Re: [rtcweb] Proposed Plan for Usage of SDP and RTP - Lower level API minus SDP

Silvia Pfeiffer <silviapfeiffer1@gmail.com> Thu, 07 March 2013 21:23 UTC

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From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
Date: Fri, 8 Mar 2013 08:22:42 +1100
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To: Peter Thatcher <pthatcher@google.com>
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Subject: Re: [rtcweb] Proposed Plan for Usage of SDP and RTP - Lower level API minus SDP
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Agreed, but it's also not sufficient. SDP is not "programmer friendly"
enough because it has too many details that are protocol-details only and
it's too hard to see the semantic bits in SDP and ignore the rest.

For example: the programmer wants to say - I want to get this video
resolution, this audio bitrate & channels, I want to use this camera and
this microphone for this call. Having to manipulate SDP directly for this
is a programmer's nightmare.

Silvia.

On Fri, Mar 8, 2013 at 8:12 AM, Peter Thatcher <pthatcher@google.com> wrote:

> You can already do that by "munging" the SDP.  It's just not very
> pleasant to do.
>
> On Thu, Mar 7, 2013 at 1:09 PM, Silvia Pfeiffer
> <silviapfeiffer1@gmail.com> wrote:
> > On Fri, Mar 8, 2013 at 5:51 AM, Mary Barnes <mary.ietf.barnes@gmail.com>
> > wrote:
> >>
> >> On Thu, Mar 7, 2013 at 12:42 PM, Eric Rescorla <ekr@rtfm.com> wrote:
> >> >
> >> > On Thu, Mar 7, 2013 at 9:56 AM, Mary Barnes <
> mary.ietf.barnes@gmail.com>
> >> > wrote:
> >> >>
> >> >> On Thu, Mar 7, 2013 at 11:43 AM, Martin Thomson
> >> >> <martin.thomson@gmail.com> wrote:
> >> >> > Obviously I (and my employer) agree with these sentiments
> >> >> > wholeheartedly.  Both Robin and Hadriel.
> >> >> >
> >> >> > That doesn't change the fact that a number of people are highly
> >> >> > motivated to protect their investment in SDP offer/answer.  For
> those
> >> >> > people, the pain that causes everyone else is clearly far less
> >> >> > important than the pain they feel at this moment.  So here we are.
> >> >>
> >> >> [MB] I originally thought that either approach could work.  I did see
> >> >> the value that folks saw in using SDP offer/answer. But after sitting
> >> >> through the interim meeting last month, I am very much of the mindset
> >> >> that using SDP O/A is a bad idea.   I think many of us thought that
> >> >> using the SDP blob would help with interoperability with "legacy" SIP
> >> >> endpoints.  I don't see that now at all.  I think we will end up with
> >> >> a very fragile solution that will be very difficult to extend/modify
> >> >> later if we continue down the SDP O/A path.
> >> >> [/MB]
> >> >>
> >> >
> >> > Hasn't the WG already been asked this question not once but
> >> > twice.
> >> [MB] Yes.  And, some of us have changed our positions based upon the
> >> challenges that the group is facing in getting the current approach
> >> specified and agreed.  I don't disagree that it is not a good thing
> >> that this is being discussed yet again.  [/MB]
> >
> >
> > [Gotta love the triple negation!]
> >
> > Why can't we have it both ways?
> >
> > Maintain the current way to get the raw SDP using createOffer, but then
> > provide an interface to change that offer before setLocalDescription.
> >
> > Even CISCO provides such an API:
> >
> http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/sip_tn/8_5_1/4-sdp_api.html
> > (I think we can do a better one than this, but it's a reference point).
> >
> > Cheers,
> > Silvia.
> >
> >
> > _______________________________________________
> > rtcweb mailing list
> > rtcweb@ietf.org
> > https://www.ietf.org/mailman/listinfo/rtcweb
> >
>