annotate Matcher.h @ 13:66082cc488c3

Pull out total energies into a separate vector (so that the frame vectors only contain the real features)

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Vamp feature extraction plugin using the MATCH audio alignment
    algorithm.

    Centre for Digital Music, Queen Mary, University of London.
    This file copyright 2007 Simon Dixon, Chris Cannam and QMUL.
    
    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 2 of the
    License, or (at your option) any later version.  See the file
    COPYING included with this distribution for more information.
*/

#ifndef _MATCHER_H_
#define _MATCHER_H_

#include <vector>
#include <iostream>
#include <sstream>
#include <cmath>

#define ADVANCE_THIS 1
#define ADVANCE_OTHER 2
#define ADVANCE_BOTH 3
#define MASK 0xfc


using std::vector;
using std::string;
using std::cerr;
using std::endl;

/** Represents an audio stream that can be matched to another audio
 *  stream of the same piece of music.  The matching algorithm uses
 *  dynamic time warping.  The distance metric is a Euclidean metric
 *  on the FFT data with the higher frequencies mapped onto a linear
 *  scale.
 */

class Matcher
{
protected:
    /** Points to the other performance with which this one is being
     *  compared.  The data for the distance metric and the dynamic
     *  time warping is shared between the two matchers. In the
     *  original version, only one of the two performance matchers
     *  contained the distance metric. (See <code>first</code>)
     */
    Matcher *otherMatcher;

    /** Indicates which performance is considered primary (the
     *  score). This is the performance shown on the vertical axis,
     *  and referred to as "this" in the codes for the direction of
     *  DTW steps. */
    bool firstPM;

    /** Sample rate of audio */
    float sampleRate;

    /** Onset time of the first note in the audio file, in order to
     *  establish synchronisation between the match file and the audio
     *  data. */
    double matchFileOffset;

    /** Flag indicating whether or not each frame of audio should be
     *  normalised to have a sum of 1.  (Default = false). */
    bool normalise1;
	
    /** Flag indicating whether or not the distance metric for pairs
     *  of audio frames should be normalised by the sum of the two
     *  frames.  (Default = false). */
    bool normalise2;

    /** Flag indicating whether or not each frame of audio should be
     *  normalised by the long term average of the summed energy.
     *  (Default = false; assumes normalise1 == false). */
    bool normalise3;
	
    /** Flag indicating whether or not the distance metric for pairs
     *  of audio frames should be normalised by the log of the sum of
     *  the frames.  (Default = false; assumes normalise2 ==
     *  false). */
    bool normalise4;

    /** Flag indicating whether or not the half-wave rectified
     *  spectral difference should be used in calculating the distance
     *  metric for pairs of audio frames, instead of the straight
     *  spectrum values. (Default = true). */
    bool useSpectralDifference;

    bool useChromaFrequencyMap;

    /** Scaling factor for distance metric; must guarantee that the
     *  final value fits in the data type used, that is, unsigned
     *  char. (Default = 16).
     */
    double scale;

    /** Spacing of audio frames (determines the amount of overlap or
     *  skip between frames). This value is expressed in
     *  seconds. (Default = 0.020s) */
    double hopTime;

    /** The size of an FFT frame in seconds. (Default = 0.04644s).
     *  Note that the value is not taken to be precise; it is adjusted
     *  so that <code>fftSize</code> is always power of 2. */
    double fftTime;

    /** The width of the search band (error margin) around the current
     *  match position, measured in seconds. Strictly speaking the
     *  width is measured backwards from the current point, since the
     *  algorithm has to work causally.
     */
    double blockTime;

    /** Spacing of audio frames in samples (see <code>hopTime</code>) */
    int hopSize;

    /** The size of an FFT frame in samples (see <code>fftTime</code>) */
    int fftSize;

    /** Width of the search band in FFT frames (see <code>blockTime</code>) */
    int blockSize;

    /** The number of frames of audio data which have been read. */
    int frameCount;

    /** RMS amplitude of the current frame. */
//    double frameRMS;

    /** Long term average frame energy (in frequency domain
     *  representation). */
    double ltAverage;

    /** The number of frames sequentially processed by this matcher,
     *  without a frame of the other matcher being processed.
     */
    int runCount;

    /** Interactive control of the matching process allows pausing
     *  computation of the cost matrices in one direction.
     */
    bool paused;

    /** The total number of frames of audio data to be read. */
    int maxFrames;

    /** A mapping function for mapping FFT bins to final frequency
     *  bins.  The mapping is linear (1-1) until the resolution
     *  reaches 2 points per semitone, then logarithmic with a
     *  semitone resolution.  e.g. for 44.1kHz sampling rate and
     *  fftSize of 2048 (46ms), bin spacing is 21.5Hz, which is mapped
     *  linearly for bins 0-34 (0 to 732Hz), and logarithmically for
     *  the remaining bins (midi notes 79 to 127, bins 35 to 83),
     *  where all energy above note 127 is mapped into the final
     *  bin. */
    vector<int> freqMap;

    /** The number of entries in <code>freqMap</code>. Note that the
     *  length of the array is greater, because its size is not known
     *  at creation time. */
    int freqMapSize;

    /** The most recent frame; used for calculating the frame to frame
     *  spectral difference. These are therefore frequency warped but
     *  not yet normalised. */
    vector<double> prevFrame;
    vector<double> newFrame;

    /** A block of previously seen frames are stored in this structure
     *  for calculation of the distance matrix as the new frames are
     *  read in.  One can think of the structure of the array as a
     *  circular buffer of vectors.  These are the frames with all
     *  applicable processing applied (e.g. spectral difference,
     *  normalisation), unlike prevFrame and newFrame. The total
     *  energy of frames[i] is stored in totalEnergies[i]. */
    vector<vector<double> > frames;

    /** The total energy of each frame in the frames block. */ 
    vector<double> totalEnergies;

    /** The best path cost matrix. */
    int **bestPathCost;

    /** The distance matrix. */
    unsigned char **distance;

    /** The bounds of each row of data in the distance and path cost matrices.*/
    int *first;
    int *last;

    /** Height of each column in distance and bestPathCost matrices */
    int *distYSizes;

    /** Width of distance and bestPathCost matrices and first and last vectors */
    int  distXSize;

    /** Total number of audio frames, or -1 for live or compressed input. */
    long fileLength;

    bool initialised;

//!!!    bool atEnd; //!!!

    /** Disable or enable debugging output */
    static bool silent;

    static const double decay;
    static const double silenceThreshold;
    static const int MAX_RUN_COUNT;

    friend class Finder; //!!!

public:
    /** Constructor for Matcher.
     *
     *  @param p The Matcher representing the performance with which
     *  this one is going to be matched.  Some information is shared
     *  between the two matchers (currently one possesses the distance
     *  matrix and optimal path matrix).
     */
    Matcher(float rate, Matcher *p);

    ~Matcher();

    /** For debugging, outputs information about the Matcher to
     *  standard error.
     */
    void print();

    /** Gives some basic `header' information about the Matcher. */
    string toString();

    /** Adds a link to the Matcher object representing the performance
     *  which is going to be matched to this one.
     *
     *  @param p the Matcher representing the other performance
     */
    void setOtherMatcher(Matcher *p) {
        otherMatcher = p;
    } // setOtherMatcher()

    int getFFTSize() {
        return fftSize;
    }
    
    int getHopSize() {
        return hopSize;
    }

    int getFrameCount() { 
        return frameCount;
    }

    void setHopSize(int);

protected:
    template <typename T>
    void initVector(vector<T> &vec, int sz, T dflt = 0) {
        vec.clear();
        while ((int)vec.size() < sz) vec.push_back(dflt);
    }

    template <typename T>
    void initMatrix(vector<vector<T> > &mat, int hsz, int vsz,
                    T dflt = 0, int fillTo = -1) {
        mat.clear();
        if (fillTo < 0) fillTo = hsz;
        for (int i = 0; i < hsz; ++i) {
            mat.push_back(vector<T>());
            if (i < fillTo) {
                while ((int)mat[i].size() < vsz) {
                    mat[i].push_back(dflt);
                }
            }
        }
    }

    void init();

    void makeFreqMap(int fftSize, float sampleRate);

    /** Creates a map of FFT frequency bins to comparison bins.  Where
     *  the spacing of FFT bins is less than 0.5 semitones, the
     *  mapping is one to one. Where the spacing is greater than 0.5
     *  semitones, the FFT energy is mapped into semitone-wide
     *  bins. No scaling is performed; that is the energy is summed
     *  into the comparison bins. See also processFrame()
     */
    void makeStandardFrequencyMap(int fftSize, float sampleRate);

    void makeChromaFrequencyMap(int fftSize, float sampleRate);

    /** Processes a frame of audio data by first computing the STFT
     *  with a Hamming window, then mapping the frequency bins into a
     *  part-linear part-logarithmic array, then (optionally)
     *  computing the half-wave rectified spectral difference from the
     *  previous frame, then (optionally) normalising to a sum of 1,
     *  then calculating the distance to all frames stored in the
     *  otherMatcher and storing them in the distance matrix, and
     *  finally updating the optimal path matrix using the dynamic
     *  time warping algorithm.
     */
    void processFrame(double *reBuffer, double *imBuffer);

    /** Calculates the Manhattan distance between two vectors, with an
     *  optional normalisation by the combined values in the
     *  vectors. Since the vectors contain energy, this could be
     *  considered as a squared Euclidean distance metric. Note that
     *  normalisation assumes the values are all non-negative.
     *
     *  @param f1 one of the vectors involved in the distance calculation
     *  @param f2 one of the vectors involved in the distance calculation
     *  @return the distance, scaled and truncated to an integer
     */
    int calcDistance(const vector<double> &f1, const vector<double> &f2);

    /** Retrieves values from the minimum cost matrix.
     *
     *  @param i the frame number of this Matcher
     *  @param j the frame number of the other Matcher
     *  @return the cost of the minimum cost path to this location
     */
    int getValue(int i, int j, bool firstAttempt);

    /** Stores entries in the distance matrix and the optimal path matrix.
     *
     *  @param i the frame number of this Matcher
     *  @param j the frame number of the other Matcher
     *  @param dir the direction from which this position is reached with
     *  minimum cost
     *  @param value the cost of the minimum path except the current step
     *  @param dMN the distance cost between the two frames
     */
    void setValue(int i, int j, int dir, int value, int dMN);

    friend class MatchFeeder;

}; // class Matcher

#endif