Changeset 455

Timestamp:

May 18, 2006 6:35:05 PM (18 years ago)

Author:

bennylp

Message:

Changed the way average jitter is calculated in rtcp

Location:

pjproject/trunk/pjmedia

Files:

• include/pjmedia/rtcp.h (modified) (3 diffs)
• src/pjmedia/rtcp.c (modified) (7 diffs)

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

@@ -176 +176 @@
 
     struct {
+        unsigned    count;      /**< Number of updates.                     */
         unsigned    min;        /**< Minimum jitter (in usec)               */
         unsigned    avg;        /**< Average jitter (in usec)               */
@@ -216 +217 @@
  */
 typedef struct pjmedia_rtcp_stat pjmedia_rtcp_stat;
+
+
+#if defined(PJ_HAS_FLOATING_POINT) && PJ_HAS_FLOATING_POINT!=0
+  typedef double PJMEDIA_AVG_JITTER_TYPE;
+#else
+  typedef pj_uint32_t PJMEDIA_AVG_JITTER_TYPE;
+#endif;
 
 
@@ -245 +253 @@
     
     pjmedia_rtcp_stat       stat;       /**< Bidirectional stream stat.     */
+
+    /* Keep jitter calculation in floating point to prevent the values
+     * from being rounded-down to nearest integer.
+     */
+    PJMEDIA_AVG_JITTER_TYPE avg_jitter; /**< Average RX jitter.             */
 };
 

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

@@ -139 +139 @@
     /* Reset statistics */
     pj_memset(&sess->stat, 0, sizeof(pjmedia_rtcp_stat));
+    sess->avg_jitter = 0;
 
     /* Name */
@@ -286 +287 @@
             }
 
+            /* Add to average */
+            sess->avg_jitter = 
+                (jitter + sess->avg_jitter * sess->stat.rx.jitter.count) /
+                (sess->stat.rx.jitter.count + 1);
+            sess->stat.rx.jitter.avg = (unsigned)sess->avg_jitter;
+            ++sess->stat.rx.jitter.count;
+
             /* Update jitter stat */
             if (jitter < sess->stat.rx.jitter.min)
@@ -291 +299 @@
             if (jitter > sess->stat.rx.jitter.max)
                 sess->stat.rx.jitter.max = jitter;
+
             sess->stat.rx.jitter.last = jitter;
         }
@@ -394 +403 @@
 
     /* Update jitter statistics */
-    if (sess->stat.tx.update_cnt == 0)
+    if (sess->stat.tx.jitter.count == 0)
         sess->stat.tx.jitter.min = jitter;
     if (jitter < sess->stat.tx.jitter.min && jitter)
@@ -401 +410 @@
         sess->stat.tx.jitter.max = jitter;
     sess->stat.tx.jitter.avg = 
-        (sess->stat.tx.jitter.avg * sess->stat.tx.update_cnt + jitter) /
-        (sess->stat.tx.update_cnt + 1);
+        (sess->stat.tx.jitter.avg * sess->stat.tx.jitter.count + jitter) /
+        (sess->stat.tx.jitter.count + 1);
+    ++sess->stat.tx.jitter.count;
     sess->stat.tx.jitter.last = jitter;
 
@@ -509 +519 @@
 {
     pj_uint32_t expected, expected_interval, received_interval, lost_interval;
-    pj_uint32_t jitter_samp, jitter;
     pjmedia_rtcp_pkt *rtcp_pkt = &sess->rtcp_pkt;
     pj_timestamp ts_now;
@@ -528 +537 @@
 
     /* Jitter */
-    jitter_samp = (sess->jitter >> 4);
-    rtcp_pkt->rr.jitter = pj_htonl(jitter_samp);
-    
-    /* Calculate jitter in usec, avoiding overflows */
-    if (jitter_samp <= 4294)
-        jitter = jitter_samp * 1000000 / sess->clock_rate;
-    else {
-        jitter = jitter_samp * 1000 / sess->clock_rate;
-        jitter *= 1000;
-    }
-
-    /* Update jitter statistics */
-    sess->stat.rx.jitter.avg = 
-        (sess->stat.rx.jitter.avg * sess->stat.rx.update_cnt + jitter) /
-        (sess->stat.rx.update_cnt + 1);
+    rtcp_pkt->rr.jitter = pj_htonl(sess->jitter >> 4);
+    
     
     /* Total lost. */