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gstreamer/gst/dtmf/tone_detect.c
Olivier Crête d1db40df6e dtmfdetect: Add DTMF tone detector 
It looks at raw audio data and emits messages when DTMF is detected.
The dtmf detector is the same Goertzel implementation used in FreeSwitch
and Asterisk. It is in the public domain.
2009-11-05 10:39:37 -05:00

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/*
* DTMF Receiver module, part of:
* BSD Telephony Of Mexico "Zapata" Telecom Library, version 1.10 12/9/01
*
* Part of the "Zapata" Computer Telephony Technology.
*
* See http://www.bsdtelephony.com.mx
*
*
* The technologies, software, hardware, designs, drawings, scheumatics, board
* layouts and/or artwork, concepts, methodologies (including the use of all
* of these, and that which is derived from the use of all of these), all other
* intellectual properties contained herein, and all intellectual property
* rights have been and shall continue to be expressly for the benefit of all
* mankind, and are perpetually placed in the public domain, and may be used,
* copied, and/or modified by anyone, in any manner, for any legal purpose,
* without restriction.
*
* This module written by Stephen Underwood.
*/
/*
tone_detect.c - General telephony tone detection, and specific
detection of DTMF.
Copyright (C) 2001 Steve Underwood <steveu@coppice.org>
Despite my general liking of the GPL, I place this code in the
public domain for the benefit of all mankind - even the slimy
ones who might try to proprietize my work and use it to my
detriment.
*/
#include <math.h>
#include <stdint.h>
#include <string.h>
#include <stdio.h>
#include <time.h>
#include <fcntl.h>
#include "tone_detect.h"
#define FALSE 0
#define TRUE (!FALSE)
//#define USE_3DNOW
/* Basic DTMF specs:
*
* Minimum tone on = 40ms
* Minimum tone off = 50ms
* Maximum digit rate = 10 per second
* Normal twist <= 8dB accepted
* Reverse twist <= 4dB accepted
* S/N >= 15dB will detect OK
* Attenuation <= 26dB will detect OK
* Frequency tolerance +- 1.5% will detect, +-3.5% will reject
*/
#define SAMPLE_RATE 8000.0
#define DTMF_THRESHOLD 8.0e7
#define FAX_THRESHOLD 8.0e7
#define FAX_2ND_HARMONIC 2.0 /* 4dB */
#define DTMF_NORMAL_TWIST 6.3 /* 8dB */
#define DTMF_REVERSE_TWIST ((isradio) ? 4.0 : 2.5) /* 4dB normal */
#define DTMF_RELATIVE_PEAK_ROW 6.3 /* 8dB */
#define DTMF_RELATIVE_PEAK_COL 6.3 /* 8dB */
#define DTMF_2ND_HARMONIC_ROW ((isradio) ? 1.7 : 2.5) /* 4dB normal */
#define DTMF_2ND_HARMONIC_COL 63.1 /* 18dB */
static tone_detection_descriptor_t dtmf_detect_row[4];
static tone_detection_descriptor_t dtmf_detect_col[4];
static tone_detection_descriptor_t dtmf_detect_row_2nd[4];
static tone_detection_descriptor_t dtmf_detect_col_2nd[4];
static tone_detection_descriptor_t fax_detect;
static tone_detection_descriptor_t fax_detect_2nd;
static float dtmf_row[] =
{
697.0, 770.0, 852.0, 941.0
};
static float dtmf_col[] =
{
1209.0, 1336.0, 1477.0, 1633.0
};
static float fax_freq = 1100.0;
static char dtmf_positions[] = "123A" "456B" "789C" "*0#D";
static void goertzel_init(goertzel_state_t *s,
tone_detection_descriptor_t *t)
{
s->v2 =
s->v3 = 0.0;
s->fac = t->fac;
}
/*- End of function --------------------------------------------------------*/
#if defined(USE_3DNOW)
static inline void _dtmf_goertzel_update(goertzel_state_t *s,
float x[],
int samples)
{
int n;
float v;
int i;
float vv[16];
vv[4] = s[0].v2;
vv[5] = s[1].v2;
vv[6] = s[2].v2;
vv[7] = s[3].v2;
vv[8] = s[0].v3;
vv[9] = s[1].v3;
vv[10] = s[2].v3;
vv[11] = s[3].v3;
vv[12] = s[0].fac;
vv[13] = s[1].fac;
vv[14] = s[2].fac;
vv[15] = s[3].fac;
//v1 = s->v2;
//s->v2 = s->v3;
//s->v3 = s->fac*s->v2 - v1 + x[0];
__asm__ __volatile__ (
" femms;\n"
" movq 16(%%edx),%%mm2;\n"
" movq 24(%%edx),%%mm3;\n"
" movq 32(%%edx),%%mm4;\n"
" movq 40(%%edx),%%mm5;\n"
" movq 48(%%edx),%%mm6;\n"
" movq 56(%%edx),%%mm7;\n"
" jmp 1f;\n"
" .align 32;\n"
" 1: ;\n"
" prefetch (%%eax);\n"
" movq %%mm3,%%mm1;\n"
" movq %%mm2,%%mm0;\n"
" movq %%mm5,%%mm3;\n"
" movq %%mm4,%%mm2;\n"
" pfmul %%mm7,%%mm5;\n"
" pfmul %%mm6,%%mm4;\n"
" pfsub %%mm1,%%mm5;\n"
" pfsub %%mm0,%%mm4;\n"
" movq (%%eax),%%mm0;\n"
" movq %%mm0,%%mm1;\n"
" punpckldq %%mm0,%%mm1;\n"
" add $4,%%eax;\n"
" pfadd %%mm1,%%mm5;\n"
" pfadd %%mm1,%%mm4;\n"
" dec %%ecx;\n"
" jnz 1b;\n"
" movq %%mm2,16(%%edx);\n"
" movq %%mm3,24(%%edx);\n"
" movq %%mm4,32(%%edx);\n"
" movq %%mm5,40(%%edx);\n"
" femms;\n"
:
: "c" (samples), "a" (x), "d" (vv)
: "memory", "eax", "ecx");
s[0].v2 = vv[4];
s[1].v2 = vv[5];
s[2].v2 = vv[6];
s[3].v2 = vv[7];
s[0].v3 = vv[8];
s[1].v3 = vv[9];
s[2].v3 = vv[10];
s[3].v3 = vv[11];
}
#endif
/*- End of function --------------------------------------------------------*/
void zap_goertzel_update(goertzel_state_t *s,
int16_t x[],
int samples)
{
int i;
float v1;
for (i = 0; i < samples; i++)
{
v1 = s->v2;
s->v2 = s->v3;
s->v3 = s->fac*s->v2 - v1 + x[i];
}
}
/*- End of function --------------------------------------------------------*/
float zap_goertzel_result (goertzel_state_t *s)
{
return s->v3*s->v3 + s->v2*s->v2 - s->v2*s->v3*s->fac;
}
/*- End of function --------------------------------------------------------*/
void zap_dtmf_detect_init (dtmf_detect_state_t *s)
{
int i;
float theta;
s->hit1 =
s->hit2 = 0;
for (i = 0; i < 4; i++)
{
theta = 2.0*M_PI*(dtmf_row[i]/SAMPLE_RATE);
dtmf_detect_row[i].fac = 2.0*cos(theta);
theta = 2.0*M_PI*(dtmf_col[i]/SAMPLE_RATE);
dtmf_detect_col[i].fac = 2.0*cos(theta);
theta = 2.0*M_PI*(dtmf_row[i]*2.0/SAMPLE_RATE);
dtmf_detect_row_2nd[i].fac = 2.0*cos(theta);
theta = 2.0*M_PI*(dtmf_col[i]*2.0/SAMPLE_RATE);
dtmf_detect_col_2nd[i].fac = 2.0*cos(theta);
goertzel_init (&s->row_out[i], &dtmf_detect_row[i]);
goertzel_init (&s->col_out[i], &dtmf_detect_col[i]);
goertzel_init (&s->row_out2nd[i], &dtmf_detect_row_2nd[i]);
goertzel_init (&s->col_out2nd[i], &dtmf_detect_col_2nd[i]);
s->energy = 0.0;
}
/* Same for the fax dector */
theta = 2.0*M_PI*(fax_freq/SAMPLE_RATE);
fax_detect.fac = 2.0 * cos(theta);
goertzel_init (&s->fax_tone, &fax_detect);
/* Same for the fax dector 2nd harmonic */
theta = 2.0*M_PI*(fax_freq * 2.0/SAMPLE_RATE);
fax_detect_2nd.fac = 2.0 * cos(theta);
goertzel_init (&s->fax_tone2nd, &fax_detect_2nd);
s->current_sample = 0;
s->detected_digits = 0;
s->lost_digits = 0;
s->digits[0] = '\0';
s->mhit = 0;
}
/*- End of function --------------------------------------------------------*/
int zap_dtmf_detect (dtmf_detect_state_t *s,
int16_t amp[],
int samples,
int isradio)
{
float row_energy[4];
float col_energy[4];
float fax_energy;
float fax_energy_2nd;
float famp;
float v1;
int i;
int j;
int sample;
int best_row;
int best_col;
int hit;
int limit;
hit = 0;
for (sample = 0; sample < samples; sample = limit)
{
/* 102 is optimised to meet the DTMF specs. */
if ((samples - sample) >= (102 - s->current_sample))
limit = sample + (102 - s->current_sample);
else
limit = samples;
#if defined(USE_3DNOW)
_dtmf_goertzel_update (s->row_out, amp + sample, limit - sample);
_dtmf_goertzel_update (s->col_out, amp + sample, limit - sample);
_dtmf_goertzel_update (s->row_out2nd, amp + sample, limit2 - sample);
_dtmf_goertzel_update (s->col_out2nd, amp + sample, limit2 - sample);
/* XXX Need to fax detect for 3dnow too XXX */
#warning "Fax Support Broken"
#else
/* The following unrolled loop takes only 35% (rough estimate) of the
time of a rolled loop on the machine on which it was developed */
for (j = sample; j < limit; j++)
{
famp = amp[j];
s->energy += famp*famp;
/* With GCC 2.95, the following unrolled code seems to take about 35%
(rough estimate) as long as a neat little 0-3 loop */
v1 = s->row_out[0].v2;
s->row_out[0].v2 = s->row_out[0].v3;
s->row_out[0].v3 = s->row_out[0].fac*s->row_out[0].v2 - v1 + famp;
v1 = s->col_out[0].v2;
s->col_out[0].v2 = s->col_out[0].v3;
s->col_out[0].v3 = s->col_out[0].fac*s->col_out[0].v2 - v1 + famp;
v1 = s->row_out[1].v2;
s->row_out[1].v2 = s->row_out[1].v3;
s->row_out[1].v3 = s->row_out[1].fac*s->row_out[1].v2 - v1 + famp;
v1 = s->col_out[1].v2;
s->col_out[1].v2 = s->col_out[1].v3;
s->col_out[1].v3 = s->col_out[1].fac*s->col_out[1].v2 - v1 + famp;
v1 = s->row_out[2].v2;
s->row_out[2].v2 = s->row_out[2].v3;
s->row_out[2].v3 = s->row_out[2].fac*s->row_out[2].v2 - v1 + famp;
v1 = s->col_out[2].v2;
s->col_out[2].v2 = s->col_out[2].v3;
s->col_out[2].v3 = s->col_out[2].fac*s->col_out[2].v2 - v1 + famp;
v1 = s->row_out[3].v2;
s->row_out[3].v2 = s->row_out[3].v3;
s->row_out[3].v3 = s->row_out[3].fac*s->row_out[3].v2 - v1 + famp;
v1 = s->col_out[3].v2;
s->col_out[3].v2 = s->col_out[3].v3;
s->col_out[3].v3 = s->col_out[3].fac*s->col_out[3].v2 - v1 + famp;
v1 = s->col_out2nd[0].v2;
s->col_out2nd[0].v2 = s->col_out2nd[0].v3;
s->col_out2nd[0].v3 = s->col_out2nd[0].fac*s->col_out2nd[0].v2 - v1 + famp;
v1 = s->row_out2nd[0].v2;
s->row_out2nd[0].v2 = s->row_out2nd[0].v3;
s->row_out2nd[0].v3 = s->row_out2nd[0].fac*s->row_out2nd[0].v2 - v1 + famp;
v1 = s->col_out2nd[1].v2;
s->col_out2nd[1].v2 = s->col_out2nd[1].v3;
s->col_out2nd[1].v3 = s->col_out2nd[1].fac*s->col_out2nd[1].v2 - v1 + famp;
v1 = s->row_out2nd[1].v2;
s->row_out2nd[1].v2 = s->row_out2nd[1].v3;
s->row_out2nd[1].v3 = s->row_out2nd[1].fac*s->row_out2nd[1].v2 - v1 + famp;
v1 = s->col_out2nd[2].v2;
s->col_out2nd[2].v2 = s->col_out2nd[2].v3;
s->col_out2nd[2].v3 = s->col_out2nd[2].fac*s->col_out2nd[2].v2 - v1 + famp;
v1 = s->row_out2nd[2].v2;
s->row_out2nd[2].v2 = s->row_out2nd[2].v3;
s->row_out2nd[2].v3 = s->row_out2nd[2].fac*s->row_out2nd[2].v2 - v1 + famp;
v1 = s->col_out2nd[3].v2;
s->col_out2nd[3].v2 = s->col_out2nd[3].v3;
s->col_out2nd[3].v3 = s->col_out2nd[3].fac*s->col_out2nd[3].v2 - v1 + famp;
v1 = s->row_out2nd[3].v2;
s->row_out2nd[3].v2 = s->row_out2nd[3].v3;
s->row_out2nd[3].v3 = s->row_out2nd[3].fac*s->row_out2nd[3].v2 - v1 + famp;
/* Update fax tone */
v1 = s->fax_tone.v2;
s->fax_tone.v2 = s->fax_tone.v3;
s->fax_tone.v3 = s->fax_tone.fac*s->fax_tone.v2 - v1 + famp;
v1 = s->fax_tone.v2;
s->fax_tone2nd.v2 = s->fax_tone2nd.v3;
s->fax_tone2nd.v3 = s->fax_tone2nd.fac*s->fax_tone2nd.v2 - v1 + famp;
}
#endif
s->current_sample += (limit - sample);
if (s->current_sample < 102)
continue;
/* Detect the fax energy, too */
fax_energy = zap_goertzel_result(&s->fax_tone);
/* We are at the end of a DTMF detection block */
/* Find the peak row and the peak column */
row_energy[0] = zap_goertzel_result (&s->row_out[0]);
col_energy[0] = zap_goertzel_result (&s->col_out[0]);
for (best_row = best_col = 0, i = 1; i < 4; i++)
{
row_energy[i] = zap_goertzel_result (&s->row_out[i]);
if (row_energy[i] > row_energy[best_row])
best_row = i;
col_energy[i] = zap_goertzel_result (&s->col_out[i]);
if (col_energy[i] > col_energy[best_col])
best_col = i;
}
hit = 0;
/* Basic signal level test and the twist test */
if (row_energy[best_row] >= DTMF_THRESHOLD
&&
col_energy[best_col] >= DTMF_THRESHOLD
&&
col_energy[best_col] < row_energy[best_row]*DTMF_REVERSE_TWIST
&&
col_energy[best_col]*DTMF_NORMAL_TWIST > row_energy[best_row])
{
/* Relative peak test */
for (i = 0; i < 4; i++)
{
if ((i != best_col && col_energy[i]*DTMF_RELATIVE_PEAK_COL > col_energy[best_col])
||
(i != best_row && row_energy[i]*DTMF_RELATIVE_PEAK_ROW > row_energy[best_row]))
{
break;
}
}
/* ... and second harmonic test */
if (i >= 4
&&
(row_energy[best_row] + col_energy[best_col]) > 42.0*s->energy
&&
zap_goertzel_result (&s->col_out2nd[best_col])*DTMF_2ND_HARMONIC_COL < col_energy[best_col]
&&
zap_goertzel_result (&s->row_out2nd[best_row])*DTMF_2ND_HARMONIC_ROW < row_energy[best_row])
{
hit = dtmf_positions[(best_row << 2) + best_col];
/* Look for two successive similar results */
/* The logic in the next test is:
We need two successive identical clean detects, with
something different preceeding it. This can work with
back to back differing digits. More importantly, it
can work with nasty phones that give a very wobbly start
to a digit. */
if (hit == s->hit3 && s->hit3 != s->hit2)
{
s->mhit = hit;
s->digit_hits[(best_row << 2) + best_col]++;
s->detected_digits++;
if (s->current_digits < MAX_DTMF_DIGITS)
{
s->digits[s->current_digits++] = hit;
s->digits[s->current_digits] = '\0';
}
else
{
s->lost_digits++;
}
}
}
}
if (!hit && (fax_energy >= FAX_THRESHOLD) && (fax_energy > s->energy * 21.0)) {
fax_energy_2nd = zap_goertzel_result(&s->fax_tone2nd);
if (fax_energy_2nd * FAX_2ND_HARMONIC < fax_energy) {
#if 0
printf("Fax energy/Second Harmonic: %f/%f\n", fax_energy, fax_energy_2nd);
#endif
/* XXX Probably need better checking than just this the energy XXX */
hit = 'f';
s->fax_hits++;
} /* Don't reset fax hits counter */
} else {
if (s->fax_hits > 5) {
s->mhit = 'f';
s->detected_digits++;
if (s->current_digits < MAX_DTMF_DIGITS)
{
s->digits[s->current_digits++] = hit;
s->digits[s->current_digits] = '\0';
}
else
{
s->lost_digits++;
}
}
s->fax_hits = 0;
}
s->hit1 = s->hit2;
s->hit2 = s->hit3;
s->hit3 = hit;
/* Reinitialise the detector for the next block */
for (i = 0; i < 4; i++)
{
goertzel_init (&s->row_out[i], &dtmf_detect_row[i]);
goertzel_init (&s->col_out[i], &dtmf_detect_col[i]);
goertzel_init (&s->row_out2nd[i], &dtmf_detect_row_2nd[i]);
goertzel_init (&s->col_out2nd[i], &dtmf_detect_col_2nd[i]);
}
goertzel_init (&s->fax_tone, &fax_detect);
goertzel_init (&s->fax_tone2nd, &fax_detect_2nd);
s->energy = 0.0;
s->current_sample = 0;
}
if ((!s->mhit) || (s->mhit != hit))
{
s->mhit = 0;
return(0);
}
return (hit);
}
/*- End of function --------------------------------------------------------*/
int zap_dtmf_get (dtmf_detect_state_t *s,
char *buf,
int max)
{
if (max > s->current_digits)
max = s->current_digits;
if (max > 0)
{
memcpy (buf, s->digits, max);
memmove (s->digits, s->digits + max, s->current_digits - max);
s->current_digits -= max;
}
buf[max] = '\0';
return max;
}
/*- End of function --------------------------------------------------------*/
/*- End of file ------------------------------------------------------------*/
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