annotate src/OnsetDetectionFunction.h @ 60:bf256abf1dd4

Did more commenting. Added documentation.

//=======================================================================
/** @file OnsetDetectionFunction.h
 *  @brief A class for calculating onset detection functions
 *  @author Adam Stark
 *  @copyright Copyright (C) 2008-2014  Queen Mary University of London
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
//=======================================================================

#ifndef __ONSETDETECTIONFUNCTION_H
#define __ONSETDETECTIONFUNCTION_H

#include "fftw3.h"

//=======================================================================
/** The type of onset detection function to calculate */
enum OnsetDetectionFunctionType
{
    EnergyEnvelope,
    EnergyDifference,
    SpectralDifference,
    SpectralDifferenceHWR,
    PhaseDeviation,
    ComplexSpectralDifference,
    ComplexSpectralDifferenceHWR,
    HighFrequencyContent,
    HighFrequencySpectralDifference,
    HighFrequencySpectralDifferenceHWR
};

//=======================================================================
/** The type of window to use when calculating onset detection function samples */
enum WindowType
{
    RectangularWindow,
    HanningWindow,
    HammingWindow,
    BlackmanWindow,
    TukeyWindow
};

class OnsetDetectionFunction
{
public:
    
    /** Constructor 
     * @param hopSize_ the hop size in audio samples
     * @param frameSize_ the frame size in audio samples
     * @param onsetDetectionFunctionType_ the type of onset detection function to use - (see OnsetDetectionFunctionType)
     * @param windowType the type of window to use (see WindowType)
     */
	OnsetDetectionFunction(int hopSize_,int frameSize_,int onsetDetectionFunctionType_,int windowType);
    
    /** Destructor */
	~OnsetDetectionFunction();
    
    /** Initialisation Function 
     * @param hopSize_ the hop size in audio samples
     * @param frameSize_ the frame size in audio samples
     * @param onsetDetectionFunctionType_ the type of onset detection function to use - (see OnsetDetectionFunctionType)
     * @param windowType the type of window to use (see WindowType)
     */
	void initialise(int hopSize_,int frameSize_,int onsetDetectionFunctionType_,int windowType);
	
    /** Process input frame and calculate detection function sample 
     * @param buffer a pointer to an array containing the audio samples to be processed
     * @returns the onset detection function sample
     */
	double calculateOnsetDetectionFunctionSample(double *buffer);
    
    /** Set the detection function type 
     * @param onsetDetectionFunctionType_ the type of onset detection function to use - (see OnsetDetectionFunctionType)
     */
	void setOnsetDetectionFunctionType(int onsetDetectionFunctionType_);
	
private:
	
    /** Perform the FFT on the data in 'frame' */
	void performFFT();

    //=======================================================================
    /** Calculate energy envelope detection function sample */
	double energyEnvelope();
    
    /** Calculate energy difference detection function sample */
	double energyDifference();
    
    /** Calculate spectral difference detection function sample */
	double spectralDifference();
    
    /** Calculate spectral difference (half wave rectified) detection function sample */
	double spectralDifferenceHWR();
    
    /** Calculate phase deviation detection function sample */
	double phaseDeviation();
    
    /** Calculate complex spectral difference detection function sample */
	double complexSpectralDifference();
    
    /** Calculate complex spectral difference detection function sample (half-wave rectified) */
	double complexSpectralDifferenceHWR();
    
    /** Calculate high frequency content detection function sample */
	double highFrequencyContent();
    
    /** Calculate high frequency spectral difference detection function sample */
	double highFrequencySpectralDifference();
    
    /** Calculate high frequency spectral difference detection function sample (half-wave rectified) */
	double highFrequencySpectralDifferenceHWR();

    //=======================================================================
    /** Calculate a Rectangular window */
	void calculateRectangularWindow();
    
    /** Calculate a Hanning window */
	void calculateHanningWindow();
    
    /** Calculate a Hamming window */
	void calclulateHammingWindow();
    
    /** Calculate a Blackman window */
	void calculateBlackmanWindow();
    
    /** Calculate a Tukey window */
	void calculateTukeyWindow();

    //=======================================================================
	/** Set phase values between [-pi, pi] 
     * @param phaseVal the phase value to process
     * @returns the wrapped phase value
     */
	double princarg(double phaseVal);
	
	
	double pi;							/**< pi, the constant */
	
	int frameSize;						/**< audio framesize */
	int hopSize;						/**< audio hopsize */
	int onsetDetectionFunctionType;		/**< type of detection function */
	
	fftw_plan p;						/**< fftw plan */
	fftw_complex *complexIn;			/**< to hold complex fft values for input */
	fftw_complex *complexOut;			/**< to hold complex fft values for output */
	
	int initialised;					/**< flag indicating whether buffers and FFT plans are initialised */

	double *frame;						/**< audio frame */
	double *window;						/**< window */
	
	double prevEnergySum;				/**< to hold the previous energy sum value */
	
	double *magSpec;					/**< magnitude spectrum */
	double *prevMagSpec;                /**< previous magnitude spectrum */
	
	double *phase;						/**< FFT phase values */
	double *prevPhase;					/**< previous phase values */
	double *prevPhase2;                 /**< second order previous phase values */

};


#endif