Should PiP video removed from the DOM leave PiP?

[beaufortfrancois]

In Chrome and Safari, a video element not attached to the DOM can start playing and enter Picture-in-Picture. When video is attached to the DOM while playing in Picture-in-Picture, browser implementations differ though when video is removed from the DOM:

• In Chrome, it pauses the video as HTML spec says and nothing more.
• In Safari, it pauses the video as well but also leaves Picture-in-Picture.

It looks like Safari takes a hint from the Fullscreen API:

Whenever the removing steps run with a removedNode, run these steps:

1. Let document be removedNode’s node document.
2. Let nodes be removedNode’s shadow-including inclusive descendants that have their fullscreen flag set, in shadow-including tree order.
3. For each node in nodes:
   1. If node is document’s fullscreen element, exit fullscreen document.
   2. Otherwise, unfullscreen node.
   3. If document’s top layer contains node, remove node from document’s top layer.

Note that the Fullscreen API doesn't allow an element not atttached to the DOM to enter fullscreen unlike Picture-in-Picture that does not prevent it.

[beaufortfrancois]

It would be great if spec could document the intended behavior for this.

@jernoble @mounirlamouri Let me know what you think and I'll update the spec.

[mounirlamouri]

Given that you can send a video not in the document in PIP, I see no reason why leaving the document should exit Picture-in-Picture. I don't have a strong opinion because it's probably an edge case anyway. Is there a specific reason why Safari did this?

[jernoble]

We're debating this internally. We think it was just a side effect of our original conflation of "fullscreen presentation modes" and "picture-in-picture", and not intended as an explicit policy.

WebKit has always supported entering video fullscreen from a non-DOM

[mounirlamouri]

@beaufortfrancois should we close?

[beaufortfrancois]

Sure. Let's close.

[beaufortfrancois]

It looks like Safari updated their behaviour:

When a video is playing in the picture-in-picture mode, do not pause it or exit the
picture-in-picture mode when detaching the video element from the DOM.

Source: https://trac.webkit.org/changeset/265904/webkit/

@mounirlamouri Shall we update Chrome and not pause as well for consistency?

[mounirlamouri]

The issue with not pausing is that it goes against the HTML specification requirements (see just above https://html.spec.whatwg.org/multipage/media.html#seeking).

That means the WebKit change is against spec. I would rather not have the Picture-in-Picture specification changes the behaviour of the HTML specification. We could obviously ask for the HTML specification to update this section if we believe it's worth it.

[beaufortfrancois]

@pliu6 @jernoble Do you have plans to update the HTML spec?

[beaufortfrancois]

@jernoble (gentle ping)

[beaufortfrancois]

@pliu6 (gentle ping)

[jernoble]

Raised an issue against HTML: whatwg/html#6271

[beaufortfrancois]

I've just updated Chromium to make sure video do not pause when playing in Picture-in-Picture and subsequently removed from the Document. See CL at https://chromium-review.googlesource.com/c/chromium/src/+/2627311

I've also added some web platform tests at web-platform-tests/wpt#27185 and make sure both Chrome and Safari browsers pass them.

[mounirlamouri]

Removing agenda label as it sounds that this is reaching a conclusion.