source: src/temporal/c_weighting.h @ e5e693e

feature/autosinkfeature/cnnfeature/cnn_orgfeature/constantqfeature/crepefeature/crepe_orgfeature/pitchshiftfeature/pydocstringsfeature/timestretchfix/ffmpeg5pitchshiftsamplertimestretchyinfft+
Last change on this file since e5e693e was f530f12, checked in by Paul Brossier <piem@piem.org>, 15 years ago

src/temporal/{a,c}_weighting.{c,h}: set_a,c_weighting return 1 on error, 0 on success

  • Property mode set to 100644
File size: 2.5 KB
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1/*
2  Copyright (C) 2003-2009 Paul Brossier <piem@aubio.org>
3
4  This file is part of aubio.
5
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.
10
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.
15
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/>.
18
19*/
20
21#ifndef _CDESIGN_H
22#define _CDESIGN_H
23
24/** \file
25
26  Create a C-weighting filter
27 
28  This file creates a C-weighting digital filter, which reduces low and high
29  frequencies and enhance the middle ones to reflect the ability of the human
30  hearing.
31 
32  The implementation is based on the following standard:
33
34    - IEC/CD 1672: Electroacoustics-Sound Level Meters, IEC, Geneva, Nov.  1996,
35  for A- and C-weighting filters.
36 
37  See also:
38 
39    - <a href="http://en.wikipedia.org/wiki/A-weighting">A-Weighting on
40  Wikipedia</a>
41    - <a href="http://en.wikipedia.org/wiki/Weighting_filter">Weighting filter on
42  Wikipedia</a>
43    - <a href="http://www.mathworks.com/matlabcentral/fileexchange/69">Christophe
44  Couvreur's 'octave' toolbox</a>
45 
46  The coefficients in this file have been computed using Christophe Couvreur's
47  scripts in octave 3.0 (debian package 1:3.0.5-6+b2 with octave-signal
48  1.0.9-1+b1 on i386), with <pre> [b, a] = cdsign(1/Fs) </pre> for various
49  sampling frequencies (8000, 11025, 16000, 22050, 24000, 32000, 44100, 48000,
50  88200, 96000, and 192000 Hz).
51
52  The sampling frequency should normally be higher than 20kHz, but most common
53  file sampling rates have been included for completeness.
54
55*/
56
57#ifdef __cplusplus
58extern "C" {
59#endif
60
61/** create new C-design filter
62
63  \param samplerate sampling frequency of the signal to filter. Should be one of
64  8000, 11025, 16000, 22050, 24000, 32000, 44100, 48000, 88200, 96000, and
65  192000 Hz
66  \param channels number of channels to allocate
67
68  \return a new filter object
69
70*/
71aubio_filter_t * new_aubio_filter_c_weighting (uint_t samplerate, uint_t channels);
72
73/** set feedback and feedforward coefficients of a C-weighting filter
74
75  \param f filter object to get coefficients from
76
77*/
78uint_t aubio_filter_set_c_weighting (aubio_filter_t *f);
79
80#ifdef __cplusplus
81}
82#endif
83
84#endif /* _CDESIGN_H */
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