libs/qm-dsp/dsp/mfcc/MFCC.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 2005 Nicolas Chetry, copyright 2008 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 #ifndef MFCC_H
  17 #define MFCC_H
  18
  19 #include "base/Window.h"
  20
  21 class FFTReal;
  22
  23 struct MFCCConfig {
  24     int FS;
  25     int fftsize;
  26     int nceps;
  27     double logpower;
  28     bool want_c0;
  29     WindowType window;
  30     MFCCConfig(int _FS) :
  31         FS(_FS), fftsize(2048), nceps(19),
  32         logpower(1.0), want_c0(true), window(HammingWindow) { }
  33 };
  34
  35 class MFCC
  36 {
  37 public:
  38     MFCC(MFCCConfig config);
  39     virtual ~MFCC();
  40
  41     /**
  42      * Process time-domain input data.  inframe must contain
  43      * getfftlength() samples.  outceps must contain space for nceps
  44      * values, plus one if want_c0 is specified.
  45      */
  46     int process(const double *inframe, double *outceps);
  47
  48     /**
  49      * Process time-domain input data.  real and imag must contain
  50      * getfftlength()/2+1 elements (i.e. the conjugate half of the FFT
  51      * is not expected).  outceps must contain space for nceps values,
  52      * plus one if want_c0 is specified.
  53      */
  54     int process(const double *real, const double *imag, double *outceps);
  55
  56     int getfftlength() const { return fftSize; }
  57
  58 private:
  59     /* Filter bank parameters */
  60     double  lowestFrequency;
  61     int     linearFilters;
  62     double  linearSpacing;
  63     int     logFilters;
  64     double  logSpacing;
  65
  66     /* FFT length */
  67     int     fftSize;
  68
  69     int     totalFilters;
  70     double  logPower;
  71
  72     /* Misc. */
  73     int     samplingRate;
  74     int     nceps;
  75
  76     /* MFCC vector */
  77     double  *ceps;
  78
  79     double  **mfccDCTMatrix;
  80     double  **mfccFilterWeights;
  81
  82     /* The analysis window */
  83     Window<double> *window;
  84
  85     /* For the FFT */
  86     double *realOut;
  87     double *imagOut;
  88     double *fftMag;
  89     double *earMag;
  90     FFTReal *fft;
  91
  92     /* Set if user want C0 */
  93     int WANT_C0;
  94 };
  95
  96
  97 #endif
  98