[Speex-dev] agc

Jean-Marc Valin Jean-Marc.Valin at USherbrooke.ca
Wed Aug 9 16:59:22 PDT 2006

Le mercredi 09 août 2006 à 13:24 -0400, Christopher Bader a écrit :
> Hi,
> I'm a new Speex list member, and so far I'm very impressed with Speex.
> BUT automatic gain control seems to me to be virtually unusable.  If a
> recorded utterance begins with even a tiny noise, that noise is
> amplified to the maximum volume.  (See, e.g. the initial utterance in
> the TIMIT corpus, "She kept your dark suit...")
> This seems like a bug to me.  If list members agree, any idea on how
> to fix it?

This is an inherent problem with any AGC. Before someone actually 
speaks, there's no way to know what level to use, so the AGC just 
"guesses" that noise is speech. The only way to fix it is with 
kludges and/or a priori knowledge.


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