[Speex-dev] actual solutions AEC different sampling clock

Lorenzo Fundaró lfundaro at etu.utc.fr
Tue Mar 8 09:52:46 PST 2011


I was looking at the old emails on this mailing list concerning problems
with AEC when having playback and capture at different sampling clock.
Several propositions came along like:

* Cross correlation
* clock skew estimation
* sample interpolation
* resampling the signal
* ...

I would like to know whether a working solution has been found as today or
are we always bound to use a sound card having both the playback and capture
synchronized ?
My application does calls between two computers that are using a usb webcam
with a built-in microphone and their speakers are connected to the sound
card. Both computers are running under Ubuntu GNU/Linux and I can't get the
AEC to work properly.

Like some have asked on this list, I wonder how programs like the gmail
voice/video plugin or skype manage to overcome this situation, knowing that
a lot of today's users have a  webcam with a built-in microphone whose
sampling clock may differ from their speakers.

I will appreciate any help.
Thanks in advance,

Lorenzo Fundaró García
Université de Technologie de Compiègne
Génie Informatique
Tel. +33 6 21 13 65 48
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