source: src/fft.h @ 961c39c3

feature/autosinkfeature/cnnfeature/cnn_orgfeature/constantqfeature/crepefeature/crepe_orgfeature/pitchshiftfeature/pydocstringsfeature/timestretchfix/ffmpeg5pitchshiftsamplertimestretchyinfft+
Last change on this file since 961c39c3 was d88ea06, checked in by Paul Brossier <piem@altern.org>, 18 years ago

add some documentation
add some documentation

  • Property mode set to 100644
File size: 3.9 KB
Line 
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 FFTW3F_SUPPORT
35#define FFTW_TYPE fftwf_complex
36#else
37#define FFTW_TYPE fftw_complex
38#endif
39#else
40#if FFTW3F_SUPPORT
41/** fft data type */
42#define FFTW_TYPE float
43#else
44/** fft data type */
45#define FFTW_TYPE double
46#endif
47#endif
48
49#ifdef __cplusplus
50extern "C" {
51#endif
52
53/** fft data type */
54typedef FFTW_TYPE fft_data_t;
55
56/** FFT object
57 
58  This object computes forward and backward FFTs, using the complex type to
59  store the results. The phase vocoder or aubio_mfft_t objects should be
60  preferred to using directly aubio_fft_t. The FFT are computed using FFTW3
61  (although support for another library could be added).
62
63*/
64typedef struct _aubio_fft_t aubio_fft_t;
65
66/** create new FFT computation object
67
68  \param size length of the FFT
69
70*/
71aubio_fft_t * new_aubio_fft(uint_t size);
72/** delete FFT object
73
74  \param s fft object as returned by new_aubio_fft
75
76*/
77void del_aubio_fft(aubio_fft_t * s);
78/** compute forward FFT
79
80  \param s fft object as returned by new_aubio_fft
81  \param data input signal
82  \param spectrum output spectrum
83  \param size length of the input vector
84
85*/
86void aubio_fft_do (const aubio_fft_t *s, const smpl_t * data,
87    fft_data_t * spectrum, const uint_t size);
88/** compute backward (inverse) FFT
89
90  \param s fft object as returned by new_aubio_fft
91  \param spectrum input spectrum
92  \param data output signal
93  \param size length of the input vector
94
95*/
96void aubio_fft_rdo(const aubio_fft_t *s, const fft_data_t * spectrum,
97    smpl_t * data, const uint_t size);
98/** compute norm vector from input spectrum
99
100  \param norm magnitude vector output
101  \param spectrum spectral data input
102  \param size size of the vectors
103
104*/
105void aubio_fft_getnorm(smpl_t * norm, fft_data_t * spectrum, uint_t size);
106/** compute phase vector from input spectrum
107 
108  \param phase phase vector output
109  \param spectrum spectral data input
110  \param size size of the vectors
111
112*/
113void aubio_fft_getphas(smpl_t * phase, fft_data_t * spectrum, uint_t size);
114
115/** FFT object (using cvec)
116
117  This object works similarly as aubio_fft_t, except the spectral data is
118  stored in a cvec_t as two vectors, magnitude and phase.
119
120*/
121typedef struct _aubio_mfft_t aubio_mfft_t;
122
123/** create new FFT computation object
124
125  \param winsize length of the FFT
126  \param channels number of channels
127
128*/
129aubio_mfft_t * new_aubio_mfft(uint_t winsize, uint_t channels);
130/** compute forward FFT
131
132  \param fft fft object as returned by new_aubio_mfft
133  \param in input signal
134  \param fftgrain output spectrum
135
136*/
137void aubio_mfft_do (aubio_mfft_t * fft,fvec_t * in,cvec_t * fftgrain);
138/** compute backward (inverse) FFT
139
140  \param fft fft object as returned by new_aubio_mfft
141  \param fftgrain input spectrum (cvec)
142  \param out output signal
143
144*/
145void aubio_mfft_rdo(aubio_mfft_t * fft,cvec_t * fftgrain, fvec_t * out);
146/** delete FFT object
147
148  \param fft fft object as returned by new_aubio_mfft
149
150*/
151void del_aubio_mfft(aubio_mfft_t * fft);
152
153
154#ifdef __cplusplus
155}
156#endif
157
158#endif
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