fft.h

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/*
  Copyright (C) 2003-2013 Paul Brossier <piem@aubio.org>
 
  This file is part of aubio.
 
  aubio 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 3 of the License, or
  (at your option) any later version.
 
  aubio is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.
 
  You should have received a copy of the GNU General Public License
  along with aubio.  If not, see <http://www.gnu.org/licenses/>.
 
*/
 
/** \file
 
  Fast Fourier Transform
 
  Depending on how aubio was compiled, FFT are computed using one of:
    - [Ooura](http://www.kurims.kyoto-u.ac.jp/~ooura/fft.html)
    - [FFTW3](http://www.fftw.org)
    - [vDSP](https://developer.apple.com/library/mac/#documentation/Accelerate/Reference/vDSPRef/Reference/reference.html)
 
  \example spectral/test-fft.c
 
*/
 
#ifndef AUBIO_FFT_H
#define AUBIO_FFT_H
 
#ifdef __cplusplus
extern "C" {
#endif
 
/** FFT object
 
  This object computes forward and backward FFTs.
 
*/
typedef struct _aubio_fft_t aubio_fft_t;
 
/** create new FFT computation object
 
  \param size length of the FFT
 
*/
aubio_fft_t * new_aubio_fft (uint_t size);
/** delete FFT object
 
  \param s fft object as returned by new_aubio_fft
 
*/
void del_aubio_fft(aubio_fft_t * s);
 
/** compute forward FFT
 
  \param s fft object as returned by new_aubio_fft
  \param input input signal
  \param spectrum output spectrum
 
*/
void aubio_fft_do (aubio_fft_t *s, const fvec_t * input, cvec_t * spectrum);
/** compute backward (inverse) FFT
 
  \param s fft object as returned by new_aubio_fft
  \param spectrum input spectrum
  \param output output signal
 
*/
void aubio_fft_rdo (aubio_fft_t *s, const cvec_t * spectrum, fvec_t * output);
 
/** compute forward FFT
 
  \param s fft object as returned by new_aubio_fft
  \param input real input signal
  \param compspec complex output fft real/imag
 
*/
void aubio_fft_do_complex (aubio_fft_t *s, const fvec_t * input, fvec_t * compspec);
/** compute backward (inverse) FFT from real/imag
 
  \param s fft object as returned by new_aubio_fft
  \param compspec real/imag input fft array
  \param output real output array
 
*/
void aubio_fft_rdo_complex (aubio_fft_t *s, const fvec_t * compspec, fvec_t * output);
 
/** convert real/imag spectrum to norm/phas spectrum
 
  \param compspec real/imag input fft array
  \param spectrum cvec norm/phas output array
 
*/
void aubio_fft_get_spectrum(const fvec_t * compspec, cvec_t * spectrum);
/** convert real/imag spectrum to norm/phas spectrum
 
  \param compspec real/imag input fft array
  \param spectrum cvec norm/phas output array
 
*/
void aubio_fft_get_realimag(const cvec_t * spectrum, fvec_t * compspec);
 
/** compute phas spectrum from real/imag parts
 
  \param compspec real/imag input fft array
  \param spectrum cvec norm/phas output array
 
*/
void aubio_fft_get_phas(const fvec_t * compspec, cvec_t * spectrum);
/** compute imaginary part from the norm/phas cvec
 
  \param spectrum norm/phas input array
  \param compspec real/imag output fft array
 
*/
void aubio_fft_get_imag(const cvec_t * spectrum, fvec_t * compspec);
 
/** compute norm component from real/imag parts
 
  \param compspec real/imag input fft array
  \param spectrum cvec norm/phas output array
 
*/
void aubio_fft_get_norm(const fvec_t * compspec, cvec_t * spectrum);
/** compute real part from norm/phas components
 
  \param spectrum norm/phas input array
  \param compspec real/imag output fft array
 
*/
void aubio_fft_get_real(const cvec_t * spectrum, fvec_t * compspec);
 
#ifdef __cplusplus
}
#endif
 
#endif /* AUBIO_FFT_H */