source: src/spectral/fft.h @ e4a8882

/*
  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 */