Re: [mediacapture-screen-share] Is it meaningful to select window audio to be system or window at surface selection time? (#325)

> I wonder what happens if surface changes.

The captured surface changes in response to the user's interaction with the UA and/or OS. That interaction gives a clear indication of the user's intentions. It is up to the UX employed by either the UA or OS to communicate to the user the effect this would have on audio, and to solicit an explicit decision by the user if necessary.

If we posit a hypothetical Chromium-style "share something else" button that shows a dialog identical to the original getDisplayMedia dialog, then I would expect the original hint to apply equally here as it did for the original gDM invocation.

> I also wonder whether the goal is to improve privacy by reducing exposure of audio, or whether it is a convenience.

The goal is to let the user's servants - their OS, their UA and their Web app - all work in coordination. 
- With `windowAudio` correctly employed by the Web app, the UA does not offer the user to share audio which the app would subsequently ignore. Consistent messaging and predictable behavior means the user can more confidently participate in video calls.
- There is a privacy aspect here, albeit minor. Namely, `windowAudio` is one more building block towards the greater edifice that is - only ever ask the user to grant the minimum necessary set of permissions to accomplish the goal.
- Similarly, there is a minor convenience aspect, in that `windowAudio` allows the UA to surface the right audio source for the task at hand.

> an approach would be to allow selection of the audio dynamically via either the track (a constraint maybe) or CaptureController (an attribute setter).

I don't think this would be wise. Once the user makes their selection of audio source, that should not ever change except for through trusted user interaction with a trusted UX - that of the UA or the OS.

> That may allow a scenario where user can dynamically switch between the two audio via some HTML UX.

If this is a requirement for you, I am open to discussing ways to solve it. But please note my previous reply and the complications it alludes to.

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Received on Monday, 2 June 2025 14:39:38 UTC