io.spokestack.spokestack.webrtc

Class AcousticNoiseSuppressor

java.lang.Object

io.spokestack.spokestack.webrtc.AcousticNoiseSuppressor

All Implemented Interfaces:

SpeechProcessor, AutoCloseable

public class AcousticNoiseSuppressor
extends Object
implements SpeechProcessor

Acoustic Noise Suppressor (ANS) pipeline component

AcousticNoiseSuppressor is a speech pipeline component that implements automatic noise separation and suppression. The denoised frames are written back to the frame buffer in-place. The VAD implementation is based on the webrtc noise suppressor in the Chromium browser. It supports 16-bit PCM samples with a frame rate multiple of 10ms.

This pipeline component supports the following configuration properties:

• sample-rate (int): audio sample rate, in Hz (supports 8000/16000/32000/48000Hz)
• frame-width (int): audio frame width, in ms (supports 10/20/30ms)
• ans-policy (string): noise policy, one of the following:
  • mild: mild supression (6dB)
  • medium: medium supression (10dB)
  • aggressive: aggressive supression (15dB)
  • very-aggressive: very aggressive supression (undocumented)

Field Summary

Fields

Modifier and Type	Field and Description
static String	DEFAULT_POLICY default suppressor policy.

Constructor Summary

Constructors

Constructor and Description
AcousticNoiseSuppressor(SpeechConfig config) constructs a new suppressor instance.

Method Summary

Modifier and Type	Method and Description
void	close() destroys the unmanaged ans instance.
void	process(SpeechContext context, ByteBuffer frame) processes a frame of audio.
void	reset() resets all state internal to the stage.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

DEFAULT_POLICY

public static final String DEFAULT_POLICY

default suppressor policy.

See Also:

Constant Field Values

Constructor Detail

AcousticNoiseSuppressor

public AcousticNoiseSuppressor(SpeechConfig config)

constructs a new suppressor instance.

Parameters:

config - the pipeline configuration instance

Method Detail

reset

public void reset()

Description copied from interface: SpeechProcessor

resets all state internal to the stage.

Specified by:

reset in interface SpeechProcessor

close

public void close()

destroys the unmanaged ans instance.

Specified by:

close in interface AutoCloseable

process

public void process(SpeechContext context,
                    ByteBuffer frame)

processes a frame of audio.

Specified by:

process in interface SpeechProcessor

Parameters:

context - the current speech context

frame - the audio frame to detect