[Speex-dev] Stream Synchronization for Echo Cancellation

Tom Grandgent
Wed, 01 Nov 2006 06:49:58 -0000

Isn't this the same problem described starting at the bottom of
this page?
http://www.embeddedstar.com/articles/2003/7/article20030720-11.html

Jean-Marc Valin <jean-marc.valin@usherbrooke.ca>
wrote:
>
> > As it says in 5.4.1 of the good book "Using a different soundcard
to do
> > the capture and playback will *not* work, regardless of what you may
> > think. The only exception to that is if the two cards can be made to
> > have their sampling clock 'locked' on the same clock
source."
> >
> > It seems to me that it should be possible to achieve synchronization
> > using some combination of cross-correlation, clock skew estimation,
and
> > sample interpolation. But there are so many details to consider, I bet
> > it would take a long time to get right.
>
> When you get that to work, please let me know and we'll publish some
> papers about it. Until then, your best hope is in echo *suppression*
> (i.e. frequency-dependent gain), although even that could be a bit tricky.
>
> 	Jean-Marc
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