1 /* 2 * Copyright (c) 2011 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 WEBRTC_MODULES_VIDEO_CODING_INTER_FRAME_DELAY_H_ 12 #define WEBRTC_MODULES_VIDEO_CODING_INTER_FRAME_DELAY_H_ 13 14 #include "webrtc/typedefs.h" 15 16 namespace webrtc { 17 18 class VCMInterFrameDelay { 19 public: 20 explicit VCMInterFrameDelay(int64_t currentWallClock); 21 22 // Resets the estimate. Zeros are given as parameters. 23 void Reset(int64_t currentWallClock); 24 25 // Calculates the delay of a frame with the given timestamp. 26 // This method is called when the frame is complete. 27 // 28 // Input: 29 // - timestamp : RTP timestamp of a received frame 30 // - *delay : Pointer to memory where the result should be 31 // stored 32 // - currentWallClock : The current time in milliseconds. 33 // Should be -1 for normal operation, only used 34 // for testing. 35 // Return value : true if OK, false when reordered timestamps 36 bool CalculateDelay(uint32_t timestamp, 37 int64_t* delay, 38 int64_t currentWallClock); 39 40 // Returns the current difference between incoming timestamps 41 // 42 // Return value : Wrap-around compensated difference between 43 // incoming 44 // timestamps. 45 uint32_t CurrentTimeStampDiffMs() const; 46 47 private: 48 // Controls if the RTP timestamp counter has had a wrap around 49 // between the current and the previously received frame. 50 // 51 // Input: 52 // - timestmap : RTP timestamp of the current frame. 53 void CheckForWrapArounds(uint32_t timestamp); 54 55 int64_t _zeroWallClock; // Local timestamp of the first video packet received 56 int32_t _wrapArounds; // Number of wrapArounds detected 57 // The previous timestamp passed to the delay estimate 58 uint32_t _prevTimestamp; 59 // The previous wall clock timestamp used by the delay estimate 60 int64_t _prevWallClock; 61 // Wrap-around compensated difference between incoming timestamps 62 int64_t _dTS; 63 }; 64 65 } // namespace webrtc 66 67 #endif // WEBRTC_MODULES_VIDEO_CODING_INTER_FRAME_DELAY_H_ 68