Restructure: Move dtmf from common code to 'libdtmf'
This commit is contained in:
Andreas Eversberg
6
src/libdtmf/Makefile.am
Normal file
6
src/libdtmf/Makefile.am
Normal file
@@ -0,0 +1,6 @@
|
||||
AM_CPPFLAGS = -Wall -Wextra -g $(all_includes)
|
||||
|
||||
noinst_LIBRARIES = libdtmf.a
|
||||
|
||||
libdtmf_a_SOURCES = \
|
||||
dtmf_encode.c
|
||||
123
src/libdtmf/dtmf_encode.c
Normal file
123
src/libdtmf/dtmf_encode.c
Normal file
@@ -0,0 +1,123 @@
|
||||
/* 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 "../common/sample.h"
|
||||
#include "dtmf_encode.h"
|
||||
|
||||
#define PI M_PI
|
||||
|
||||
#define PEAK_DTMF_LOW 0.2818 /* -11 dBm, relative to 0 dBm level */
|
||||
#define PEAK_DTMF_HIGH 0.3548 /* -9 dBm, relative to 0 dBm level */
|
||||
#define DTMF_DURATION 0.100 /* duration in seconds */
|
||||
|
||||
static sample_t dsp_sine_dtmf_low[65536];
|
||||
static sample_t dsp_sine_dtmf_high[65536];
|
||||
|
||||
void dtmf_encode_init(dtmf_enc_t *dtmf, int samplerate, double dBm_level)
|
||||
{
|
||||
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 < 65536; i++) {
|
||||
dsp_sine_dtmf_low[i] = sin((double)i / 65536.0 * 2.0 * PI) * PEAK_DTMF_LOW * dBm_level;
|
||||
dsp_sine_dtmf_high[i] = sin((double)i / 65536.0 * 2.0 * PI) * PEAK_DTMF_HIGH * dBm_level;
|
||||
}
|
||||
}
|
||||
|
||||
/* set dtmf tone */
|
||||
void dtmf_encode_set_tone(dtmf_enc_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->phaseshift65536[0] = 65536.0 / ((double)dtmf->samplerate / f1);
|
||||
dtmf->phaseshift65536[1] = 65536.0 / ((double)dtmf->samplerate / f2);
|
||||
}
|
||||
|
||||
/* Generate audio stream from DTMF tone. Keep phase for next call of function. */
|
||||
void dtmf_encode(dtmf_enc_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->phaseshift65536;
|
||||
phase = dtmf->phase65536;
|
||||
pos = dtmf->pos;
|
||||
max = dtmf->max;
|
||||
|
||||
for (i = 0; i < length; i++) {
|
||||
*samples++ = dsp_sine_dtmf_low[(uint16_t)phase[0]]
|
||||
+ dsp_sine_dtmf_high[(uint16_t)phase[1]];
|
||||
phase[0] += phaseshift[0];
|
||||
if (phase[0] >= 65536)
|
||||
phase[0] -= 65536;
|
||||
phase[1] += phaseshift[1];
|
||||
if (phase[1] >= 65536)
|
||||
phase[1] -= 65536;
|
||||
|
||||
/* 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));
|
||||
}
|
||||
|
||||
14
src/libdtmf/dtmf_encode.h
Normal file
14
src/libdtmf/dtmf_encode.h
Normal file
@@ -0,0 +1,14 @@
|
||||
|
||||
typedef struct dtmf_enc {
|
||||
int samplerate; /* samplerate */
|
||||
char tone; /* current tone to be played */
|
||||
int pos; /* sample counter for tone */
|
||||
int max; /* max number of samples for tone duration */
|
||||
double phaseshift65536[2]; /* how much the phase of sine wave changes per sample */
|
||||
double phase65536[2]; /* current phase */
|
||||
} dtmf_enc_t;
|
||||
|
||||
void dtmf_encode_init(dtmf_enc_t *dtmf, int samplerate, double dBm_level);
|
||||
void dtmf_encode_set_tone(dtmf_enc_t *dtmf, char tone);
|
||||
void dtmf_encode(dtmf_enc_t *dtmf, sample_t *samples, int length);
|
||||
|
||||
Reference in New Issue
Block a user