Re: [rtcweb] Proposal for a JS API for NoPlan (adding multiple sources without encoding them in SDP)

Bernard Aboba <> Thu, 27 June 2013 00:19 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id E94CA11E816D for <>; Wed, 26 Jun 2013 17:19:53 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -101.8
X-Spam-Status: No, score=-101.8 tagged_above=-999 required=5 tests=[AWL=-0.598, BAYES_00=-2.599, HTML_MESSAGE=0.001, MIME_QP_LONG_LINE=1.396, USER_IN_WHITELIST=-100]
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id 6tM7MUH+ARuM for <>; Wed, 26 Jun 2013 17:19:49 -0700 (PDT)
Received: from ( []) by (Postfix) with ESMTP id 207D011E814D for <>; Wed, 26 Jun 2013 17:19:49 -0700 (PDT)
Received: from BLU403-EAS148 ([]) by with Microsoft SMTPSVC(6.0.3790.4675); Wed, 26 Jun 2013 17:19:46 -0700
X-TMN: [BmfGB+qEs9StH3s303vYdYObAH2dAXZQ]
X-Originating-Email: []
Message-ID: <BLU403-EAS148552B821ED225C03D441D93750@phx.gbl>
Content-Type: multipart/alternative; boundary="Apple-Mail-67A4D29A-9B6A-45F8-987D-1F665A39AAB8"
Content-Transfer-Encoding: 7bit
References: <> <> <> <> <> <> <BLU169-W13367E5FDE396829D364D62938C0@phx.gbl> <>
From: Bernard Aboba <>
MIME-Version: 1.0 (1.0)
In-Reply-To: <>
Date: Wed, 26 Jun 2013 17:19:41 -0700
To: Peter Thatcher <>
X-OriginalArrivalTime: 27 Jun 2013 00:19:46.0305 (UTC) FILETIME=[07618710:01CE72CC]
Cc: "" <>
Subject: Re: [rtcweb] Proposal for a JS API for NoPlan (adding multiple sources without encoding them in SDP)
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Real-Time Communication in WEB-browsers working group list <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Thu, 27 Jun 2013 00:19:54 -0000

I do think No Plan represents progress toward containing the SDP monster in WebRTC 1.0, particularly for video scenarios. However, I also agree with Robin's arguments against SDP and O/ A, particularly for a server-side API (e.g. Node.js modules) where the current API makes no sense at all. So my perspective is to contain the monster in 1.0, then go with 2.0 first on server, then on the browser. 

On Jun 17, 2013, at 10:34 PM, "Peter Thatcher" <> wrote:

> I like your comparison to the data channels.  As I just pointed out in another email, I think it was good that we "contained the SDP monster", as you put it, with createDataChannel.  One of the purposes of createLocalStream/createRemoteStream is to allow a JS app, if it chooses, to "contain the SDP monster" when adding media streams.  It would still be needed for setting up the PeerConnection's transport (a monster container for a future day perhaps), but that's still significant progress in my book, and it does so with simple additions to the PeerConnection that don't attempt to blow up the WG.
> On Mon, Jun 17, 2013 at 5:14 PM, Bernard Aboba <> wrote:
>> 2) Dissadvantages of using SDP in WebRTC.
>> Roman said:
>> "An unmanageable monster was created which currently stays in the way of developing new functionality (bundle), building applications (does not provide obvious ways to implement obvious tasks, like adding an extra stream without re-negotiating all the existing ones) and even interop with existing SIP endpoints (which was the original but now is complicated since it would require a non trivial set of constraints and subsequent SDP manipulation)."
>> [BA] Hard to argue with this, but I would point out that by far the ugliest part of the monster is the video hindquarters.  While one could argue that we have been living with the warts of SDP for audio and therefore know the workarounds, with video there are substantial interoperability issues, *even among vendors who utilize the same codec*, sometimes even in relatively basic scenarios (e.g. P2P video call with H.264/SVC).  So the "multivendor legacy of interop" just doesn't exist yet (at least, based on standards).
>> So as I see it, it does represent progress that we have contained the SDP monster's impact on the  the data channel, and I welcome Peter's effort to enable applications who don't care about SDP to minimize its usage even if it is not eliminated entirely.   
>> _______________________________________________
>> rtcweb mailing list