Current File : //usr/share/doc/libasound2-plugins/speexdsp.txt
Speex Preprocessing Plugin
==========================
This plugin provides a pre-processing of a mono stream like denoise
using libspeex DSP API. You can use the plugin with the plugin type
"speex" like below:
pcm.my_pcm {
type speex
slave.pcm "default"
}
Then record like
% arecord -fdat -c1 -Dplug:my_pcm foo.wav
so that you'll get 48kHz mono stream with the denoising effect.
Right now, the plugin supports only a mono stream.
The accepted format is only S16.
The following parameters can be set optionally:
* frames
This controls the frames of the intermediate buffer. This
corresponds to the latency of the filter. As default it's 64.
* denoise
A boolean value to enable/disable the denoise function. Default is
yes.
* agc
A boolean value to enable/disable the auto-gain control function.
Default is no.
* agc_level
A float value for the automatic gain-control level. Default is 8000.
* dereverb
A boolean value to enable/disable dereverb function. Default is no.
* echo
A boolean value to enable/disable echo-cancellation function.
Default is no.
* filter_length
Number of samples of echo to cancel. As default it's 256.
For example, you can enable agc like
pcm.my_pcm {
type speex
slave.pcm "default"
agc 1
agc_level 8000
}
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