source: src/temporal/filter.c @ 23493b5

feature/autosinkfeature/constantqfeature/pitchshiftfeature/pydocstringsfeature/timestretchpitchshiftsamplertimestretchyinfft+
Last change on this file since 23493b5 was 23493b5, checked in by Paul Brossier <piem@piem.org>, 3 years ago

src/temporal/: add const qualifiers

  • Property mode set to 100644
File size: 3.4 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
22/* Requires lsmp_t to be long or double. float will NOT give reliable
23 * results */
24
25#include "aubio_priv.h"
26#include "fvec.h"
27#include "lvec.h"
28#include "mathutils.h"
29#include "temporal/filter.h"
30
31struct _aubio_filter_t
32{
33  uint_t order;
34  uint_t samplerate;
35  lvec_t *a;
36  lvec_t *b;
37  lvec_t *y;
38  lvec_t *x;
39};
40
41void
42aubio_filter_do_outplace (aubio_filter_t * f, const fvec_t * in, fvec_t * out)
43{
44  fvec_copy (in, out);
45  aubio_filter_do (f, out);
46}
47
48void
49aubio_filter_do (aubio_filter_t * f, fvec_t * in)
50{
51  uint_t j, l, order = f->order;
52  lsmp_t *x = f->x->data;
53  lsmp_t *y = f->y->data;
54  lsmp_t *a = f->a->data;
55  lsmp_t *b = f->b->data;
56
57  for (j = 0; j < in->length; j++) {
58    /* new input */
59    x[0] = KILL_DENORMAL (in->data[j]);
60    y[0] = b[0] * x[0];
61    for (l = 1; l < order; l++) {
62      y[0] += b[l] * x[l];
63      y[0] -= a[l] * y[l];
64    }
65    /* new output */
66    in->data[j] = y[0];
67    /* store for next sample */
68    for (l = order - 1; l > 0; l--) {
69      x[l] = x[l - 1];
70      y[l] = y[l - 1];
71    }
72  }
73}
74
75/* The rough way: reset memory of filter between each run to avoid end effects. */
76void
77aubio_filter_do_filtfilt (aubio_filter_t * f, fvec_t * in, fvec_t * tmp)
78{
79  uint_t j;
80  uint_t length = in->length;
81  /* apply filtering */
82  aubio_filter_do (f, in);
83  aubio_filter_do_reset (f);
84  /* mirror */
85  for (j = 0; j < length; j++)
86    tmp->data[length - j - 1] = in->data[j];
87  /* apply filtering on mirrored */
88  aubio_filter_do (f, tmp);
89  aubio_filter_do_reset (f);
90  /* invert back */
91  for (j = 0; j < length; j++)
92    in->data[j] = tmp->data[length - j - 1];
93}
94
95lvec_t *
96aubio_filter_get_feedback (const aubio_filter_t * f)
97{
98  return f->a;
99}
100
101lvec_t *
102aubio_filter_get_feedforward (const aubio_filter_t * f)
103{
104  return f->b;
105}
106
107uint_t
108aubio_filter_get_order (const aubio_filter_t * f)
109{
110  return f->order;
111}
112
113uint_t
114aubio_filter_get_samplerate (const aubio_filter_t * f)
115{
116  return f->samplerate;
117}
118
119uint_t
120aubio_filter_set_samplerate (aubio_filter_t * f, uint_t samplerate)
121{
122  f->samplerate = samplerate;
123  return AUBIO_OK;
124}
125
126void
127aubio_filter_do_reset (aubio_filter_t * f)
128{
129  lvec_zeros (f->x);
130  lvec_zeros (f->y);
131}
132
133aubio_filter_t *
134new_aubio_filter (uint_t order)
135{
136  aubio_filter_t *f = AUBIO_NEW (aubio_filter_t);
137  if ((sint_t)order < 1) {
138    AUBIO_FREE(f);
139    return NULL;
140  }
141  f->x = new_lvec (order);
142  f->y = new_lvec (order);
143  f->a = new_lvec (order);
144  f->b = new_lvec (order);
145  /* by default, samplerate is not set */
146  f->samplerate = 0;
147  f->order = order;
148  /* set default to identity */
149  f->a->data[0] = 1.;
150  f->b->data[0] = 1.;
151  return f;
152}
153
154void
155del_aubio_filter (aubio_filter_t * f)
156{
157  del_lvec (f->a);
158  del_lvec (f->b);
159  del_lvec (f->x);
160  del_lvec (f->y);
161  AUBIO_FREE (f);
162  return;
163}
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