source: src/spectral/fft.h @ 7cec717

feature/autosinkfeature/constantqfeature/pitchshiftfeature/pydocstringsfeature/timestretchpitchshiftsamplertimestretchyinfft+
Last change on this file since 7cec717 was 7cec717, checked in by Paul Brossier <piem@piem.org>, 11 years ago

src/spectral/fft.h: improve fftw types comments

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File size: 4.3 KB
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1/*
2   Copyright (C) 2003 Paul Brossier
3
4   This program is free software; you can redistribute it and/or modify
5   it under the terms of the GNU General Public License as published by
6   the Free Software Foundation; either version 2 of the License, or
7   (at your option) any later version.
8
9   This program is distributed in the hope that it will be useful,
10   but WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12   GNU General Public License for more details.
13
14   You should have received a copy of the GNU General Public License
15   along with this program; if not, write to the Free Software
16   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17   
18*/
19
20/** \file
21
22  Fast Fourier Transform object
23
24*/
25
26#ifndef FFT_H_
27#define FFT_H_
28
29/* note that <complex.h> is not included here but only in aubio_priv.h, so that
30 * c++ projects can still use their own complex definition. */
31#include <fftw3.h>
32
33#ifdef HAVE_COMPLEX_H
34#if HAVE_FFTW3F
35/** fft data type with complex.h and fftw3f */
36#define FFTW_TYPE fftwf_complex
37#else
38/** fft data type with complex.h and fftw3 */
39#define FFTW_TYPE fftw_complex
40#endif
41#else
42#if HAVE_FFTW3F
43/** fft data type without complex.h and with fftw3f */
44#define FFTW_TYPE float
45#else
46/** fft data type without complex.h and with fftw */
47#define FFTW_TYPE double
48#endif
49#endif
50
51#ifdef __cplusplus
52extern "C" {
53#endif
54
55/** fft data type */
56typedef FFTW_TYPE fft_data_t;
57
58/** FFT object
59 
60  This object computes forward and backward FFTs, using the complex type to
61  store the results. The phase vocoder or aubio_mfft_t objects should be
62  preferred to using directly aubio_fft_t. The FFT are computed using FFTW3
63  (although support for another library could be added).
64
65*/
66typedef struct _aubio_fft_t aubio_fft_t;
67
68/** create new FFT computation object
69
70  \param size length of the FFT
71  \param channels number of channels
72
73*/
74aubio_fft_t * new_aubio_fft(uint_t size, uint_t channels);
75/** delete FFT object
76
77  \param s fft object as returned by new_aubio_fft
78
79*/
80void del_aubio_fft(aubio_fft_t * s);
81
82/** compute forward FFT
83
84  \param s fft object as returned by new_aubio_fft
85  \param input input signal
86  \param spectrum output spectrum
87
88*/
89void aubio_fft_do (aubio_fft_t *s, fvec_t * input, cvec_t * spectrum);
90/** compute backward (inverse) FFT
91
92  \param s fft object as returned by new_aubio_fft
93  \param spectrum input spectrum
94  \param output output signal
95
96*/
97void aubio_fft_rdo (aubio_fft_t *s, cvec_t * spectrum, fvec_t * output);
98
99/** compute forward FFT
100
101  \param s fft object as returned by new_aubio_fft
102  \param input real input signal
103  \param compspec complex output fft real/imag
104
105*/
106void aubio_fft_do_complex (aubio_fft_t *s, fvec_t * input, fvec_t * compspec);
107/** compute backward (inverse) FFT from real/imag
108
109  \param s fft object as returned by new_aubio_fft
110  \param compspec real/imag input fft array
111  \param output real output array
112
113*/
114void aubio_fft_rdo_complex (aubio_fft_t *s, fvec_t * compspec, fvec_t * output);
115
116/** convert real/imag spectrum to norm/phas spectrum
117
118  \param compspec real/imag input fft array
119  \param spectrum cvec norm/phas output array
120
121*/
122void aubio_fft_get_spectrum(fvec_t * compspec, cvec_t * spectrum);
123/** convert real/imag spectrum to norm/phas spectrum
124
125  \param compspec real/imag input fft array
126  \param spectrum cvec norm/phas output array
127
128*/
129void aubio_fft_get_realimag(cvec_t * spectrum, fvec_t * compspec);
130
131/** compute phas spectrum from real/imag parts
132
133  \param compspec real/imag input fft array
134  \param spectrum cvec norm/phas output array
135
136*/
137void aubio_fft_get_phas(fvec_t * compspec, cvec_t * spectrum);
138/** compute imaginary part from the norm/phas cvec
139
140  \param spectrum norm/phas input array
141  \param compspec real/imag output fft array
142
143*/
144void aubio_fft_get_imag(cvec_t * spectrum, fvec_t * compspec);
145
146/** compute norm component from real/imag parts
147
148  \param compspec real/imag input fft array
149  \param spectrum cvec norm/phas output array
150
151*/
152void aubio_fft_get_norm(fvec_t * compspec, cvec_t * spectrum);
153/** compute real part from norm/phas components
154
155  \param spectrum norm/phas input array
156  \param compspec real/imag output fft array
157
158*/
159void aubio_fft_get_real(cvec_t * spectrum, fvec_t * compspec);
160
161#ifdef __cplusplus
162}
163#endif
164
165#endif // FFT_H_
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