[codec] Discussion around ITU LS

Cullen Jennings <fluffy@cisco.com> Tue, 06 September 2011 20:52 UTC

Return-Path: <fluffy@cisco.com>
X-Original-To: codec@ietfa.amsl.com
Delivered-To: codec@ietfa.amsl.com
Received: from localhost (localhost []) by ietfa.amsl.com (Postfix) with ESMTP id 76D6521F8EB9 for <codec@ietfa.amsl.com>; Tue, 6 Sep 2011 13:52:41 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -103.303
X-Spam-Status: No, score=-103.303 tagged_above=-999 required=5 tests=[AWL=-0.704, BAYES_00=-2.599, USER_IN_WHITELIST=-100]
Received: from mail.ietf.org ([]) by localhost (ietfa.amsl.com []) (amavisd-new, port 10024) with ESMTP id Q3YyBnH-3+MV for <codec@ietfa.amsl.com>; Tue, 6 Sep 2011 13:52:41 -0700 (PDT)
Received: from mtv-iport-2.cisco.com (mtv-iport-2.cisco.com []) by ietfa.amsl.com (Postfix) with ESMTP id 02B8F21F8EB6 for <codec@ietf.org>; Tue, 6 Sep 2011 13:52:41 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=fluffy@cisco.com; l=1908; q=dns/txt; s=iport; t=1315342468; x=1316552068; h=from:content-transfer-encoding:subject:date:message-id: cc:to:mime-version; bh=MW7ddwP+fsF9l6OCVBhOpDhKDbpZD1MIvQl/8fBPCrQ=; b=SK2ZML0xXPzjCnoXtGLe5VrI/hZHtn91D99K54k0K9oEw9WZziUjCbql NlH19curVeMUoyv0px8+V0nIwhe0Bi4SFf1rCpH/Hl4tbhEY76qjBhjdl g9bfY9ZZWI8Ok4arh0MyMc14/YClgnuRCjdJfCp86jdJnNlhauUUa9aq9 k=;
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: ApQHAACIZk6rRDoJ/2dsb2JhbABDmSOOZHiBSxQBJz8tfUmHVZplAZ86hgpgBIdri0OFD4wd
X-IronPort-AV: E=Sophos;i="4.68,341,1312156800"; d="scan'208";a="510403"
Received: from mtv-core-4.cisco.com ([]) by mtv-iport-2.cisco.com with ESMTP; 06 Sep 2011 20:54:27 +0000
Received: from [] (sjc-fluffy-8914.cisco.com []) by mtv-core-4.cisco.com (8.14.3/8.14.3) with ESMTP id p86KsQld021780; Tue, 6 Sep 2011 20:54:26 GMT
From: Cullen Jennings <fluffy@cisco.com>
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: quoted-printable
Date: Tue, 6 Sep 2011 14:54:26 -0600
Message-Id: <35921B63-3FBC-411D-B587-4AB81F218E57@cisco.com>
To: codec@ietf.org
Mime-Version: 1.0 (Apple Message framework v1084)
X-Mailer: Apple Mail (2.1084)
Cc: Jonathan Rosenberg <jonathan.rosenberg@skype.net>
Subject: [codec] Discussion around ITU LS
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: Tue, 06 Sep 2011 20:52:41 -0000

We received the LS at 


This raises some inter sting points that I think are worth some list discussion.

Section 1. 

Some issues are pointed out with the example code. Can these be fixed? 

WIll the implementation include switching between SILK and CELT modes. 

My understanding is the reference code is not meant to be an optimized version or work on a wide variety of platforms. It is simply supposed to be one implementation that defines the algorithm on a given architecture. Is this correct?

What would people like to see with respect to test vectors? 

Does the WG consider  time shortening / stretching functionality they would want to include in opus as a technique to use for PLC?

Section 2.

The goals of the WG are to develop a RF codec. We have several IPR filings reported. You can find them at 
https://datatracker.ietf.org/ipr/search/?option=document_search&id_document_tag=206670667. Not all of them offer RF terms. The IETF does not want to be involved in deterring if the claimed IPR is valid or not - we simple report the claims we have. Many participants of the WG have looked at IPR disclosures and feel this codec meets the goals of the WG. The question we need to ask in LC is do people think this is ready to publish. 

Section 3.

Given the current state of who was willing to step up to do listening tests before the IESG has finalized a codec. I suspect that it will be difficult to get significantly better testing than we have today before moving to a Proposed Standard. Once we have the frozen specification in the form of a Proposed Standard, I expect to see continued work on characterization and testing. Christian has volunteer to be editor on the working group draft to capture these results.