1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
|
/* DTMF coder
*
* (C) 2016 by Andreas Eversberg <jolly@eversberg.eu>
* All Rights Reserved
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdint.h>
#include <string.h>
#include <math.h>
#include "sample.h"
#include "dtmf.h"
#define PI M_PI
#define TX_PEAK_DTMF 7000 /* single dtmf tone peak (note this is half to total peak) */
#define DTMF_DURATION 0.100 /* duration in seconds */
static double dsp_sine_dtmf[256];
void dtmf_init(dtmf_t *dtmf, int samplerate)
{
int i;
memset(dtmf, 0, sizeof(*dtmf));
dtmf->samplerate = samplerate;
dtmf->max = (int)((double)samplerate * DTMF_DURATION + 0.5);
// FIXME: do this globally and not per instance */
for (i = 0; i < 256; i++)
dsp_sine_dtmf[i] = (int)(sin((double)i / 256.0 * 2.0 * PI) * TX_PEAK_DTMF);
}
/* set dtmf tone */
void dtmf_set_tone(dtmf_t *dtmf, char tone)
{
double f1, f2;
switch(tone) {
case '1': f1 = 697.0; f2 = 1209.0; break;
case '2': f1 = 697.0; f2 = 1336.0; break;
case '3': f1 = 697.0; f2 = 1477.0; break;
case'a':case 'A': f1 = 697.0; f2 = 1633.0; break;
case '4': f1 = 770.0; f2 = 1209.0; break;
case '5': f1 = 770.0; f2 = 1336.0; break;
case '6': f1 = 770.0; f2 = 1477.0; break;
case'b':case 'B': f1 = 770.0; f2 = 1633.0; break;
case '7': f1 = 852.0; f2 = 1209.0; break;
case '8': f1 = 852.0; f2 = 1336.0; break;
case '9': f1 = 852.0; f2 = 1477.0; break;
case'c':case 'C': f1 = 852.0; f2 = 1633.0; break;
case '*': f1 = 941.0; f2 = 1209.0; break;
case '0': f1 = 941.0; f2 = 1336.0; break;
case '#': f1 = 941.0; f2 = 1477.0; break;
case'd':case 'D': f1 = 941.0; f2 = 1633.0; break;
default:
dtmf->tone = 0;
return;
}
dtmf->tone = tone;
dtmf->pos = 0;
dtmf->phaseshift256[0] = 256.0 / ((double)dtmf->samplerate / f1);
dtmf->phaseshift256[1] = 256.0 / ((double)dtmf->samplerate / f2);
}
/* Generate audio stream from DTMF tone. Keep phase for next call of function. */
void dtmf_tone(dtmf_t *dtmf, sample_t *samples, int length)
{
double *phaseshift, *phase;
int i, pos, max;
/* use silence, if no tone */
if (!dtmf->tone) {
memset(samples, 0, length * sizeof(*samples));
return;
}
phaseshift = dtmf->phaseshift256;
phase = dtmf->phase256;
pos = dtmf->pos;
max = dtmf->max;
for (i = 0; i < length; i++) {
*samples++ = dsp_sine_dtmf[((uint8_t)phase[0]) & 0xff]
+ dsp_sine_dtmf[((uint8_t)phase[1]) & 0xff];
phase[0] += phaseshift[0];
if (phase[0] >= 256)
phase[0] -= 256;
phase[1] += phaseshift[1];
if (phase[1] >= 256)
phase[1] -= 256;
/* tone ends */
if (++pos == max) {
dtmf->tone = 0;
break;
}
}
length -= i;
dtmf->pos = pos;
/* if tone ends, fill rest with silence */
if (length)
memset(samples, 0, length * sizeof(*samples));
}
|
