libs/qm-dsp/dsp/tempotracking/TempoTrackV2.h

   1 /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
   2
   3 /*
   4     QM DSP Library
   5
   6     Centre for Digital Music, Queen Mary, University of London.
   7     This file copyright 2008-2009 Matthew Davies and QMUL.
   8
   9     This program is free software; you can redistribute it and/or
  10     modify it under the terms of the GNU General Public License as
  11     published by the Free Software Foundation; either version 2 of the
  12     License, or (at your option) any later version.  See the file
  13     COPYING included with this distribution for more information.
  14 */
  15
  16
  17 #ifndef TEMPOTRACKV2_H
  18 #define TEMPOTRACKV2_H
  19
  20 #include <vector>
  21
  22 using std::vector;
  23
  24 //!!! Question: how far is this actually sample rate dependent?  I
  25 // think it does produce plausible results for e.g. 48000 as well as
  26 // 44100, but surely the fixed window sizes and comb filtering will
  27 // make it prefer double or half time when run at e.g. 96000?
  28
  29 class TempoTrackV2
  30 {
  31 public:
  32     /**
  33      * Construct a tempo tracker that will operate on beat detection
  34      * function data calculated from audio at the given sample rate
  35      * with the given frame increment.
  36      *
  37      * Currently the sample rate and increment are used only for the
  38      * conversion from beat frame location to bpm in the tempo array.
  39      */
  40     TempoTrackV2(float sampleRate, size_t dfIncrement);
  41     ~TempoTrackV2();
  42
  43     // Returned beat periods are given in df increment units; tempi in bpm
  44     void calculateBeatPeriod(const vector<double> &df,
  45                              vector<double> &beatPeriod,
  46                              vector<double> &tempi);
  47
  48     // Returned beat positions are given in df increment units
  49     void calculateBeats(const vector<double> &df,
  50                         const vector<double> &beatPeriod,
  51                         vector<double> &beats);
  52
  53 private:
  54     typedef vector<int> i_vec_t;
  55     typedef vector<vector<int> > i_mat_t;
  56     typedef vector<double> d_vec_t;
  57     typedef vector<vector<double> > d_mat_t;
  58
  59     float m_rate;
  60     size_t m_increment;
  61
  62     void adapt_thresh(d_vec_t &df);
  63     double mean_array(const d_vec_t &dfin, int start, int end);
  64     void filter_df(d_vec_t &df);
  65     void get_rcf(const d_vec_t &dfframe, const d_vec_t &wv, d_vec_t &rcf);
  66     void viterbi_decode(const d_mat_t &rcfmat, const d_vec_t &wv,
  67                         d_vec_t &bp, d_vec_t &tempi);
  68     double get_max_val(const d_vec_t &df);
  69     int get_max_ind(const d_vec_t &df);
  70     void normalise_vec(d_vec_t &df);
  71 };
  72
  73 #endif