Re: [rtcweb] SDP is not suitable for WebRTC

Iñaki Baz Castillo <ibc@aliax.net> Tue, 30 July 2013 08:01 UTC

Return-Path: <ibc@aliax.net>
X-Original-To: rtcweb@ietfa.amsl.com
Delivered-To: rtcweb@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 6522321E80BF for <rtcweb@ietfa.amsl.com>; Tue, 30 Jul 2013 01:01:41 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.944
X-Spam-Level:
X-Spam-Status: No, score=-1.944 tagged_above=-999 required=5 tests=[AWL=-0.467, BAYES_00=-2.599, FM_FORGED_GMAIL=0.622, J_CHICKENPOX_15=0.6, J_CHICKENPOX_18=0.6, MIME_8BIT_HEADER=0.3, RCVD_IN_DNSWL_LOW=-1]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id eokNCF1y8giu for <rtcweb@ietfa.amsl.com>; Tue, 30 Jul 2013 01:01:34 -0700 (PDT)
Received: from mail-qc0-f172.google.com (mail-qc0-f172.google.com [209.85.216.172]) by ietfa.amsl.com (Postfix) with ESMTP id C977A21E80C4 for <rtcweb@ietf.org>; Tue, 30 Jul 2013 01:01:31 -0700 (PDT)
Received: by mail-qc0-f172.google.com with SMTP id a1so857438qcx.31 for <rtcweb@ietf.org>; Tue, 30 Jul 2013 01:01:31 -0700 (PDT)
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type:content-transfer-encoding:x-gm-message-state; bh=otKA+3gwZKEk1aCGtelGWkEQBt4yfQzTEde2Sp7/tyk=; b=nnbtHdrLEJzlpRSXAgG+x+rz1iUEg/yHjAjF9iLcaNbnJASXl4bqcYJDzK1vN5Y0b9 nzR4jcvOoirZg4hqhLB9gAPhs3FvBE4ecfuRVQxiQP/HeMDjHSOzS7TYa1DqDdJqNSUq jOrQqa3EYa+pZzVp2Ror2AWdHyDcM2LqD3okG6F2C9Oao2AWxguScFlAhwohfnazJ/9q H7obl5WvHqYSE0rClblPagIbJZqUSyPbX7w5s7QbQU8wyGk7URzTKxkKfDJmcIYmtwRw jAhR7m1cyZQ9525SAqJ3YvfryrdmJlefqidBqVA2YgEtnJvf6uG9JnrVJBqSpLtELND1 N8nw==
X-Received: by 10.224.28.137 with SMTP id m9mr16682541qac.22.1375171291244; Tue, 30 Jul 2013 01:01:31 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.49.72.132 with HTTP; Tue, 30 Jul 2013 01:01:10 -0700 (PDT)
In-Reply-To: <7594FB04B1934943A5C02806D1A2204B1C4135FD@ESESSMB209.ericsson.se>
References: <CALiegfnU0U0juKu8y68K-pfkdf9NwQPxH=yM7vt=1EZEg=fxtA@mail.gmail.com> <1375119910.76535.YahooMailNeo@web171302.mail.ir2.yahoo.com> <CALiegfms3r7RSZ=nCH2fSFLnRxc8UjkL4F2d3evFs5XJOWmAbw@mail.gmail.com> <7594FB04B1934943A5C02806D1A2204B1C4132BF@ESESSMB209.ericsson.se> <CALiegfkRZHTSEfoAgfnn6vFHKgo8VwxwKnLJzkVxaXF=5ntK1Q@mail.gmail.com> <7594FB04B1934943A5C02806D1A2204B1C4135FD@ESESSMB209.ericsson.se>
From: Iñaki Baz Castillo <ibc@aliax.net>
Date: Tue, 30 Jul 2013 10:01:10 +0200
Message-ID: <CALiegf=jm74SkeAYTZnZBreu7HS6QYB7KxfxkJX5N5VHyn_eCg@mail.gmail.com>
To: Christer Holmberg <christer.holmberg@ericsson.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Gm-Message-State: ALoCoQnDH6iSVsT6BYaPeFKlFSumirsJxNU/sDNuR5bxD9xZeHssyZMKXZPMQDgUdOAKi4wPre5E
Cc: "public-webrtc@w3.org" <public-webrtc@w3.org>, "rtcweb@ietf.org" <rtcweb@ietf.org>
Subject: Re: [rtcweb] SDP is not suitable for WebRTC
X-BeenThere: rtcweb@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Real-Time Communication in WEB-browsers working group list <rtcweb.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/rtcweb>, <mailto:rtcweb-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/rtcweb>
List-Post: <mailto:rtcweb@ietf.org>
List-Help: <mailto:rtcweb-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/rtcweb>, <mailto:rtcweb-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 30 Jul 2013 08:01:43 -0000

>> The only we need is that peer-A tells peer-B about its tracks and peer-B tells peer-A about its tracks. We don't have that with SDP.
>
> Well, the peers have to use SOMETHING to do that.

Could you please explain it a bit more? If I am not wrong you insist
on the fact that, *theorically*, if a device knows (by other means)
the number of participants in a conference it can generate a SDP with
so many m lines (as in the "solution 1" I told about).

Then I recall: that is NOT possible in WebRTC. The API does not let me
to add 8 m=audio lines (all of them with a=recvonly but one with
a=sendrec).

It is not valid for me that SDP allows "magic". I am interested in
which I can do with SDP *within WebRTC* via the "SDP-blob based API".

Thanks.


-- 
Iñaki Baz Castillo
<ibc@aliax.net>