RE: [AVT] RFC3558 header-free packet format question

"Lars-Erik Jonsson (LU/EAB)" <lars-erik.jonsson@ericsson.com> Fri, 17 September 2004 06:47 UTC

Received: from ietf-mx.ietf.org (ietf-mx.ietf.org [132.151.6.1]) by ietf.org (8.9.1a/8.9.1a) with ESMTP id CAA10212 for <avt-archive@ietf.org>; Fri, 17 Sep 2004 02:47:18 -0400 (EDT)
Received: from megatron.ietf.org ([132.151.6.71]) by ietf-mx.ietf.org with esmtp (Exim 4.33) id 1C8Cc7-0000xZ-Cu for avt-archive@ietf.org; Fri, 17 Sep 2004 02:52:59 -0400
Received: from localhost.localdomain ([127.0.0.1] helo=megatron.ietf.org) by megatron.ietf.org with esmtp (Exim 4.32) id 1C8CPt-0004XP-Ck; Fri, 17 Sep 2004 02:40:21 -0400
Received: from odin.ietf.org ([132.151.1.176] helo=ietf.org) by megatron.ietf.org with esmtp (Exim 4.32) id 1C8CMU-00045l-En for avt@megatron.ietf.org; Fri, 17 Sep 2004 02:36:50 -0400
Received: from ietf-mx.ietf.org (ietf-mx.ietf.org [132.151.6.1]) by ietf.org (8.9.1a/8.9.1a) with ESMTP id CAA09795 for <avt@ietf.org>; Fri, 17 Sep 2004 02:36:49 -0400 (EDT)
Received: from eagle.ericsson.se ([193.180.251.53]) by ietf-mx.ietf.org with esmtp (Exim 4.33) id 1C8CRn-0000lE-1r for avt@ietf.org; Fri, 17 Sep 2004 02:42:30 -0400
Received: from esealmw141.al.sw.ericsson.se ([153.88.254.120]) by eagle.ericsson.se (8.12.10/8.12.10/WIREfire-1.8b) with ESMTP id i8H6abAh016332 for <avt@ietf.org>; Fri, 17 Sep 2004 08:36:37 +0200
Received: from esealnt612.al.sw.ericsson.se ([153.88.254.118]) by esealmw141.al.sw.ericsson.se with Microsoft SMTPSVC(6.0.3790.0); Fri, 17 Sep 2004 08:36:37 +0200
Received: by esealnt612.al.sw.ericsson.se with Internet Mail Service (5.5.2657.72) id <TA6X91HM>; Fri, 17 Sep 2004 08:36:37 +0200
Message-ID: <A943FD84BD9ED41193460008C7918050072E973D@ESEALNT419.al.sw.ericsson.se>
From: "Lars-Erik Jonsson (LU/EAB)" <lars-erik.jonsson@ericsson.com>
To: 'Qiaobing Xie' <Qiaobing.Xie@motorola.com>, AVT List <avt@ietf.org>
Subject: RE: [AVT] RFC3558 header-free packet format question
Date: Fri, 17 Sep 2004 08:36:21 +0200
MIME-Version: 1.0
X-Mailer: Internet Mail Service (5.5.2657.72)
Content-Type: text/plain; charset="iso-8859-1"
X-OriginalArrivalTime: 17 Sep 2004 06:36:37.0585 (UTC) FILETIME=[AED04C10:01C49C80]
X-Spam-Score: 0.0 (/)
X-Scan-Signature: 769a46790fb42fbb0b0cc700c82f7081
Cc: adamli@icsl.ucla.edu
X-BeenThere: avt@ietf.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Audio/Video Transport Working Group <avt.ietf.org>
List-Unsubscribe: <https://www1.ietf.org/mailman/listinfo/avt>, <mailto:avt-request@ietf.org?subject=unsubscribe>
List-Post: <mailto:avt@ietf.org>
List-Help: <mailto:avt-request@ietf.org?subject=help>
List-Subscribe: <https://www1.ietf.org/mailman/listinfo/avt>, <mailto:avt-request@ietf.org?subject=subscribe>
Sender: avt-bounces@ietf.org
Errors-To: avt-bounces@ietf.org
X-Spam-Score: 0.0 (/)
X-Scan-Signature: 538aad3a3c4f01d8b6a6477ca4248793

Qiaobing,

The header-free format was included to make no-overhead-over-the-air
possible, then obviously assuming IP/UDP/RTP header compression on
the wireless link. By using RFC 3242, the header overhead can be
totally eliminated under certain conditions, thus one frame per RTP
packet can make much sense.

Cheers,
/L-E


> -----Original Message-----
> From: avt-bounces@ietf.org [mailto:avt-bounces@ietf.org]On Behalf Of
> Qiaobing Xie
> Sent: den 17 september 2004 05:51
> To: AVT List
> Cc: adamli@icsl.ucla.edu
> Subject: [AVT] RFC3558 header-free packet format question
> 
> 
> Hi, Adam,
> 
> The text in section 4.2 of RFC3558 **seems** to indicate that 
> only ONE speech frame is 
> allowed per RTP packet when header-free format is used. This 
> seems to be overly limiting and 
> may severely hinder the usage of this payload format (e.g., I 
> don't think any over-the-air 
> link can afford to use one frame per RTP packet arrangement, 
> and if over-the-air link can 
> not use header-free format, what would be its purpose?). One 
> would think that as long as the 
> same codec rate (hence the layout and size) is in use, more 
> than one frame should be able to 
> be unambiguously carried in a header-free RTP packet.
> 
> Maybe I missed something.
> 
> regards,
> -Qiaobing
> 
> 
> _______________________________________________
> Audio/Video Transport Working Group
> avt@ietf.org
> https://www1.ietf.org/mailman/listinfo/avt
> 

_______________________________________________
Audio/Video Transport Working Group
avt@ietf.org
https://www1.ietf.org/mailman/listinfo/avt