Merge remote bitrate estimator changes.

R=stefan@webrtc.org
BUG=

Review URL: https://webrtc-codereview.appspot.com/33489004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7811 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/modules/remote_bitrate_estimator/inter_arrival.h

diff --git a/webrtc/modules/remote_bitrate_estimator/inter_arrival.h b/webrtc/modules/remote_bitrate_estimator/inter_arrival.h
new file mode 100644
index 0000000..ace8551
--- /dev/null
+++ b/webrtc/modules/remote_bitrate_estimator/inter_arrival.h
@@ -0,0 +1,85 @@
+/*
+ *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_INTER_ARRIVAL_H_
+#define WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_INTER_ARRIVAL_H_
+
+#include <cstddef>
+
+#include "webrtc/base/constructormagic.h"
+#include "webrtc/typedefs.h"
+
+namespace webrtc {
+
+// Helper class to compute the inter-arrival time delta and the size delta
+// between two timestamp groups. A timestamp is a 32 bit unsigned number with
+// a client defined rate.
+class InterArrival {
+ public:
+  // A timestamp group is defined as all packets with a timestamp which are at
+  // most timestamp_group_length_ticks older than the first timestamp in that
+  // group.
+  InterArrival(uint32_t timestamp_group_length_ticks,
+               double timestamp_to_ms_coeff,
+               bool enable_burst_grouping);
+
+  // This function returns true if a delta was computed, or false if the current
+  // group is still incomplete or if only one group has been completed.
+  // |timestamp| is the timestamp.
+  // |arrival_time_ms| is the local time at which the packet arrived.
+  // |packet_size| is the size of the packet.
+  // |timestamp_delta| (output) is the computed timestamp delta.
+  // |arrival_time_delta_ms| (output) is the computed arrival-time delta.
+  // |packet_size_delta| (output) is the computed size delta.
+  bool ComputeDeltas(uint32_t timestamp,
+                     int64_t arrival_time_ms,
+                     size_t packet_size,
+                     uint32_t* timestamp_delta,
+                     int64_t* arrival_time_delta_ms,
+                     int* packet_size_delta);
+
+ private:
+  struct TimestampGroup {
+    TimestampGroup()
+        : size(0),
+          first_timestamp(0),
+          timestamp(0),
+          complete_time_ms(-1) {}
+
+    bool IsFirstPacket() const {
+      return complete_time_ms == -1;
+    }
+
+    size_t size;
+    uint32_t first_timestamp;
+    uint32_t timestamp;
+    int64_t complete_time_ms;
+  };
+
+  // Returns true if the packet with timestamp |timestamp| arrived in order.
+  bool PacketInOrder(uint32_t timestamp);
+
+  // Returns true if the last packet was the end of the current batch and the
+  // packet with |timestamp| is the first of a new batch.
+  bool NewTimestampGroup(int64_t arrival_time_ms, uint32_t timestamp) const;
+
+  bool BelongsToBurst(int64_t arrival_time_ms, uint32_t timestamp) const;
+
+  const uint32_t kTimestampGroupLengthTicks;
+  TimestampGroup current_timestamp_group_;
+  TimestampGroup prev_timestamp_group_;
+  double timestamp_to_ms_coeff_;
+  bool burst_grouping_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(InterArrival);
+};
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_INTER_ARRIVAL_H_