[Speex-dev] Will the echo canceler or preprocessor work with 10ms frames?

Charlie Hedlin charlie at hedlin.com
Thu Jun 15 11:22:12 PDT 2006

I am trying to use the speex echo canceler and preprocessor with 
sipXtapi to develop a sip user agent.  the sipXmedialib call flow graph 
uses 10ms frames and I am not sure what the implications are if I try to 
change this. The documentation seemed to indicate that a 20ms frame was 
recomended, but it didn't go into the consquences of using other frame 
sizes.  We are going to use headsets in production but there is still a 
subtle echo that goes away when the microphones are muted.  I have been 
testing both with a headset and using a speaker and microphone.

The preprocessor works for AGC (I have discovered my enviroment is too 
noisy for AGC, as the background it way too loud during periods of 
silence even with a noise canceling mic), but the denoiser seems to make 
the sound tinny and distorted at times. 

The echo canceler doesn't seem to work at all.  What is the longest I 
can set the filter length to and still have it adapt in a reasonable 
time frame?  I am using 80 sample frames and a filter length of 800 
samples right now.

Thank you,
Charlie Hedlin

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