Replace uses of raw uint32's with a type-checked RtpTimeTicks data type.

media/cast/net/rtp/receiver_stats.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/cast/net/rtp/receiver_stats.h"
 
 #include "base/logging.h"
 #include "media/cast/cast_defines.h"
 #include "media/cast/net/rtp/rtp_defines.h"
 
@@ skipping 56 matching lines @@
       static_cast<uint32_t>(std::abs(jitter_.InMillisecondsRoundedUp()));
 
   // Reset interval values.
   interval_min_sequence_number_ = 0;
   interval_number_packets_ = 0;
   interval_wrap_count_ = 0;
 
   return ret;
 }
 
-void ReceiverStats::UpdateStatistics(const RtpCastHeader& header) {
+void ReceiverStats::UpdateStatistics(const RtpCastHeader& header,
+                                     int rtp_timebase) {
   const uint16_t new_seq_num = header.sequence_number;
 
   if (interval_number_packets_ == 0) {
     // First packet in the interval.
     interval_min_sequence_number_ = new_seq_num;
   }
   if (total_number_packets_ == 0) {
     // First incoming packet.
     min_sequence_number_ = new_seq_num;
     max_sequence_number_ = new_seq_num;
   }
 
   if (IsNewerSequenceNumber(new_seq_num, max_sequence_number_)) {
     // Check wrap.
     if (new_seq_num < max_sequence_number_) {
       ++sequence_number_cycles_;
       ++interval_wrap_count_;
     }
     max_sequence_number_ = new_seq_num;
   }
 
   // Compute Jitter.
-  base::TimeTicks now = clock_->NowTicks();
-  base::TimeDelta delta_new_timestamp =
-      base::TimeDelta::FromMilliseconds(header.rtp_timestamp);
+  const base::TimeTicks now = clock_->NowTicks();
   if (total_number_packets_ > 0) {
+    const base::TimeDelta packet_time_difference =
+        now - last_received_packet_time_;
+    const base::TimeDelta media_time_differerence =
+        (header.rtp_timestamp - last_received_rtp_timestamp_)
+            .ToTimeDelta(rtp_timebase);
+    const base::TimeDelta delta =
+        packet_time_difference - media_time_differerence;
     // Update jitter.
-    base::TimeDelta delta =
-        (now - last_received_packet_time_) -
-        ((delta_new_timestamp - last_received_timestamp_) / 90);
     jitter_ += (delta - jitter_) / 16;
   }
-  last_received_timestamp_ = delta_new_timestamp;
+  last_received_rtp_timestamp_ = header.rtp_timestamp;
   last_received_packet_time_ = now;
 
   // Increment counters.
   ++total_number_packets_;
   ++interval_number_packets_;
 }
 
 }  // namespace cast
 }  // namespace media