Distiguishing manually triggered vs automatically triggered `enterpictureinpicture`

[steimelchrome]

We added an enterpictureinpicture action with #295. Initially, that PR made the MediaSessionActionDetails of that action include a boolean indicating whether or not this was via an explicit user action (e.g. clicking a picture-in-picture button in the UA's UI) vs automatically triggered by the UA (e.g. because the page became hidden).

I thought the boolean (or some equivalent enum or other way to distinguish the two cases) could be useful for websites, but I didn't have any explicit use cases at the time, so after discussion in a Media WG meeting we decided to remove the boolean.

However, we've gotten some feedback from websites that being able to distinguish would be useful. One particular case is a video playback site that wants to fine-tune when it autopips vs not based on different criteria (type of video playing, how long it's playing, how the user generally interacts with pip, etc). They want the user actually clicking a pip button to always work (so they need to be registered for the enterpip action), but they want to ignore autopipping in some cases (so they need to know which it is when they receive the callback).

I propose we add a boolean to the MediaSessionActionDetails as initially proposed, but I'm open to feedback/bikeshedding

[chrisn]

Discussed in Media WG meeting, 30 April 2025, minutes.

[chrisn]

As #362 has been merged, are we ready to close this issue?

Has there been any follow up on the declarative autoplay policy preference discussed in the 30 Apr 2025 Media WG meeting?

[steimelchrome]

Yes we can close this. There's more to be done on declarative, but that can probably be done in a separate issue. There is some work here to add a policy for automatic pip, which gives sites a way to declare that they don't want it, which solves some of the issue, but there's likely more we want to do in terms of declaring a specific video element that should be autopipped. Unsure if that should live here in Media Session, inside the HTMLMediaElement itself, or some separate autopip API