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Re: Spec question: Using settings dictionaries instead of MediaConstraints

From: Harald Alvestrand <harald@alvestrand.no>
Date: Wed, 20 Jun 2012 15:21:35 +0200
Message-ID: <4FE1CE5F.7030200@alvestrand.no>
To: public-webrtc@w3.org
On 06/19/2012 03:45 PM, Justin Uberti wrote:
>
>
> On Tue, Jun 19, 2012 at 8:57 AM, Stefan Hakansson LK 
> <stefan.lk.hakansson@ericsson.com 
> <mailto:stefan.lk.hakansson@ericsson.com>> wrote:
>
>     On 06/19/2012 08:30 AM, Randell Jesup wrote:
>
>         On 6/18/2012 3:22 PM, Justin Uberti wrote:
>
>
>
>             On Mon, Jun 18, 2012 at 2:57 PM, Cullen Jennings (fluffy)
>             <fluffy@cisco.com
>             <mailto:fluffy@cisco.com><mailto:fluffy@cisco.com
>             <mailto:fluffy@cisco.com>>>  wrote:
>
>
>                 This seems like good proposal, one comment on a small
>             detail.
>
>                 On Jun 15, 2012, at 1:28 PM, Justin Uberti wrote:
>
>             >  SessionDescriptionOptions.IncludeAudio = true/false //
>             forces
>                 m=audio line to be included
>             >  SessionDescriptionOptions.IncludeVideo = true/false //
>             forces
>                 m=video line to be included
>             >  SessionDescriptionOptions.UseVoiceActivityDetection =
>             true/false
>                 // includes CN codecs if true
>
>                 I think these three should be constraints, not
>             settings because a
>                 given browser may not support any of them.
>
>
>             Practically speaking, what does that mean for applications?
>
>
>         I can conceive of a browser implementing audio but not video.
>          And a
>         gateway or other stand-alone WebRTC box/functionality might
>         include JS
>         and these JS apis for ease of programming (and might be
>         audio-only).
>         (I'd try to avoid it in production, probably, but even that
>         might not be
>         needed with modern JS JIT speed so long as it didn't have to
>         tear down
>         and restart all the time.)
>
>         CN codecs: I dislike them anyways.  :-)  An implementation
>         definitely
>         could avoid including those.
>
>
>     Many codecs have built in CN modes. I guess for those it is more a
>     question of being able to switch off the VAD.
>
>
> I agree with the scenarios mentioned - my question was mostly about 
> what does having these settings be "constraints" vs "settings" mean 
> for users of the API. Is it simply that the call must fail if the 
> request can't be satisfied?

If they are constraints, it's the caller's choice whether or not the 
call should fail if the constraint can't be satisfied (listing them in 
"mandatory" vs "optional" sections).

If they are settings, it's the specification's choice whether or not the 
call should fail if the constraint can't be satisfied; it has to be 
always handled the same.

At least that's how I read it.

              Harald
Received on Wednesday, 20 June 2012 13:22:06 UTC

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