source: roaraudio/libroardsp/filter_lowp.c @ 5961:06e7fd9e4c25

Last change on this file since 5961:06e7fd9e4c25 was 5961:06e7fd9e4c25, checked in by phi, 10 years ago

Updates of copyright and license headers

File size: 3.6 KB
Line 
1//filter_lowp.c:
2
3/*
4 *      Copyright (C) Philipp 'ph3-der-loewe' Schafft - 2008-2014
5 *
6 *  This file is part of libroardsp a part of RoarAudio,
7 *  a cross-platform sound system for both, home and professional use.
8 *  See README for details.
9 *
10 *  This file is free software; you can redistribute it and/or modify
11 *  it under the terms of the GNU General Public License version 3
12 *  as published by the Free Software Foundation.
13 *
14 *  libroardsp is distributed in the hope that it will be useful,
15 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
16 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17 *  GNU General Public License for more details.
18 *
19 *  You should have received a copy of the GNU General Public License
20 *  along with this software; see the file COPYING.  If not, write to
21 *  the Free Software Foundation, 51 Franklin Street, Fifth Floor,
22 *  Boston, MA 02110-1301, USA.
23 *
24 */
25
26#include "libroardsp.h"
27
28#ifdef ROAR_HAVE_LIBM
29
30int roardsp_lowp_init  (struct roardsp_filter * filter, struct roar_stream * stream, int id) {
31 struct roardsp_lowp * self = roar_mm_malloc(sizeof(struct roardsp_lowp));
32
33 (void)stream, (void)id;
34
35 ROAR_DBG("roardsp_lowp_init(*): self=%p", self);
36
37 if ( self == NULL )
38  return -1;
39
40 memset(self, 0, sizeof(struct roardsp_lowp));
41
42 filter->inst = (void*) self;
43
44 return roardsp_filter_reset(filter, ROARDSP_RESET_FULL);
45}
46
47int roardsp_lowp_uninit(struct roardsp_filter * filter) {
48 roar_mm_free(filter->inst);
49 return 0;
50}
51
52#define _calcX(bits,twobits) \
53int roardsp_lowp_calc##bits  (struct roardsp_filter * filter, void * data, size_t samples) { \
54 struct roardsp_lowp * self = (struct roardsp_lowp *) filter->inst; \
55 int##bits##_t * samp = (int##bits##_t *) data; \
56 register int##twobits##_t s; \
57 size_t i, c; \
58 size_t channels = filter->channels; \
59\
60 if ( channels > ROAR_MAX_CHANNELS ) \
61  return -1; \
62\
63 samples /= channels; \
64\
65 ROAR_DBG("roardsp_lowp_calc16(*): filtering %i frames of %i channels...", samples, channels); \
66\
67/*  *      output[N] = input[N] * A + output[N-1] * B */ \
68\
69 for (i = 0; i < samples; i++) { \
70  for (c = 0; c < channels; c++) { \
71   s = (int##twobits##_t)samp[i*channels + c] * self->a + (int##twobits##_t)self->old[c] * self->b; \
72\
73   s /= 65536; \
74\
75   samp[i*channels + c] = s; \
76   self->old[        c] = s; \
77  } \
78 } \
79\
80 return 0; \
81}
82
83_calcX(8,32) /* we need 32 bit not 16 bit here as we multiplay with 65536 internally */
84_calcX(16,32)
85_calcX(32,64)
86
87int roardsp_lowp_ctl   (struct roardsp_filter * filter, int cmd, void * data) {
88 struct roardsp_lowp * self = (struct roardsp_lowp *) filter->inst;
89 float lp;
90 float oldfreq;
91 float newfreq;
92
93 if ( cmd != ROARDSP_FCTL_FREQ ) {
94  roar_err_set(ROAR_ERROR_BADRQC);
95  return -1;
96 }
97
98 newfreq = *(float*)data;
99
100 lp = exp(-2.0 * M_PI * newfreq / (float) filter->rate) * 65536.;
101
102 self->b = lp;
103 self->a = 65536. - lp;
104
105 oldfreq = self->freq / 1000.;
106 self->freq = newfreq * 1000.;
107
108 *(float*)data = oldfreq;
109
110 ROAR_DBG("roardsp_lowp_ctl(*): oldfreq=%f, newfreq=%f", oldfreq, newfreq);
111
112 return 0;
113}
114
115int roardsp_lowp_reset (struct roardsp_filter * filter, int what) {
116 struct roardsp_lowp * self;
117 float freq;
118
119 if ( filter == NULL )
120  return -1;
121
122 if ( filter->inst == NULL )
123  return -1;
124
125 self = filter->inst;
126 freq = filter->rate/2.45;
127
128 switch (what) {
129  case ROARDSP_RESET_NONE:
130    return  0;
131   break;
132  case ROARDSP_RESET_FULL:
133    roardsp_lowp_ctl(filter, ROARDSP_FCTL_FREQ, &freq);
134  case ROARDSP_RESET_STATE:
135    memset(self->old, 0, sizeof(int32_t)*ROAR_MAX_CHANNELS);
136    return  0;
137   break;
138  default:
139    return -1;
140 }
141
142 return -1;
143}
144
145#endif
146
147//ll
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