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Comment by jdiff | Hacker News Reader

Interesting that the video being used as a showcase is dropping so many frames. Is QuickShell particularly heavy, the system recording particularly anemic, or something else? For the first half of the video I didn't realize QuickShell supported transitions at all and thought it only had hard cuts between different states. It looks like a very interesting project though and a worthy time sink, especially with those transitions being supported.

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It’s something else, in your connection or your computer. The video plays fine on the old iPad mini I’m using right now and shows transitions from the very first action.

The video is 125fps (according to ffprobe) and appears smooth on my 120Hz display, so maybe you're the one dropping frames.

125 fps should actually be a huge red flag, not that the video FPS is the be-all-end-all of what the render FPS actually was anyways, as that's extremely unlikely to be their (that is the recorder's) refresh rate. Since the other video has a different (but equally odd) refresh rate, we know it isn't their refresh rate for sure, which also means we know there would at least be judder (recording at a mismatched framerate from the content) or at worst drops.

This all strongly hints to the videos being variable frame rate encoded. A quick dump of the timestamps with ffprobe and then a quick transform to the deltas seems to agree with this https://pastebin.com/raw/PbbNGBVy

The most common frametime is 0.006945, which aligns with a 144 Hz target refresh rate. This makes sense as 144 Hz makes perfect sense as their monitor's refresh rate. Ignoring timestamp rounding differences, these are the inconsistent frametime buckets:

   0.006945, 0.01389, 0.020836, 0.027782, 0.034726, 0.041672, 0.048617, 0.062508, 0.076399, 0.097235, 0.10418, 0.118071, 0.145852, 0.166689, 0.229196, 0.256978, 0.29865, 0.354213, 0.395886, 0.513957, 0.770935

Watching a VFR recording of a 144 Hz desktop on a 120 Hz display may still seem smooth to you (after all, movies are 24 FPS and most online videos only 60 FPS) but it does not preclude frame targets being missed, as the data shows.

VFR video is relatively uncommon as well, so I wonder if that's why people are reporting so many performance issues viewing the video with different setups. I.e. between all of the reports of stuttering, it's probably both the video itself and the devices trying to play the oddly encoded video.

Yeah, it's outstandingly smooth for a web video.

The page actually crashed my computer the first time. ("Why did you try again?" I've had the same issue with a couple of other specific things — most notably the clipping interface on Twitch, which causes it reliably — and I'm trying to figure out an ultimate cause; but I really don't know what I'm doing there.)

fwiw in Firefox on my old Android phone I saw the same choppiness watching it in page but downloading & watching it locally it was smooth.

On very fast WiFi & the video is only 2MB so I can only presume something in the page is competing for device perf.

FF is certainly choppier

I can also watch it totally fine in a cheap recent Android phone at Firefox

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