Fix YADB (Yet Another DTMF Bug) ((C) Russell Bryant, 2007, TM, Patent Pending).

This set of changes came from a debugging session I had with Dwayne Hubbard.
When he called into his home FXO, ran the Echo application, and pressed a
digit, the digit would be echoed back and would never end.  This is fixed,
along with a couple other little improvements.

* When chan_zap is in the middle of playing a digit to a channel, it feeds
  back null frames, not voice frames.  So, I have modified ast_read to check
  the timing on emulated DTMF when it receives null frames, in addition to
  where it was doing this on voice frames.
* Make a tweak to setting the duration on emulated DTMF digits.  If there was
  no duration specified, it set it to be the minimum, instead of the default.
* Instead of timing the emulated digits off of the number of samples in audio
  frames that pass through, just use time values.  Now there is no code in this
  section that assumes 8kHz audio.


git-svn-id: http://svn.digium.com/svn/asterisk/branches/1.4@62942 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 26 insertions, 9 deletions

diff --git a/main/channel.c b/main/channel.c
index cd568da0e..bf1c9fec8 100644
--- a/main/channel.c
+++ b/main/channel.c
@@ -2293,10 +2293,13 @@ static struct ast_frame *__ast_read(struct ast_channel *chan, int dropaudio)
 					ast_set_flag(chan, AST_FLAG_EMULATE_DTMF);
 					chan->emulate_dtmf_digit = f->subclass;
 					chan->dtmf_tv = ast_tvnow();
-					if (f->len && f->len > AST_MIN_DTMF_DURATION)
-						chan->emulate_dtmf_duration = f->len;
-					else
-						chan->emulate_dtmf_duration = AST_MIN_DTMF_DURATION;
+					if (f->len) {
+						if (f->len > AST_MIN_DTMF_DURATION)
+							chan->emulate_dtmf_duration = f->len;
+						else 
+							chan->emulate_dtmf_duration = AST_MIN_DTMF_DURATION;
+					} else
+						chan->emulate_dtmf_duration = AST_DEFAULT_EMULATE_DTMF_DURATION;
 				}
 			} else {
 				struct timeval now = ast_tvnow();
@@ -2324,9 +2327,23 @@ static struct ast_frame *__ast_read(struct ast_channel *chan, int dropaudio)
 				chan->dtmf_tv = ast_tvnow();
 			}
 			break;
+		case AST_FRAME_NULL:
+			if (ast_test_flag(chan, AST_FLAG_EMULATE_DTMF)) {
+				struct timeval now = ast_tvnow();
+				if (ast_tvdiff_ms(now, chan->dtmf_tv) >= chan->emulate_dtmf_duration) {
+					chan->emulate_dtmf_duration = 0;
+					f->frametype = AST_FRAME_DTMF_END;
+					f->subclass = chan->emulate_dtmf_digit;
+					f->len = ast_tvdiff_ms(now, chan->dtmf_tv);
+					chan->dtmf_tv = now;
+					ast_clear_flag(chan, AST_FLAG_EMULATE_DTMF);
+					chan->emulate_dtmf_digit = 0;
+				}
+			}
+			break;
 		case AST_FRAME_VOICE:
-			/* The EMULATE_DTMF flag must be cleared here as opposed to when the samples
-			 * first get to zero, because we want to make sure we pass at least one
+			/* The EMULATE_DTMF flag must be cleared here as opposed to when the duration
+			 * is reached , because we want to make sure we pass at least one
 			 * voice frame through before starting the next digit, to ensure a gap
 			 * between DTMF digits. */
 			if (ast_test_flag(chan, AST_FLAG_EMULATE_DTMF) && !chan->emulate_dtmf_duration) {
@@ -2338,15 +2355,15 @@ static struct ast_frame *__ast_read(struct ast_channel *chan, int dropaudio)
 				ast_frfree(f);
 				f = &ast_null_frame;
 			} else if (ast_test_flag(chan, AST_FLAG_EMULATE_DTMF)) {
-				if ((f->samples / 8) >= chan->emulate_dtmf_duration) { /* XXX 8kHz */
-					struct timeval now = ast_tvnow();
+				struct timeval now = ast_tvnow();
+				if (ast_tvdiff_ms(now, chan->dtmf_tv) >= chan->emulate_dtmf_duration) {
 					chan->emulate_dtmf_duration = 0;
 					f->frametype = AST_FRAME_DTMF_END;
 					f->subclass = chan->emulate_dtmf_digit;
 					f->len = ast_tvdiff_ms(now, chan->dtmf_tv);
 					chan->dtmf_tv = now;
 				} else {
-					chan->emulate_dtmf_duration -= f->samples / 8; /* XXX 8kHz */
+					/* Drop voice frames while we're still in the middle of the digit */
 					ast_frfree(f);
 					f = &ast_null_frame;
 				}