annotate dsp/segmentation/Segmenter.h @ 298:255e431ae3d4

* Key detector: when returning key strengths, use the peak value of the
  three underlying chromagram correlations (from 36-bin chromagram)
  corresponding to each key, instead of the mean.
  Rationale: This is the same method as used when returning the key value,
  and it's nice to have the same results in both returned value and plot.
  The peak performed better than the sum with a simple test set of triads,
  so it seems reasonable to change the plot to match the key output rather
  than the other way around.

* FFT: kiss_fftr returns only the non-conjugate bins, synthesise the rest
  rather than leaving them (perhaps dangerously) undefined.  Fixes an
  uninitialised data error in chromagram that could cause garbage results
  from key detector.

* Constant Q: remove precalculated values again, I reckon they're not
  proving such a good tradeoff.

#ifndef _SEGMENTER_H
#define _SEGMENTER_H

/*
 *  Segmenter.h
 *  soundbite
 *
 *  Created by Mark Levy on 23/03/2006.
 *  Copyright 2006 Centre for Digital Music, Queen Mary, University of London. All rights reserved.
 *
 */

#include <vector>
#include <iostream>

using std::vector;
using std::ostream;

class Segment
{
public:
	int start;		// in samples
	int end;
	int type;
};

class Segmentation
{
public:
	int nsegtypes;		// number of segment types, so possible types are {0,1,...,nsegtypes-1}
	int samplerate;
	vector<Segment> segments;	
};

ostream& operator<<(ostream& os, const Segmentation& s);

class Segmenter
{
public:
	Segmenter() {}
	virtual ~Segmenter() {}
	virtual void initialise(int samplerate) = 0;	// must be called before any other methods
	virtual int getWindowsize() = 0;				// required window size for calls to extractFeatures()
	virtual int getHopsize() = 0;					// required hop size for calls to extractFeatures()
	virtual void extractFeatures(const double* samples, int nsamples) = 0;
	virtual void segment() = 0;						// call once all the features have been extracted
	virtual void segment(int m) = 0;				// specify desired number of segment-types
	virtual void clear() { features.clear(); }
	const Segmentation& getSegmentation() const { return segmentation; } 
protected:
	vector<vector<double> > features;
	Segmentation segmentation;
	int samplerate;
};

#endif