mirror of
https://github.com/mollyim/webrtc.git
synced 2025-05-13 05:40:42 +01:00
92ea95e34a
In https://webrtc-review.googlesource.com/c/src/+/1560 we moved WebRTC from src/webrtc to src/ (in order to preserve an healthy git history). This CL takes care of fixing header guards, #include paths, etc... NOPRESUBMIT=true NOTREECHECKS=true NOTRY=true TBR=tommi@webrtc.org Bug: chromium:611808 Change-Id: Iea91618212bee0af16aa3f05071eab8f93706578 Reviewed-on: https://webrtc-review.googlesource.com/1561 Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org> Reviewed-by: Henrik Kjellander <kjellander@webrtc.org> Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org> Cr-Commit-Position: refs/heads/master@{#19846}
107 lines
3.5 KiB
C++
107 lines
3.5 KiB
C++
/*
|
|
* Copyright (c) 2011 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 "modules/video_coding/inter_frame_delay.h"
|
|
|
|
namespace webrtc {
|
|
|
|
VCMInterFrameDelay::VCMInterFrameDelay(int64_t currentWallClock) {
|
|
Reset(currentWallClock);
|
|
}
|
|
|
|
// Resets the delay estimate
|
|
void VCMInterFrameDelay::Reset(int64_t currentWallClock) {
|
|
_zeroWallClock = currentWallClock;
|
|
_wrapArounds = 0;
|
|
_prevWallClock = 0;
|
|
_prevTimestamp = 0;
|
|
_dTS = 0;
|
|
}
|
|
|
|
// Calculates the delay of a frame with the given timestamp.
|
|
// This method is called when the frame is complete.
|
|
bool VCMInterFrameDelay::CalculateDelay(uint32_t timestamp,
|
|
int64_t* delay,
|
|
int64_t currentWallClock) {
|
|
if (_prevWallClock == 0) {
|
|
// First set of data, initialization, wait for next frame
|
|
_prevWallClock = currentWallClock;
|
|
_prevTimestamp = timestamp;
|
|
*delay = 0;
|
|
return true;
|
|
}
|
|
|
|
int32_t prevWrapArounds = _wrapArounds;
|
|
CheckForWrapArounds(timestamp);
|
|
|
|
// This will be -1 for backward wrap arounds and +1 for forward wrap arounds
|
|
int32_t wrapAroundsSincePrev = _wrapArounds - prevWrapArounds;
|
|
|
|
// Account for reordering in jitter variance estimate in the future?
|
|
// Note that this also captures incomplete frames which are grabbed
|
|
// for decoding after a later frame has been complete, i.e. real
|
|
// packet losses.
|
|
if ((wrapAroundsSincePrev == 0 && timestamp < _prevTimestamp) ||
|
|
wrapAroundsSincePrev < 0) {
|
|
*delay = 0;
|
|
return false;
|
|
}
|
|
|
|
// Compute the compensated timestamp difference and convert it to ms and
|
|
// round it to closest integer.
|
|
_dTS = static_cast<int64_t>(
|
|
(timestamp + wrapAroundsSincePrev * (static_cast<int64_t>(1) << 32) -
|
|
_prevTimestamp) /
|
|
90.0 +
|
|
0.5);
|
|
|
|
// frameDelay is the difference of dT and dTS -- i.e. the difference of
|
|
// the wall clock time difference and the timestamp difference between
|
|
// two following frames.
|
|
*delay = static_cast<int64_t>(currentWallClock - _prevWallClock - _dTS);
|
|
|
|
_prevTimestamp = timestamp;
|
|
_prevWallClock = currentWallClock;
|
|
|
|
return true;
|
|
}
|
|
|
|
// Returns the current difference between incoming timestamps
|
|
uint32_t VCMInterFrameDelay::CurrentTimeStampDiffMs() const {
|
|
if (_dTS < 0) {
|
|
return 0;
|
|
}
|
|
return static_cast<uint32_t>(_dTS);
|
|
}
|
|
|
|
// Investigates if the timestamp clock has overflowed since the last timestamp
|
|
// and
|
|
// keeps track of the number of wrap arounds since reset.
|
|
void VCMInterFrameDelay::CheckForWrapArounds(uint32_t timestamp) {
|
|
if (timestamp < _prevTimestamp) {
|
|
// This difference will probably be less than -2^31 if we have had a wrap
|
|
// around
|
|
// (e.g. timestamp = 1, _previousTimestamp = 2^32 - 1). Since it is cast to
|
|
// a Word32,
|
|
// it should be positive.
|
|
if (static_cast<int32_t>(timestamp - _prevTimestamp) > 0) {
|
|
// Forward wrap around
|
|
_wrapArounds++;
|
|
}
|
|
// This difference will probably be less than -2^31 if we have had a
|
|
// backward
|
|
// wrap around.
|
|
// Since it is cast to a Word32, it should be positive.
|
|
} else if (static_cast<int32_t>(_prevTimestamp - timestamp) > 0) {
|
|
// Backward wrap around
|
|
_wrapArounds--;
|
|
}
|
|
}
|
|
} // namespace webrtc
|