[Speex-dev] AGC in svn/AGC new options

Jean-Marc Valin jean-marc.valin at usherbrooke.ca
Tue Feb 27 14:33:26 PST 2007

> I'm currently trying the svn's AGC. I'm not getting expected
> results while using it. I currently only tried to enable it
> and keep the agc level to 8000 and the other default parameters.

I recently rewrote it, so a few glitches are expected.

> I wish to get some information about the new other parameters
> and which value should be tried for MAX_GAIN and INCREMENT stuff...

Start from the defaults and tweek only as necessary. All these
parameters are about preventing the gain from changing too much.

> I also wish to know more about AGC: is it usually used on microphone
> or on incoming stream? or both?

You probably want it on the microphone side, but *AFTER* the echo
canceller and the noise suppressor (the preprocessor does the ordering
correctly if you enable both). Having it on the receive side after the
decoder also could make sense if the sender is not using an AGC.


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