[Speex-dev] Deallocation bug in speex

Jean-Marc Valin Jean-Marc.Valin at USherbrooke.ca
Wed Jun 22 21:24:34 PDT 2005

> 1) What does the ref and echo mean in your function call? "Echo" for me
> would be the nearend (microfone + echo) and "Ref" should be the farend
> (nearend speaker).

No. The "ref" signal is for the mic and the "echo" signal is the signal
being played in the speakers. That would explain why it's not working
for you.

> But if I use them like that, nothing happens!
> 2) What's the filter length I should be using anyway?

See the manual (shipped with 1.1.10) for more details. Basically, I
recommend about one third to one half of the reverberation time. For 8
kHz in a small room, that means around 800 samples long.

> 3) I guess the output parameter is the mic ("echo" signal) without the "ref"
> (farend speaker) influence, right?

Well, it's the "ref" without "echo" influence.

> 4) Does the Y output have some use?

See manual. The optional Y output can be used to couple the AEC with the
denoiser so that it removes the residual echo.


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