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Re: [rtcweb] [MMUSIC] SDP work needed for WebRTC stuff

From: Maire Reavy <mdr@reavy.org>
Date: Mon, 10 Dec 2012 22:08:21 -0500
Message-ID: <50C6A3A5.3060009@reavy.org>
To: Eric Rescorla <ekr@rtfm.com>
CC: Ted Hardie <ted.ietf@gmail.com>, "Cullen Jennings (fluffy)" <fluffy@cisco.com>, "<rtcweb@ietf.org>" <rtcweb@ietf.org>, mmusic WG <mmusic@ietf.org>, "<public-webrtc@w3.org>" <public-webrtc@w3.org>
I agree with Ekr on all points.  We have put off resolving the SDP 
issues as long as we can, and the lack of resolution has started to 
impact our WebRTC implementation (in Firefox) already.  I feel we need 
to maximize our chances of resolving the SDP issues as soon as we can.

To me that means meeting in person as soon as possible to hammer this 
stuff out.

Please let's find a way to discuss this in person.  I think it's a big 
mistake if we rely on a virtual meeting only.

Thanks.
-Maire


On 12/10/2012 8:18 PM, Eric Rescorla wrote:
> I feel like the priorities here are kind of confused.
>
> It seems to me that the purpose of having a physical interim is to resolve
> issues that are hard to resolve on the list or teleconferences. As I 
> mentioned
> earlier, the SDP issues are the most important to resolve now and have
> also proven to be among the most intractable. How does it make sense
> to try to resolve those at a "virtual" interim while having people fly
> to a "physical" interim for three days?
>
> I would strongly encourage the chairs to figure out how to have at least
> one of the days of this interim devoted solely to resolving the SDP
> issues (really, my preference would be to take these issues one at
> a time and do nothing else until they are resolved!). I'm not expert
> enough at the RAI WG mechanics to know what's required, so perhaps
> this requires making this also an MMUSIC interim or a mini-RAI interim,
> but if so that's what we should do, even if it means we need to reschedule
> or move it.
>
> Best,
> -Ekr
>
> On Mon, Dec 10, 2012 at 9:36 AM, Ted Hardie <ted.ietf@gmail.com 
> <mailto:ted.ietf@gmail.com>> wrote:
>
>     On Mon, Dec 10, 2012 at 5:16 AM, DRAGE, Keith (Keith)
>     <keith.drage@alcatel-lucent.com
>     <mailto:keith.drage@alcatel-lucent.com>> wrote:
>
>         This is not just MMUSIC, there are bits of AVTCORE and AVTEXT
>         responsibility in there as well.
>
>         And I don't see how you can suddenly extend the interim of
>         RTCWEB to the scope of other working groups, without even
>         having a discussion with all the relevant chairs.
>
>
>     That's not how I read the overall sentiment--people are simply
>     saying that they need this work done and are willing to put in the
>     effort to get it done.  It would, in fact, be ideal if some of the
>     MMUSIC questions were resolve *before* an RTCWEB/WEBRTC interim,
>     as we can then work through what is decided.
>
>     Put another way, I take it as encouragement to MMUSIC folks that
>     they would find a January virtual interim very well received/attended.
>
>     Ted
>
>         I'd further note that Jonathan Lennox has an action (with the
>         support of quite a number of other people) to produce an
>         internet draft on trying to sort out the terminology concents
>         that exist within RTP at the moment. This would be the basis
>         for progressing a number of these issues. That would probably
>         have to be an RAI wide draft.
>
>         There has been some progress on this - maybe Jonathan can
>         report on where this now is. I know he was waiting on
>         volunteers for some of the sections and on input from others
>         where volunteers already existed.
>
>         Keith
>
>         > -----Original Message-----
>         > From: mmusic-bounces@ietf.org
>         <mailto:mmusic-bounces@ietf.org>
>         [mailto:mmusic-bounces@ietf.org
>         <mailto:mmusic-bounces@ietf.org>] On Behalf
>         > Of Cullen Jennings (fluffy)
>         > Sent: 09 December 2012 00:20
>         > To: Eric Rescorla
>         > Cc: <rtcweb@ietf.org <mailto:rtcweb@ietf.org>>; mmusic WG;
>         <public-webrtc@w3.org <mailto:public-webrtc@w3.org>>
>         > Subject: Re: [MMUSIC] SDP work needed for WebRTC stuff
>         >
>         >
>         > On Dec 8, 2012, at 4:21 PM, Eric Rescorla <ekr@rtfm.com
>         <mailto:ekr@rtfm.com>> wrote:
>         >
>         > > +rtcweb
>         > >
>         > > On Sat, Dec 8, 2012 at 2:41 PM, Cullen Jennings (fluffy)
>         > <fluffy@cisco.com <mailto:fluffy@cisco.com>> wrote:
>         > >
>         > > I was looking over everything that needs to be completed
>         to finish a
>         > fist cut of the WebRTC related work. There are a handful of
>         big SDP
>         > problems that are currently blocking some of the WebRTC work
>         and I'd like
>         > to figure out how to make some progress on them.
>         > >
>         > > Let me loosely characterize them as
>         > >
>         > > 1) If we have several video streams, how do theses map up
>         to 1 or more m
>         > lines.
>         > >
>         > > 2) if we are doing port multiplexing, what does the SDP
>         look like (the
>         > bundle problem)
>         > >
>         > > 3) How do we map the RTCWeb track and stream label concepts to
>         > identifiers in SDP
>         > >
>         > > 3) SDP for application running over SCTP/DTLS
>         > >
>         > > I don't want to speak for all the various chairs but I am
>         under the
>         > impression that most of chairs of related groups in W3C and
>         IETF believe
>         > these are issues that need to be resolved primarily in the
>         MMUSIC WG and
>         > that they impact both WebRTC and CLUE as well as the general
>         long term use
>         > of SDP in SIP and other protocols.
>         > >
>         > > I'd like to get some discussion going on how we can make
>         some progress
>         > on these. I don't think we are going to solve these in 20
>         minutes of
>         > discussion at an IETF meeting so I think we probably need
>         some interim
>         > (virtual or face to face) to sort this out.
>         > >
>         > > Thoughts?
>         > >
>         > > Wow, I'm totally confused here.
>         > >
>         > > I had assumed that the SDP-related issues were going to be
>         the main
>         > > topics at the WebRTC/RTCWEB interim in January. Is that
>         not the case?
>         >
>         > So far the interim was only talking about being a WebRTC &
>         RTCWeb so this
>         > SDP stuff would be out of scope. Perhaps it would be better
>         to have some
>         > of the time for mmusic topics?
>         >
>         >
>         > >
>         > > IMO the lack of clarity around how to encode various media
>         > > configurations into SDP is the major thing blocking
>         progress here. In
>         > > particular, Firefox has opted not to implement
>         multiplexing of media
>         > > streams over the same transport flow (whether of the bundle or
>         > > multiple m-line variety) until the SDP for it is
>         well-defined. The
>         > > same thing applies to the question of how to map multiple
>         m-lines to
>         > > incoming MediaStreams/Tracks.
>         > >
>         > > We really need to cover these issues in the interim.
>         > >
>         > > -Ekr
>         > >
>         > >
>         >
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Received on Tuesday, 11 December 2012 03:08:51 GMT

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