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1 /*
2  *  Copyright (c) 2020 The WebRTC project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #ifndef VIDEO_RTP_STREAMS_SYNCHRONIZER2_H_
12 #define VIDEO_RTP_STREAMS_SYNCHRONIZER2_H_
13 
14 #include <memory>
15 
16 #include "api/sequence_checker.h"
17 #include "api/task_queue/task_queue_base.h"
18 #include "rtc_base/system/no_unique_address.h"
19 #include "rtc_base/task_utils/repeating_task.h"
20 #include "video/stream_synchronization.h"
21 
22 namespace webrtc {
23 
24 class Syncable;
25 
26 namespace internal {
27 
28 // RtpStreamsSynchronizer is responsible for synchronizing audio and video for
29 // a given audio receive stream and video receive stream.
30 class RtpStreamsSynchronizer {
31  public:
32   RtpStreamsSynchronizer(TaskQueueBase* main_queue, Syncable* syncable_video);
33   ~RtpStreamsSynchronizer();
34 
35   void ConfigureSync(Syncable* syncable_audio);
36 
37   // Gets the estimated playout NTP timestamp for the video frame with
38   // `rtp_timestamp` and the sync offset between the current played out audio
39   // frame and the video frame. Returns true on success, false otherwise.
40   // The `estimated_freq_khz` is the frequency used in the RTP to NTP timestamp
41   // conversion.
42   bool GetStreamSyncOffsetInMs(uint32_t rtp_timestamp,
43                                int64_t render_time_ms,
44                                int64_t* video_playout_ntp_ms,
45                                int64_t* stream_offset_ms,
46                                double* estimated_freq_khz) const;
47 
48  private:
49   void UpdateDelay();
50 
51   TaskQueueBase* const task_queue_;
52 
53   // Used to check if we're running on the main thread/task queue.
54   // The reason we currently don't use RTC_DCHECK_RUN_ON(task_queue_) is because
55   // we might be running on an rtc::Thread implementation of TaskQueue, which
56   // does not consistently set itself as the active TaskQueue.
57   // Instead, we rely on a SequenceChecker for now.
58   RTC_NO_UNIQUE_ADDRESS SequenceChecker main_checker_;
59 
60   Syncable* const syncable_video_;
61 
62   Syncable* syncable_audio_ RTC_GUARDED_BY(main_checker_) = nullptr;
63   std::unique_ptr<StreamSynchronization> sync_ RTC_GUARDED_BY(main_checker_);
64   StreamSynchronization::Measurements audio_measurement_
65       RTC_GUARDED_BY(main_checker_);
66   StreamSynchronization::Measurements video_measurement_
67       RTC_GUARDED_BY(main_checker_);
68   RepeatingTaskHandle repeating_task_ RTC_GUARDED_BY(main_checker_);
69   int64_t last_stats_log_ms_ RTC_GUARDED_BY(&main_checker_);
70 };
71 
72 }  // namespace internal
73 }  // namespace webrtc
74 
75 #endif  // VIDEO_RTP_STREAMS_SYNCHRONIZER2_H_
76