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/*
* 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 MODULES_REMOTE_BITRATE_ESTIMATOR_INTER_ARRIVAL_H_
#define MODULES_REMOTE_BITRATE_ESTIMATOR_INTER_ARRIVAL_H_
#include <stddef.h>
#include <stdint.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:
// After this many packet groups received out of order InterArrival will
// reset, assuming that clocks have made a jump.
static constexpr int kReorderedResetThreshold = 3;
static constexpr int64_t kArrivalTimeOffsetThresholdMs = 3000;
// 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);
InterArrival() = delete;
InterArrival(const InterArrival&) = delete;
InterArrival& operator=(const InterArrival&) = delete;
// 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,
int64_t system_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),
first_arrival_ms(-1),
complete_time_ms(-1) {}
bool IsFirstPacket() const { return complete_time_ms == -1; }
size_t size;
uint32_t first_timestamp;
uint32_t timestamp;
int64_t first_arrival_ms;
int64_t complete_time_ms;
int64_t last_system_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;
void Reset();
const uint32_t kTimestampGroupLengthTicks;
TimestampGroup current_timestamp_group_;
TimestampGroup prev_timestamp_group_;
double timestamp_to_ms_coeff_;
int num_consecutive_reordered_packets_;
};
} // namespace webrtc
#endif // MODULES_REMOTE_BITRATE_ESTIMATOR_INTER_ARRIVAL_H_
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