[Speex-dev] AEC params

[Jean-Marc Valin]

First, read the part of the manual (included in 1.1.11) about echo
cancellation.

	Jean-Marc 

On Mon, 2005-12-12 at 21:49 -0800, Suchibrata Kar wrote:
> Hi:
> 
> I have been trying to test the speex AEC by playing a
> voice sample (pre-recorded) as a echo and capturing a
> new voice sample and playing the pre-recorded one, for
> reference. [Sampling rate 8 KHz, frame size 64]
> 
> For some reason, I dont see any removal of echo. Does
> anybody have a idea of * Testing the AEC in some other
> mechanism
> or
> * Getting some sample files for testing AEC
> 
> Thanks
> Su
> 
> 
> --- Jean-Marc Valin <Jean-Marc.Valin at USherbrooke.ca>
> wrote:
> 
> > Le lundi 12 décembre 2005 à 02:57 -0800, Suchibrata
> > Kar a écrit :
> > > Hi:
> > > 
> > > Can anyone give some insight on:
> > > 
> > > 1) As per the Speex manual, there is a mention of
> > the
> > > relationship between input frame and echo frame
> > (Pg
> > > 19, Para 2). I was wondering of what would be the
> > > ideal delay between these two frames, so that the
> > echo
> > > is already fed to the canceller and the echo
> > > cancellation filter is not inefficient.
> > 
> > Smallest as possible as long as your 100% sure that
> > it's positive. In
> > practice, half a frame is good.
> > 
> > > 2) Corresponding to the above mentioned delay,
> > what
> > > filter length should we define while creating the
> > echo
> > > canceller state so that we can expect the AEC to
> > > remove or reduce the echo.
> > 
> > So far, my rule of thumb is to use about half of the
> > 60 dB reverberation
> > time. For example, in a small room, the
> > reverberation time is in the
> > order of 250 ms, so a tail length of 125 ms would be
> > good.
> > 
> > 	Jean-Marc
> > 
> 
> 
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