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- fixed a small bug in the in-band DTMF detector which caused some registerKeyPressed() to get lost

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- fixed duration calculation of in-band DTMF codes
- cleaned up the in-band DTMF detection code (a litle bit)


git-svn-id: http://svn.berlios.de/svnroot/repos/sems/trunk@318 8eb893ce-cfd4-0310-b710-fb5ebe64c474
sayer/1.4-spce2.6
Stefan Keller 20 years ago
parent 08f5e36e8c
commit 7551933f09
2 changed files with 79 additions and 95 deletions
Show Stats Download Patch File Download Diff File

159
core/AmDtmfDetector.cpp
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@ -374,54 +374,31 @@ static int IVR_dtmf_matrix[4][4] =
};
#define DTMF_TRESH 100000 /* above this is dtmf */
#define SILENCE_TRESH 100 /* below this is silence */
#define H2_TRESH 35000 /* 2nd harmonic */
#define DTMF_DUR 25 /* nr of samples to detect a DTMF tone */
#define AMP_BITS 9 /* bits per sample, reduced to avoid overflow */
#define NCOEFF 16 /* number of frequencies to be analyzed */
#define LOGRP 0
#define HIGRP 1
#define REL_NCOEFF 8 /* number of frequencies to be analyzed */
#define REL_DTMF_TRESH 4000 /* above this is dtmf */
#define REL_SILENCE_TRESH 200 /* below this is silence */
#define REL_AMP_BITS 9 /* bits per sample, reduced to avoid overflow */
#define PI 3.1415926
#define NELEMSOF(x) (sizeof(x)/sizeof(*x))
typedef struct {
int freq; /* frequency */
int grp; /* low/high group */
int k; /* k */
int k2; /* k for 1st harmonic */
} dtmf_t;
static int cos2pik[NCOEFF] = { /* 2 * cos(2 * PI * k / N), precalculated */
55812, 29528, 53603, 24032,
51193, 14443, 48590, 6517
}; // high group missing...
/* For DTMF recognition:
* 2 * cos(2 * PI * k / N) precalculated for all k
*/
static int rel_cos2pik[REL_NCOEFF] =
{
55813, 53604, 51193, 48591, // low group
38114, 33057, 25889, 18332 // high group
};
static dtmf_t dtmf_tones[8] =
{
{ 697, LOGRP, 0, 1 },
{ 770, LOGRP, 2, 3 },
{ 852, LOGRP, 4, 5 },
{ 941, LOGRP, 6, 7 },
{1209, HIGRP, 8, 9 },
{1336, HIGRP, 10, 11 },
{1477, HIGRP, 12, 13 },
{1633, HIGRP, 14, 15 }
{ 697, LOGRP},
{ 770, LOGRP},
{ 852, LOGRP},
{ 941, LOGRP},
{1209, HIGRP},
{1336, HIGRP},
{1477, HIGRP},
{1633, HIGRP}
};
static char dtmf_matrix[4][4] =
@ -436,21 +413,15 @@ AmInbandDtmfDetector::AmInbandDtmfDetector(AmDtmfDetector *owner)
: m_owner(owner),
m_last(' '),
m_idx(0),
m_count(0)
m_count(0),
SAMPLERATE(8000)
{
/* precalculate 2 * cos (2 PI k / N) */
int i, kp, k;
kp = 0;
for(i = 0; i < 8; i++)
{
k = (int)rint((double)dtmf_tones[i].freq * DTMF_NPOINTS / SAMPLERATE);
cos2pik[kp] = (int)(2 * 32768 * cos(2 * PI * k / DTMF_NPOINTS));
dtmf_tones[i].k = kp++;
k = (int)rint((double)dtmf_tones[i].freq * 2 * DTMF_NPOINTS / SAMPLERATE);
cos2pik[kp] = (int)(2 * 32768 * cos(2 * PI * k / DTMF_NPOINTS));
dtmf_tones[i].k2 = kp++;
}
for(unsigned i = 0; i < NELEMSOF(rel_cos2pik); i++) {
// FIXME: fixed samplerate. won't work for wideband
int k = (int)((double)dtmf_tones[i].freq * REL_DTMF_NPOINTS / SAMPLERATE + 0.5);
rel_cos2pik[i] = (int)(2 * 32768 * cos(2 * PI * k / REL_DTMF_NPOINTS));
}
}
/*
@ -463,32 +434,32 @@ void AmInbandDtmfDetector::isdn_audio_goertzel_relative()
{
int sk, sk1, sk2;
for (int k = 0; k < REL_NCOEFF; k++)
{
sk = sk1 = sk2 = 0;
for (int n = 0; n < REL_DTMF_NPOINTS; n++)
{
sk = m_buf[n] + ((rel_cos2pik[k] * sk1) >> 15) - sk2;
sk2 = sk1;
sk1 = sk;
}
/* Avoid overflows */
sk >>= 1;
sk2 >>= 1;
/* compute |X(k)|**2 */
/* report overflows. This should not happen. */
/* Comment this out if desired */
/*if (sk < -32768 || sk > 32767)
DBG("isdn_audio: dtmf goertzel overflow, sk=%d\n", sk);
if (sk2 < -32768 || sk2 > 32767)
DBG("isdn_audio: dtmf goertzel overflow, sk2=%d\n", sk2);
*/
m_result[k] =
((sk * sk) >> REL_AMP_BITS) -
((((rel_cos2pik[k] * sk) >> 15) * sk2) >> REL_AMP_BITS) +
((sk2 * sk2) >> REL_AMP_BITS);
for (int k = 0; k < REL_NCOEFF; k++) {
// like m_buf, sk..sk2 are in (32-REL_AMP_BITS).REL_AMP_BITS fixed-point format
sk = sk1 = sk2 = 0;
for (int n = 0; n < REL_DTMF_NPOINTS; n++) {
sk = m_buf[n] + ((rel_cos2pik[k] * sk1) >> 15) - sk2;
sk2 = sk1;
sk1 = sk;
}
/* Avoid overflows */
sk >>= 1;
sk2 >>= 1;
/* compute |X(k)|**2 */
/* report overflows. This should not happen. */
/* Comment this out if desired */
/*if (sk < -32768 || sk > 32767)
DBG("isdn_audio: dtmf goertzel overflow, sk=%d\n", sk);
if (sk2 < -32768 || sk2 > 32767)
DBG("isdn_audio: dtmf goertzel overflow, sk2=%d\n", sk2);
*/
// note that the result still is in (32-REL_AMP_BITS).REL_AMP_BITS format
m_result[k] =
((sk * sk) >> REL_AMP_BITS) -
((((rel_cos2pik[k] * sk) >> 15) * sk2) >> REL_AMP_BITS) +
((sk2 * sk2) >> REL_AMP_BITS);
}
}
@ -549,7 +520,8 @@ void AmInbandDtmfDetector::isdn_audio_eval_dtmf_relative()
if (what != m_last)
{
gettimeofday(&m_startTime, NULL);
m_startTime.tv_sec = m_last_ts / SAMPLERATE;
m_startTime.tv_usec = (m_last_ts * 1000 / SAMPLERATE) % 1000;
}
} else
what = '.';
@ -559,7 +531,7 @@ void AmInbandDtmfDetector::isdn_audio_eval_dtmf_relative()
}
if (what != ' ' && what != '.')
{
if (m_count++ >= DTMF_INTERVAL)
if (++m_count >= DTMF_INTERVAL)
{
m_owner->registerKeyPressed(m_lastCode, Dtmf::SOURCE_INBAND);
}
@ -569,7 +541,8 @@ void AmInbandDtmfDetector::isdn_audio_eval_dtmf_relative()
if (m_last != ' ' && m_last != '.' && m_count >= DTMF_INTERVAL)
{
struct timeval stop;
gettimeofday(&stop, NULL);
stop.tv_sec = m_last_ts / SAMPLERATE;
stop.tv_usec = (m_last_ts * 1000 / SAMPLERATE) % 1000;
m_owner->registerKeyReleased(m_lastCode, Dtmf::SOURCE_INBAND, m_startTime, stop);
}
m_count = 0;
@ -577,32 +550,36 @@ void AmInbandDtmfDetector::isdn_audio_eval_dtmf_relative()
m_last = what;
}
void AmInbandDtmfDetector::isdn_audio_calc_dtmf(const signed short* buf, int len)
void AmInbandDtmfDetector::isdn_audio_calc_dtmf(const signed short* buf, int len, unsigned int ts)
{
int c;
while (len)
{
c = (len < (DTMF_NPOINTS - m_idx)) ? len : (DTMF_NPOINTS - m_idx);
if(m_idx == 0) m_last_ts = ts;
if (c <= 0)
break;
while (len) {
c = (len < ((int)NELEMSOF(m_buf) - m_idx)) ? len : (NELEMSOF(m_buf) - m_idx);
for (int i = 0; i < c; i++) {
m_buf[m_idx++] = (*buf++) >> (15 - AMP_BITS);
}
if (m_idx == DTMF_NPOINTS)
{
isdn_audio_goertzel_relative();
isdn_audio_eval_dtmf_relative();
m_idx = 0;
}
len -= c;
if (c <= 0) break;
for (int i = 0; i < c; i++) {
// m_buf is in (32-REL_AMP_BITS).REL_AMP_BITS fixed-point format, the samples
// itself are in the last REL_AMP_BITS bits, i.e. they go from -1.0 to +1.0
// (or more exactly from -1.0 to ~+0.996)
m_buf[m_idx++] = (*buf++) >> (15 - REL_AMP_BITS);
}
if (m_idx == NELEMSOF(m_buf)) {
isdn_audio_goertzel_relative();
isdn_audio_eval_dtmf_relative();
m_idx = 0;
m_last_ts = ts + c;
}
len -= c;
ts += c;
}
}
int AmInbandDtmfDetector::streamPut(const unsigned char* samples, unsigned int size, unsigned int)
int AmInbandDtmfDetector::streamPut(const unsigned char* samples, unsigned int size, unsigned int user_ts)
{
isdn_audio_calc_dtmf((const signed short *)samples, size / 2);
isdn_audio_calc_dtmf((const signed short *)samples, size / 2, user_ts);
return size;
}

15
core/AmDtmfDetector.h
Unescape View File

@ -174,26 +174,33 @@ class AmInbandDtmfDetector
*/
struct timeval m_startTime;
static const int DTMF_NPOINTS = 205; /* Number of samples for DTMF recognition */
static const int REL_DTMF_NPOINTS = 205; /* Number of samples for DTMF recognition */
static const int SAMPLERATE = 8000;
static const int REL_NCOEFF = 8; /* number of frequencies to be analyzed */
const int SAMPLERATE;
/**
* DTMF recognition successfull only if no less than DTMF_INTERVAL
* audio packets were processed and all gave the same result
*/
static const int DTMF_INTERVAL = 3;
int m_buf[DTMF_NPOINTS];
/* For DTMF recognition:
* 2 * cos(2 * PI * k / N) precalculated for all k
*/
int rel_cos2pik[REL_NCOEFF];
int m_buf[REL_DTMF_NPOINTS];
char m_last;
int m_idx;
int m_result[16];
int m_lastCode;
int m_last_ts; // timestamp representative for the currently analysed filter block
int m_count;
void isdn_audio_goertzel_relative();
void isdn_audio_eval_dtmf_relative();
void isdn_audio_calc_dtmf(const signed short* buf, int len);
void isdn_audio_calc_dtmf(const signed short* buf, int len, unsigned int ts);
public:
AmInbandDtmfDetector(AmDtmfDetector *owner);

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