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Re: [Bug 20816] "Hold" unspecified

From: Iñaki Baz Castillo <ibc@aliax.net>
Date: Fri, 19 Apr 2013 15:47:15 +0200
Message-ID: <CALiegfm=+oVCAo0eAX5c8EEkjZ+6GfX9UBmqtie-CWiMLOZ3Dg@mail.gmail.com>
To: Harald Alvestrand <harald@alvestrand.no>
Cc: José Luis Millán <jmillan@aliax.net>, "public-webrtc@w3.org" <public-webrtc@w3.org>
2013/4/19 Harald Alvestrand <harald@alvestrand.no>:
> So first:
> - What do you mean by "hold"?

"Putting a peer on hold" means:

1) Muting my local streams.
2) And tell the peer about it.

Step 2 in SDP is achieved by re-sending my local SDP to the peer with
"a=sendonly" or "a=inactive" (better) within each "m" section.
The peer accepts it by sending its remote SDP with "a=recvonly" or "a=inactive".

> - Where is the specification of how other people are using SDP to achieve
> the thing you mean?

RFC 4566 "SDP":


Of course anyone can notify the peer about "hold" in tons of ways, bu
when dealing with SIP and SDP (and WebRTC deals with SDP) IMHO it
should be possible to reuse the SDP itself for those kind of common

Related issues:


So this is about how to use the WebRTC API to make modifications to
the local SDP in order to reuse and send to the peer a modified
version of the SDP (i.e. for putting the remote on hold).

And this is also about how to realize when I receive a new SDP which
is the same as the previous one but with "a=inactive" or "a=sendonly"
or "a=recvonly" lines. Is it some callback called? or can I find those
SDP attribute values in pc.localDescriptions ?

...or should I manually parse the received SDP with JS?

Iñaki Baz Castillo
Received on Friday, 19 April 2013 13:48:03 UTC

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