Re: [codec] draft-spittka-payload-rtp-opus-00: a=fmtp:101 application=audio

Harald Alvestrand <harald@alvestrand.no> Mon, 30 July 2012 16:54 UTC

Return-Path: <harald@alvestrand.no>
X-Original-To: codec@ietfa.amsl.com
Delivered-To: codec@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id C096B11E8132 for <codec@ietfa.amsl.com>; Mon, 30 Jul 2012 09:54:15 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -110.305
X-Spam-Level:
X-Spam-Status: No, score=-110.305 tagged_above=-999 required=5 tests=[AWL=0.294, BAYES_00=-2.599, RCVD_IN_DNSWL_HI=-8, USER_IN_WHITELIST=-100]
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 u6julSYIKwzi for <codec@ietfa.amsl.com>; Mon, 30 Jul 2012 09:54:15 -0700 (PDT)
Received: from eikenes.alvestrand.no (eikenes.alvestrand.no [158.38.152.233]) by ietfa.amsl.com (Postfix) with ESMTP id CE11A11E8130 for <codec@ietf.org>; Mon, 30 Jul 2012 09:54:14 -0700 (PDT)
Received: from localhost (localhost [127.0.0.1]) by eikenes.alvestrand.no (Postfix) with ESMTP id 65D3639E13F for <codec@ietf.org>; Mon, 30 Jul 2012 18:54:13 +0200 (CEST)
X-Virus-Scanned: Debian amavisd-new at eikenes.alvestrand.no
Received: from eikenes.alvestrand.no ([127.0.0.1]) by localhost (eikenes.alvestrand.no [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Fbm81QxXrfm2 for <codec@ietf.org>; Mon, 30 Jul 2012 18:54:12 +0200 (CEST)
Received: from [IPv6:2001:df8:0:16:221:6aff:fe8f:cf14] (unknown [IPv6:2001:df8:0:16:221:6aff:fe8f:cf14]) by eikenes.alvestrand.no (Postfix) with ESMTPSA id 682BB39E058 for <codec@ietf.org>; Mon, 30 Jul 2012 18:54:12 +0200 (CEST)
Message-ID: <5016BC45.9010304@alvestrand.no>
Date: Mon, 30 Jul 2012 09:54:29 -0700
From: Harald Alvestrand <harald@alvestrand.no>
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:13.0) Gecko/20120615 Thunderbird/13.0.1
MIME-Version: 1.0
To: codec@ietf.org
References: <619CA092-0565-41EE-AD7B-D2F836B22337@ibp.de> <4FD7BCCA.5000708@jmvalin.ca> <D3DD025A-B14C-4494-8973-B24B44375DE4@ibp.de> <4FD7E0F1.4080801@mozilla.com> <47991A48-3BEF-44CE-B416-693373693F96@ibp.de> <4FD9FE2D.8070408@mozilla.com>
In-Reply-To: <4FD9FE2D.8070408@mozilla.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Subject: Re: [codec] draft-spittka-payload-rtp-opus-00: a=fmtp:101 application=audio
X-BeenThere: codec@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Codec WG <codec.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/codec>, <mailto:codec-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/codec>
List-Post: <mailto:codec@ietf.org>
List-Help: <mailto:codec-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/codec>, <mailto:codec-request@ietf.org?subject=subscribe>
X-List-Received-Date: Mon, 30 Jul 2012 16:54:16 -0000

On 06/14/2012 08:07 AM, Jean-Marc Valin wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> On 06/13/2012 06:52 PM, Lars Immisch wrote:
>> Well, the draft talks about "audio mode" and "voice mode" [1]. I
>> should have suggested the parameter name "mode" and not
>> "application" to stay within the draft's language.
> Actually, the audio mode/voice mode will go away in the next revision
> - -- it's just not needed considering that the sender knows better.
>
>> But how can the receiver say: "encode at high bit-rate"? I don't
>> see how that can be done.
> You can do that with the b=AS: parameter
>
Ooops...... do you mean RFC 3550 section 6.2 bandwidth, as referred to 
by RFC 4566 section 5.8?

in the case where we send multiple tracks in a session, the SDP b= 
parameter applies to the total bandwidth of the media streams covered by 
the SDP m= line or SDP session.

If there are mulitple tracks with potentially different bitrates, the 
allocation of bandwidth between the tracks has to be done by the sender.