be.tarsos.dsp.onsets

Class BeatRootSpectralFluxOnsetDetector

java.lang.Object

be.tarsos.dsp.onsets.BeatRootSpectralFluxOnsetDetector

All Implemented Interfaces:

AudioProcessor, OnsetDetector

public class BeatRootSpectralFluxOnsetDetector
extends java.lang.Object
implements AudioProcessor, OnsetDetector

A non real-time spectral flux onset detection method, as implemented in the BeatRoot system of Centre for Digital Music, Queen Mary, University of London.

This onset detection function does not, NOT work in real-time. It analyzes an audio-stream and detects onsets during a post processing step.

Author:

Joren Six, Simon Dixon

Field Summary

Fields

Modifier and Type	Field and Description
static int	energyOversampleFactor Ratio between rate of sampling the signal energy (for the amplitude envelope) and the hop size
static int	normaliseMode Determines method of normalization.
static double	rangeThreshold For dynamic range compression, this value is added to the log magnitude in each frequency bin and any remaining negative values are then set to zero.
static double	silenceThreshold RMS frame energy below this value results in the frame being set to zero, so that normalization does not have undesired side-effects.

Constructor Summary

Constructors

Constructor and Description
BeatRootSpectralFluxOnsetDetector(AudioDispatcher d, int fftSize, int hopSize)

Method Summary

Modifier and Type	Method and Description
boolean	process(AudioEvent audioEvent) Process the audio event.
void	processingFinished() Notify the AudioProcessor that no more data is available and processing has finished.
void	setHandler(OnsetHandler handler)

Methods inherited from class java.lang.Object

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

Field Detail

silenceThreshold

public static double silenceThreshold

RMS frame energy below this value results in the frame being set to zero, so that normalization does not have undesired side-effects.

rangeThreshold

public static double rangeThreshold

For dynamic range compression, this value is added to the log magnitude in each frequency bin and any remaining negative values are then set to zero.

normaliseMode

public static int normaliseMode

Determines method of normalization. Values can be:

• 0: no normalization
• 1: normalization by current frame energy
• 2: normalization by exponential average of frame energy

energyOversampleFactor

public static int energyOversampleFactor

Ratio between rate of sampling the signal energy (for the amplitude envelope) and the hop size

Constructor Detail

BeatRootSpectralFluxOnsetDetector

public BeatRootSpectralFluxOnsetDetector(AudioDispatcher d,
                                         int fftSize,
                                         int hopSize)

Method Detail

process

public boolean process(AudioEvent audioEvent)

Description copied from interface: AudioProcessor

Process the audio event. Do the actual signal processing on an (optionally) overlapping buffer.

Specified by:

process in interface AudioProcessor

Parameters:

audioEvent - The audio event that contains audio data.

Returns:

False if the chain needs to stop here, true otherwise. This can be used to implement e.g. a silence detector.

setHandler

public void setHandler(OnsetHandler handler)

Specified by:

setHandler in interface OnsetDetector

processingFinished

public void processingFinished()

Description copied from interface: AudioProcessor

Notify the AudioProcessor that no more data is available and processing has finished. Can be used to deallocate resources or cleanup.

Specified by:

processingFinished in interface AudioProcessor