[Speex-dev] problems with echo cancellation filter

[Jean-Marc Valin]

> some noises, echo is removed, but sometimes you can hear some noises  
> instead of echo.
> I was trying with many different parameters for buffer length (40ms and  
> 20ms), filter length (from 100ms to 4s) and echo tail (2 to 5 buffers),  
> but could not find the right setting.

This doesn't make sense. The filter length and echo tail are the same
thing.

> it happens that the filter suddenly stops working and returns silence, so  
> you don't hear anything.

The problem is probably that the filter diverged and started producing
NaNs. Not quite sure what's the cause or how to fix that. Have you
tested with the testecho.c sample file?

	Jean-Marc