IETF CLUE WG Interim meeting, September 17, 2013 Time: 9:30am EDT - 11:30am EDT Participants: ------------ Paul Kyzivat Mary Barnes Roberta Presta Stephan Wenger Rob Hansen Mark Duckworth Roni Even Christian Groves Keith Drage Stephane Cazeaux Christer Holmberg Recording: ------------ https://ietf.webex.com/ietf/ldr.php?AT=pb&SP=MC&rID=16017692&rKey=95edee0ed7b2bdec Raw notes by Rob Hansen: ------------------------ No comments on WGLC for the telepresence requirements document on the mailing list - needs to be reviewed and people need to post comments on the mailing list The current RTCP draft has expired; Roni presented the status about a revised draft. As yet, Jonathon and Roni have not submitted a revised document because it requires changes based on the work in other groups. FEC (forward error correction) in particular was raised an issue - Roni and Jonathon plan to make a proposal, hopefully keeping it out of the CLUE signalling. Roni took an action to post a note to the list about the FEC issue. The work being done on appId and the SDP unified plan for RTCweb both may have impact on CLUE; appId is a more general form of captureId. The unified approach is more difficult, as the current signalling in CLUE depends on m-line attributes such as 'label'. Keith clarified that the taxonomy draft would be an informative reference. There was discussion of how much CLUE should be tied to the unified plan. Rob took an action to look at how the CLUE signalling interacts with the unified plan. Mark presented some slides on the framework. One major open issue is switching, which has individual drafts from both Mark and Christian. More comments are needed on the mailing list about these drafts. Roles were also raised as an issue. There was a suggestion to move the framework to the standards track, as there are some specifications in the framework that are required for a successful implementation. Mary clarified that she felt that the framework document was a normative reference for other documents, but not for an implementer - Keith wanted to make sure that this was made clear in the abstract. Mary also raised a ticket that some decisions need to be made before the security section can be completed. Mark committed to proposing some changes on the encoding group limitations as per IETF87, removing codec-specific limitations and pixels-per-second from the endpoint group constraints. There was some discussion here that clarified that there was no intention to remove encoding groups as a whole. Due to time limitation, the 'roles' section of the agenda was skipped, and Christian presented his proposal on improving how switching would be implemented in CLUE. The issue is that to solve many problems with CLUE the original capture information is required, but with switching and composed as present that is not available. The proposal is to have a new capture type (MCC) indicating that multiple captures are combined herein. Captures that a part of a MCC do not have to have an encoding (meaning that they can only be obtained via an MCC; they can't be requested directly). There was discussion of how the reciever could determine which capture they were currently receiving when it was being received - the RTP mapping has been focused on describing an encoding, so not all the tools will apply there. There was also discussion of whether there was actually a need for this information on a packet-by-packet basis - correcting for geometry would be one of the use cases here. There was also discussion of the fact that for large conferences this could result in very large advertisments, and that it would also potentially involve a lot more advertisments being sent as people joined or left the conference. Again, for large advertisments this would likely require new advertisments. There was discussion of how this relates to Mark's switching draft, and how this can solve the problems raised there. Mark suggested that an example of how to solve the problems raised in his draft would be usefu; Christian volunteered to provide such an example. Paul asked whether people had cycles to work on actually providing the originating capture information, or whether we were willing to live with the simple approach currently in the framework. Mark, Christian, Roni and Roberta all expressed interest in this issue, and again there was a call for more conversation on the list. With ten minutes left we skipped the signalling and moved to the wrap-up. Mary suggested that we kept the protocol and signalling documents seperate for the time being to simplify the editorial task. There are still many tasks that need to be solved on the signalling side, with little work being done by anyone but Paul.