- From: Harald Alvestrand <harald@alvestrand.no>
- Date: Fri, 26 Oct 2012 13:47:11 +0200
- To: "public-webrtc@w3.org" <public-webrtc@w3.org>
Wearing my implementor's hat, reporting on a discussion:
The text in section 11.1 about OfferToReceiveAudio and
OfferToReceiveVideo talks about offers, but doesn't say what should be
done with answers. If the language was interpreted exactly as it stands,
the result of doing a CreateAnswer without adding any streams would be
to create an SDP that rejected the Audio and Video m-lines - which
doesn't make much sense.
A reasonable interpretation should be this (all refer to the responding
RTCPeerConnection):
- When no OfferToReceive* is present, and no streams are added, all m=
lines from sender are accepted. (Query: should they be accepted in
a=recvonly mode?)
- When OfferToReceive* is nandatory false, and no streams are added, the
corresponding m= line is rejected (by setting the port number to 0).
- I don't think we can add m= lines in an answer, so when the incoming
offer has no video line, and the OfferToReceiveVideo is true, the
answerer fires negotiationneeded immediately after returning to the
no-outstanding-offer state, so that the answerer can offer an upgrade to
add video.
Does this make sense? If so, can it be added?
Harald
Received on Friday, 26 October 2012 11:47:40 UTC