notes and code for my payphone project
asterisk: halve DTMF_TO_TOTAL_ENERGY when relaxdtmf=yes
This, along with custom DTMF twist values of 20 in dsp.conf, seem to
be required to get coins to be detected through the mouthpiece of my
payphone
+14
-13
+14
-13
asterisk-dsp_recognize_coins.patch
+14
-13
asterisk-dsp_recognize_coins.patch
···
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1
# initially adapted from https://github.com/saizai/wumpusphone/blob/master/asterisk-1.8.0.patch#L251
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# less invastive version from https://github.com/hharte/1dcoinctrl/blob/master/asterisk/main/dsp.c-patch
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-
# updated for asterisk 13.12.1
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+
# updated for asterisk 18.4.0
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-
--- main/dsp.c.orig Thu Oct 27 13:48:03 2016
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-
+++ main/dsp.c Sun Oct 30 10:30:35 2016
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-
@@ -272,10 +272,11 @@ typedef struct
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+
--- main/dsp.c.bak.orig Thu May 6 10:34:57 2021
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+
+++ main/dsp.c Wed Jul 28 13:42:09 2021
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+
@@ -278,10 +278,11 @@ typedef struct
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} tone_detect_state_t;
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10
···
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int hits; /* How many successive hits we have seen already */
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int misses; /* How many successive misses we have seen already */
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int lasthit;
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-
@@ -309,15 +310,16 @@ typedef struct
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+
@@ -315,15 +316,16 @@ typedef struct
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} digit_detect_state_t;
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static const float dtmf_row[] = {
···
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static const char bell_mf_positions[] = "1247C-358A--69*---0B----#";
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static int thresholds[THRESHOLD_MAX];
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static float dtmf_normal_twist; /* AT&T = 8dB */
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-
@@ -514,7 +516,7 @@ static void ast_dtmf_detect_init(dtmf_detect_state_t *
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+
@@ -522,7 +524,7 @@ static void ast_dtmf_detect_init(dtmf_detect_state_t *
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{
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int i;
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···
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goertzel_init(&s->row_out[i], dtmf_row[i], sample_rate);
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goertzel_init(&s->col_out[i], dtmf_col[i], sample_rate);
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}
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-
@@ -674,8 +676,8 @@ static void store_digit(digit_detect_state_t *s, char
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+
@@ -682,8 +684,8 @@ static void store_digit(digit_detect_state_t *s, char
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static int dtmf_detect(struct ast_dsp *dsp, digit_detect_state_t *s, int16_t amp[], int samples, int squelch, int relax)
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{
···
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int i;
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int j;
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int sample;
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-
@@ -714,6 +716,8 @@ static int dtmf_detect(struct ast_dsp *dsp, digit_dete
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+
@@ -722,6 +724,8 @@ static int dtmf_detect(struct ast_dsp *dsp, digit_dete
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goertzel_sample(s->td.dtmf.col_out + 2, samp);
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goertzel_sample(s->td.dtmf.row_out + 3, samp);
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goertzel_sample(s->td.dtmf.col_out + 3, samp);
···
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}
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s->td.dtmf.current_sample += (limit - sample);
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if (s->td.dtmf.current_sample < DTMF_GSIZE) {
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-
@@ -724,7 +728,7 @@ static int dtmf_detect(struct ast_dsp *dsp, digit_dete
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+
@@ -732,7 +736,7 @@ static int dtmf_detect(struct ast_dsp *dsp, digit_dete
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row_energy[0] = goertzel_result(&s->td.dtmf.row_out[0]);
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col_energy[0] = goertzel_result(&s->td.dtmf.col_out[0]);
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···
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row_energy[i] = goertzel_result(&s->td.dtmf.row_out[i]);
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if (row_energy[i] > row_energy[best_row]) {
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best_row = i;
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-
@@ -745,7 +749,7 @@ static int dtmf_detect(struct ast_dsp *dsp, digit_dete
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+
@@ -753,7 +757,7 @@ static int dtmf_detect(struct ast_dsp *dsp, digit_dete
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col_energy[best_col] < row_energy[best_row] * (relax ? relax_dtmf_reverse_twist : dtmf_reverse_twist) &&
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row_energy[best_row] < col_energy[best_col] * (relax ? relax_dtmf_normal_twist : dtmf_normal_twist)) {
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/* Relative peak test */
···
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if ((i != best_col &&
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col_energy[i] * DTMF_RELATIVE_PEAK_COL > col_energy[best_col]) ||
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(i != best_row
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-
@@ -754,10 +758,10 @@ static int dtmf_detect(struct ast_dsp *dsp, digit_dete
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+
@@ -762,10 +766,10 @@ static int dtmf_detect(struct ast_dsp *dsp, digit_dete
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}
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}
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/* ... and fraction of total energy test */
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- if (i >= 4 &&
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+
- (row_energy[best_row] + col_energy[best_col]) > DTMF_TO_TOTAL_ENERGY * s->td.dtmf.energy) {
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+ if (i >= DTMF_MATRIX_SIZE &&
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-
(row_energy[best_row] + col_energy[best_col]) > DTMF_TO_TOTAL_ENERGY * s->td.dtmf.energy) {
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+
+ (row_energy[best_row] + col_energy[best_col]) > (DTMF_TO_TOTAL_ENERGY / (relax ? 2 : 1)) * s->td.dtmf.energy) {
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/* Got a hit */
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- hit = dtmf_positions[(best_row << 2) + best_col];
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+ hit = dtmf_positions[(best_row * DTMF_MATRIX_SIZE) + best_col];
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ast_debug(10, "DTMF hit '%c'\n", hit);
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}
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}
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-
@@ -860,7 +864,7 @@ static int dtmf_detect(struct ast_dsp *dsp, digit_dete
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+
@@ -868,7 +872,7 @@ static int dtmf_detect(struct ast_dsp *dsp, digit_dete
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}
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/* Reinitialise the detector for the next block */