annotate src/BTrack.h @ 17:a31841af2bbc develop

Before this commit, the OnsetDetectionFunction class used double precision, and the BTrack class used floats. I have now made BTrack use double precision also. This works fine and the only cost of doing this is that we have to perform one array copy into floating point format so that sample rate conversion (which has to be in floating point format) can take place.

//=======================================================================
/** @file BTrack.h
 *  @brief BTrack - a real-time beat tracker
 *  @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 __BTRACK_H
#define __BTRACK_H

class BTrack {
	
public:
    
    /** constructor */
	BTrack();
    
    /** destructor */
	~BTrack();		
	
    /** Initialise with frame size and set all frame sizes accordingly */
	void initialise(int fsize);
    
    /** Add new sample to buffer and apply beat tracking */
	void process(double df_sample);
   
    /** Set the tempo of the beat tracker */
	void settempo(double tempo);
    
    /** fix tempo to roughly around some value */
	void fixtempo(double tempo);
    
    /** do not fix the tempo anymore */
	void unfixtempo();
	
	int playbeat;
	double cscoreval;
	double est_tempo;
			
private:
    
    /** Convert detection function from N samples to 512 */
	void dfconvert();
    
    /** update the cumulative score */
	void updatecumscore(double df_sample);
	
    /** predicts the next beat */
    void predictbeat();
    
    /** Calculates the current tempo expressed as the beat period in detection function samples */
    void calcTempo();
    
    /** calculates an adaptive threshold which is used to remove low level energy from detection 
     * function and emphasise peaks 
     */
	void adapt_thresh(double *x,int N);
    
    /** calculates the mean of values in an array from index locations [start,end] */
	double mean_array(double *array,int start,int end);
    
    /** normalises a given array */
	void normalise(double *array,int N);
    
    /** calculates the balanced autocorrelation of the smoothed detection function */
	void acf_bal(double *df_thresh);
    
    /** returns the output of the comb filter */
	void getrcfoutput();
	
	// buffers
	double *dfbuffer;			/**< to hold detection function */
	double df512[512];			/**< to hold resampled detection function */
	double *cumscore;			/**<  to hold cumulative score */
	
	double acf[512];				/**<  to hold autocorrelation function */
	
	double wv[128];				/**<  to hold weighting vector */
	
	double rcf[128];				/**<  to hold comb filter output */
	double t_obs[41];			/**<  to hold tempo version of comb filter output */
	
	double delta[41];			/**<  to hold final tempo candidate array */
	double prev_delta[41];		/**<  previous delta */
	double prev_delta_fix[41];	/**<  fixed tempo version of previous delta */
	
	double t_tmat[41][41];		/**<  transition matrix */
	
	
	// parameters
	double tightness;
	double alpha;
	double bperiod;
	double tempo;
	
	
	double p_fact;
	
	
	//
	int m0;				// indicates when the next point to predict the next beat is
	int beat;
	
	int dfbuffer_size;
		
	
	int framesize;
	
	
	int tempofix;
	

};

#endif