Changeset 384 for pjproject/trunk/pjmedia/src/pjmedia/rtcp.c

Timestamp:

Apr 5, 2006 4:56:19 PM (18 years ago)

Author:

bennylp

Message:

Fixed bug in RTT calculation in RTCP and increase RTT resolution to usec

File:

• pjproject/trunk/pjmedia/src/pjmedia/rtcp.c (modified) (6 diffs)

pjproject/trunk/pjmedia/src/pjmedia/rtcp.c

@@ -20 +20 @@
 #include <pjmedia/errno.h>
 #include <pj/assert.h>
+#include <pj/log.h>
 #include <pj/os.h>
 #include <pj/sock.h>
 #include <pj/string.h>
 
+#define THIS_FILE "rtcp.c"
 
 #define RTCP_SR   200
@@ -33 +35 @@
 #endif
 
+#if 0
+#   define TRACE_(x)    PJ_LOG(3,x)
+#else
+#   define TRACE_(x)
+#endif
 
 /*
@@ -183 +190 @@
     pj_get_timestamp(&session->rtcp_lsr_time);
 
-    /* Calculate ee_delay if it has RR */
+    /* Calculate RTT if it has RR */
     if (size >= sizeof(pjmedia_rtcp_pkt)) {
         
         /* Can only calculate if LSR and DLSR is present in RR */
         if (rtcp->rr.lsr && rtcp->rr.dlsr) {
-            pj_uint32_t lsr, now, dlsr, eedelay;
+            pj_uint32_t lsr, now, dlsr;
+            pj_uint64_t eedelay;
             pjmedia_rtcp_ntp_rec ntp;
 
@@ -207 +215 @@
             eedelay = now - lsr - dlsr;
 
-            /* Convert end to end delay to msec: 
+            /* Convert end to end delay to usec (keeping the calculation in
+             * 64bit space)::
              *   session->ee_delay = (eedelay * 1000) / 65536;
              */
-            session->ee_delay = (eedelay * 1000) >> 16;
+            eedelay = (eedelay * 1000000) >> 16;
+
+            TRACE_((THIS_FILE, "Rx RTCP: lsr=%p, dlsr=%p (%d:%03dms), "
+                               "now=%p, rtt=%p",
+                    lsr, dlsr, dlsr/65536, (dlsr%65536)*1000/65536,
+                    now, (pj_uint32_t)eedelay));
+            
+            /* Only save calculation if "now" is greater than lsr, or
+             * otherwise rtt will be invalid 
+             */
+            if (now-dlsr >= lsr) {
+                session->rtt_us = (pj_uint32_t)eedelay;
+            } else {
+                TRACE_((THIS_FILE, "NTP clock running backwards?"));
+            }
         }
     }
@@ -272 +295 @@
     rtcp_pkt->sr.ntp_frac = pj_htonl(ntp.lo);
     
-    if (session->rtcp_lsr_time.u64 == 0 || session->rtcp_lsr.lo == 0) {
+    if (session->rtcp_lsr_time.u64 == 0) {
         rtcp_pkt->rr.lsr = 0;
         rtcp_pkt->rr.dlsr = 0;
@@ -290 +313 @@
         pj_get_timestamp(&ts);
 
+        /* Calculate DLSR */
+        ts.u64 -= session->rtcp_lsr_time.u64;
+
         /* Convert interval to 1/65536 seconds value */
         ts.u64 = ((ts.u64 - session->rtcp_lsr_time.u64) << 16) /