Subject: Re: [AVT] Re: I-D ACTION:draft-ietf-avt-forward-shifted-red-00.txt

From: Qiaobing Xie <[email-masked]>
Date: Thu, 04 Oct 2007 20:45:23 -0500

Hi, Ingemar

Sorry for slow response (I am on vacation and having very limited
email access).

The restriction imposed by RFC2198 that only allow the redundant data
be shifted backward seems quite arbitrary. The intention of this draft
is just to relax that restriction so that the redundant data can be
shifted forward. There are cases where forward shifting of the
redundant data can be advantageous (as illustrated by the anti-shadow
example in Appendix A in the draft).

In other words, improving the delay is not the gaol of this draft.

regards,

-Qiaobing

Ingemar Johansson S wrote:

Hi

Read the draft and although I understand the concept I fail to realize
what is gained with forward shifted redundancy. Could you please
elaborate what the possible gain with forward shifted redundancy is,
compared to what is specified in RFC2198. As I see it both alternatives
will eventually give the same delay.

Regards
Ingemar

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Sent: den 22 september 2007 18:00
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Subject: avt Digest, Vol 41, Issue 22

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Message: 1
Date: Fri, 21 Sep 2007 12:15:01 -0400
From: [email-masked]
Subject: [AVT] I-D ACTION:draft-ietf-avt-forward-shifted-red-00.txt
To: [email-masked]
Cc: [email-masked]
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A New Internet-Draft is available from the on-line
Internet-Drafts directories.
This draft is a work item of the Audio/Video Transport
Working Group of the IETF.

Title : Forward-shifted RTP Redundancy Payload Support
Author(s) : Q. Xie, J. Schumacher
Filename : draft-ietf-avt-forward-shifted-red-00.txt
Pages : 13
Date : 2007-9-21

This document defines a simple enhancement to RFC 2198 to
support RTP
sessions with forward-shifted redundant encodings, i.e., redundant
data is sent before the corresponding primary data.
Forward-shifted
redundancy can be used to conceal losses of a large number of
consecutive media frames (e.g., consecutive loss of seconds or even
tens of seconds of media).

A URL for this Internet-Draft is:
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fted-red-00.txt

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