[Speex-dev] Echo Cancellation for silent echo signal

Jean-Marc Valin jean-marc.valin at usherbrooke.ca
Wed Sep 20 16:59:57 PDT 2006

> When speech is played in speaker, we are feeding that speech to echo
> canceller for cancelling its echo from captured data and the echo
> canceller work very well. But when there is no speech, we are feeding
> samples of value zero to speaker and the same to echo canceller. But
> microphone is always capturing something. But when speech is played
> again after these zeros(silent period) and when this speech is input
> to echo canceller for cancellation, we are not getting initial
> performance from echo canceller. will zero data affect adaptation? Is
> there any way to increase the rate of adaptation as it takes more
> time to adapt especially for intermittent speech with time gap in
> between words?

Normally, zeros should cause problems as the adaptation should freeze by
itself. If you have any files that reproduce the problem with
testecho.c, I can have a look at them.


> Thanks in advance Jam
> I usually try to go past English grammar (I'm not a native speaker 
> either), but this is bad to the point that it's very hard for me to
> even understand what you mean. Can you please proofread what you
> write a bit more and send it again?
> Jean-Marc
> On Wed, 2006-07-19 at 09:47 +0800, Yong Chen wrote:
>> Hi Jean-Marc, I am developing a voice chat for win32 using
>> speex,when I do echo cancellation, after 2 seconds adaptation, the
>> echo canceller work very well,but after process silent(zero) echo
>> signal(when enabled VAD,DTX),it work very bad,I have to reset it,
>> it seems adapt faster then do not rest it, so I always here echo
>> produce by my fisrt two second speech,how can I solve this problem?
>> thank you ver much. Best regards
>> Yong Chen admin at seeyoucn.com
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