[xrblock] Comments on draft-ietf-xrblock-rtcp-xr-synchronization-00

"Claire Bi(jiayu)" <bijy@sttri.com.cn> Thu, 18 October 2012 01:20 UTC

Return-Path: <bijy@sttri.com.cn>
X-Original-To: xrblock@ietfa.amsl.com
Delivered-To: xrblock@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 73D1121F85D5 for <xrblock@ietfa.amsl.com>; Wed, 17 Oct 2012 18:20:04 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: 2.267
X-Spam-Level: **
X-Spam-Status: No, score=2.267 tagged_above=-999 required=5 tests=[AWL=-0.858, BAYES_50=0.001, HTML_MESSAGE=0.001, MIME_HTML_ONLY=1.457, SARE_RECV_IP_218078=1.666]
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 5TFyvQDz00C1 for <xrblock@ietfa.amsl.com>; Wed, 17 Oct 2012 18:20:00 -0700 (PDT)
Received: from corp.21cn.com (corp.forptr.21cn.com [121.14.129.39]) by ietfa.amsl.com (Postfix) with ESMTP id 2EBD121F861A for <xrblock@ietf.org>; Wed, 17 Oct 2012 18:19:59 -0700 (PDT)
Received: from ip?218.80.215.132? (entas2.inner-hermes.com [10.27.101.2]) by corp.21cn.com (HERMES) with ESMTP id 13EA419400A for <xrblock@ietf.org>; Thu, 18 Oct 2012 09:19:55 +0800 (CST)
HMM_ATTACHE_NUM: 0000
HMM_SOURCE_IP: wmail.10.27.101.2.1115858708
HMM_SOURCE_TYPE: WEBMAIL
Received: from ip<218.80.215.132> ([218.80.215.132]) by 21CN-entas2(MEDUSA 10.27.101.2) with ESMTP id 1350523195.28655 for xrblock@ietf.org ; Thu Oct 18 09:19:58 2012
0/X-Total-Score: 0:
2/X-Total-Score: 3:
X-FILTER-SCORE: to=<9993838d90848c618a8695874f909388>, score=<1350523198KwNQRIf99K99w99N99Q9+EXvXvXvXvvXvvvvvXvvvvXv>
Date: Thu, 18 Oct 2012 09:19:55 +0800
From: "Claire Bi(jiayu)" <bijy@sttri.com.cn>
To: xrblock <xrblock@ietf.org>
Message-ID: <691926375.1521350523195312.JavaMail.hermes@ent-web2>
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="----=_Part_177_1590862445.1350523195081"
HMM_WEBCLN_IP: 10.27.10.84
X-HERMES-SENDMODE: normal
X-HERMES-SET: KoH0oguRsun5ALVzckz3EqaqqOumqw==
Subject: [xrblock] Comments on draft-ietf-xrblock-rtcp-xr-synchronization-00
X-BeenThere: xrblock@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Metric Blocks for use with RTCP's Extended Report Framework working group discussion list <xrblock.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/xrblock>, <mailto:xrblock-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/xrblock>
List-Post: <mailto:xrblock@ietf.org>
List-Help: <mailto:xrblock-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/xrblock>, <mailto:xrblock-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 18 Oct 2012 01:20:09 -0000

Hi,

I was asked to review draft-ietf-xrblock-rtcp-xr-synchronization-00 and have the following several comments.

1. Section 2.1, Synchronization Offset
Is Synchronization Offset a absolute value or relative value? Is Synchronizztion Offset delay variance or Delay Variation?
 
2. Section 3, last Paragraph said:
"
   For example,
   one audio stream and one video stream belong to the same session and
   audio stream are transmitted lag behind video stream for multiple
   tens of milliseconds.  The RTP Flows Synchronization Offset block can
   be used to report such synchronization offset between video stream
   and audio stream
"
Would you like to provide a reference to this example?
 
3. Section 4.2
s/Statistics Summary Report Block/RTP Flows Initial Synchronization Delay Report Block
 
4. Section4.2 Definition of Initial Synchronization Delay
It is not clear how to use in-band mapping of RTP and NTP-format timestamps to calculate
the intial Synchronization Delay, it is better to add text to clarify this.
 
 
Claire