1 /* GStreamer
2 * Copyright (C) 2009 Tiago Katcipis <tiagokatcipis@gmail.com>
3 * Copyright (C) 2009 Paulo Pizarro <paulo.pizarro@gmail.com>
4 * Copyright (C) 2009 Rogério Santos <rogerio.santos@digitro.com.br>
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Library General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This library 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 GNU
14 * Library General Public License for more details.
15 *
16 * You should have received a copy of the GNU Library General Public
17 * License along with this library; if not, write to the
18 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
19 * Boston, MA 02110-1301, USA.
20 */
21
22 #include <string.h>
23 #include <stdio.h>
24 #include <stdlib.h>
25 #include <math.h>
26 #include <glib.h>
27 #include "vad_private.h"
28
29 #define VAD_POWER_ALPHA 0x0800 /* Q16 */
30 #define VAD_ZCR_THRESHOLD 0
31 #define VAD_BUFFER_SIZE 256
32
33
34 union pgen
35 {
36 guint64 a;
37 gpointer v;
38 guint64 *l;
39 guchar *b;
40 guint16 *w;
41 gint16 *s;
42 };
43
44 struct _cqueue_s
45 {
46 union pgen base;
47 union pgen tail;
48 union pgen head;
49 gint size;
50 };
51
52 typedef struct _cqueue_s cqueue_t;
53
54 struct _vad_s
55 {
56 gint16 vad_buffer[VAD_BUFFER_SIZE];
57 cqueue_t cqueue;
58 gint vad_state;
59 guint64 hysteresis;
60 guint64 vad_samples;
61 guint64 vad_power;
62 guint64 threshold;
63 long vad_zcr;
64 };
65
66 VADFilter *
vad_new(guint64 hysteresis,gint threshold)67 vad_new (guint64 hysteresis, gint threshold)
68 {
69 VADFilter *vad = malloc (sizeof (VADFilter));
70 vad_reset (vad);
71 vad->hysteresis = hysteresis;
72 vad_set_threshold (vad, threshold);
73 return vad;
74 }
75
76 void
vad_reset(VADFilter * vad)77 vad_reset (VADFilter * vad)
78 {
79 memset (vad, 0, sizeof (*vad));
80 vad->cqueue.base.s = vad->vad_buffer;
81 vad->cqueue.tail.a = vad->cqueue.head.a = 0;
82 vad->cqueue.size = VAD_BUFFER_SIZE;
83 vad->vad_state = VAD_SILENCE;
84 }
85
86 void
vad_destroy(VADFilter * p)87 vad_destroy (VADFilter * p)
88 {
89 free (p);
90 }
91
92 void
vad_set_hysteresis(struct _vad_s * p,guint64 hysteresis)93 vad_set_hysteresis (struct _vad_s *p, guint64 hysteresis)
94 {
95 p->hysteresis = hysteresis;
96 }
97
98 guint64
vad_get_hysteresis(struct _vad_s * p)99 vad_get_hysteresis (struct _vad_s *p)
100 {
101 return p->hysteresis;
102 }
103
104 void
vad_set_threshold(struct _vad_s * p,gint threshold_db)105 vad_set_threshold (struct _vad_s *p, gint threshold_db)
106 {
107 gint power = (gint) (threshold_db / 10.0);
108 p->threshold = (guint64) (pow (10, (power)) * 4294967295UL);
109 }
110
111 gint
vad_get_threshold_as_db(struct _vad_s * p)112 vad_get_threshold_as_db (struct _vad_s *p)
113 {
114 return (gint) (10 * log10 (p->threshold / 4294967295.0));
115 }
116
117 gint
vad_update(struct _vad_s * p,gint16 * data,gint len)118 vad_update (struct _vad_s * p, gint16 * data, gint len)
119 {
120 guint64 tail;
121 gint frame_type;
122 gint16 sample;
123 gint i;
124
125 for (i = 0; i < len; i++) {
126 p->vad_power = VAD_POWER_ALPHA * ((data[i] * data[i] >> 14) & 0xFFFF) +
127 (0xFFFF - VAD_POWER_ALPHA) * (p->vad_power >> 16) +
128 ((0xFFFF - VAD_POWER_ALPHA) * (p->vad_power & 0xFFFF) >> 16);
129 /* Update VAD buffer */
130 p->cqueue.base.s[p->cqueue.head.a] = data[i];
131 p->cqueue.head.a = (p->cqueue.head.a + 1) & (p->cqueue.size - 1);
132 if (p->cqueue.head.a == p->cqueue.tail.a)
133 p->cqueue.tail.a = (p->cqueue.tail.a + 1) & (p->cqueue.size - 1);
134 }
135
136 tail = p->cqueue.tail.a;
137 p->vad_zcr = 0;
138 for (;;) {
139 sample = p->cqueue.base.s[tail];
140 tail = (tail + 1) & (p->cqueue.size - 1);
141 if (tail == p->cqueue.head.a)
142 break;
143 p->vad_zcr +=
144 ((sample & 0x8000) != (p->cqueue.base.s[tail] & 0x8000)) ? 1 : -1;
145 }
146
147 frame_type = (p->vad_power > p->threshold
148 && p->vad_zcr < VAD_ZCR_THRESHOLD) ? VAD_VOICE : VAD_SILENCE;
149
150 if (p->vad_state != frame_type) {
151 /* Voice to silence transition */
152 if (p->vad_state == VAD_VOICE) {
153 p->vad_samples += len;
154 if (p->vad_samples >= p->hysteresis) {
155 p->vad_state = frame_type;
156 p->vad_samples = 0;
157 }
158 } else {
159 p->vad_state = frame_type;
160 p->vad_samples = 0;
161 }
162 } else {
163 p->vad_samples = 0;
164 }
165
166 return p->vad_state;
167 }
168