Asterisk func speex



Apply automatic gain control or noise reduction to audio on a channel.

Asterisk version

Introduced with Asterisk 1.6.x?



The parameter "channeldirection" is required: This can be either rx or tx


You must have speex installed, and you must have loaded.

The AGC function will apply automatic gain control to the audio on the channel that it is executed on. Using rx for audio received and tx for audio transmitted to the channel. When using this function you set a target audio level. It is primarily intended for use with analog lines, but could be useful for other channels as well. The target volume is set with a number between 1-32768. The larger the number the louder (more gain) the channel will receive.

The DENOISE function can be set to either ON or OFF. It will apply noise reduction to audio on the channel that it is executed on. It is very useful for noisy analog lines, especially when adjusting gains or using AGC. Use rx for audio received from the channel and tx to apply the filter to the audio being sent to the channel.


exten => 1,1,Set(AGC(rx)=8000)
exten => 1,2,Set(AGC(tx)=off)

exten => 1,1,Set(DENOISE(rx)=on)
exten => 1,2,Set(DENOISE(tx)=off)

See also

Created by: JustRumours, Last modification: Thu 30 of Apr, 2009 (14:30 UTC)
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