Subject: [rtcweb] JSEP Section 5.3.1: Effect of setLocal/setRemote on transceiver.direction

From: Bernard Aboba <[email-masked]>
Date: Tue, 1 Nov 2016 15:33:50 -0700

JSEP Section 5.3.1 says:

   o  A direction attribute, determined by applying the rules regarding
      the offered direction specified in [RFC3264], Section 6.1
<https://tools.ietf.org/html/rfc3264#section-6.1>, and
      then intersecting with the direction of the associated
      RtpTransceiver.  For example, in the case where an m= section is
      offered as "sendonly", and the local transceiver is set to
      "sendrecv", the result in the answer is a "recvonly" direction.

[BA] Overall, this raises the question whether
setLocal/setRemoteDescription can change the
value of transceiver.direction to something other than what was set in
transceiver.setDirection(),
and if so, whether the change is persistent.

For example:

transceiver.setDirection("sendrecv");

// ...

pc.setRemoteDescription(sendOnlyOffer).then(

// Is transceiver.direction now "recvonly"?

)

pc.createOffer().then{

// Does the offer created indicate "sendrecv" or "recvonly"?

}

A similar question was raised on the W3C WEBRTC WG list by Taylor:
https://lists.w3.org/Archives/Public/public-webrtc/2016Nov/0009.html