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

Re: Additional requirement - audio-only communication

From: Ian Hickson <ian@hixie.ch>
Date: Tue, 6 Sep 2011 20:00:31 +0000 (UTC)
To: Matthew Kaufman <matthew.kaufman@skype.net>
cc: Eric Rescorla <ekr@rtfm.com>, Harald Alvestrand <harald@alvestrand.no>, Stefan Håkansson LK <stefan.lk.hakansson@ericsson.com>, "public-webrtc@w3.org" <public-webrtc@w3.org>
Message-ID: <Pine.LNX.4.64.1109061957360.9867@ps20323.dreamhostps.com>
On Mon, 5 Sep 2011, Matthew Kaufman wrote:
> 
> We need something like:
>   getUserMediaCapabilities(options, successCallback);

This would be a privacy leak (whether I have audio/video capabilities 
should not be broadcast to the whole Web). Also, it wouldn't handle cases 
such as a user plugging in a device in response to a site's request.


> 3. RTP choices should be exposed by allowing RTP media streams to exist,
> rather than putting the RTP parameter setting in the PeerConnection (and
> controlling the encoding using SDP to/from that PeerConnection object)
> 
> Example from above continues:
> 
>     rtpStream = new RTPMediaStream(encodedStream);
>     rtpStream.payloadType = 131;
>     rtpStream.ssrc = 15;
> 
>     // note that if we tried to combine A+V into a single stream, we need a
> more expressive (and yet uglier) way to set the PT and SSRC for each
> 
>     // and we created our peerConnection earlier...
> 
>    peerConnection.addStream(rtpStream);  // the only other alternative to this
> part of my proposal is to change addStream to take the PT and SSRC as
> parameters, but that's not nearly as clean

What's the use case?


> Note that all of this still allows for passing SDP around if you want. 
> You simply need to write Javascript to convert the capabilities into an 
> offer and the answer back into explicit settings for the encoder(s) as 
> well as the RTP bits. But more likely, you'd pass SDP around *only* for 
> federation, and use something else (like just passing a JSON blob that 
> came out of the configuration check right up to the web server to be 
> handled there).

Sounds horrible. Surely we want to make this as simple as possible for 
authors to use, which would mean making this completely opaque, so that 
they don't have to touch any of it, even if the remote endpoint is a 
tranditional SIP stack (e.g. an IP desk phone).

-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Tuesday, 6 September 2011 20:02:23 UTC

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