[Speex-dev] AEC with different soundcards

Alexander Chemeris Alexander.Chemeris at sipez.com
Tue Jul 7 06:43:49 PDT 2009

AFAIK, that's a common point for all AECs. But some of them
solve the problem by resampling on of the end to keep it in sync
with the other.

On Tue, Jul 7, 2009 at 5:14 PM, ggb<ggb at tid.es> wrote:
> Thank you John.
> On 07/06/2009 11:03 PM, John Ridges wrote:
> ly synchronized, and therefore the clock drift adds a non-linear
> factor to the audio path. The AEC can only cancel linear changes to the
> audio path, and so the AEC never converges.
> Is this a limitation common to all the AEC implementations/algorithms, or
> just the speex one?
> One solution is to measure
> the clock drift and resample either the input or output signal so that
> they *are* synchronized, and then the AEC can converge. It's not fun,
> but it works.
> Could you detail me how to measure the clock drift?  Any pointer to doc or
> example?
> I apologize for my lack of knowledge in this topic,
> G.
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Alexander Chemeris.

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