Bug 277100 – Video in background tab is unpausing at random

• Status: NEW
• Component: Media

[Eric S]

I currently have about a half-dozen tabs open that have an embedded video (using the <video> element) on the page, which I have paused (or never started). There are also dozens of other tabs open, across four or five windows total.

Sometimes, seemingly at random, one of the tabs with the paused video will unpause itself - without any interaction on my part. The tab with the video is still not the foreground tab when this happens.

Some things I've noticed that might help with reproducibility:
- It seems more common (maybe exclusive to?) when video playback is sped up
- It seems to happen most often when focusing the Safari window when another application had previously been in the foreground
- I can only remember this happening on the WWDC videos on developer.apple.com (so it's possibly specific to that site)
- I usually have a different application open that's also playing video (which is, I believe, also using Webkit)
- I do not believe it's ever happened with videos on the foreground tab

Here's a URL where I've experienced this: https://developer.apple.com/videos/play/wwdc2024/10169/?time=1169

Happy to answer any other questions that might be relevant.

Safari Version 17.5 (19618.2.12.11.6), macOS Sonoma 14.5, M2 Pro Mac mini. It is NOT a brand new issue; it's happened on and off for at least a couple months.

[Radar WebKit Bug Importer]

<rdar://problem/133016340>

[Jer Noble]

Hello! This is a known issue on developer.apple.com, where they're reacting to a readyState change from HAVE_CURRENT_DATA to HAVE_FUTURE_DATA by playing the video, even if it's paused. We've reached out to developer.apple.com with repro steps, so hopefully this can get resolved outside of a software change in WebKit.

[Eric S]

Sounds great, I greatly appreciate you passing it to the right team! Thank you!