[Webkit-unassigned] [Bug 235845] REGRESSION: iOS 15.4b1 – gl.texture2D uploads not working

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=235845

--- Comment #13 from Nicholas Butko <nb at 8thwall.com> ---
The rationale for a multi-texture pipeline (not double-buffering per se) is laid out above. Keeping a pipeline of textures is a requirement. In order to power the same pipeline with a single texture in getUserMedia would require a framebuffer pipeline instead, adding an extra unneeded draw-with-shader to copy the full resolution texture to a framebuffer in addition to the texture upload. Is there another pipelining paradigm that's expected to be more efficient?

video.currentTime increments by ~16ms per frame. If the framerate were lower than 60FPS, we would expect that this should not increment.

Setting `framerate: {min: 60}` improves the current sample somewhat, but still gives unacceptable visible artifacts which are also not present in iOS 15.3.

We had seen similar issues previously, which we had noted in https://bugs.webkit.org/show_bug.cgi?id=206636. It was suggested in Jan 2020 that this had been fixed, and in our testing this issue no longer reproduced in iOS 14 and above. We have since removed our workarounds for iOS Safari versions 14 and higher.

The current issue is a REGRESSION from 15.3 to 15.4 beta. The hypothesized cause for the issue only accounts for the observed regressions if 15.3 had a framerate that was always higher than 60FPS AND 15.4 beta sets a lower default AND doesn't reliably provide 60FPS at 60FPS capture.

Regardless, this is a business critical regression in iOS 15.4 beta. If the fix for https://bugs.webkit.org/show_bug.cgi?id=203148 is also expected to fix this issue, we look forward to testing in upcoming versions of iOS 15.4 beta.

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