Bånder

OnsetDetection extends BaseAlgorithm
in package

OnsetDetection

Inputs:

[vector_real] spectrum - the input spectrum [vector_real] phase - the phase vector corresponding to this spectrum (used only by the "complex" method)

Outputs:

[real] onsetDetection - the value of the detection function in the current frame

Parameters:

method: string ∈ {hfc,complex,complex_phase,flux,melflux,rms} (default = "hfc") the method used for onset detection

sampleRate: real ∈ (0,inf) (default = 44100) the sampling rate of the audio signal [Hz]

Description:

This algorithm computes various onset detection functions. The output of this algorithm should be post-processed in order to determine whether the frame contains an onset or not. Namely, it could be fed to the Onsets algorithm. It is recommended that the input "spectrum" is generated by the Spectrum algorithm. Four methods are available:

  • 'HFC', the High Frequency Content detection function which accurately detects percussive events (see HFC algorithm for details).
  • 'complex', the Complex-Domain spectral difference function [1] taking into account changes in magnitude and phase. It emphasizes note onsets either as a result of significant change in energy in the magnitude spectrum, and/or a deviation from the expected phase values in the phase spectrum, caused by a change in pitch.
  • 'complex_phase', the simplified Complex-Domain spectral difference function [2] taking into account phase changes, weighted by magnitude. TODO:It reacts better on tonal sounds such as bowed string, but tends to over-detect percussive events.
  • 'flux', the Spectral Flux detection function which characterizes changes in magnitude spectrum. See Flux algorithm for details.
  • 'melflux', the spectral difference function, similar to spectral flux, but using half-rectified energy changes in Mel-frequency bands of the spectrum [3].
  • 'rms', the difference function, measuring the half-rectified change of the RMS of the magnitude spectrum (i.e., measuring overall energy flux) [4].

If using the 'HFC' detection function, make sure to adhere to HFC's input requirements when providing an input spectrum. Input vectors of different size or empty input spectra will raise exceptions. If using the 'complex' detection function, suggested parameters for computation of "spectrum" and "phase" are 44100Hz sample rate, frame size of 1024 and hopSize of 512 samples, which results in a resolution of 11.6ms, and a Hann window.

References: [1] Bello, Juan P., Chris Duxbury, Mike Davies, and Mark Sandler, On the use of phase and energy for musical onset detection in the complex domain, Signal Processing Letters, IEEE 11, no. 6 (2004): 553-556.

[2] P. Brossier, J. P. Bello, and M. D. Plumbley, "Fast labelling of notes in music signals," in International Symposium on Music Information Retrieval (ISMIR’04), 2004, pp. 331–336.

[3] D. P. W. Ellis, "Beat Tracking by Dynamic Programming," Journal of New Music Research, vol. 36, no. 1, pp. 51–60, 2007.

[4] J. Laroche, "Efficient Tempo and Beat Tracking in Audio Recordings," JAES, vol. 51, no. 4, pp. 226–233, 2003.

Category: Rhythm Mode: standard

Table of Contents

Properties

$algorithmName  : string
$category  : string
$essentia  : EssentiaFFI
$mode  : string
$parameters  : array<string|int, mixed>
$algorithmHandle  : CData|null
$configured  : bool

Methods

__construct()  : mixed
__destruct()  : mixed
compute()  : array<string|int, mixed>
getAlgorithmName()  : string
getCategory()  : string
getMode()  : string
getParameters()  : array<string|int, mixed>
setParameter()  : self
configure()  : void
isValidParameter()  : bool
validateInput()  : void
cleanupAlgorithm()  : void
configureAlgorithmParameters()  : void
estimateOutputSize()  : int
executeAlgorithm()  : array<string|int, mixed>
executeGenericAlgorithm()  : array<string|int, mixed>
executeSpecificAlgorithm()  : array<string|int, mixed>
getAlgorithmCreateFunction()  : string
getValidParameters()  : array<string|int, mixed>
initializeAlgorithm()  : void
prepareInput()  : mixed
processOutput()  : array<string|int, mixed>
processRhythmOutput()  : array<string|int, mixed>
processSpectralOutput()  : array<string|int, mixed>
processStatsOutput()  : array<string|int, mixed>
processTemporalOutput()  : array<string|int, mixed>
processTonalOutput()  : array<string|int, mixed>
setAlgorithmParameter()  : void
setArrayParameter()  : void
validateAlgorithmInput()  : void

Properties

$algorithmName

protected string $algorithmName = 'OnsetDetection'

$parameters

protected array<string|int, mixed> $parameters = []

Methods

__construct()

public __construct([array<string|int, mixed> $parameters = [] ]) : mixed
Parameters
$parameters : array<string|int, mixed> = []

compute()

public compute(mixed $input) : array<string|int, mixed>
Parameters
$input : mixed
Return values
array<string|int, mixed>

getAlgorithmName()

public getAlgorithmName() : string
Return values
string

getCategory()

public getCategory() : string
Return values
string

getParameters()

public getParameters() : array<string|int, mixed>
Return values
array<string|int, mixed>

setParameter()

public setParameter(string $key, mixed $value) : self
Parameters
$key : string
$value : mixed
Return values
self

configure()

protected configure(array<string|int, mixed> $parameters) : void
Parameters
$parameters : array<string|int, mixed>

isValidParameter()

protected isValidParameter(string $parameter) : bool
Parameters
$parameter : string
Return values
bool

validateInput()

protected validateInput(mixed $input, string $expectedType) : void
Parameters
$input : mixed
$expectedType : string

configureAlgorithmParameters()

private configureAlgorithmParameters() : void

estimateOutputSize()

private estimateOutputSize(mixed $input) : int
Parameters
$input : mixed
Return values
int

executeAlgorithm()

private executeAlgorithm(mixed $input) : array<string|int, mixed>
Parameters
$input : mixed
Return values
array<string|int, mixed>

executeGenericAlgorithm()

private executeGenericAlgorithm(FFI $ffi, mixed $input) : array<string|int, mixed>
Parameters
$ffi : FFI
$input : mixed
Return values
array<string|int, mixed>

executeSpecificAlgorithm()

private executeSpecificAlgorithm(FFI $ffi, mixed $input) : array<string|int, mixed>
Parameters
$ffi : FFI
$input : mixed
Return values
array<string|int, mixed>

getAlgorithmCreateFunction()

private getAlgorithmCreateFunction() : string
Return values
string

getValidParameters()

private getValidParameters() : array<string|int, mixed>
Return values
array<string|int, mixed>

prepareInput()

private prepareInput(mixed $input) : mixed
Parameters
$input : mixed

processOutput()

private processOutput(array<string|int, mixed> $result) : array<string|int, mixed>
Parameters
$result : array<string|int, mixed>
Return values
array<string|int, mixed>

processRhythmOutput()

private processRhythmOutput(array<string|int, mixed> $result) : array<string|int, mixed>
Parameters
$result : array<string|int, mixed>
Return values
array<string|int, mixed>

processSpectralOutput()

private processSpectralOutput(array<string|int, mixed> $result) : array<string|int, mixed>
Parameters
$result : array<string|int, mixed>
Return values
array<string|int, mixed>

processStatsOutput()

private processStatsOutput(array<string|int, mixed> $result) : array<string|int, mixed>
Parameters
$result : array<string|int, mixed>
Return values
array<string|int, mixed>

processTemporalOutput()

private processTemporalOutput(array<string|int, mixed> $result) : array<string|int, mixed>
Parameters
$result : array<string|int, mixed>
Return values
array<string|int, mixed>

processTonalOutput()

private processTonalOutput(array<string|int, mixed> $result) : array<string|int, mixed>
Parameters
$result : array<string|int, mixed>
Return values
array<string|int, mixed>

setAlgorithmParameter()

private setAlgorithmParameter(FFI $ffi, string $key, mixed $value) : void
Parameters
$ffi : FFI
$key : string
$value : mixed

setArrayParameter()

private setArrayParameter(FFI $ffi, string $key, array<string|int, mixed> $value) : void
Parameters
$ffi : FFI
$key : string
$value : array<string|int, mixed>

validateAlgorithmInput()

private validateAlgorithmInput(mixed $input) : void
Parameters
$input : mixed 

        

        
    




    

    

                                

                

                                
    

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