Blame doc/speexdsp.txt

Packit 675970
Speex Preprocessing Plugin
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==========================
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This plugin provides a pre-processing of a mono stream like denoise
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using libspeex DSP API.  You can use the plugin with the plugin type
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"speex" like below:
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	pcm.my_pcm {
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		type speex
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		slave.pcm "default"
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	}
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Then record like
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	% arecord -fdat -c1 -Dplug:my_pcm foo.wav
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so that you'll get 48kHz mono stream with the denoising effect.
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Right now, the plugin supports only a mono stream.
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The accepted format is only S16.
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The following parameters can be set optionally:
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* frames
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  This controls the frames of the intermediate buffer.  This
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  corresponds to the latency of the filter.  As default it's 64.
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* denoise
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  A boolean value to enable/disable the denoise function.  Default is
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  yes.
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* agc
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  A boolean value to enable/disable the auto-gain control function.
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  Default is no.
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* agc_level
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  A float value for the automatic gain-control level.  Default is 8000.
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* dereverb
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  A boolean value to enable/disable dereverb function.  Default is no.
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* echo
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  A boolean value to enable/disable echo-cancellation function.
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  Default is no.
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* filter_length
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  Number of samples of echo to cancel.  As default it's 256.
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For example, you can enable agc like
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	pcm.my_pcm {
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		type speex
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		slave.pcm "default"
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		agc 1
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		agc_level 8000
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	}