[Speex-dev] Echo cancellor causing synthetic noise..?

Tim Na hna at alu.edu
Sat Dec 22 12:10:37 PST 2007


Merry Christmas to all. :)

I have been trying out new 1.2beta3 here and facing some noise problems, (I
can't say this is 1.2beta3 problem because I haven't tried out previous
version yet) and was wondering if anyone also has faced and solved similar

When the speex encoding/decoding (wideband) process starts, the voice is
crispy clear with almost no noise in the background, but as I run it for a
long time, noise start building up and even with (scary?) synthetic sounds
as well. (these noises continue even when I disable mic recording thus only
allowing all zero data from input device - sampling still goes on)  When I
only use the raw PCM data without speex codec, these symptoms didn't happen.

The speex library often prints this statement to my window.
" --> warning: The echo canceller started acting funny and got slapped
(reset). It swears it will behave now."

I am using win32 (Visual C++ 2005), compiled speex source code personally
with very few minor additions to code, using window's media interface (wave
in/out) in multi-thread environment. To transfer the data from wave in to
out, I use local-loop UDP transport.

I have set 10 quality, complexity 4, VBR on, VBR quality 10.0, DENOISE on,
echo canceller linked with preprocessor.


- Tim

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