W3C home > Mailing lists > Public > public-webrtc@w3.org > August 2011

Re: Additional requirement - audio-only communication

From: Randell Jesup <randell-ietf@jesup.org>
Date: Wed, 24 Aug 2011 11:22:40 -0400
Message-ID: <4E551740.9070309@jesup.org>
To: public-webrtc@w3.org
On 8/24/2011 5:12 AM, Elwell, John wrote:
> I agree. I was referring to signaling between the web apps
>> happening before the creation of PeerConnection. One way to
>> solve this would be to have such signaling ("I would like to
>> communicate, would you?", "yes, but I only want audio")
>> happening before creating the PeerConnection objects, using a
>> mechanism outside the scope of this standard. That way the
>> applications would have this knowledge when doing "addStream"
>> (or even "getUserMedia").
Randell wrote:
>> I'm confused: why would not this be handled in the Offer/Answer phase?
>> (either within SIP if we use it, or within Offer/Answer if we
>> don't use SIP).
> [JRE] When a side initiating a communication sends an SDP offer, there is an implicit assumption that only media that the user wants to use are included in that offer. Somehow, via the user interface used to establish the communication, the user indicates a desire for audio only, audio plus video, etc..
> So if the SDP offer is to be generated from the browser (I think this is still under discussion), I can see that the browser API needs a means, prior to the offer being generated, for the application to indicate the media to be offered.

Yes, obviously the offerer needs to indicate what streams he wants to 
for (or open a generic connection, then add streams, but that will 
slow down startup).

Your example above indicated a limited form of offer-answer occurring before
the "real" offer-answer, and I'm not sure that it's needed (or useful).

Randell Jesup
Received on Wednesday, 24 August 2011 15:25:39 UTC

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