Re: [mediacapture-screen-share] Either fully support or remove audio capture entirely: "MAY" re audio capture is ambiguous (#140)

@jan-ivar 

> The API is not ambiguous: it clearly states that applications may not rely on audio being returned. This means an app cannot force a user to share audio, which was intentional.

The goal is not to force a user to capture audio. 

The goal for disambiguation is to allow a user to capture audio.

> The use case we had consensus to include was complementary audio for screen-sharing, at a user's discretion. Audio-only capture was deemed out of scope.

That use case is not possible at Firefox or Chromium without using `getUserMedia()`. At Chromium that use case is not possible at all using only the browser. The user must first record a `MediaStream` and set the device to `Monitor of <device>` during the recording to change the device, due to Chromium only supplying a specific class of device to capture, that is, internal microphone.

The use case that you describe as being consensus is no possible right now. Consider 

`$ mpv blade_runner.webm`

then

`navigator.mediaDevices.getDisplayMedia({video: true, audio: true})` 

at a browser, which satisfies 

> An audio source may be a particular application, window, browser, the entire system audio or any combination thereof.

and nullifies 

>  If the user agent knows no audio will be shared for the lifetime of the stream it MUST NOT include an audio track in the resulting stream.

However, given the use case consensus agreed upon, if file issues at Chromium and Firefox right now, the implementers could simply say "we don't want to capture audio, for no reason" and the specification cannot be cited as a primary source for the requirement to capture both vide _and_ the audio output by `mpv` or similar media playback application, thus rendering the "MAY" effectively a "DON'T HAVE TO IF WE DON'T WANT TO, FOR NO REASON", which is ambiguous, or, essentially, "WILL NOT", making any mention of audio capture in the specification as to having teeth moot.



-- 
GitHub Notification of comment by guest271314
Please view or discuss this issue at https://github.com/w3c/mediacapture-screen-share/issues/140#issuecomment-629705824 using your GitHub account

Received on Saturday, 16 May 2020 21:07:33 UTC