Fix an issue where dsp.c would interpret multiple dtmf events from a single key press.
authorJonathan Rose <jrose@digium.com>
Thu, 5 Jan 2012 22:02:33 +0000 (22:02 +0000)
committerJonathan Rose <jrose@digium.com>
Thu, 5 Jan 2012 22:02:33 +0000 (22:02 +0000)
When receiving calls from a mobile phone into a DISA system on a connection with
significant interference, the reporter's Asterisk system would interpret DTMF incorrectly
and replicate digits received. This patch resolves that by increasing the number of
frames a mismatch has to be detected before assuming the DTMF is over by 1 frame and
adjusts dtmf_detect function to reset hits and misses only when an edge is detected.

(closes issue ASTERISK-17493)
Reported by: Alec Davis
Patches:
bug18904-refactor.diff.txt uploaded by Alec Davis (license 5546)
Review: https://reviewboard.asterisk.org/r/1130/
........

Merged revisions 349728 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........

Merged revisions 349729 from http://svn.asterisk.org/svn/asterisk/branches/10

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@349730 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/dsp.c

index 0f89553..ec25f96 100644 (file)
@@ -201,9 +201,9 @@ enum gsamp_thresh {
 #define DTMF_GSIZE             102
 
 /* How many successive hits needed to consider begin of a digit */
-#define DTMF_HITS_TO_BEGIN     2
+#define DTMF_HITS_TO_BEGIN     4
 /* How many successive misses needed to consider end of a digit */
-#define DTMF_MISSES_TO_END     3
+#define DTMF_MISSES_TO_END     4
 
 /*!
  * \brief The default silence threshold we will use if an alternate
@@ -721,42 +721,41 @@ static int dtmf_detect(struct ast_dsp *dsp, digit_detect_state_t *s, int16_t amp
                        }
                }
 
-               if (s->td.dtmf.current_hit) {
-                       /* We are in the middle of a digit already */
-                       if (hit != s->td.dtmf.current_hit) {
-                               s->td.dtmf.misses++;
-                               if (s->td.dtmf.misses == s->td.dtmf.misses_to_end) {
-                                       /* There were enough misses to consider digit ended */
-                                       s->td.dtmf.current_hit = 0;
+               if (hit == s->td.dtmf.lasthit) {
+                       if (s->td.dtmf.current_hit) {
+                               /* We are in the middle of a digit already */
+                               if (hit) {
+                                       if (hit != s->td.dtmf.current_hit) {
+                                               /* Look for a start of a new digit.
+                                                  This is because hits_to_begin may be smaller than misses_to_end
+                                                  and we may find the beginning of new digit before we consider last one ended. */
+                                               s->td.dtmf.current_hit = 0;
+                                       } else {
+                                               /* Current hit was same as last, so increment digit duration (of last digit) */
+                                               s->digitlen[s->current_digits - 1] += DTMF_GSIZE;
+                                       }
+                               } else {
+                                       /* No Digit */
+                                       s->td.dtmf.misses++;
+                                       if (s->td.dtmf.misses == s->td.dtmf.misses_to_end) {
+                                               /* There were enough misses to consider digit ended */
+                                               s->td.dtmf.current_hit = 0;
+                                       }
                                }
-                       } else {
-                               s->td.dtmf.misses = 0;
-                               /* Current hit was same as last, so increment digit duration (of last digit) */
-                               s->digitlen[s->current_digits - 1] += DTMF_GSIZE;
-                       }
-               }
-
-               /* Look for a start of a new digit no matter if we are already in the middle of some
-                  digit or not. This is because hits_to_begin may be smaller than misses_to_end
-                  and we may find begin of new digit before we consider last one ended. */
-               if (hit) {
-                       if (hit == s->td.dtmf.lasthit) {
+                       } else if (hit) {
+                               /* Detecting new digit */
                                s->td.dtmf.hits++;
-                       } else {
-                               s->td.dtmf.hits = 1;
-                       }
-
-                       if (s->td.dtmf.hits == s->td.dtmf.hits_to_begin && hit != s->td.dtmf.current_hit) {
-                               store_digit(s, hit);
-                               s->td.dtmf.current_hit = hit;
-                               s->td.dtmf.misses = 0;
+                               if (s->td.dtmf.hits == s->td.dtmf.hits_to_begin) {
+                                       store_digit(s, hit);
+                                       s->td.dtmf.current_hit = hit;
+                               }
                        }
                } else {
-                       s->td.dtmf.hits = 0;
+                       s->td.dtmf.hits = 1;
+                       s->td.dtmf.misses = 1;
+                       s->td.dtmf.lasthit = hit;
                }
 
-               s->td.dtmf.lasthit = hit;
-
                /* If we had a hit in this block, include it into mute fragment */
                if (squelch && hit) {
                        if (mute.end < sample - DTMF_GSIZE) {