annotate dsp/tempotracking/TempoTrackV2.h @ 321:f1e6be2de9a5

A threshold (delta) is added in the peak picking parameters structure (PPickParams). It is used as an offset when computing the smoothed detection function. A constructor for the structure PPickParams is also added to set the parameters to 0 when a structure instance is created. Hence programmes using the peak picking parameter structure and which do not set the delta parameter (e.g. QM Vamp note onset detector) won't be affected by the modifications.

Functions modified:
- dsp/onsets/PeakPicking.cpp
- dsp/onsets/PeakPicking.h
- dsp/signalconditioning/DFProcess.cpp
- dsp/signalconditioning/DFProcess.h

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

/*
    QM DSP Library

    Centre for Digital Music, Queen Mary, University of London.
    This file copyright 2008-2009 Matthew Davies 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 TEMPOTRACKV2_H
#define TEMPOTRACKV2_H

#include <vector>

using std::vector;

//!!! Question: how far is this actually sample rate dependent?  I
// think it does produce plausible results for e.g. 48000 as well as
// 44100, but surely the fixed window sizes and comb filtering will
// make it prefer double or half time when run at e.g. 96000?

class TempoTrackV2  
{
public:
    /**
     * Construct a tempo tracker that will operate on beat detection
     * function data calculated from audio at the given sample rate
     * with the given frame increment.
     *
     * Currently the sample rate and increment are used only for the
     * conversion from beat frame location to bpm in the tempo array.
     */
    TempoTrackV2(float sampleRate, size_t dfIncrement);
    ~TempoTrackV2();

    // Returned beat periods are given in df increment units; tempi in bpm
    void calculateBeatPeriod(const vector<double> &df,
                             vector<double> &beatPeriod,
                             vector<double> &tempi);

    // Returned beat positions are given in df increment units
    void calculateBeats(const vector<double> &df,
                        const vector<double> &beatPeriod,
                        vector<double> &beats);

private:
    typedef vector<int> i_vec_t;
    typedef vector<vector<int> > i_mat_t;
    typedef vector<double> d_vec_t;
    typedef vector<vector<double> > d_mat_t;

    float m_rate;
    size_t m_increment;

    void adapt_thresh(d_vec_t &df);
    double mean_array(const d_vec_t &dfin, int start, int end);
    void filter_df(d_vec_t &df);
    void get_rcf(const d_vec_t &dfframe, const d_vec_t &wv, d_vec_t &rcf);
    void viterbi_decode(const d_mat_t &rcfmat, const d_vec_t &wv,
                        d_vec_t &bp, d_vec_t &tempi);
    double get_max_val(const d_vec_t &df);
    int get_max_ind(const d_vec_t &df);
    void normalise_vec(d_vec_t &df);
};

#endif