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Re: [codec] #8: Sample rates?

"Kevin P. Fleming" <kpfleming@digium.com> Tue, 13 April 2010 11:44 UTC

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Date: Tue, 13 Apr 2010 06:41:35 -0500
From: "Kevin P. Fleming" <kpfleming@digium.com>
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To: stephen botzko <stephen.botzko@gmail.com>
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Cc: codec@ietf.org
Subject: Re: [codec] #8: Sample rates?
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stephen botzko wrote:

> Dynamically changing sample rates on the system level adds some
> complexity for RTP, since the timestamp granularity is supposed to be
> the sample rate.

And jitter buffers, and anything else that is based on timestamps and
sample rates/counts. If the desire is for the codec to be able to change
sample rates to adjust to network conditions, then I agree with
Stephen... the 'external' sample rate (input to the encoder and output
from the decoder) should be fixed, and this is what would be negotiated
in SDP and used for RTP timestamps. The codec can downsample in the
encoder and upsample in the decoder if it has decided to transmit fewer
bits across the network.

-- 
Kevin P. Fleming
Digium, Inc. | Director of Software Technologies
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
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