libs/rubberband/src/FFT.h

   1 /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
   2
   3 /*
   4     Rubber Band
   5     An audio time-stretching and pitch-shifting library.
   6     Copyright 2007-2008 Chris Cannam.
   7
   8     This program is free software; you can redistribute it and/or
   9     modify it under the terms of the GNU General Public License as
  10     published by the Free Software Foundation; either version 2 of the
  11     License, or (at your option) any later version.  See the file
  12     COPYING included with this distribution for more information.
  13 */
  14
  15 #ifndef _RUBBERBAND_FFT_H_
  16 #define _RUBBERBAND_FFT_H_
  17
  18 #include "sysutils.h"
  19
  20 namespace RubberBand {
  21
  22 class FFTImpl;
  23
  24 /**
  25  * Provide the basic FFT computations we need, using one of a set of
  26  * candidate FFT implementations (depending on compile flags).
  27  *
  28  * Implements real->complex FFTs of power-of-two sizes only.  Note
  29  * that only the first half of the output signal is returned (the
  30  * complex conjugates half is omitted), so the "complex" arrays need
  31  * room for size/2+1 elements.
  32  *
  33  * Not thread safe: use a separate instance per thread.
  34  */
  35
  36 class FFT
  37 {
  38 public:
  39     enum Exception { InvalidSize };
  40
  41     FFT(int size, int debugLevel = 0); // may throw InvalidSize
  42     ~FFT();
  43
  44     void forward(const double *R__ realIn, double *R__ realOut, double *R__ imagOut);
  45     void forwardPolar(const double *R__ realIn, double *R__ magOut, double *R__ phaseOut);
  46     void forwardMagnitude(const double *R__ realIn, double *R__ magOut);
  47
  48     void forward(const float *R__ realIn, float *R__ realOut, float *R__ imagOut);
  49     void forwardPolar(const float *R__ realIn, float *R__ magOut, float *R__ phaseOut);
  50     void forwardMagnitude(const float *R__ realIn, float *R__ magOut);
  51
  52     void inverse(const double *R__ realIn, const double *R__ imagIn, double *R__ realOut);
  53     void inversePolar(const double *R__ magIn, const double *R__ phaseIn, double *R__ realOut);
  54     void inverseCepstral(const double *R__ magIn, double *R__ cepOut);
  55
  56     void inverse(const float *R__ realIn, const float *R__ imagIn, float *R__ realOut);
  57     void inversePolar(const float *R__ magIn, const float *R__ phaseIn, float *R__ realOut);
  58     void inverseCepstral(const float *R__ magIn, float *R__ cepOut);
  59
  60     // Calling one or both of these is optional -- if neither is
  61     // called, the first call to a forward or inverse method will call
  62     // init().  You only need call these if you don't want to risk
  63     // expensive allocations etc happening in forward or inverse.
  64     void initFloat();
  65     void initDouble();
  66
  67     float *getFloatTimeBuffer();
  68     double *getDoubleTimeBuffer();
  69
  70     static void tune();
  71
  72 protected:
  73     FFTImpl *d;
  74     static int m_method;
  75 };
  76
  77 }
  78
  79 #endif
  80