Re: [rtcweb] Convey "label"

Stefan Håkansson LK <stefan.lk.hakansson@ericsson.com> Fri, 09 September 2011 13:11 UTC

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Subject: Re: [rtcweb] Convey "label"
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On 2011-09-09 14:58, Justin Uberti wrote:
>
>
> On Fri, Sep 9, 2011 at 3:55 AM, Olle E. Johansson <oej@edvina.net
> <mailto:oej@edvina.net>> wrote:
>
>
>     9 sep 2011 kl. 09:07 skrev Colin Perkins:
>
>      > On 9 Sep 2011, at 07:53, Olle E. Johansson wrote:
>      >> 9 sep 2011 kl. 08:51 skrev Stefan Håkansson LK:
>      >>> there was a discussion yesterday of how to convey the Id (aka
>     "label") of a MediaStream object when it is sent over a
>     PeerConnection. Presumable this info would be in the SDP offer (or
>     whatever we end up using). There was a discussion on if CNAME could
>     be used or if we need something new.
>      >>>
>      >>> You mentioned that it would be quite easy to add a new element
>     or attribute if we would need that. Could you explain a bit more?
>      >>
>      >> Just a kind reminder that there are application specific fields
>     that we can use in RTCP too...
>      >
>      >
>      > I was actually thinking of a new RTCP SDES item type to convey
>     the label.
>      >
>     Side note: I know we're not talking SIP, but it actually touches
>     Hadriel's Session ID proposal too...
>
>
> It's not clear to me that we need a MediaStream to have a label, or any
> identifier other than CNAME, unless it's meant to be some sort of
> "display name" for that particular stream. If there are other expected
> usages of the label, I'd be interested to know what they are.
The main purpose of an identifier of MediaStream's I see is to be able 
to reference them after transport over a PeerConnection. If several 
MediaStreams are sent over a PC, you need to be able to reference them - 
all the receiving app gets is "addstream" events.

Of course you could add them one by one in a determined order, but that 
would mean that set up takes longer than required.

I'm not sure CNAME can fulfill this purpose in all cases or not.