 (without strobing) is more visible on OLED than LCD, so the refresh rate race is more uncapped with faster-GtG technologies. I'm looking forward to the 1000Hz OLEDs coming before the end of the decade, but we should support the OLED industry and buy 240Hz OLEDs to help push the refresh rate race that the LCD guard has difficulty doing (without strobing). LCD will still remain important, but 240-vs-360Hz is throttling very badly due to LCD GtG, it's a 1.5x difference throttled to 1.1x due to various things like GtG and jitters masking the differences.

Now, I still love strobe backlights, e.g. my XG2431 can massively outperform OLED for 60-120Hz material, at the cost of a screen dimming, poorer blacks, etc. So, if one wants to get motion that looks as close-as-possible to CRT, as an LCD can feasibly get, the tips at www.blurbusters.com/xg2431 allows 60fps material to have less than 1/20th the motion blur of an average 60Hz LCDs -- most other brands DRM-lock their strobe backlights only to work at 100Hz and up, and never lower (due to flicker). Some hate flicker, but it's fine for some content (fast video etc).

3. Slightly off topic, but kind of related - if you were to be running at 1000hz but the game runs at 60fps, or 500fps, would that also not introduce a huge amount of double image effect? or would the content be smooth?

While you get images during stationary gaze (like www.testufo.com/mousearrow behaves the same on impulsed and sample and hold) -- you are referring to the double images of CRT 30fps at 60Hz.

That does not happen on flickerless (sample and hold) displays. There are no double images (during eye tracking) on sample and hold. It's a function of impulsing to insert black gaps in motion blur, creating the duplicate image effect. Continuous-shine sample and hold displays create no gaps in their motion blur for repeat refreshes, so perfect framepaced 60fps on 240Hz, 360Hz, 480Hz, 720Hz, 960Hz, 1440Hz, 2880Hz all look exactly the same amount of persistence-based motion blur (assuming GtG=0), the same as 1/60sec photo.

Impulsed:



Sample and hold:



Blur Comparision Between Two at Framerate=Hz



Obviously if motion is faster than 960 pixels/sec, such as 3840 pixels/sec, the 1000Hz isn't enough, and you have more motion blur becoming visible again. At 8000 pixels/sec on an 8K 1000Hz display would have 8 pixels of motion blur (eyetracking) or 8 pixels of phantom array (stationary gaze).

Long term, we will say goodbye to strobing, and say hello to brute-framerate-based motion blur reduction. Check out Lagless Frame Generation for Esports Of Future, as we can generate 1000fps 1000Hz UE5.x-quality RTX ON graphics on tomorrow's GPUs this decade. Comrade Stinger's video was a wakeup call, especially after Linus Tech Tips talked about it, that we can use superior lagless replacements for interpolation, thanks to the invention of between-frame inputreads and reprojection/timewarping existing frames to inputread-currency (including, later on, aggregate objects such as enemy positions). It's like how Netflix is 23 fake frames per second and 1 real frame per second, due to the interpolation/prediction maths built into MPEG standards and H.26X standards over the last 30 years. We can't notice the difference, and someday we will also fake frames in more than one way than faking real life via texture-mapped triangle polygons, to allow us to do 1000fps 1000Hz.

Anyway...

Want to learn more about refresh rate science and physics?

Blur Busters Area 51 Research Portal: blurbusters.com/area51

Hope this helps.

Cheers,

[Sptz]

If you're quality/stutter-priority instead of latency-priority (VSYNC OFF is less laggy), Variable Refresh Rate is best most of the time for most games. Just remember to tweak it correctly.
....Newest drivers will be very happy with VRR as long as you set "Vertical Sync"="Use Application Setting" for the global part of NVCP. This will automatically use GSYNC+VSYNC ON when you set VSYNC OFF in newer games (2023 tip), due to the way some drivers now override tearing during VRR.

VERY enlightening read. Thank you Chief. Apologies for necro'ing but I'm very curious about this section.

So, in modern games, NVCP Vsync at "use 3d application setting" with GSYNC ON means the game will use GSYNC+VSYNC even with in-game VSYNC set to OFF? This seems very confusing and counterproductive. What turning VSYNC in-game to ON do then?

[Chief Blur Buster]

So, in modern games, NVCP Vsync at "use 3d application setting" with GSYNC ON means the game will use GSYNC+VSYNC even with in-game VSYNC set to OFF?

Depends. Game-dependant, driver-dependant, and GPU-generation-dependant.

In 2014, the answer was no.

In 2023, the answer is sometimes yes.

The old GSYNC 101 HOWTO is more universal (will work with anything 2014 to 2023), doing "VSYNC OFF in game, VSYNC ON in drivers" is the only guaranteed universal method.

However, with newer games, newer drivers, and newer games, VRR is more intuitive as "Use Application Setting".

This seems very confusing and counterproductive.

In theory it's less counterproductive than the old-fashioned "VSYNC OFF in game, VSYNC ON in drivers" which was the only way to reliably do VRR properly for years.

Do you realize how that conflicting advice that is MORE confusing?

What turning VSYNC in-game to ON do then?

It can affect the gametime logic, since many game engines (e.g. Unity) switches to a fixed game clock during VSYNC ON mode. I really HATE when games do that, but the most common historic advice was to use VSYNC OFF in the game engine to allow floating frame rates to breathe organically.

Both VSYNC OFF and VRR is more variable framerate than VSYNC ON, and thusly, causes most game engines to use asynchronous gametime clocks that better keeps gametime:photontime in sync (light hitting eyeballs from the monitor, is more in sync with the game time clocks)