Merged revisions 80820 via svnmerge from
authorRussell Bryant <russell@russellbryant.com>
Fri, 24 Aug 2007 20:25:39 +0000 (20:25 +0000)
committerRussell Bryant <russell@russellbryant.com>
Fri, 24 Aug 2007 20:25:39 +0000 (20:25 +0000)
https://origsvn.digium.com/svn/asterisk/branches/1.4

........
r80820 | russell | 2007-08-24 15:24:05 -0500 (Fri, 24 Aug 2007) | 7 lines

Improve the debouncing logic in the DTMF detector to fix some reliability
issues.  Previously, this code used a shift register of hits and non-hits.
However, if the start of the digit isn't clean, it is possible for the
leading edge detector to miss the digit.  These changes replace the flawed
shift register logic and also does the debouncing on the trailing edge as well.
(closes issue #10535, many thanks to softins for the patch)

........

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@80821 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/dsp.c

index 428873e..f9f33a0 100644 (file)
@@ -218,7 +218,7 @@ typedef struct
        int hit3;
        int hit4;
 #else
-       int hits[3];
+       int lasthit;
 #endif 
        int mhit;
        float energy;
@@ -383,7 +383,7 @@ static void ast_dtmf_detect_init (dtmf_detect_state_t *s)
        s->hit4 = 
        s->hit2 = 0;
 #else
-       s->hits[0] = s->hits[1] = s->hits[2] = 0;
+       s->lasthit = 0;
 #endif
        for (i = 0;  i < 4;  i++) {
                goertzel_init (&s->row_out[i], dtmf_row[i], 102);
@@ -588,6 +588,7 @@ static int dtmf_detect (dtmf_detect_state_t *s, int16_t amp[], int samples,
                                                amp[i] = 0;
                                        *writeback = 1;
                                }
+#ifdef OLD_DSP_ROUTINES
                                /* Look for two successive similar results */
                                /* The logic in the next test is:
                                   We need two successive identical clean detects, with
@@ -595,7 +596,6 @@ static int dtmf_detect (dtmf_detect_state_t *s, int16_t amp[], int samples,
                                   back to back differing digits. More importantly, it
                                   can work with nasty phones that give a very wobbly start
                                   to a digit */
-#ifdef OLD_DSP_ROUTINES
                                if (hit == s->hit3  &&  s->hit3 != s->hit2) {
                                        s->mhit = hit;
                                        s->digit_hits[(best_row << 2) + best_col]++;
@@ -607,21 +607,33 @@ static int dtmf_detect (dtmf_detect_state_t *s, int16_t amp[], int samples,
                                                s->lost_digits++;
                                        }
                                }
-#else                          
-                               if (hit == s->hits[2]  &&  hit != s->hits[1]  &&  hit != s->hits[0]) {
-                                       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++;
-                                       }
-                               }
 #endif
                        }
                } 
+
+#ifndef OLD_DSP_ROUTINES
+               /* 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->lasthit  &&  hit != s->mhit) {
+                       if (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++;
+                               }
+                       }
+                       s->mhit = hit;
+               }
+#endif
+
 #ifdef FAX_DETECT
                if (!hit && (fax_energy >= FAX_THRESHOLD) && 
                        (fax_energy >= DTMF_TO_TOTAL_ENERGY*s->energy) &&
@@ -652,9 +664,7 @@ static int dtmf_detect (dtmf_detect_state_t *s, int16_t amp[], int samples,
                s->hit2 = s->hit3;
                s->hit3 = hit;
 #else
-               s->hits[0] = s->hits[1];
-               s->hits[1] = s->hits[2];
-               s->hits[2] = hit;
+               s->lasthit = hit;
 #endif         
                /* Reinitialise the detector for the next block */
                for (i = 0;  i < 4;  i++) {
@@ -674,11 +684,15 @@ static int dtmf_detect (dtmf_detect_state_t *s, int16_t amp[], int samples,
                s->energy = 0.0;
                s->current_sample = 0;
        }
+#ifdef OLD_DSP_ROUTINES
        if ((!s->mhit) || (s->mhit != hit)) {
                s->mhit = 0;
                return(0);
        }
        return (hit);
+#else
+       return (s->mhit);       /* return the debounced hit */
+#endif
 }
 
 /* MF goertzel size */
@@ -1690,7 +1704,7 @@ void ast_dsp_digitreset(struct ast_dsp *dsp)
 #endif
                dsp->td.dtmf.hit1 = dsp->td.dtmf.hit2 = dsp->td.dtmf.hit3 = dsp->td.dtmf.hit4 = dsp->td.dtmf.mhit = 0;
 #else
-               dsp->td.dtmf.hits[2] = dsp->td.dtmf.hits[1] = dsp->td.dtmf.hits[0] =  dsp->td.dtmf.mhit = 0;
+               dsp->td.dtmf.lasthit = dsp->td.dtmf.mhit = 0;
 #endif         
                dsp->td.dtmf.energy = 0.0;
                dsp->td.dtmf.current_sample = 0;