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

Peter Thatcher <pthatcher@google.com> Mon, 08 July 2013 14:51 UTC

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From: Peter Thatcher <pthatcher@google.com>
Date: Mon, 8 Jul 2013 07:51:12 -0700
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Subject: Re: [rtcweb] Summary of Application Developers' opinions of the current WebRTC API and SDP as a control surface
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On Fri, Jul 5, 2013 at 11:33 PM, Stefan Håkansson LK <
stefan.lk.hakansson@ericsson.com>; wrote:

> On 7/3/13 11:37 PM, Eric Rescorla wrote:
> > On Wed, Jul 3, 2013 at 2:25 PM, Peter Thatcher <pthatcher@google.com
> > <mailto:pthatcher@google.com>> wrote:
> >
> >     On Wed, Jul 3, 2013 at 2:20 PM, Eric Rescorla <ekr@rtfm.com
> >     <mailto:ekr@rtfm.com>> wrote:
> >
> >         On Wed, Jul 3, 2013 at 2:06 PM, Peter Thatcher
> >         <pthatcher@google.com <mailto:pthatcher@google.com>> wrote:
> >
> >             Camp #0:  I've used SDP for years and I'm very comfortable
> >             with it.  Using SDP as the control surface really helps my
> >             use case, which is legacy interop.  Defining an API without
> >             SDP would be too much work, and probably fail.  Look at what
> >             happened with SDPng!  Supporting all these advanced use
> >             cases doesn't seem worth it.   If developers are doing that
> >             much advanced stuff, they can learn to munge SDP.  It isn't
> >             that bad.
> >
> >
> >         Hmm... That's not my understanding of the situation at all.
> >
> >         Rather, I believe the expectation is that you shouldn't have to
> >         modify the
> >         SDP but rather there should be API points to cover most of the
> >         use cases
> >         that people want. This isn't to say that all those API points
> >         exist or that
> >         they work or whatever.
> >
> >         -Ekr
> >
> >
> >     I'm glad to be wrong here.  Is the phrase "you shouldn't have to
> >     modify the SDP but rather there should be API points to cover most
> >     of the use cases"  the consensus of the working group?
> >
> >
> > I thought it was, but I'm not the chair, so maybe you could ask Harald or
> > Stefan.
>
> I definitely think this is the consensus of the working group.
>
> I think the exception would be when interoperating with other systems
> that use another dialect of SDP - I don't think we could cover such
> translations with API points.
>

Are you trying to say "API points couldn't cover uses cases where different
dialects of SDP go over the wire"?  Because I would have to disagree with
that.  I think we could very easily support such uses cases with rather
minor changes to the API.  In fact, the proposal I made for adding just 3
methods (the NoPlan JS API) allows for either Plan A or Plan B (or even
Jingle, mostly), which would make things a lot easier for such use cases.

Now, my design might not be the optimal.  Perhaps we could do better.  But
I think it is possible to serve all these uses cases with a pleasant API.


>
> >
> >
> >     Along with that, is "use Jingle for signalling" included in your set
> >     of "most of the use cases"?
> >
> >
> > No, I don't think it is, since it's not SDP.
> >
> > Maybe I could phrase this differently: It was my understanding that you
> > should have
> > API points to get the PC to emit SDP that would express the policies,
> > preferences,
> > actions, etc. that the application wants. If you want something that's
> > not SDP you would
> > need to gateway.
> >
> > This may or may not be a satisfactory state of affairs, but it was the
> > rule I was using
> > (based on what I thought the WG expected) for when use cases needed new
> API
> > points.
> >
> > -Ekr
> >
>
>