Re: [codec] Multi-mode frame concatenation

Jean-Marc Valin <jmvalin@jmvalin.ca> Fri, 29 July 2011 19:34 UTC

Return-Path: <jmvalin@jmvalin.ca>
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 BED8B5E801F for <codec@ietfa.amsl.com>; Fri, 29 Jul 2011 12:34:48 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.599
X-Spam-Level:
X-Spam-Status: No, score=-2.599 tagged_above=-999 required=5 tests=[BAYES_00=-2.599]
Received: from mail.ietf.org ([64.170.98.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ss2lYklz0S6n for <codec@ietfa.amsl.com>; Fri, 29 Jul 2011 12:34:48 -0700 (PDT)
Received: from relais.videotron.net (relais.videotron.net [24.201.245.25]) by ietfa.amsl.com (Postfix) with ESMTP id 40E835E8011 for <codec@ietf.org>; Fri, 29 Jul 2011 12:34:48 -0700 (PDT)
MIME-version: 1.0
Content-transfer-encoding: 7BIT
Content-type: text/plain; CHARSET=US-ASCII
Received: from groupe-jaro.sites.intello.com ([207.253.240.61]) by VL-VM-MRA001.ip.videotron.ca (Oracle Communications Messaging Exchange Server 7u4-18.01 64bit (built Jul 15 2010)) with ESMTP id <0LP4004WJ11ZKW60@VL-VM-MRA001.ip.videotron.ca> for codec@ietf.org; Fri, 29 Jul 2011 15:34:47 -0400 (EDT)
Received: from [172.16.55.73] (AU83N-1 [172.16.55.73]) by groupe-jaro.sites.intello.com (8.13.8/8.13.8) with ESMTP id p6TJYk25032305; Fri, 29 Jul 2011 15:34:47 -0400
Message-id: <4E330B56.3050204@jmvalin.ca>
Date: Fri, 29 Jul 2011 15:34:46 -0400
From: Jean-Marc Valin <jmvalin@jmvalin.ca>
User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:5.0) Gecko/20110624 Thunderbird/5.0
To: Jonathan Lennox <jonathan@vidyo.com>
References: <4E320353.5050505@fas.harvard.edu> <CAEW_Rkva4BmyXqVYzVHmuq3FX8yxRBp876P8pRRt_k2VeMGqXQ@mail.gmail.com> <4E32EE61.1040304@fas.harvard.edu> <CAEW_RksrWp+Jx2pbd=RN4mFxje=GXY0BfCNt2YLG4Y24YUj3bg@mail.gmail.com> <4E32F852.4070508@fas.harvard.edu> <86F5A93D-0750-424B-B943-A7D3C4C4A501@vidyo.com>
In-reply-to: <86F5A93D-0750-424B-B943-A7D3C4C4A501@vidyo.com>
X-Enigmail-Version: 1.2
Cc: "bens@alum.mit.edu" <bens@alum.mit.edu>, "codec@ietf.org" <codec@ietf.org>
Subject: Re: [codec] Multi-mode frame concatenation
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: Fri, 29 Jul 2011 19:34:48 -0000

Good idea. We were thinking of reserving the first two bytes "Op", which
is an invalid given the framing restrictions.

	Jean-Marc

On 11-07-29 02:37 PM, Jonathan Lennox wrote:
> On Jul 29, 2011, at 2:13 PM, Benjamin M. Schwartz wrote:
> 
>> On 07/29/2011 01:53 PM, Ralph Giles wrote:
>>> Do you mean using lower values of M when the config field indicates
>>> the frame has a longer duration?
>>
>> Nope.  I mean that once M is invalid, the other two bits are also
>> available for signaling.  I would not regard M=49, p=1, v=0 (byte==113) as
>> a multi-mode packet indicator, so it's still available for something else.
> 
> It would probably be a good idea to explicitly reserve some extension values for the external container, analogous to the way that H.264 reserves NAL Unit Types 24-31.  This ensures that the RTP payload format can both support a mode where it directly places Opus packets into an RTP payload, and also (if necessary) a mode where it add some additional framing or other transport-related data around them.
> 
> --
> Jonathan Lennox
> jonathan@vidyo.com
> 
> 
> _______________________________________________
> codec mailing list
> codec@ietf.org
> https://www.ietf.org/mailman/listinfo/codec
> 
>