clock_offset_estimator_impl.cc | Explore in Territory

// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "cast/streaming/impl/clock_offset_estimator_impl.h"

#include <algorithm>
#include <memory>
#include <utility>

#include "platform/base/trivial_clock_traits.h"

namespace openscreen::cast {
namespace {

// The lower this is, the faster we adjust to clock drift (but with more
// jitter). Each successful call to BoundCalculator::UpdateBound() uses this as
// the weight of the bound upte.
constexpr size_t kBoundUpdateWeight = …;

// This should be large enough so that we can collect all 3 events before
// the entry gets removed from the map.
constexpr size_t kMaxEventTimesMapSize = …;

// Bitwise merging of values to produce an ordered key for entries in the
// BoundCalculator::events_ map. Since std::map is sorted by key value, we
// ensure that the Packet ID is first (since the RTP timestamp may roll over
// eventually).
//
//  0         1         2         3         4         5         6
//  0 2 4 6 8 0 2 4 6 8 0 2 4 6 8 0 2 4 6 8 0 2 4 6 8 0 2 4 6 8 0 2 4
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// |   Packet ID   |               RTP Timestamp                 |*| (is_audio)
// +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
uint64_t MakeEventKey(RtpTimeTicks rtp, uint16_t packet_id, bool audio) { … }

}  // namespace

std::unique_ptr<ClockOffsetEstimator> ClockOffsetEstimator::Create() { … }

ClockOffsetEstimatorImpl::ClockOffsetEstimatorImpl() = default;
ClockOffsetEstimatorImpl::ClockOffsetEstimatorImpl(
    ClockOffsetEstimatorImpl&&) noexcept = default;
ClockOffsetEstimatorImpl& ClockOffsetEstimatorImpl::operator=(
    ClockOffsetEstimatorImpl&&) = default;
ClockOffsetEstimatorImpl::~ClockOffsetEstimatorImpl() = default;

void ClockOffsetEstimatorImpl::OnFrameEvent(const FrameEvent& frame_event) { … }

void ClockOffsetEstimatorImpl::OnPacketEvent(const PacketEvent& packet_event) { … }

bool ClockOffsetEstimatorImpl::GetReceiverOffsetBounds(
    Clock::duration& frame_bound,
    Clock::duration& packet_bound) const { … }

std::optional<Clock::duration> ClockOffsetEstimatorImpl::GetEstimatedOffset()
    const { … }

ClockOffsetEstimatorImpl::BoundCalculator::BoundCalculator() = default;
ClockOffsetEstimatorImpl::BoundCalculator::BoundCalculator(
    BoundCalculator&&) noexcept = default;
ClockOffsetEstimatorImpl::BoundCalculator&
ClockOffsetEstimatorImpl::BoundCalculator::operator=(BoundCalculator&&) =
    default;
ClockOffsetEstimatorImpl::BoundCalculator::~BoundCalculator() = default;

void ClockOffsetEstimatorImpl::BoundCalculator::SetSent(RtpTimeTicks rtp,
                                                        uint16_t packet_id,
                                                        bool audio,
                                                        Clock::time_point t) { … }

void ClockOffsetEstimatorImpl::BoundCalculator::SetReceived(
    RtpTimeTicks rtp,
    uint16_t packet_id,
    bool audio,
    Clock::time_point t) { … }

void ClockOffsetEstimatorImpl::BoundCalculator::UpdateBound(
    Clock::time_point sent,
    Clock::time_point received) { … }

void ClockOffsetEstimatorImpl::BoundCalculator::CheckUpdate(uint64_t key) { … }

}  // namespace openscreen::cast
chromium/third_party/openscreen/src/cast/streaming/impl/clock_offset_estimator_impl.cc
