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Minor clarification: Default OfferToReceiveVideo in CreateAnswer

From: Harald Alvestrand <harald@alvestrand.no>
Date: Thu, 14 Feb 2013 22:39:58 +0100
Message-ID: <511D59AE.4020008@alvestrand.no>
To: "public-webrtc@w3.org" <public-webrtc@w3.org>
I hope this is minor....

current text from section 13.1 of the webrtc spec:


    This is an enum type constraint that can take the values "true" and
    "false". The default is a non mandatory "true" for
    an|RTCPeerConnection|object that has a video stream at the point in
    time when the constraints are being evaluated and is non mandatory
    "false" otherwise.

I interpreted this as "if you're in createAnswer, the default is "true" 
if you have an offer for video in the offer, OR if you have a video 
track in a stream added to the PeerConnection". But another developer 
interpreted this as saying that if you have no local video streams, and 
get an offer with video, you should reject the video.

When I got back to reading the spec, I discovered that it was indeed 
possible to interpret it like that - and especially for the case where 
you don't see a video track signalled in the video m= line of the 
incoming offer. But I think the interpretation I thought I had is what 
the text should have said.

Suggested rephrase:

"The default is a non mandatory "true" for an RTCPeerConnection that has 
a video track in one of its local streams, or has video in either its 
LocalDescription or RemoteDescription, and a non mandatory "false" 

That way, if anyone suggests video, video will be acceptable if no 
constraints are set.

Makes sense?

Received on Thursday, 14 February 2013 21:40:27 UTC

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