[Speex-dev] Stream Synchronization for Echo Cancellation

Jean-Marc Valin jean-marc.valin at usherbrooke.ca
Wed Nov 1 00:22:56 PST 2006

> 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.

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