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Re: [AVT] RE: <draft-ietf-avt-rtp-vmr-wb-03.txt>: sampling rate

Qiaobing Xie <Qiaobing.Xie@motorola.com> Fri, 24 September 2004 12:25 UTC

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Date: Fri, 24 Sep 2004 20:16:45 +0800
From: Qiaobing Xie <Qiaobing.Xie@motorola.com>
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To: Colin Perkins <csp@csperkins.org>
Subject: Re: [AVT] RE: <draft-ietf-avt-rtp-vmr-wb-03.txt>: sampling rate
References: <0B08EA1BF5F6304992CDC985EE02209E02342B61@sdebe002.americas.nokia.com> <751B9B52-03EA-11D9-A048-000A957FC5F2@csperkins.org> <ybur7p8ynaq.fsf@jesup.eng.tvol.net.jesup.eng.tvol.net> <366D9364-0D38-11D9-A100-000A957FC5F2@csperkins.org>
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Cc: Randell Jesup <rjesup@wgate.com>, magnus.westerlund@ericsson.com, avt@ietf.org, sassan.ahmadi@nokia.com
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Hi, Colin,

Colin Perkins wrote:

<snip>
>> Not that such things exist currently, but playing devil's advocate,
>> one could create a codec that takes a variable-sampling-rate input
>> depending on current conditions.  (Similar to video codecs that vary the
>> frame rate, resolution, and/or bitrate within a stream.)
> 
> Sure, one could. I don't think it would be a good idea though: the 
> convention that the sampling rate equals the timestamp rate is very 
> helpful when building multi-format systems.

The practical need in 3GPP2 (and possibly other systems) to feed mixed sampling rate input 
(depending on conditions in the call flow) to vmr-wb codec in a single session has already 
been explained in this discussion. I think it is quite equivalent to the scenario depicted 
by Randell.

regards,
-Qiaobing


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