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/*
* Copyright (c) 2021 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_RTP_RTCP_SOURCE_CAPTURE_CLOCK_OFFSET_UPDATER_H_
#define MODULES_RTP_RTCP_SOURCE_CAPTURE_CLOCK_OFFSET_UPDATER_H_
#include <stdint.h>
#include <optional>
#include "api/units/time_delta.h"
namespace webrtc {
//
// Helper class for calculating the clock offset against the capturer's clock.
//
// This is achieved by adjusting the estimated capture clock offset in received
// Absolute Capture Time RTP header extension (see
// https://webrtc.org/experiments/rtp-hdrext/abs-capture-time/), which
// represents the clock offset between a remote sender and the capturer, by
// adding local-to-remote clock offset.
class CaptureClockOffsetUpdater {
public:
// Adjusts remote_capture_clock_offset, which originates from Absolute Capture
// Time RTP header extension, to get the local clock offset against the
// capturer's clock.
std::optional<int64_t> AdjustEstimatedCaptureClockOffset(
std::optional<int64_t> remote_capture_clock_offset) const;
// Sets the NTP clock offset between the sender system (which may be different
// from the capture system) and the local system. This information is normally
// provided by passing half the value of the Round-Trip Time estimation given
// by RTCP sender reports (see DLSR/DLRR).
//
// Note that the value must be in Q32.32-formatted fixed-point seconds.
void SetRemoteToLocalClockOffset(std::optional<int64_t> offset_q32x32);
// Converts a signed Q32.32-formatted fixed-point to a TimeDelta.
static std::optional<TimeDelta> ConvertsToTimeDela(
std::optional<int64_t> q32x32);
private:
std::optional<int64_t> remote_to_local_clock_offset_;
};
} // namespace webrtc
#endif // MODULES_RTP_RTCP_SOURCE_CAPTURE_CLOCK_OFFSET_UPDATER_H_
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