W3C home > Mailing lists > Public > public-media-capture@w3.org > February 2014

Re: About the Mandatory constraints

From: Randy Lin <rlin@mozilla.com>
Date: Thu, 6 Feb 2014 02:55:39 -0800 (PST)
To: public-media-capture@w3.org
Cc: Stefan Håkansson LK <stefan.lk.hakansson@ericsson.com>, Robert O'Callahan <rocallahan@mozilla.com>
Message-ID: <54487239.6798811.1391684139117.JavaMail.zimbra@mozilla.com>
For MediaRecorder API, application may 
1, want to record only audio part from media stream contains audio/video tracks.
2. choose to use prefer mimeType encoder if platform already supported.
3, query platform supported mimeTypes.
IMHO MediaRecorder may have an API to control the encoder behavior, at least mimeType chooser.
-------------------------------------
-rlin

----- Original Message -----
From: "Robert O'Callahan" <robert@ocallahan.org>
To: "Stefan Håkansson LK" <stefan.lk.hakansson@ericsson.com>
Cc: public-media-capture@w3.org
Sent: Thursday, February 6, 2014 6:09:03 PM
Subject: Re: About the Mandatory constraints

On Thu, Feb 6, 2014 at 7:34 AM, Stefan Håkansson LK <
stefan.lk.hakansson@ericsson.com> wrote:

> Just to be clear: I think we have debated the mandatory constraints for
> gUM several times, and we always come back to the same conclusion:
> people want them. One use is when the app developer wants to avoid
> disturbing the user, or even indicate e.g. that video communication is
> possible, if the equipment does not fulfill the requirements the app
> developer has.
>

That's a good point which I had overlooked; thank you for correcting me.

That gUM needs mandatory constraints but MediaRecorder does not actually
strengthens my case that they should not share Constraints machinery, IMHO.

Given that gUM should have some form of mandatory constraints, we could
easily add them without the abstract Constrainable machinery. The details
of how we add them are relatively inconsequential, but for example, we
could have a GetUserMediaOptions dictionary representing a single
constraint set and have a GetUserMediaOptionsCollection dictionary that
provides the 'optional'/'mandatory' syntax currently required by
Constraints. [Personally I suggest lighter-weight syntax that allows a
single sequence of GetUserMediaOptions, but gives GetUserMediaOptions a
'mandatory' boolean member to make that set of options mandatory.
('mandatory' would only be honoured on the first element of the list.).]

Rob
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Received on Thursday, 6 February 2014 10:56:06 UTC

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