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

Jim Barnett <Jim.Barnett@genesyslab.com> Mon, 08 July 2013 15:30 UTC

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From: Jim Barnett <Jim.Barnett@genesyslab.com>
To: Roman Shpount <roman@telurix.com>, =?iso-8859-1?Q?Stefan_H=E5kansson_LK?= <stefan.lk.hakansson@ericsson.com>
Thread-Topic: [rtcweb] Summary of Application Developers' opinions of the current WebRTC API and SDP as a control surface
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Date: Mon, 8 Jul 2013 15:29:55 +0000
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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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As I recall the consensus, developers are supposed to be able to modify the SDP, but we needed to specify what parts of the SDP could be modified.  In other words, there might be some limits to what could be modified, but we haven't yet determined/agreed on what they are.


-          Jim

From: rtcweb-bounces@ietf.org [mailto:rtcweb-bounces@ietf.org] On Behalf Of Roman Shpount
Sent: Monday, July 08, 2013 11:23 AM
To: Stefan Håkansson LK
Cc: <rtcweb@ietf.org>;
Subject: Re: [rtcweb] Summary of Application Developers' opinions of the current WebRTC API and SDP as a control surface

On Mon, Jul 8, 2013 at 8:11 AM, Stefan Håkansson LK <stefan.lk.hakansson@ericsson.com<mailto:stefan.lk.hakansson@ericsson.com>> wrote:
> On Sat, Jul 6, 2013 at 2:33 AM, Stefan Håkansson LK
> <stefan.lk.hakansson@ericsson.com<mailto:stefan.lk.hakansson@ericsson.com>
> <mailto:stefan.lk.hakansson@ericsson.com<mailto:stefan.lk.hakansson@ericsson.com>>> wrote:
>
>     On 7/3/13 11:37 PM, Eric Rescorla wrote:
>      >     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.
>
>
> Can you point out when exactly this consensus was reached? This is news
> to me, but I definitely could have missed something.
No I can't really. To be clear, no consensus call (or similar) has been
held. But every time this is discussed, what I hear is people agreeing
and no objections. It was discussed a bit, e.g., at the f2f at TPAC last
year, if you read the minutes [1] you will find some traces of that
discussion.

And, I don't understand why there would be a debate about this. There
are obviously many who want to define APIs (or constraints) that allow
most use-cases to be met without having to modify the SDP. Why would
anyone have anything against that? If there is anyone who really wants
to modify the SDP instead (I have no clue why, but anyway) they can
still do that.

[1] http://lists.w3.org/Archives/Public/public-webrtc/2012Nov/0072.html

I would not disagree that there should not be any debate that things that can be done through API should be done through API. My question is, was there ever consensus that SDP should be a opaque non modifiable blob which should not be used within the application to control things. Or is SDP just a more advanced API surface that is supposed to be used to implement more advanced scenarios? Is this group even suppose to specify what can be modified in by the application SDP or is it supposed to be an empty set? So, was there ever a consensus that "developers MUST NOT touch SDP"?

_____________
Roman Shpount