2 Copyright (C) 2003-2009 Paul Brossier <piem@aubio.org>
4 This file is part of aubio.
6 aubio is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
11 aubio is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with aubio. If not, see <http://www.gnu.org/licenses/>.
23 Fast Fourier Transform
25 \example src/spectral/test-fft.c
38 This object computes forward and backward FFTs, using the complex type to
39 store the results. The phase vocoder or aubio_mfft_t objects should be
40 preferred to using directly aubio_fft_t. The FFT are computed using FFTW3
41 (although support for another library could be added).
44 typedef struct _aubio_fft_t aubio_fft_t;
46 /** create new FFT computation object
48 \param size length of the FFT
51 aubio_fft_t * new_aubio_fft (uint_t size);
54 \param s fft object as returned by new_aubio_fft
57 void del_aubio_fft(aubio_fft_t * s);
59 /** compute forward FFT
61 \param s fft object as returned by new_aubio_fft
62 \param input input signal
63 \param spectrum output spectrum
66 void aubio_fft_do (aubio_fft_t *s, fvec_t * input, cvec_t * spectrum);
67 /** compute backward (inverse) FFT
69 \param s fft object as returned by new_aubio_fft
70 \param spectrum input spectrum
71 \param output output signal
74 void aubio_fft_rdo (aubio_fft_t *s, cvec_t * spectrum, fvec_t * output);
76 /** compute forward FFT
78 \param s fft object as returned by new_aubio_fft
79 \param input real input signal
80 \param compspec complex output fft real/imag
83 void aubio_fft_do_complex (aubio_fft_t *s, fvec_t * input, fvec_t * compspec);
84 /** compute backward (inverse) FFT from real/imag
86 \param s fft object as returned by new_aubio_fft
87 \param compspec real/imag input fft array
88 \param output real output array
91 void aubio_fft_rdo_complex (aubio_fft_t *s, fvec_t * compspec, fvec_t * output);
93 /** convert real/imag spectrum to norm/phas spectrum
95 \param compspec real/imag input fft array
96 \param spectrum cvec norm/phas output array
99 void aubio_fft_get_spectrum(fvec_t * compspec, cvec_t * spectrum);
100 /** convert real/imag spectrum to norm/phas spectrum
102 \param compspec real/imag input fft array
103 \param spectrum cvec norm/phas output array
106 void aubio_fft_get_realimag(cvec_t * spectrum, fvec_t * compspec);
108 /** compute phas spectrum from real/imag parts
110 \param compspec real/imag input fft array
111 \param spectrum cvec norm/phas output array
114 void aubio_fft_get_phas(fvec_t * compspec, cvec_t * spectrum);
115 /** compute imaginary part from the norm/phas cvec
117 \param spectrum norm/phas input array
118 \param compspec real/imag output fft array
121 void aubio_fft_get_imag(cvec_t * spectrum, fvec_t * compspec);
123 /** compute norm component from real/imag parts
125 \param compspec real/imag input fft array
126 \param spectrum cvec norm/phas output array
129 void aubio_fft_get_norm(fvec_t * compspec, cvec_t * spectrum);
130 /** compute real part from norm/phas components
132 \param spectrum norm/phas input array
133 \param compspec real/imag output fft array
136 void aubio_fft_get_real(cvec_t * spectrum, fvec_t * compspec);