Subject: [rtcweb] Comments on draft-nandakumar-rtcweb-sdp

From: Peter Thatcher <[email-masked]>
Date: Fri, 24 Jul 2015 03:11:54 -0700

In the WG meeting today, we were asked to
read draft-nandakumar-rtcweb-sdp.  So I read it.  Here are my comments:

1.  The annotated examples with ASCII art tables are really nice.  I like
that part.  Detailed, readable, and thorough.

2.  The diagrams with offer/answer diagrams imply certain models of
signalling which might not be in use by WebRTC applications.  I think
instead they should be modeled as calls to createOffer, createAnswer,
setLocalDescription and setRemoteDescription.  There are applications
already that basically build custom SDP with JS to use it as an API and
doesn't send the SDP over the signalling.   Developers doing such things
would find examples of SDP useful, but the diagrams which assume signalling
wouldn't fit.

In other words, instead of this document being "Examples of SDP that is
signalled", I think it should be "Examples of SDP that can be put into
setLocalDescription and setRemoteDescription, and returned by createOffer
and createAnswer".

I think Harald said something similar in the WG meeting.

---

From: Iñaki Baz Castillo <[email-masked]>
Date: Fri, 24 Jul 2015 15:12:19 +0200

2015-07-24 12:11 GMT+02:00 Peter Thatcher <[email-masked]>:
> There are applications already that basically build custom SDP with JS to
> use it as an API and doesn't send the SDP over the signalling.

The fact that developers are capable of building SDP monsters for
local use based on custom signaled data, and still must feed the
RTCPeerConnection with them, makes me unhappy. Typically the JS app
parses data sent by the peer/server via HTTP or WebSocket, but when it
comes to WebRTC 1.0 the JS app must re-build a blob for the browser to
parse it. The more I think about it the less sense it has.

>  instead of this document being "Examples of SDP that is signalled", I think it should be "Examples of SDP that can be put into setLocalDescription and setRemoteDescription, and returned by createOffer and createAnswer".

If the draft was about inputs for setLocalDescription, etc, it should
be part of the W3C WebRTC specification, am I wrong?

Said that, the draft looks very well (given what we have: the SDP).

-- 
Iñaki Baz Castillo
<[email-masked]>