OnsetStrength (Jipes 0.9.17 API)

java.lang.Object
- com.tagtraum.jipes.audio.OnsetStrength

All Implemented Interfaces:

SignalProcessor<AudioSpectrum,AudioBuffer>
```
public class OnsetStrength
extends Object
implements SignalProcessor<AudioSpectrum,AudioBuffer>
```
Processes AudioSpectrum to compute an onset strength signal in the form of an AudioBuffer produced on flush().
This particular onset strength is defined as the bandwise difference log(power(k,t)+1)-log(power(k,t-1)+1) for the band k and the spectrum t. Differences for all bands in the valid frequency range are averaged. Note, that the input is half-wave rectified, i.e. only increases in power are taken into account. You can manipulate the incFactor to require a certain amount of increase, i.e. power(k,t)>incFactor*power(k,t-1) is evaluated before a difference is computed.
You may specify lower and upper frequency bounds, to only take a certain frequency range into account. Often a lower bound of 30Hz is a good idea.
Hopsize is a required parameter, if you want the resulting buffers to use the correct AudioFormat. If not specified, hopsize will default to the number of samples of the first input spectrum.
This processor produces output only upon flush(). The produced buffer will contain all onset strength values. The values are normalized, i.e. divided by their max.

Author:

Hendrik Schreiber

Constructor Summary

Constructors
Constructor and Description
`OnsetStrength()` Creates an onset strength signal with no frequency boundaries a hopsize equal to `AudioBuffer.getNumberOfSamples()` of the first processed spectrum and an incFactor of `1f`.
`OnsetStrength(int low, int high, int hopSize)` Creates an onset strength signal with the given lower and upper frequency bounds, hopsize and an incFactor of `1f`.
`OnsetStrength(Object id, int low, int high, int hopSize, float incFactor)` Creates an onset strength signal with the given lower and upper frequency bounds, hopsize and incFactor.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`<O2> SignalProcessor<AudioBuffer,O2>`	`connectTo(SignalProcessor<AudioBuffer,O2> floatO2SignalProcessor)` Connects this processor to another processor to forward processed data to.
`protected double`	`difference(float power, float lastPower)` Computes the difference between a power and its predecessor.
`<O2> SignalProcessor<AudioBuffer,O2>`	`disconnectFrom(SignalProcessor<AudioBuffer,O2> floatO2SignalProcessor)` Disconnects a child processor.
`boolean`	`equals(Object o)`
`void`	`flush()` Asks to complete all pending operations.
`SignalProcessor<AudioBuffer,?>[]`	`getConnectedProcessors()` Lists all connected processors.
`Object`	`getId()` Arbitrary object to identify a processor.
`AudioBuffer`	`getOutput()` First calls `SignalProcessor.flush()`, then returns the pending output, should there be any.
`int`	`hashCode()`
`void`	`process(AudioSpectrum spectrum)` Asks this processor to work on the provided data and pipe the output to the connected processors' own `SignalProcessor.process(Object)` method. Implementing methods must not modify or hold on to the provided data.
`String`	`toString()`
`protected boolean`	`useFrequency(float frequency)` Indicate, whether the power for the given frequency should be taken into account.
`protected boolean`	`usePower(float power, float lastPower)` Indicate, whether we should proceed calculating the difference in some way, for the given power and its predecessor (for a given frequency).

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - OnsetStrength
```
public OnsetStrength(Object id,
                     int low,
                     int high,
                     int hopSize,
                     float incFactor)
```
    Creates an onset strength signal with the given lower and upper frequency bounds, hopsize and incFactor.
    
    Parameters:
    
    id - SignalPump id
    
    low - lower freq boundary in Hz
    
    high - upper freq boundary in Hz
    
    hopSize - hop size
    
    incFactor - incFactor
  - OnsetStrength
```
public OnsetStrength(int low,
                     int high,
                     int hopSize)
```
    Creates an onset strength signal with the given lower and upper frequency bounds, hopsize and an incFactor of 1f.
    
    Parameters:
    
    low - lower freq boundary in Hz
    
    high - upper freq boundary in Hz
    
    hopSize - hop size
  - OnsetStrength
```
public OnsetStrength()
```
    Creates an onset strength signal with no frequency boundaries a hopsize equal to AudioBuffer.getNumberOfSamples() of the first processed spectrum and an incFactor of 1f.
- Method Detail
  - process
```
public void process(AudioSpectrum spectrum)
             throws IOException
```
    Description copied from interface: SignalProcessor
    
    Asks this processor to work on the provided data and pipe the output to the connected processors' own SignalProcessor.process(Object) method.
    Implementing methods must not modify or hold on to the provided data. In other words: the provided object does not belong to you, its values are only guaranteed to be stable for the duration of the call.
    If you need to hold on to data, create a copy of the provided data via a copy constructor or the Object.clone() method.
    It is the responsibility of implementing classes to call the SignalProcessor.process(Object) method of any connected processors. To manage connected processors classes may want to use a SignalProcessorSupport instance.
    
    Specified by:
    
    process in interface SignalProcessor<AudioSpectrum,AudioBuffer>
    
    Parameters:
    
    spectrum - data to process
    
    Throws:
    
    IOException - if a processing error occurs
    
    See Also:
    
    SignalProcessor.getConnectedProcessors()
  - difference
```
protected double difference(float power,
                            float lastPower)
```
    Computes the difference between a power and its predecessor. By default their logs are computed first. Called from process(AudioSpectrum).
    
    Parameters:
    
    power - power
    
    lastPower - previous power (same band)
    
    Returns:
    
    some difference
  - usePower
```
protected boolean usePower(float power,
                           float lastPower)
```
    Indicate, whether we should proceed calculating the difference in some way, for the given power and its predecessor (for a given frequency). Called from process(AudioSpectrum).
    
    Parameters:
    
    power - power
    
    lastPower - previous power (same band)
    
    Returns:
    
    true or false
  - useFrequency
```
protected boolean useFrequency(float frequency)
```
    Indicate, whether the power for the given frequency should be taken into account. Called from process(AudioSpectrum).
    
    Parameters:
    
    frequency - frequency (of a given power)
    
    Returns:
    
    true or false
  - flush
```
public void flush()
           throws IOException
```
    Description copied from interface: SignalProcessor
    
    Asks to complete all pending operations. This method may be called multiple times without any adverse effects. It's the implementation's responsibility to call its kids' SignalProcessor.flush() method.
    
    Specified by:
    
    flush in interface SignalProcessor<AudioSpectrum,AudioBuffer>
    
    Throws:
    
    IOException - if a processing error occurs
  - getOutput
```
public AudioBuffer getOutput()
                      throws IOException
```
    Description copied from interface: SignalProcessor
    
    First calls SignalProcessor.flush(), then returns the pending output, should there be any. Note that this call may only succeed once to preserve memory.
    
    Specified by:
    
    getOutput in interface SignalProcessor<AudioSpectrum,AudioBuffer>
    
    Returns:
    
    output, if available. If not, null is returned
    
    Throws:
    
    IOException - if a processing error occurs
  - getId
```
public Object getId()
```
    Description copied from interface: SignalProcessor
    
    Arbitrary object to identify a processor. This is useful for associating with results provided by SignalProcessor.getOutput().
    
    Specified by:
    
    getId in interface SignalProcessor<AudioSpectrum,AudioBuffer>
    
    Returns:
    
    arbitrary non-null object. If this method returns null, potential results will not be associated with an identifier and potentially dropped
    
    See Also:
    
    SignalPump.pump()
  - connectTo
```
public <O2> SignalProcessor<AudioBuffer,O2> connectTo(SignalProcessor<AudioBuffer,O2> floatO2SignalProcessor)
```
    Description copied from interface: SignalProcessor
    
    Connects this processor to another processor to forward processed data to. This method returns its parameter and therefore encourages method chaining to build processing chains/pipelines.
    
    Specified by:
    
    connectTo in interface SignalProcessor<AudioSpectrum,AudioBuffer>
    
    Type Parameters:
    
    O2 - output type of the processor we want to connect to
    
    Parameters:
    
    floatO2SignalProcessor - processor
    
    Returns:
    
    the just added processor
    
    See Also:
    
    SignalProcessor.disconnectFrom(SignalProcessor), SignalProcessor.getConnectedProcessors(), SignalPipeline
  - disconnectFrom
```
public <O2> SignalProcessor<AudioBuffer,O2> disconnectFrom(SignalProcessor<AudioBuffer,O2> floatO2SignalProcessor)
```
    Description copied from interface: SignalProcessor
    
    Disconnects a child processor.
    
    Specified by:
    
    disconnectFrom in interface SignalProcessor<AudioSpectrum,AudioBuffer>
    
    Type Parameters:
    
    O2 - output type of the processor we want to disconnect from
    
    Parameters:
    
    floatO2SignalProcessor - processor
    
    Returns:
    
    the processor, if it was indeed removed
    
    See Also:
    
    SignalProcessor.connectTo(SignalProcessor), SignalProcessor.getConnectedProcessors()
  - getConnectedProcessors
```
public SignalProcessor<AudioBuffer,?>[] getConnectedProcessors()
```
    Description copied from interface: SignalProcessor
    
    Lists all connected processors.
    
    Specified by:
    
    getConnectedProcessors in interface SignalProcessor<AudioSpectrum,AudioBuffer>
    
    Returns:
    
    array of registered processors, never null
    
    See Also:
    
    SignalProcessor.disconnectFrom(SignalProcessor), SignalProcessor.connectTo(SignalProcessor)
  - equals
```
public boolean equals(Object o)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object

Class OnsetStrength

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

OnsetStrength

OnsetStrength

OnsetStrength

Method Detail

process

difference

usePower

useFrequency

flush

getOutput

getId

connectTo

disconnectFrom

getConnectedProcessors

equals

hashCode

toString