aubio: spectral/filterbank_mel.h Source File

aubio 0.4.9

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filterbank_mel.h
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1/*
2 Copyright (C) 2007-2013 Paul Brossier <piem@aubio.org>
3 and Amaury Hazan <ahazan@iua.upf.edu>
4
5 This file is part of aubio.
6
7 aubio is free software: you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation, either version 3 of the License, or
10 (at your option) any later version.
11
12 aubio is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with aubio. If not, see <http://www.gnu.org/licenses/>.
19
20*/
21
22/** \file
23
24 Filterbank object coefficients initialization
25
26 Functions to create set the ::aubio_filterbank_t coefficients to
27 - ::aubio_filterbank_set_triangle_bands: overlapping triangular bands,
28 - ::aubio_filterbank_set_mel_coeffs_slaney: Mel frequency bands.
29
30 \example spectral/test-filterbank_mel.c
31
32*/
33
34#ifndef AUBIO_FILTERBANK_MEL_H
35#define AUBIO_FILTERBANK_MEL_H
36
37#ifdef __cplusplus
38extern "C"
39{
40#endif
41
42/** filterbank initialization with triangular and overlapping bands
43
44 \param fb filterbank object
45 \param freqs arbitrary array of boundary frequencies
46 \param samplerate audio sampling rate
47
48 This function computes the coefficients of the filterbank based on the
49 boundaries found in freqs, in Hz, and using triangular overlapping bands.
50
51*/
52 uint_t aubio_filterbank_set_triangle_bands (aubio_filterbank_t * fb,
53 const fvec_t * freqs, smpl_t samplerate);
54
55/** filterbank initialization for Mel filters using Slaney's coefficients
56
57 \param fb filterbank object
58 \param samplerate audio sampling rate, in Hz
59
60 The filter coefficients are built to match exactly Malcolm Slaney's Auditory
61 Toolbox implementation (see file mfcc.m). The number of filters should be 40.
62
63 References
64 ----------
65
66 Malcolm Slaney, *Auditory Toolbox Version 2, Technical Report #1998-010*
67 https://engineering.purdue.edu/~malcolm/interval/1998-010/
68
69*/
70 uint_t aubio_filterbank_set_mel_coeffs_slaney (aubio_filterbank_t * fb,
71 smpl_t samplerate);
72
73/** Mel filterbank initialization
74
75 \param fb filterbank object
76 \param samplerate audio sampling rate
77 \param fmin start frequency, in Hz
78 \param fmax end frequency, in Hz
79
80 The filterbank will be initialized with bands linearly spaced in the mel
81 scale, from `fmin` to `fmax`.
82
83 References
84 ----------
85
86 Malcolm Slaney, *Auditory Toolbox Version 2, Technical Report #1998-010*
87 https://engineering.purdue.edu/~malcolm/interval/1998-010/
88
89*/
90 uint_t aubio_filterbank_set_mel_coeffs(aubio_filterbank_t * fb,
91 smpl_t samplerate, smpl_t fmin, smpl_t fmax);
92
93/** Mel filterbank initialization
94
95 \param fb filterbank object
96 \param samplerate audio sampling rate
97 \param fmin start frequency, in Hz
98 \param fmax end frequency, in Hz
99
100 The bank of filters will be initalized to to cover linearly spaced bands in
101 the Htk mel scale, from `fmin` to `fmax`.
102
103 References
104 ----------
105
106 Douglas O'Shaughnessy (1987). *Speech communication: human and machine*.
107 Addison-Wesley. p. 150. ISBN 978-0-201-16520-3.
108
109 HTK Speech Recognition Toolkit: http://htk.eng.cam.ac.uk/
110
111*/
112 uint_t aubio_filterbank_set_mel_coeffs_htk(aubio_filterbank_t * fb,
113 smpl_t samplerate, smpl_t fmin, smpl_t fmax);
114
115#ifdef __cplusplus
116}
117#endif
118
119#endif /* AUBIO_FILTERBANK_MEL_H */
aubio_filterbank_t
struct _aubio_filterbank_t aubio_filterbank_t
filterbank object
Definition filterbank.h:45
aubio_filterbank_set_mel_coeffs_slaney
uint_t aubio_filterbank_set_mel_coeffs_slaney(aubio_filterbank_t *fb, smpl_t samplerate)
filterbank initialization for Mel filters using Slaney's coefficients
aubio_filterbank_set_mel_coeffs
uint_t aubio_filterbank_set_mel_coeffs(aubio_filterbank_t *fb, smpl_t samplerate, smpl_t fmin, smpl_t fmax)
Mel filterbank initialization.
aubio_filterbank_set_triangle_bands
uint_t aubio_filterbank_set_triangle_bands(aubio_filterbank_t *fb, const fvec_t *freqs, smpl_t samplerate)
filterbank initialization with triangular and overlapping bands
aubio_filterbank_set_mel_coeffs_htk
uint_t aubio_filterbank_set_mel_coeffs_htk(aubio_filterbank_t *fb, smpl_t samplerate, smpl_t fmin, smpl_t fmax)
Mel filterbank initialization.
fvec_t
Buffer for real data.
Definition fvec.h:67
uint_t
unsigned int uint_t
unsigned integer
Definition types.h:60
smpl_t
float smpl_t
short sample format (32 or 64 bits)
Definition types.h:41