blob: 5734a50e146d6ea683183aa4c3ac428f9cd98038 [file] [log] [blame]
* Copyright (c) 2014 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.
#include <stdint.h>
#include "absl/types/optional.h"
#include "rtc_base/constructor_magic.h"
#include "rtc_base/numerics/moving_median_filter.h"
#include "system_wrappers/include/rtp_to_ntp_estimator.h"
namespace webrtc {
class Clock;
// RemoteNtpTimeEstimator can be used to estimate a given RTP timestamp's NTP
// time in local timebase.
// Note that it needs to be trained with at least 2 RTCP SR (by calling
// `UpdateRtcpTimestamp`) before it can be used.
class RemoteNtpTimeEstimator {
explicit RemoteNtpTimeEstimator(Clock* clock);
// Updates the estimator with round trip time `rtt`, NTP seconds `ntp_secs`,
// NTP fraction `ntp_frac` and RTP timestamp `rtp_timestamp`.
bool UpdateRtcpTimestamp(int64_t rtt,
uint32_t ntp_secs,
uint32_t ntp_frac,
uint32_t rtp_timestamp);
// Estimates the NTP timestamp in local timebase from `rtp_timestamp`.
// Returns the NTP timestamp in ms when success. -1 if failed.
int64_t Estimate(uint32_t rtp_timestamp);
// Estimates the offset, in milliseconds, between the remote clock and the
// local one. This is equal to local NTP clock - remote NTP clock.
absl::optional<int64_t> EstimateRemoteToLocalClockOffsetMs();
Clock* clock_;
MovingMedianFilter<int64_t> ntp_clocks_offset_estimator_;
RtpToNtpEstimator rtp_to_ntp_;
int64_t last_timing_log_ms_;
} // namespace webrtc