Merge Steve's timestamp patch (bug #3119)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@4523 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_iax2.c b/channels/chan_iax2.c
index d4044bc..ca9009e 100755 (executable)
--- a/channels/chan_iax2.c
+++ b/channels/chan_iax2.c
@@ -360,6 +360,8 @@ struct chan_iax2_pvt {
        unsigned int lastsent;
        /* Next outgoing timestamp if everything is good */
        unsigned int nextpred;
+       /* True if the last voice we transmitted was not silence/CNG */
+       int notsilenttx;
        /* Ping time */
        unsigned int pingtime;
        /* Max time for initial response */
@@ -2805,6 +2807,18 @@ static unsigned int fix_peerts(struct timeval *tv, int callno, unsigned int ts)
        return ms + ts;
 }
 
+static void add_ms(struct timeval *tv, int ms) {
+  tv->tv_usec += ms * 1000;
+  if(tv->tv_usec > 1000000) {
+      tv->tv_usec -= 1000000;
+      tv->tv_sec++;
+  }
+  if(tv->tv_usec < 0) {
+      tv->tv_usec += 1000000;
+      tv->tv_sec--;
+  }
+}
+
 static unsigned int calc_timestamp(struct chan_iax2_pvt *p, unsigned int ts, struct ast_frame *f)
 {
        struct timeval tv;
@@ -2825,6 +2839,8 @@ static unsigned int calc_timestamp(struct chan_iax2_pvt *p, unsigned int ts, str
                        delivery = &f->delivery;
                } else if (f->frametype == AST_FRAME_IAX) {
                        genuine = 1;
+               } else if (f->frametype == AST_FRAME_CNG) {
+                       p->notsilenttx = 0;     
                }
        }
        if (!p->offset.tv_sec && !p->offset.tv_usec) {
@@ -2849,15 +2865,33 @@ static unsigned int calc_timestamp(struct chan_iax2_pvt *p, unsigned int ts, str
                        ms = 0;
                if (voice) {
                        /* On a voice frame, use predicted values if appropriate */
-                       if (abs(ms - p->nextpred) <= MAX_TIMESTAMP_SKEW) {
+                       if (p->notsilenttx && abs(ms - p->nextpred) <= MAX_TIMESTAMP_SKEW) {
+                               /* Adjust our txcore, keeping voice and 
+                                       non-voice synchronized */
+                               add_ms(&p->offset, (int)(ms - p->nextpred)/10);
+
                                if (!p->nextpred) {
                                        p->nextpred = ms; /*f->samples / 8;*/
                                        if (p->nextpred <= p->lastsent)
                                                p->nextpred = p->lastsent + 3;
                                }
                                ms = p->nextpred;
-                       } else
+                       } else {
+                              /* in this case, just use the actual
+                               * time, since we're either way off
+                               * (shouldn't happen), or we're  ending a
+                               * silent period -- and seed the next
+                               * predicted time.  Also, round ms to the
+                               * next multiple of frame size (so our
+                               * silent periods are multiples of
+                               * frame size too) */
+                               int diff = ms % (f->samples / 8);
+                               if(diff)
+                                   ms += f->samples/8 - diff;
+
                                p->nextpred = ms;
+                               p->notsilenttx = 1;
+                       }
                } else {
                        /* On a dataframe, use last value + 3 (to accomodate jitter buffer shrinking) if appropriate unless
                           it's a genuine frame */