| /* |
| * Copyright (c) 2012 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_SYSTEM_WRAPPERS_INCLUDE_RTP_TO_NTP_ESTIMATOR_H_ |
| #define WEBRTC_SYSTEM_WRAPPERS_INCLUDE_RTP_TO_NTP_ESTIMATOR_H_ |
| |
| #include <list> |
| |
| #include "webrtc/system_wrappers/include/ntp_time.h" |
| #include "webrtc/typedefs.h" |
| |
| namespace webrtc { |
| // Class for converting an RTP timestamp to the NTP domain in milliseconds. |
| // The class needs to be trained with (at least 2) RTP/NTP timestamp pairs from |
| // RTCP sender reports before the convertion can be done. |
| class RtpToNtpEstimator { |
| public: |
| RtpToNtpEstimator(); |
| ~RtpToNtpEstimator(); |
| |
| // RTP and NTP timestamp pair from a RTCP SR report. |
| struct RtcpMeasurement { |
| RtcpMeasurement(uint32_t ntp_secs, uint32_t ntp_frac, uint32_t timestamp); |
| bool IsEqual(const RtcpMeasurement& other) const; |
| |
| NtpTime ntp_time; |
| uint32_t rtp_timestamp; |
| }; |
| |
| // Estimated parameters from RTP and NTP timestamp pairs in |measurements_|. |
| struct Parameters { |
| double frequency_khz = 0.0; |
| double offset_ms = 0.0; |
| bool calculated = false; |
| }; |
| |
| // Updates measurements with RTP/NTP timestamp pair from a RTCP sender report. |
| // |new_rtcp_sr| is set to true if a new report is added. |
| bool UpdateMeasurements(uint32_t ntp_secs, |
| uint32_t ntp_frac, |
| uint32_t rtp_timestamp, |
| bool* new_rtcp_sr); |
| |
| // Converts an RTP timestamp to the NTP domain in milliseconds. |
| // Returns true on success, false otherwise. |
| bool Estimate(int64_t rtp_timestamp, int64_t* rtp_timestamp_ms) const; |
| |
| const Parameters& params() const { return params_; } |
| |
| static const int kMaxInvalidSamples = 3; |
| |
| private: |
| void UpdateParameters(); |
| |
| int consecutive_invalid_samples_; |
| std::list<RtcpMeasurement> measurements_; |
| Parameters params_; |
| }; |
| |
| // Returns: |
| // 1: forward wrap around. |
| // 0: no wrap around. |
| // -1: backwards wrap around (i.e. reordering). |
| int CheckForWrapArounds(uint32_t new_timestamp, uint32_t old_timestamp); |
| |
| } // namespace webrtc |
| |
| #endif // WEBRTC_SYSTEM_WRAPPERS_INCLUDE_RTP_TO_NTP_ESTIMATOR_H_ |