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 }