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

Colin Perkins <csp@csperkins.org> Sat, 11 September 2004 12:17 UTC

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From: Colin Perkins <csp@csperkins.org>
Subject: Re: [AVT] RE: <draft-ietf-avt-rtp-vmr-wb-03.txt>: sampling rate
Date: Sat, 11 Sep 2004 13:05:33 +0100
To: Qiaobing Xie <Qiaobing.Xie@motorola.com>
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Cc: Magnus Westerlund <magnus.westerlund@ericsson.com>, avt@ietf.org, sassan.ahmadi@nokia.com
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On 10 Sep 2004, at 08:28, Qiaobing Xie wrote:

> Hi, Magnus/Sassan,
>
> <snip>
>
>>> 1- Only one RTP timestamp clock rate of 16000 Hz is used throughout 
>>> the I-D.
>> I think this is a good change that simplify things.
>
> Agreed. I'd also like to suggest that some new text be added to 
> capture the essence of this sampling rate discussion... we don't want 
> further readers of the RFC to get the wrong impression that only 16k 
> speech/music can be passed through vmr-wb codec. Some explanation over 
> why only 16k timestamp rate is defined for the payload and how one can 
> still work with 8k media would definitely help, especially to those 
> who are unfamiliar with the codec internal operation.

This is an RTP payload format issue; what the codec does internally is 
not relevant. If the input to the codec is 8kHz, the RTP timestamp rate 
should be 8kHz, as with all other RTP payload formats.

Colin


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