W3C home > Mailing lists > Public > public-media-capture@w3.org > June 2012

Re: Implementation suggestions

From: Anant Narayanan <anant@mozilla.com>
Date: Wed, 06 Jun 2012 23:23:18 -0700
Message-ID: <4FD048D6.9020307@mozilla.com>
To: Stefan Hakansson LK <stefan.lk.hakansson@ericsson.com>
CC: public-media-capture@w3.org
Hi Stefan,

On 06/05/2012 11:45 PM, Stefan Hakansson LK wrote:
> * It is said that resources that are allocated already as a result of
> earlier calls to getUserMedia should be presented as busy (with the
> option to terminate that stream and allow use for the current
> getUserMedia instead. My question: what about resources that are taken
> by other native apps than the browser? Could this be detected, and could
> any understandable info be presented to the user?

I think this depends greatly on the operating environment. This is 
possible on some browsers in some operating systems, but not all. I 
added language to this effect.

> * On the same theme: it is said that if the user selects to allocate a
> resource that is already taken by an earlier call to getUserMedia, the
> existing LocalMediaStream should be stopped. However, perhaps the
> conflict is only for one of several tracks in the existing
> LocalMediaStream. An alternative approach could be that only the
> relevant tracks of the existing LocalMediaStream are ended (and the
> stream ended only if all tracks are "taken").

Good point! Only the track should be removed. Fixed.

> * It is said that "the user be allowed to select any available hardware
> as a source"; should it not be gated by available HW that fulfills
> mandatory constraints?

That's correct, fixed!

> * About using files: I guess we need to spec how the browser should find
> such files. I mean, the browser can't scan the entire computer for files
> of certain types every time getUserMedia is called, rigth?

I was thinking something along the lines of a file picker, I added that 
in as a suggestion.

> * Should there a way for the application to indicate that it wants only
> one audio and one video track when calling getUserMedia? If this was
> possible, the browser could then make the selections "exclusive-or" when
> set, "and" when not set.

I think there should be a normative way for non-trusted applications to 
specify a limited set of constraints to do this kind of thing. Let's 
discuss some proposals and see if we can reach some consensus.

Received on Thursday, 7 June 2012 06:23:58 UTC

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