Changeset 385

Timestamp:

Apr 5, 2006 5:13:42 PM (19 years ago)

Author:

bennylp

Message:

Fixed RTT calculation bug in RTCP

Location:

pjproject/trunk/pjmedia

Files:

• include/pjmedia/rtcp.h (modified) (1 diff)
• src/pjmedia/rtcp.c (modified) (4 diffs)

pjproject/trunk/pjmedia/include/pjmedia/rtcp.h

@@ -164 +164 @@
     pj_timestamp            ts_freq;    /**< System timestamp frequency.    */
 
-    pjmedia_rtcp_ntp_rec    rtcp_lsr;   /**< NTP ts in last SR received    */
-    pj_timestamp            rtcp_lsr_time;/**< Time when last SR is received*/
+    pj_uint32_t             rx_lsr;     /**< NTP ts in last SR received     */
+    pj_timestamp            rx_lsr_time;/**< Time when last SR is received  */
     pj_uint32_t             peer_ssrc;  /**< Peer SSRC                      */
     unsigned                rtt_us;     /**< End-to-end delay, in usec.     */

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

@@ -77 +77 @@
 
     /* Init time */
-    s->rtcp_lsr.hi = s->rtcp_lsr.lo = 0;
-    s->rtcp_lsr_time.u64 = 0;
+    s->rx_lsr = 0;
+    s->rx_lsr_time.u64 = 0;
     
     /* Init common RTCP header */
@@ -183 +183 @@
     pj_assert(size >= sizeof(pjmedia_rtcp_common)+sizeof(pjmedia_rtcp_sr));
 
-    /* Save NTP timestamp */
-    session->rtcp_lsr.hi = pj_ntohl(rtcp->sr.ntp_sec);
-    session->rtcp_lsr.lo = pj_ntohl(rtcp->sr.ntp_frac);
+    /* Save LSR from NTP timestamp of RTCP packet */
+    session->rx_lsr = ((pj_ntohl(rtcp->sr.ntp_sec) & 0x0000FFFF) << 16) | 
+                         ((pj_ntohl(rtcp->sr.ntp_frac) >> 16) & 0xFFFF);
 
     /* Calculate SR arrival time for DLSR */
-    pj_get_timestamp(&session->rtcp_lsr_time);
+    pj_get_timestamp(&session->rx_lsr_time);
 
     /* Calculate RTT if it has RR */
@@ -295 +295 @@
     rtcp_pkt->sr.ntp_frac = pj_htonl(ntp.lo);
     
-    if (session->rtcp_lsr_time.u64 == 0) {
+    if (session->rx_lsr_time.u64 == 0 || session->rx_lsr == 0) {
         rtcp_pkt->rr.lsr = 0;
         rtcp_pkt->rr.dlsr = 0;
     } else {
         pj_timestamp ts;
+        pj_uint32_t lsr = session->rx_lsr;
+        pj_uint64_t lsr_time = session->rx_lsr_time.u64;
         
         /* Fill in LSR.
            LSR is the middle 32bit of the last SR NTP time received.
          */
-        rtcp_pkt->rr.lsr = ((session->rtcp_lsr.hi & 0x0000FFFF) << 16) | 
-                           ((session->rtcp_lsr.lo >> 16) & 0xFFFF);
-        rtcp_pkt->rr.lsr = pj_htonl(rtcp_pkt->rr.lsr);
+        rtcp_pkt->rr.lsr = pj_htonl(lsr);
         
         /* Fill in DLSR.
@@ -313 +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) / 
-                    session->ts_freq.u64;
+        ts.u64 = ((ts.u64 - lsr_time) << 16) / session->ts_freq.u64;
 
         rtcp_pkt->rr.dlsr = pj_htonl( (pj_uint32_t)ts.u64 );