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Re: [rtcweb] Summary of Application Developers' opinions of the current WebRTC API and SDP as a control surface

From: Peter Thatcher <pthatcher@google.com>
Date: Thu, 18 Jul 2013 08:12:04 -0700
Message-ID: <CAJrXDUHHVfyE2bCaQu3pR4F=XHvEp64xMwwdRy586FkrOjO3dw@mail.gmail.com>
To: "Matthew Kaufman (SKYPE)" <matthew.kaufman@skype.net>
Cc: Bernard Aboba <bernard_aboba@hotmail.com>, Stefan HÃ¥kansson LK <stefan.lk.hakansson@ericsson.com>, "<rtcweb@ietf.org>" <rtcweb@ietf.org>, "public-webrtc@w3.org" <public-webrtc@w3.org>
On Wed, Jul 17, 2013 at 2:58 PM, Matthew Kaufman (SKYPE) <
matthew.kaufman@skype.net> wrote:

> Bernard Aboba:
> >
> > The problem was that we never defined what mangling browsers had to
> > support. Given all the SDP specs that is actually a huge work item.
> This is exactly what my slides that weren't presented last November
> started to touch upon. It only takes a few minutes with RFC3264 and its
> references to start documenting cases that are clearly "valid SDP
> offer/answer" and yet for which I cannot for the life of me figure out what
> a browser should do if they're presented.

I believe I began paying attention to the mailing lists after you sent out
theses slides that you didn't present.  I'm interested in seeing them, and
while I could dig through archives to find them, if convenient, could you
please give me a link to the slides?  Thanks.

> Just off the top of my head:
> Can I...
> - Change the t= line to be something other than t=0 0?
> - Change the rtpmap associations before calling setLocal?
> - Change a=sendrecv to a=recvonly before calling setLocal?
> - What do you do when you see a=content:sl ?
> - What if someone adds an r= or p= or e=?
> - What is the RFC that describes a=group:BUNDLE (as seen in some browser
> implementations)?
> - Can I remove a=group:BUNDLE (or add it) before calling setLocal?
> - How about removing a=rtcp-mux?
> - Should I do something special at my end if you set
> a=ice-options:google-ice ?
> - If you put a=ssrc lines in there, can I change the ssrc before passing
> it back to setLocal?
> - Can I delete the a=ssrc lines?
> - Is a=rtcp:1 IN IP4 valid or not?
> - What about in the o= line?
> - If I get a bunch of a=candidate lines, can I swap them around to change
> the priority before calling setLocal?
> - What if someone claims SAVP instead of SAVPF but gives me rtcp info?
> At the *very least* for each and every line that comes from createOffer
> and createAnswer you must be able to answer the following:
> - Can I delete it?
> - Duplicate it?
> - Change it?
> - If not, how are violation handled? (Both when passed to another browser
> at the far end and when these modifications happen before calling setLocal)
>  - And can I add additional valid SDP to what came from createOffer or
> createAnswer and pass it back to setLocal or not?
> We appear to be nowhere near a document which explains the answers to
> these questions, certainly not in the W3C WG, and not in any IETF RFC or
> draft I can locate.

> Matthew Kaufman
> _______________________________________________
> rtcweb mailing list
> rtcweb@ietf.org
> https://www.ietf.org/mailman/listinfo/rtcweb
Received on Thursday, 18 July 2013 15:13:16 UTC

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