Bug 173434

Available rAF() Synchronization/Performance Test Suites: www.vsynctester.com www.testufo.com/#test=animation-time-graph www.testufo.com/#test=animation-time-graph&measure=rendering Related Articles: www.blurbusters.com/blur-busters-working-on-changes-to-html-5-2/ (Note: I am an Invited Expert in W3C Web Platform Working Group)

A comment was made by someone that 120fps and higher would ideally be done via a user request (like .requestFullScreen() API). If this is absolutely necessary to ask the user, discoverability of refresh rate should be provided (e.g. returns "120"), along with discoverability of a throttle (e.g. returns "60"). Consensus in talks indicates improved discoverability is essential. It is necessary to inform the JavaScript applications what the refresh rate is, and what the current throttle is (awareness of running animations at lower than refresh rate). Currently, this is impossible -- several websites such as http://www.testufo.com relies on heuristics to discover the current refresh rate -- but this can be completely impossible in the very few browsers (such as iPad 120Hz Safari) throttled/locked to the assumption of 60 animation callbacks per second regardless of refresh rate. This discoverability of refresh rate & animation throttles would be put in as part of Phase 1 of the pending W3C HTML work, issue #375 VSYNC & Refresh Rate extensions to HTML standard: PHASE 1 -- Discoverability -- https://github.com/w3c/html/issues/375#issuecomment-306591154 PHASE 2 -- New API changes -- https://github.com/w3c/html/issues/375#issuecomment-306603305

This problem will become bigger once the rumored 120 Hz iPhone comes out in 2020. There needs to be a solution to this. Google "test my refresh rate" and TestUFO is #1 in all search engines.

We follow the WHATWG HTML spec, not the W3C one.

At the minimum, a nominal support for 120Hz requestAnimationFrame() only. FireFox and Opera are compliant despite them using WHATWG. It's not mutually exclusive... There is nothing in WHATWG specifying that it must be limited to 60Hz. Many vendors including NVIDIA quotes TestUFO as their test of choice. For example, NVIDIA announced a partnership with BlurBusters in a TestUFO demo that is compatible with their 360 Hz gaming monitor -- https://www.nvidia.com/en-us/geforce/news/nvidia-geforce-360hz-esports-gaming-monitor/ There is a dramatic spike of mobile visitors to TestUFO, now being visited by million visits per month. Other websites, have started to assume that requestAnimationFrame matches refresh rate, and even Microsoft Edge (the Chromium version) now is compliant. Apple Safari is now the lone browser that cannot do 120Hz requestAnimationFrame()

New article: Competing mobile phone manufacturers are using TestUFO to show off 120 Hz and 144 Hz: https://www.lowyat.net/2020/203823/xiaomi-releases-demo-video-of-redmi-k30-5g-display-running-with-144hz-refresh-rate/ You see the YouTube video. Apparently, they modified generic Webkit to be 144fps compatible, so ignore the "UNSUPPORTED" message (it will be remedied in a future version of TestUFO update) It would be in Apple's business interests to make sure that 120 Hz iPhone (when it comes out later this year), supports 120fps requestAnimationFrame() minimally. It is not mutually exclusive with complying with the WHATWG specification. Power consumption is also indeed a legitimate worry but this can be solved by giving the user the choice of Performance versus Efficiency. Google "Blur Busters" in the news lately. As an entity in the Refresh Rate Race to future Retina Refresh Rates, we're square and center in many of these standardization initiatives. Minimal fps=Hz sync support is easy to do, and (now with Microsoft falling in line) is quite defacto standardized in all web browsers by all vendors on all desktops, tablets, and mobiles -- with the sole exception of Apple. We should probably join WHATWG to send this memo. I have lots of Apple devices (own 4 iPads) and being in the Apple ecosysystem too, it is a bit concerning that Apple has been a laggard in the refresh rate race. The spatial retina resolution cow was milked, and now the pressure is on commoditizing retina refresh rates, so it is no longer a fad. 4K was insanely expensive 20 years ago, and now 4K is a Walmart sale. High-Hz will be pervasive as it is another area of progress that has freed up thanks to technology. Browsers need to keep up, and Apple should too. Politics on power vs performance can be solved by a simple setting.

I should also add, I understand requestAnimationFrame was never originally intended to be the primary VSYNC method. However, ALL methods that syncs to VSYNC (whether be scrolling, or WebGL, or requestAnimationFrame), needs to be high-Hz compatible -- The existing politics on excluding requestAnimationFrame needs to be re-evaluated on the mainstream basis -- The widespread logical mutual agreement to "everything we did in the past that syncs to VSYNC should best-effort sync to Hz" -- rather than cherrypicking which APIs are allowed to sync to Hz, when in the past they used to (at 60Hz). It's a new refresh rate race that needs to be evaluated on its genuine human-benefits merits, including making sure past APIs are compatible with this new reality. Much like how browser APIs had to be changed to account for retina resolution screens in a broad-spectrum manner without cherrypicking. The same is true for retina refresh rates.

I should also add, I understand requestAnimationFrame was never originally intended to be the primary VSYNC method. However, ALL methods that syncs to VSYNC (whether be scrolling, or WebGL, or requestAnimationFrame), needs to be high-Hz compatible -- The existing politics on excluding requestAnimationFrame needs to be re-evaluated on the mainstream basis -- The widespread logical mutual agreement to "everything we did in the past that syncs to VSYNC should best-effort sync to Hz" -- rather than cherrypicking which APIs are allowed to sync to Hz, when in the past they used to (at 60Hz). It's a new refresh rate race that needs to be evaluated on its genuine human-benefits merits, including making sure past APIs are compatible with this new reality. Much like how browser APIs had to be changed to account for retina resolution screens in a broad-spectrum manner without cherrypicking. The same is true for retina refresh rates.

It appears that Generic WebKit now supports 144 Hz in the new smartphone: https://www.blurbusters.com/xiaomi-uses-testufo-to-demo-144-hz-redmi-5g- smartphone-apple-does-not-support-120-hz-testufo/ I have published the above article to the media side of Blur Busters (Blur Busters also has a laboratory side too). Currently, Blur Busters has media plans to more loudly call-out the 120 Hz browser limitation once Apple launches the upcoming 120 Hz smartphone. Will attempt to join the WHATWG prior to them, time-permitting, to try to faciliate an accelerated resolution -- but it would be nice to see Apple make some headway towards falling in line with defacto industry standard.

I have formally joined WHATWG and have submitted an issue relating to this; https://github.com/whatwg/meta/issues/158

I want you to support 120hz of iPad.

As a game developer, lover of performance, and user of Apple products, I think the 120Hz capable iPads should allow 120Hz games within the browser. The users deserve the best experience possible, especially if the device is plugged into power. Otherwise why not limit the whole of the app store's apps to 60Hz also? It doesn't make sense.

There needs to be support for different refresh rates as WebGL scenes are all over the place if the user/viewer is not @ 60hz refresh rate. requestAnimationFrame(fn,refreshRate) I tried my website on latest version of chrome dated 31/03/21 today with my monitor set to 120hz, it virtually maxed out all my cores on my i9 9900k and didn't touch my GPU (RTX 3080), not to mention it struggled to get above 22fps, where as if I had my refresh rate set to 60hz the WebGL scene would be locked at 60fps not a problem. Yes checked chrome was using hardware acceleration, tried it on and off, same result. Firefox on the other hand, didn't touch the CPU but used the GPU (which is correct) and nearly managed to get to 120fps, bounced around at 100 to 115. So then I changed to 75hz refresh rate, chrome one again started to use my GPU instead of my CPU and managed to get 75fps, still overshooting 60fps and firefox was the same. This is an old issue in the gaming industry, when one processor / gpu is faster than another measures were needed to maintain consistent speeds of animation between the different hardware. It's only going to get more and more common with new monitors to be running at varying different refresh frequencies (75, 90, 100, 110, 120, 240 etc), there even one that run at 300hz or 400hz or something, completely stupid imo, but it exists.

I would also love to see 120Hz support in Safari on iPad Pro (and any potential iPhones with ProMotion). If battery is a significant concern, could I suggest that web apps at least have access to 120Hz `requestAnimationFrame` for WebGL animations when they are added to the home screen? Let me explain my motivation: I'm collaborating on a library to animate Rubik's Cubes and similar puzzles. https://js.cubing.net/cubing/ https://github.com/cubing/cubing.js For some applications, it's valuable to animate solves in real time. - Solvers regularly perform more than 10 moves per second, with someone recently reaching 14 moves per second in a real-world solve: https://www.youtube.com/watch?v=ebPh2i53TBk - People can also solve virtual cubes using a keyboard at comparable speeds, where they would benefit from high frame rates similar to gamers. - There is a physical robot that can even reach 50 moves per second: https://www.youtube.com/watch?v=nt00QzKuNVY Sticking with the real solve example, with 14 moves per second at 60Hz: that's only ≈4 frames to animate a move, with faster moves potentially having only 2 or 3 frames. At this rate, moves would almost jump from start to finish, whereas 120Hz would offer a few frames of interpolation for the eye to follow. Empirically, this kind of difference can really make the animation much easier for cubers to follow along with. Also for context: I just measured our drawing code, and we're able to draw fairly complex puzzles at about 6ms per frame: https://experiments.cubing.net/cubing.js/stress-tests/40x40x40.html For some situations (e.g. smaller canvas, simpler puzzle, simpler rotations), I've been able to observe close to 1ms per frame. That shows that there is definitely room to support 120Hz while keeping web apps responsive. I would really prefer not to look into other devices or workarounds. The iPad Pro is really convenient and powerful for running web apps, and I would love to be able to use it for 120Hz WebGL animations. 😃

The refreshRate is redundant for the requestAnimationFrame function. You only need requestAnimationFrame(fn). Your code will be like this: const FPS = 240 const MILLISECONDS_PER_FRAME = 1000 / FPS let tStart = Date.now() let tickTarget, tick = 0 function fn() { tickTarget = (Date.now() - tStart) / MILLISECONDS_PER_FRAME while (tick < tickTarget) { // perform MILLISECONDS_PER_FRAME worth of game animation calculations } // render your game requestAnimationFrame(fn) } requestAnimationFrame(fn) Now your game will run with maximum smoothness at any refresh rate up to 240fps. It's really just the basics of game programming ;)

@jdspugh I'm not a games programmer, but ah yes, that time old classic of fps not syncing with computer cpu/gpu and capabilities and frame rates. Aka Delta Time. Different languages different ways, same thing. I should have looked into the functionality of requestAnimationFrame more... But cheers for the code and the memory recollection of that solution.

@jdspugh are you sure about that? The documentation at: https://developer.mozilla.org/en-US/docs/Web/API/window/requestAnimationFrame would suggest refreshrate *does* matter to using requestAnimationFrame specifically: >The number of callbacks is usually 60 times per second, but will generally match >the display refresh rate in most web browsers as per W3C recommendation. note the usage of "usually", "generally", "most".

@mksl My code snippet will run a game's simulation logic at the specified rate e.g. 240 fps. The render rate will depend on the device: 30/60/120 fps etc. So the game will function the same i.e. not speed up or slow down on devices with different refresh rates but the number of simulation updates the user sees will depend on the device's refresh rate. Even though the above code overcomes the problem of simulating games on devices with different refresh rates, I still believe there must be a way for the game to specify its preferred refresh rate. So something like requestAnimationFrame(fn,refreshRate), as proposed, is necessary. For reference, and to spur on this discussion and implementation: Since the last message I posted I've been coding on the Oculus Quest 2. It already provides a way to query the available refresh rates and set your desired refresh rate. It's incredibly pleasing and relieving to see this actually works in practise and I've been getting 120fps on the device from my WebXR code. For VR applications the refresh rate is way more critical which, I guess, is why the discussion and implementation of this feature has been accelerated and arrived on these devices already. This is how to code setting the device's maximum frame rate: --- const gRenderer = new WebGLRenderer() gRenderer.xr.addEventListener('sessionstart', event => { const gXrSession = gRenderer.xr.getSession() if (gXrSession.supportedFrameRates) { gXrSession.updateTargetFrameRate(Math.max(...gXrSession.supportedFrameRates)) } ... } --- gXrSession.supportedFrameRates on the Oculus Quest 2 return a Float32Array with the values [60, 72, 80, 90, 120]

<rdar://problem/88669060>

Our current thinking on high frequency animations is at https://github.com/WebKit/explainers/tree/main/animation-frame-rate

Web Animation API is missing a mandatory capability that we require to continue to be peer-reviewed (we are in over 25+ peer reviewed papers) We need single-framedrop detection capability (e.g. running at 59fps at 60Hz, or running at 239fps at 240Hz). To fix this, requires an animation-frame presentation callback as part of Web Animation API, e.g. the exact (relative-time) now() moment that a frame is presented from OS to GPU driver, e.g. Present() or glxxSwapBuffers() or similar page flip / frame buffer blit is called. requestAnimationFrame() provides such information, while Web Animation API does not. Because of this, Web Animation API produces lower-science-quality results, especially when a camera is pointed at a TestUFO animation (part of a NIST.gov peer reviewed paper) Even for effects almost visible to human eye, but visible in camera photographs; More information: https://github.com/WebKit/explainers/issues/85#issuecomment-1203341375

> requestAnimationFrame() provides such information, while Web Animation API does not. I'm curious about this claim. How does requestAnimationFrame() provide this information? According to the HTML spec [https://html.spec.whatwg.org/multipage/webappapis.html#event-loop-processing-model] both requestAnimationFrame() and Web Animations use the same `now` timestamp.

T(In reply to Simon Fraser (smfr) from comment #22) > > requestAnimationFrame() provides such information, while Web Animation API does not. > > I'm curious about this claim. How does requestAnimationFrame() provide this > information? According to the HTML spec > [https://html.spec.whatwg.org/multipage/webappapis.html#event-loop- > processing-model] both requestAnimationFrame() and Web Animations use the > same `now` timestamp. For requestAnimationFrame(), the per-frame realtime timestamp workflow is: 1. Provide a callback function to requestAnimationFrame() 2. The callback function provides an extremely accurate refresh cycle timestamp. These timestamps usable for detecting framedrops in FireFox and Chromium engines. So if an animation runs only 119 frames per second at 120Hz, it is called 119 times per second. Collecting the timestamps show an obvious two-refresh-cycle gap (2/120sec), which allows me to detect single dropped frames instantly (in order to invalidate scientific tests) There is no equivalent functionality I can find in Web Animation API that provides per-frame timestamps of visible frame presentation in real-time. If this is not documented, the Web Animation API specification need to be updated to be more clear of the existence of this functionality -- but as far as it reads, there is no similar functionality available. A longer explanation of why Web Animation API does not yet replace requestAnimationFrame() for TestUFO needs is at: https://github.com/WebKit/explainers/issues/85#issuecomment-1203341375

Additional Note (for those unfamiliar with existence of A leads to existence of B) I should also add that it ends up being a very accurate refresh cycle timestamp by the virtue of requestAnimationFrame() being specified in W3C section 7.1.4.2. The fact that browsers are effectively VSYNC ON means frame presentation blocks until a refresh cycle, and then immediately after, the engine calls requestAnimationFrame() callback for rendering the next frame. The fact that it's called immediately after the refresh cycle unblocks the previous frame, means I've got scientifically accurate refresh cycle timestamps The algorithm works correctly on Apple devices at 60Hz actually -- indeed it works correctly on Apple devices at 60Hz, but not at 120Hz (because you don't allow requestAnimationFrame to work at 120fps 120Hz in Safari) See the Catch-22?

Note -- no mistake, we really want to use Web Animation API, but we need a callback extension capable of providing timestamps accurate enough to almost instantly detect single missed frames in realtime (e.g. a refresh cycle doesn't get a new frame) -- This is very accurate in the TestUFO engine from realtime heuristical analysis of the requestAnimationFrame() timestamps, which can be monitored in realtime at www.testufo.com/animation-time-graph (insert some CPU spikes there such as opening new tabs and intentionally slowing down the GPU -- and you will see spikes appear, and spikes that exceed half a refresh cycle are assumed to be framedrops. Real world measurements confirm such (even with Safari 60Hz). How can we submit a request to extend Web Animation API to meet TestUFO needs (addition of a per-frame callback function similar to requestAnimationFrame's callback function)? We don't have to do any drawing in the callback, if that is discouraged, but we need identical timestamp quality to requestAnimationFrame for the reasons already explained at https://github.com/WebKit/explainers/issues/85#issuecomment-1203341375 We really want to use Web Animation API. Help us out on this missing functionality in Web Animation API?

Question: How can we submit a proposal to add a real-time frame-presentation timetamp callback feature to Web Animation API? (similar to the 'callback' feature of requestAnimationFrame) Pre-requisites: - Callback is executed everytime a frame is successfully visibly presented to display. - Callback function either receives a timestamp parameter (preferred) or I can execute now() at top of function (backup plan) Since all web browsers are inherently VSYNC ON technology, callbacks during full framerate=Hz operation defacto aligns automatically to real-world refresh cycle timestamps (to within 100 microseconds on Chrome on an RTX card, and to within 1 millisecond on 60Hz Apple Macs). But since requestAnimationFrame is being deprecated (and does not support 120Hz anyway), I need a path. Help me; how can I help the standardization? Help me; how can I help Apple sell 120Hz? TestUFO is the world's most popular 120Hz-showoff demo.

With the Web Animations API proposed at https://github.com/WebKit/explainers/tree/main/animation-frame-rate, where you can create an animation that will give you a JS callback on every frame, you'll be able to get exactly the same information you can get with requestAnimationFrame(), at least in WebKit. If other browsers are passing a timestamp to requestAnimationFrame() which is not just the "now" timestamp from the HTML spec, and this different timestamp gives you additional information, then you should lobby for those browsers to standardize whatever they are doing.

Thanks for the tip, I need to study if our team is incorrectly using the new APIs, or if we've discovered a major inconsistency between browsers in their timestamp handling between different browsers in Web Animation API (far more inconsistent than requestAnimationFrame). We will now do further research on a wider number of browsers. However, a scientific correction: > If other browsers are passing a timestamp to requestAnimationFrame() which is not just the "now" timestamp from the HTML spec, and this different timestamp gives you additional information, then you should lobby for those browsers to standardize whatever they are doing. Actually -- it's the same thing when it hits an equilibrium of framerate=Hz. Buring framerate=Hz situation, now() automatically settles to an equilibrium where now() is identical to refresh cycle time. One and the same thing, during max frame rat, it becomes is identical in the callback. It's a synonym during framerate=Hz now() is synonymous with refresh cycle timing when framerate=Hz, because of the way VSYNC (which existed since 1920s Biard/Farnsworth analog TVs) is a defacto comma-separator between refresh cycles. (VSYNC = Vertical Synchronization = a separator between refresh cycles, generated by all analog and digital video outputs over the last 100 years). Apple terminology sometimes call this BeamSync or displaySyncEnabled, but they're all synchronized to the VSYNC signal in the GPU -- it's the refresh cycle metronome. VSYNC is how Apple/Windows/Android/iOS synchronizes framerate=Hz for things like smooth scrolling and jank-free animations. SITUATION 1 When (framerate != Hz), it deviates so much that it signals instantly like a christmas tree within 1/Hz (i.e. reliable missed frame detection logic is easy to write with requestAnimationFrame(). The interval jitters, e.g. a dropped frame is 2/Hz sec between timestamps rather than 1/Hz sec between timestamps. SITUATION 2 When (framerate == Hz), it settles into an equilibrium that almost perfectly relative-time aligns to the VSYNC in the GPU (to an error margin of +/- 0.1 to 1ms at https://www.testufo.com/animation-time-graph ...) and it is easy to automatically decide that it's the current display refresh rate, because the interval doesn't jitter at all. Because of the fact that scientific equilibrium (2+2=4 is always true independently of OS), now() is identical to refresh cycle timestamps during SITUATION 2. Refresh rate detection is reliable in requestAnimationFrame() The way VSYNC ON in many APIs (VSYNC ON, VertSync ON, InVBlank=true, BeamSync ON, or whatever API terminology is used) -- works is that it blocks frame presentation (all APIs in all OS that synchronizes to the 100-year-old VSYNC that exists in all analog and digital video signals -- it's a 100% OS and vendor independent sync). So, when things are running maxed-out, timestamps almost perfectly aligns to refresh cycles. It's just scientific certainity, like 2+2=4, so in the spec, "now()" is identical to "refresh cycle timestamps" simply because of science of VSYNC. Conculsion: There is nothing to change in the requestAnimationFrame() standard, as it works perfectly now in all major HTML5 browsers (even in Safari too, at least at 60Hz). I'm kind of surprised you mentioned that, but perhaps it was from your unfamiliarity with a 100-year-old refresh cycle separator signal -- but at least now you know now() in the callback is generally synonymous to refresh cycle timestamps when things are running flat-out max framerate. That's why we're able to do refresh cycles so precisely in TestUFO, because we're very familiar with the VSYNC science (Blur Busters specializes in the Present()-to-Photons black box).

Update, I now realize you meant Web Animation API rather than requestAnimationFrame(): > If other browsers are passing a timestamp to WEB ANIMATION API which is not just the "now" timestamp from the HTML spec, and this different timestamp gives you additional information, then you should lobby for those browsers to standardize whatever they are doing. Perhaps that is the new insight. While requestAnimationFrame is working perfectly with correctly synonymous now()=refresh timestamps in all major browsers (except 120Hz Safari -- that is when we pull hair & throw keyboards) You're right -- we may have just very well discovered an inconsistency between different browsers' handling of Web Animation API timestamps. We now need to test all majors and see why it deviates from behavior of requestAnimiationFrame in non-synonymous "now() identical to refresh cycle timestamp" behavior, since that's literally just 2+2=5 in VSYNC science...

(In reply to mdrejhon from comment #29) > Update, I now realize you meant Web Animation API rather than > requestAnimationFrame(): > > > If other browsers are passing a timestamp to WEB ANIMATION API which is not just the "now" timestamp from the HTML spec, and this different timestamp gives you additional information, then you should lobby for those browsers to standardize whatever they are doing. No, I did mean requestAnimationFrame().

OK, in that case, Comment 38 automatically applies ( https://bugs.webkit.org/show_bug.cgi?id=173434#c28 ) There's no change needed to requestAnimationFrame standard except for lack of 120Hz Safari iOS support, because now() is scientifically synonymous with refresh cycle timestamps whenever it settles into a framerate=Hz equilibrium.

Fantastic to see 120Hz Safari working perfectly on the MacOS platform now, as long as you disable the 60fps lock setting. Once you disable that, requestAnimationFrame() works perfectly in TestUFO at 120Hz. Thank you for unlocking that, whomever did it. Now, please do the same thing on iPadOS and iOS, at least as an optional feature.

(In reply to Simon Fraser (smfr) from comment #20) > Our current thinking on high frequency animations is at > https://github.com/WebKit/explainers/tree/main/animation-frame-rate Can you confirm this is still your current thinking? The document seems out of date and if it isn't, most of the points raised seem tenuous: > We propose adding a frameRate property on the Animation interface requestAnimationFrame (rAF) is explicitly for circumventing the limitations of Animation. The example in the spec is canvas-based for a reason https://html.spec.whatwg.org/multipage/imagebitmap-and-animations.html#animation-frames > WebKit chose to restrict web content updates to 60Hz for two reasons: first, we measured a significant increase in power usage I wonder if you have the stats to back this up, but my intuition is that most calls to rAF are via popular animation libraries like GSAP and Framer Motion. The document proposes alternatives to rAF that, if widely adopted, would draw the same amount of power. If these high framerate alternatives exist, animation libraries will immediately make use of them. Throwing the battery life argument out the window. > second, we found several examples of web pages that had incorrect behavior when requestAnimationFrame() callbacks were fired at a non-60Hz frequency. Safari is only 25% of browser usage. Other browsers support vsync rAF. Most modern screens are 120/144hz. The main example of animations that would break are the typical "hello world" animation examples of the nature `rotate += 1`. It is, of course, bad practise to write this kind of animation even with a locked framerate, as slowdowns can happen. However, given Safari's relative market share, is it not more likely that the people writing these fundamentally broken examples have done so in Chrome, and are now more likely to be surprised to find their spinning 3D cube moving at half speed in Safari? You can take this fundamental principle and apply it to all your examples of "incorrect behaviour" and they'll increasingly be showing incorrect behaviour *only* in Safari. > There is generally two categories we see where the authors would want to specify an intent to update at a rate different than the default. Absent: syncing physical motion of canvas/3D etc to scroll or 120fps HTML elements. > WebKit is dedicated to push the concept of Custom Effects forward Are they? The spec looks abandoned and its suggested to be replaced with an onUpdate callback. I like the idea of a CustomEffect, I like the API, and it's clearly superior than an onUpdate callback tied to an arbitrary animation. However I also don't understand how either address your own complaints about battery life.

FYI, for those unaware, requestAnimationFrame() now works at 120fps on Apple iPads. If it is not working at 120fps, then do: Settings -> Safari -> Advanced -> Experimental Features -> "Prefer Page Rendering Updates near 60fps"

(In reply to mdrejhon from comment #34) > FYI, for those unaware, > > requestAnimationFrame() now works at 120fps on Apple iPads. > > If it is not working at 120fps, then do: > > Settings -> Safari -> Advanced -> Experimental Features -> "Prefer Page > Rendering Updates near 60fps" It's an interesting curio but not something I can reasonably tell my users when they ask why scroll-linked animations look terrible in Safari

I totally agree. Apple needs to make this easier, even if it's a permission-based API. Similar to the permission prompt for certain things (e.g. storage, full screen mode, etc). _______________________ PERMISSION PROMPT This webpage is requesting high-performance animations at frame rates above 60fps. This can result in smoother animations, but will consume more battery power. [Allow] [Deny]

I also have to call further into question the claim that the Webkit team has discovered instances where changing the tick rate of requestAnimationFrame broke behaviour on certain webpages. If this were true, or of genuine concern to the team, then why is it also the case that Webkit throttles rAF to 30fps in low power mode and within iframes? It seems to me the team has already accepted the variable-rate nature of rAF.

> I also have to call further into question the claim that the Webkit team has discovered instances where changing the tick rate of requestAnimationFrame broke behaviour on certain webpages. If this were true, or of genuine concern to the team, then why is it also the case that Webkit throttles rAF to 30fps in low power mode and within iframes? It seems to me the team has already accepted the variable-rate nature of rAF. Hello. Allow me to tell you Apple's stance as Simon Fraser explained to me: 1. High frame rate animations eat lots of power. That is understandable. SOLUTION: The user can fix this by exiting Low Power Mode. I am 100% completely fine with this, because the user CAN turn off Low Power Mode temporarily, if they urgently need 120fps for demos ("This is WHY you need to buy a 120Hz iPad") 2. IFRAME 30fps is to prevent advertisement banners eating too much power. SOLUTION: Unresolved and unoverrideable by user. This is a point of contention for me. I would like a "Same-origin" exception or a configurable option/permissions for this, because I do TestUFO EMBEDs like at https://blurbusters.com/oh-no-im-at-the-wrong-refresh-rate/ ... It shows the correct display refresh rate for Windows but the wrong refresh rate for Apple. This confuses Apple users. RECOMMENDED SOLUTION: Apple should find a way to add a setting to allow users to override this, at least for same-origin.

*** UPDATE *** requestAnimationFrame() has a bug at both 60Hz and 120Hz on any 144Hz display connected to a Mac Mini or a MacBook. TestUFO animations stubbornly run at 60fps (stutters bad) or 120fps (stutters bad). Since 144 is neither divisible by 60 nor 144. So when "Limit to 60fps" is disabled, it changes to a limit of 120fps! This is bad, because this stutters very badly when ProMotion is turned off. Apple should remove the 120fps whisper cap from requestAnimationFrame() as the MacOS experience is absolutely terrible with external gaming monitors attached. As Apple starts courting more gamers, including Vision Pro, many of its develoeprs (who do VR) already have high-Hz monitors, and are TestUFO users, and are finding TestUFO performs bad for some unknown weird reason. I am successfully showing off TestUFO at perfect 540fps at 540Hz, and Apple employees visited BOE booth at DisplayWeek 2023, and TestUFO was running www.testufo.com/framerates-versus on a laptop connected to their 500Hz LCD display. Perhaps Apple WebKit employees should talk to those Apple Display people, as I chatted to those Apple employees about my bone of contention of 120Hz requestAnimationFrame() ... TestUFO now has ~2 million visitors per month, by vendors, manufacturers, researchers. Independently, I approached a few employees of display vendors at other conventions I visited. TestUFO is also used by the manufacturer (including FoxConn) of Apple's displays too, to show off to interns why 120Hz looks so much better, etc.

Ooops, I meant "....divisible by 60 nor 120". (I wish this system would let me edit comments, like Bugzilla or GitHub Issues)

BTW, the upcoming TestUFO HDR 2.0 supports Safari DCI-P3 !!! (And Rec.2020/2100) Including display tests capable of brighter-than-white using a video workaround algorithm I've come up with. Screenshots: So, please (PLEASE), fix requestAnimationFrame 144Hz+ support for MacOS when user disables the 60fps limit. If you want to come visit me at CES 2024 to discuss the implications -- I'll be at the NanoSys-SHOEI booth, and I'd be happy to demonstrate TestUFO 2.0 on an iPad Pro 120Hz XDR in person. Contact mark [at] blurbusters.com ... A lot of booths are using TestUFO in fullscreen mode, so anytime Apple has visited a display convention, they already saw TestUFO at some booths (without the TestUFO brand). TestUFO HDR 2.0 pre-announcement with brighter-than-white photo: https://github.com/blurbusters/testufo-public#readme

BTW I have open sourced our HTML5 refresh rate calculator at: https://github.com/blurbusters/RefreshRateCalculator Apache 2.0 license -- you're welcome -- commercialize away It's the same refresh rate calculator used by vsynctester.com and testufo.com and is the world's most accurate browser-based refresh rate calculator algorithm for most platforms. It even correctly detects 600Hz-1000Hz prototype monitors connected to Windows platform (I'm Blur Busters, so I work with display manufacturers). It is accurate on Apple to about 60Hz unless "Limit Animations To 60fps" is disabled, then it's accurate to about 120Hz. If you connect a 144Hz-240Hz monitor to an Apple system, it fails.

Created attachment 469213 [details] Accidentally misleading tooltip by Safari Browser on MacOS A (potentially accidentally misleading/accidentally deceptive) tooltip by Apple; The screenshot claims matching refresh rate, but this tooltip is false when connecting a monitor of a refresh rate above 120Hz. For example, a 144Hz monitor will always permanently stutter at 60fps and 120fps, since 144 is not divisible by 60, and because of a hidden frame rate cap built into Apple Safari. With 60 vs 120 vs 240 massively more mainstream visible on OLED with its fast pixel response, I think Apple needs to either (A) correct the tooltip to say that frame rate will still be capped to 120, or (B) remove the Safari internal whisper cap of 120 for any refresh rate above 120.

To update this bug: - 120hz animations are supported on macOS and iPadOS. - Above 120hz animations are not supported on macOS with an external monitor with over a 120hz refresh rate. Other browsers support up to 240hz, for example. - 120hz animations are not supported on iOS. - 90hz animations are supported on visonOS Summary: 1. iOS needs to support 120hz animations 2. macOS needs to support up to 240hz animations.

To update this bug (again): - 120hz animations are supported on macOS and iPadOS. - Above 120hz animations are not supported on macOS with an external monitor with over a 120hz refresh rate. Chrome/firefox browsers support unlimited refresh rate animations. (Although currently the highest refresh rate monitor has 500hz). - 120hz animations are not supported on iOS. - 90hz animations are supported on visonOS. Summary: 1. iOS needs to support 120hz animations. 2. macOS needs to support up to unlimited animations. 3. The feature flag “prefer page rending updates near 60fps” needs to be off by default for macOS, iOS, and iPadOS. It is already off by default for visionOS. Also, if anyone knows of a PWA that can test screen hz/fps with vsync like testufo.com can, a comment would be appreciated. PWA are currently capped at 60hz animations because the feature flag “prefer page rending updates near 60fps” is on by default for iOS, iPadOS, and macOS. PWAs only run on system default flags.

It appears all Apple devices, including with external monitors on macs, support native animations except for iPhone Pros. Also: The “prefer page rendering updates near 60 fps” is default on in feature flags on macOS, iOS, and iPadOS. It is default off for visionOS. To support native animations in PWAs the feature flag needs to be default off for all Apple devices.

I just tried with the latest iPad Pro (2024) with the latest iPadOS 17.5, and confirmed that even after turning off the “prefer page rendering updates near 60 fps”, it doesn’t work on websites like testufo and vscode scrolling, still 60fps locked.

It's kinda opaque but: 1. Make sure iPad is not in Battery Saver mode 2. Make sure charge level is sufficiently high (>20%) 3. Make sure iPad is not in heat-based thermal throttle 4. Make sure "Prefer Page Rendering Updates Near 60fps" is disabled 5. As a last ditch, connect power cable while 100% fully charged. Report back with your findings. If everything failed, then there's an iOS 17.5 bug with that iPad.

> Also, if anyone knows of a PWA that can test screen hz/fps with vsync like > testufo.com can, a comment would be appreciated. PWA are currently capped at > 60hz animations because the feature flag “prefer page rending updates near > 60fps” is on by default for iOS, iPadOS, and macOS. PWAs only run on system > default flags. This is also a bone of contention with me too; the >60 support should be moved to a permission-based API for websites that requests a higher frame rate. This would apply to any application that initializes a CANVAS (WebGL, 2D, etc) or Web animation APIs. As Apple moves from LCDs (60-vs-120 only 1.1x clearer scrolling) to OLEDs (60-vs-120 now perfectly 2x clearer scrolling), this becomes more important to end users. Even 120-vs-480 OLED during public exhibit demos (DisplayWeek, CES, etc) was notably more visible than 60-vs-120 LCD, when watching proper smooth pan/scroll/turn tests rather than default video exhibit loops (which are usually only 60fps). Some Apple employee friends of mine proudly wears a Blur Busters UFO sticker on his MacBook, so change is slowly occuring at Apple, at least.

(In reply to Jeffrey Blanz from comment #46) > It appears all Apple devices, including with external monitors on macs, > support native animations except for iPhone Pros. I have recently gotten mixed reports on native animations support for >120Hz, I have bought way more equipment and proudly own a MacBook for 10-hour Visual Studio Code sessions that needs 120Hz and HDR testing, so MacBook is my TestUFO development machine now! TestUFO HDR launch is delayed until browsers become a bit less buggy in this area; It's been a while, but if you connect a 144Hz monitor to a Mac, Safari stubbornly still does 120fps and scrolling stutters badly. I need to do more tests, but there are possibly two reasons: (1) The internal display (e.g. MacBook display is still at 120Hz). The animations may go native if you disconnect the display. (2) Or Apple may have fixed 144Hz+ support in some situations. But with latest MacOS AND if you turn off the internal display, external displays now seem to go native - no more 120Hz interference from a concurrently-running 120Hz ProMotion display. Still wish my MacBook was OLED, as it's one of the blurriest 120Hz displays I've ever used -- Apple priorities good HDR and color, but definitely not 120Hz motion performance. It's only 1.1x better than 60Hz in scrolling clarity. Part of this is because LCD overdrive is disabled on almost all laptops, including Apple, and excellent-color LCDs are usually slower too. But OLED lets you have cake and eat it too, and so I am absurdly excited about OLEDs speeding up the refresh rate race due to more everyday consumer benefit. TechSpot mainstream writer recently wrote (in their March 22, 2024 lack of OLED burnin update) "...The 240Hz refresh rate at 4K is much better than I was expecting for productivity work. Relative to the 144Hz LCD I was using, the combination of a higher refresh rate and faster response times makes this QD-OLED much nicer to use for everyday tasks. Especially when browsing the web and scrolling through text, the speed and refresh rate combination is noticeable and provides a smoother, clearer experience – so it's not just gaming where you'll benefit from a 240Hz refresh rate..." (So, OLEDs makes the human-benefits of extra Hz much more visible -- 240Hz is no longer just for esports)

I tried following, but for websites like testufo are still locked at 60fps with latest iPadOS and iPad Pro 2024: 1. Disable power save mode, turn off “prefer page rendering near 60hz” 2. Charge battery to 100%, kill all other apps. Kill Safari multiple times. 3. Restart iPad Pro I suspect this is a bug in the latest iPadOS which will affect all iPad users. For those of you owning previous version of iPad Pro and latest iPadOS (17.5), please try and see whether it works.

(In reply to David from comment #51) > I tried following, but for websites like testufo are still locked at 60fps > with latest iPadOS and iPad Pro 2024: > > 1. Disable power save mode, turn off “prefer page rendering near 60hz” > 2. Charge battery to 100%, kill all other apps. Kill Safari multiple times. > 3. Restart iPad Pro > > I suspect this is a bug in the latest iPadOS which will affect all iPad > users. For those of you owning previous version of iPad Pro and latest > iPadOS (17.5), please try and see whether it works. I am not sure what bug you are seeing. I have tested this multiple times on iPadOS 17.5, I even just tested right now. I can attach screen shots if you really want. Also note that sometimes the perfect 60fps feature flag can reset. Make sure you force quit safari and settings. Then go back into settings and certify prefer 60fps is off. Also note: If you are using the Apple simulators with Xcode, they are capped at 60fps. You may also need to have desktop browsing enabled in settings.

I have verified the desktop browsing is on, and prefer 60fps option is off after restarting both Safari and Settings multiple times. I’m not using a simulator, if other iPad Pros don’t have the issue, maybe it’s an exclusive issue in iPad Pro 2024 (I’m using 11-inch iPad Pro 2024).

(In reply to mdrejhon from comment #50) > (In reply to Jeffrey Blanz from comment #46) > > It appears all Apple devices, including with external monitors on macs, > > support native animations except for iPhone Pros. > > I have recently gotten mixed reports on native animations support for > >120Hz, I have bought way more equipment and proudly own a MacBook for > 10-hour Visual Studio Code sessions that needs 120Hz and HDR testing, so > MacBook is my TestUFO development machine now! TestUFO HDR launch is > delayed until browsers become a bit less buggy in this area; > > It's been a while, but if you connect a 144Hz monitor to a Mac, Safari > stubbornly still does 120fps and scrolling stutters badly. I need to do > more tests, but there are possibly two reasons: > > (1) The internal display (e.g. MacBook display is still at 120Hz). > The animations may go native if you disconnect the display. > > (2) Or Apple may have fixed 144Hz+ support in some situations. > > But with latest MacOS AND if you turn off the internal display, external > displays now seem to go native - no more 120Hz interference from a > concurrently-running 120Hz ProMotion display. > > Still wish my MacBook was OLED, as it's one of the blurriest 120Hz displays > I've ever used -- Apple priorities good HDR and color, but definitely not > 120Hz motion performance. It's only 1.1x better than 60Hz in scrolling > clarity. Part of this is because LCD overdrive is disabled on almost all > laptops, including Apple, and excellent-color LCDs are usually slower too. > But OLED lets you have cake and eat it too, and so I am absurdly excited > about OLEDs speeding up the refresh rate race due to more everyday consumer > benefit. > > TechSpot mainstream writer recently wrote (in their March 22, 2024 lack of > OLED burnin update) "...The 240Hz refresh rate at 4K is much better than I > was expecting for productivity work. Relative to the 144Hz LCD I was using, > the combination of a higher refresh rate and faster response times makes > this QD-OLED much nicer to use for everyday tasks. Especially when browsing > the web and scrolling through text, the speed and refresh rate combination > is noticeable and provides a smoother, clearer experience – so it's not just > gaming where you'll benefit from a 240Hz refresh rate..." > > (So, OLEDs makes the human-benefits of extra Hz much more visible -- 240Hz > is no longer just for esports) I have had multiple friends verify that Mac’s with external displays can hit 240hz+. Even an Apple employee commuted on a form I had says he got it. Link to other post I had: https://bugs.webkit.org/show_bug.cgi?id=272753 I wonder if it is just the MacBook pros, iPad pros, MacBook airs, and iMacs that are limited when connecting to an external display. As I am pretty sure the Mac Studio, mini, and pro all support unlimited screen refresh rate on safari.

(In reply to David from comment #53) > I have verified the desktop browsing is on, and prefer 60fps option is off > after restarting both Safari and Settings multiple times. I’m not using a > simulator, if other iPad Pros don’t have the issue, maybe it’s an exclusive > issue in iPad Pro 2024 (I’m using 11-inch iPad Pro 2024). Well that is not good. I was looking forward to buying that device sometime. I am using a iPad Pro 2018. I would encourage you to submit a bug form solely for the iPad Pro 2024 not having 120 Hz animation support.

(In reply to mdrejhon from comment #50) > (In reply to Jeffrey Blanz from comment #46) > > It appears all Apple devices, including with external monitors on macs, > > support native animations except for iPhone Pros. > > I have recently gotten mixed reports on native animations support for > >120Hz, I have bought way more equipment and proudly own a MacBook for > 10-hour Visual Studio Code sessions that needs 120Hz and HDR testing, so > MacBook is my TestUFO development machine now! TestUFO HDR launch is > delayed until browsers become a bit less buggy in this area; > > It's been a while, but if you connect a 144Hz monitor to a Mac, Safari > stubbornly still does 120fps and scrolling stutters badly. I need to do > more tests, but there are possibly two reasons: > > (1) The internal display (e.g. MacBook display is still at 120Hz). > The animations may go native if you disconnect the display. > > (2) Or Apple may have fixed 144Hz+ support in some situations. > > But with latest MacOS AND if you turn off the internal display, external > displays now seem to go native - no more 120Hz interference from a > concurrently-running 120Hz ProMotion display. > > Still wish my MacBook was OLED, as it's one of the blurriest 120Hz displays > I've ever used -- Apple priorities good HDR and color, but definitely not > 120Hz motion performance. It's only 1.1x better than 60Hz in scrolling > clarity. Part of this is because LCD overdrive is disabled on almost all > laptops, including Apple, and excellent-color LCDs are usually slower too. > But OLED lets you have cake and eat it too, and so I am absurdly excited > about OLEDs speeding up the refresh rate race due to more everyday consumer > benefit. > > TechSpot mainstream writer recently wrote (in their March 22, 2024 lack of > OLED burnin update) "...The 240Hz refresh rate at 4K is much better than I > was expecting for productivity work. Relative to the 144Hz LCD I was using, > the combination of a higher refresh rate and faster response times makes > this QD-OLED much nicer to use for everyday tasks. Especially when browsing > the web and scrolling through text, the speed and refresh rate combination > is noticeable and provides a smoother, clearer experience – so it's not just > gaming where you'll benefit from a 240Hz refresh rate..." > > (So, OLEDs makes the human-benefits of extra Hz much more visible -- 240Hz > is no longer just for esports) When you hook up your MacBook Pro to a 144hz monitor, does testufo on chrome show 144hz? Wondering if this is a software limitation with outputting on external displays, and not a limitation with safari. This would be like how iPad Pros can only output 60fps to an external display, regardless if the external display is 120hz.

(In reply to Jeffrey Blanz from comment #54) > I wonder if it is just the MacBook pros, iPad pros, MacBook airs, and iMacs > that are limited when connecting to an external display. As I am pretty sure > the Mac Studio, mini, and pro all support unlimited screen refresh rate on > safari. Its not an internal/external issue. It's a concurrent discordant-Hz multi monitor issue, close the laptop lid to make an external 144Hz+ monitor become primary monitor and then 144Hz+ works. Now, Apple does opaquely disable 120Hz for unknown reasons sometimes, like from thermal/power throttling or low power, without specifically explaining why >60fps stops working. Windows is still much more reliable at >60fps at the moment...

So in all the bug is this: With the “prefer page rendering updates near 60fps” feature flag disabled, native external monitor hz/fps is not supported on safari if the following conductions are met: 1. The device has a built in screen (MacBook Pro, MacBook Air or iMac). 2. The MacBook lid is open (excluding iMac). If anyone can confirm that this happens with an external monitor that has a higher refresh rate than the native mac display please respond. Also please test to make sure you get the native hz/fps with chrome.

In the past, 120Hz never worked properly in Safari. However, there are fewer and fewer cases where 120Hz does not work. I feel this issue should still remain open until completely solved for all possible edge cases for all 120Hz Webkit devices including Safari variants.

I would actually have to say the opposite. This should be marked resolved because of the following: 1. I just tested my M1 Pro MacBook Pro, with the lid open, with safari 17.5 and a 165hz monitor. My Mac got 120hz while the external monitor got 165hz. 2. iPhone Pros will be getting 120hz fixed in 278949@main (596b3b01497f): <https://commits.webkit.org/278949@main> 3. The M4 iPad Pros will also be fixed with 278949@main (596b3b01497f): <https://commits.webkit.org/278949@main> This means that there are no longer any scenarios where native requestanimationframe is not supported, as soon as 278949@main is pushed to the public. Besides when the feature flag "prefer page rendering updates near 60fps" is enabled. That is a different issue though. You can see Antonio Quint's comment on the M4 iPads here: https://bugs.webkit.org/show_bug.cgi?id=272165 I will attach a video of external monitor support working perfectly fine with a MacBook with the lid open. I used normal safari 17.5 and tried it both with the windows in fullscreen and not in fullscreen.

(In reply to Jeffrey Blanz from comment #60) > I would actually have to say the opposite. This should be marked resolved > because of the following: Let's wait until the upstream pushes and a royal flush occurs. > 1. I just tested my M1 Pro MacBook Pro, with the lid open, with safari 17.5 > and a 165hz monitor. My Mac got 120hz while the external monitor got 165hz. Then if TestUFO running on secondary shows 165Hz, they have fixed the problem. Good, I'll update my OS to the latest MacOS. I'm one version behind. > 2. iPhone Pros will be getting 120hz fixed in 278949@main (596b3b01497f): > <https://commits.webkit.org/278949@main> Good, but it's not upstream yet. > 3. The M4 iPad Pros will also be fixed with 278949@main (596b3b01497f): > <https://commits.webkit.org/278949@main> Good, but it's not upstream yet. > This means that there are no longer any scenarios where native > requestanimationframe is not supported, as soon as 278949@main is pushed to > the public. Besides when the feature flag "prefer page rendering updates > near 60fps" is enabled. That is a different issue though. Fair. Once all checkboxes go green, I'll declare it closed. Until the issue makes it to production firmwares and devices, let's keep this open, shall we? :-) Good news indeed, though.

(In reply to Jeffrey Blanz from comment #60) > I would actually have to say the opposite. This should be marked resolved > because of the following: Let's wait until the upstream pushes and a royal flush occurs. > 1. I just tested my M1 Pro MacBook Pro, with the lid open, with safari 17.5 > and a 165hz monitor. My Mac got 120hz while the external monitor got 165hz. Then if TestUFO running on secondary shows 165Hz, they have fixed the problem. Good, I'll update my OS to the latest MacOS. I'm one version behind. > 2. iPhone Pros will be getting 120hz fixed in 278949@main (596b3b01497f): > <https://commits.webkit.org/278949@main> Good, but it's not upstream yet in public browser releases. > 3. The M4 iPad Pros will also be fixed with 278949@main (596b3b01497f): > <https://commits.webkit.org/278949@main> Good, but it's not upstream yet in public browser releases. > This means that there are no longer any scenarios where native > requestanimationframe is not supported, as soon as 278949@main is pushed to > the public. Besides when the feature flag "prefer page rendering updates > near 60fps" is enabled. That is a different issue though. Fair. Once all checkboxes go green, I'll declare it closed. Until the issue makes it to production software, let's keep this open, shall we? I keep discovering whac-a-mole issues where Safari fixes something but breaks something else, due to a lingering Webkit unanticipated side effect (like multimonitor behavior and such). It's easier to keep an issue open longer than close-and-reopen. Good news indeed, though.

> (In reply to mdrejhon from comment #61) Oops, sorry about modified duplicate. Delete #61 and keep #62.

> (In reply to mdrejhon from comment #61) Oops, sorry about modified duplicate. Delete #61 and keep #62. I don't have edit/delete priveleges unlike some of you.

Created attachment 471437 [details] Video of 165hz with external monitor with MacBook Pro

I agree, waiting to mark this resolved until the iPhone Pro and M4 iPad Pro are fixed publicly is ideal.

After this is closed I may open related-issue about discovery problems, like 120Hz displays running in 60Hz mode. Such as a permission-request to access 120Hz+ functionality (if it exists) rather than forcing user to change an advanced-menu setting. Any webpage with a large same-origin canvas (e.g. not an ad banner) should request permission for >60fps, to make it easier for users. "Webpage is requesting permission to use high frame rate (ProMotion) animations. This may consume more battery power. Allow? Yes/No" Even if Apple's own privacy rules means I can't discover its existence before user grants permission (like the fullscreen-mode permission request, or the notifications-allow permission request). But that's a different UX ballpark warranting a new opened webkit issue.

Yes, and really the "prefer page reding updates near 60fps" feature flag needs to be default off. It is default on for macOS, iOS, and iPadOS. Interestingly though, it is default off for visionOS. Also I have another bug open that aims to change this. PWA apps run off of default feature flags, meaning changing the feature flag will not affect the PWAs. This means above 60fps is disabled for all PWAs. You can see this bug here: Bug 272226 https://bugs.webkit.org/show_bug.cgi?id=272226

(In reply to mdrejhon from comment #67) > "Webpage is requesting permission to use high frame rate (ProMotion) > animations. This may consume more battery power. Allow? Yes/No" Just submitted new "Enhancement" bug: https://bugs.webkit.org/show_bug.cgi?id=274372

Created attachment 471734 [details] 120fps now supported on iPhones with iOS 18.0 dev beta 2 iPhone now support native requestanimationframe with iOS 18.0 dev beta 2! This is possibly also fixed in iOS 16.0 dev beta 1. I can not confirm this. Can anyone confirm iPadOS 18.0 dev beta 2 also fixes this issue for M4 iPad Pros? If it does then this issue will be fixed when iOS 18 is stable, possibly even iOS 17.6.

Update: This issue has been fixed on M4 iPad Pros. This issue is also only fixed in the latest iOS 18 dev beta 2, and not in the iOS 17.6 beta as originally thought. This means there is no longer any scenario where native requestanimationframe is not supported as long as the feature flag is disabled and the device iOS on iOS 18 dev beta 2 or later. This thread should be closed when iOS 18 releases in the fall.

This issue is still present on the iPhone 16 Pro and iPhone 16 Pro Max. Currently using iOS 18.1 beta 4. This issue is fixed on all other Apple devices including Macs, iPad Pros, and other iPhone Pros.

See bug 280183: https://bugs.webkit.org/show_bug.cgi?id=280183

When I transferred my devices I forgot that the feature flags reset for Safari. Because of this I had the feature flag for “prefer 60fps” turned on. I turned it off an I now get 120fps on the 16 Pro Max. This thread can now be closed as the issue has been fully fixed with iOS 18’s public release.

(In reply to Jeffrey Blanz from comment #74) > When I transferred my devices I forgot that the feature flags reset for > Safari. Because of this I had the feature flag for “prefer 60fps” turned on. > > I turned it off an I now get 120fps on the 16 Pro Max. > > This thread can now be closed as the issue has been fully fixed with iOS > 18’s public release. Thank you for doing that testing, Jeffrey. It's very helpful to get that confirmation.

Seeing Reports of 120fps not working for safari on external displays with the M5 iPad Pro. The M5 iPad Pro supports 120hz external displays, but only achieves 60fps when tested on testufo.com. This is with the prefer page rendering updates near 60fps set to Off.

Jeffrey, a colleague tested an iPad Pro (M5, 2025) running iOS 26.1 connected to a 144Hz external display yielded the expected results when the "Prefer Page Rendering Updates near 60Hz" setting disabled: TestUFO 2.1 reported 120fps frame rate and 120Hz refresh rate. If you have evidence to the contrary, please file a dedicated bug report with a screen recording if possible so that we may understand any difference in setup the affected configuration may have.