Bug 262617 – Video frame shifts when played before buffer begins using HLS

• Component: Media
• Status: RESOLVED CONFIGURATION CHANGED

[Celeste Glavin]

Created attachment 468062 [details]
This is an example from a code sandbox where a portrait video frames should take up the width and height of the video element, but they are shifted up and sometimes squished in dimensions

Repro steps:
- hit the play button before buffer begins
- seek around to unbuffered zones
- try again and again

Expected:
- Video plays once buffered and takes up the full video element container

Actual:
- Video frame fluctuates in size, sometimes squishing the aspect ratio and then resizing up (or, sometimes we were noticing it shift to the left) 


Notes:
- from within our app, we were not able to reproduce this when we removed the poster attribute (but that is not desired)
- we haven't been able to reproduce in Safari 17



Example of the repro code:

<div className="App">
      <video
        controls={true}
        width="270px"
        height="480px"
        src="path/to/hls/manifest"
      />
</div>

[Alexey Proskuryakov]

Thank you for the report.

> - we haven't been able to reproduce in Safari 17

I'm marking this as resolved then, as this appears to have been fixed in WebKit already.

[Celeste Glavin]

This breaks the video player for all users using Safari 16.2 through 16.6 -> can you provide any information as to what was fixed? Or if there are workarounds to this issue?

[Alexey Proskuryakov]

CC'ing some folks who may know, but if this doesn't ring a bell, this could be difficult to find out.