9c6a0c7f6d
adding 30% drift to media generator (e.g. audio frame generated every 7ms instead of promised 10ms) works fine adding 2% drift to video ntp-timestamp-stamper makes A/V sync fail. BUG=webrtc:5504 R=pbos@webrtc.org,stefan@webrtc.org Review URL: https://codereview.webrtc.org/1674413004 Cr-Commit-Position: refs/heads/master@{#11556}
58 lines
1.9 KiB
C++
58 lines
1.9 KiB
C++
/*
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* Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "webrtc/test/drifting_clock.h"
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#include "webrtc/base/checks.h"
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namespace webrtc {
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namespace test {
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const float DriftingClock::kDoubleSpeed = 2.0f;
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const float DriftingClock::kNoDrift = 1.0f;
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const float DriftingClock::kHalfSpeed = 0.5f;
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DriftingClock::DriftingClock(Clock* clock, float speed)
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: clock_(clock),
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drift_(speed - 1.0f),
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start_time_(clock_->TimeInMicroseconds()) {
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RTC_CHECK(clock);
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RTC_CHECK_GT(speed, 0.0f);
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}
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float DriftingClock::Drift() const {
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int64_t now = clock_->TimeInMicroseconds();
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RTC_DCHECK_GE(now, start_time_);
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return (now - start_time_) * drift_;
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}
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int64_t DriftingClock::TimeInMilliseconds() const {
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return clock_->TimeInMilliseconds() + Drift() / 1000.;
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}
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int64_t DriftingClock::TimeInMicroseconds() const {
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return clock_->TimeInMicroseconds() + Drift();
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}
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void DriftingClock::CurrentNtp(uint32_t& seconds, uint32_t& fractions) const {
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// NTP precision is 1/2^32 seconds, i.e. 2^32 ntp fractions = 1 second.
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const double kNtpFracPerMicroSecond = 4294.967296; // = 2^32 / 10^6
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clock_->CurrentNtp(seconds, fractions);
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uint64_t total_fractions = (static_cast<uint64_t>(seconds) << 32) | fractions;
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total_fractions += Drift() * kNtpFracPerMicroSecond;
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seconds = total_fractions >> 32;
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fractions = static_cast<uint32_t>(total_fractions);
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}
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int64_t DriftingClock::CurrentNtpInMilliseconds() const {
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return clock_->CurrentNtpInMilliseconds() + Drift() / 1000.;
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}
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} // namespace test
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} // namespace webrtc
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