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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "media/base/wall_clock_time_source.h"
#include "base/logging.h"
namespace media {
WallClockTimeSource::WallClockTimeSource()
: tick_clock_(&default_tick_clock_), ticking_(false), playback_rate_(1.0) {
}
WallClockTimeSource::~WallClockTimeSource() {
}
void WallClockTimeSource::StartTicking() {
DVLOG(1) << __FUNCTION__;
base::AutoLock auto_lock(lock_);
DCHECK(!ticking_);
ticking_ = true;
reference_time_ = tick_clock_->NowTicks();
}
void WallClockTimeSource::StopTicking() {
DVLOG(1) << __FUNCTION__;
base::AutoLock auto_lock(lock_);
DCHECK(ticking_);
base_timestamp_ = CurrentMediaTime_Locked();
ticking_ = false;
reference_time_ = tick_clock_->NowTicks();
}
void WallClockTimeSource::SetPlaybackRate(double playback_rate) {
DVLOG(1) << __FUNCTION__ << "(" << playback_rate << ")";
base::AutoLock auto_lock(lock_);
// Estimate current media time using old rate to use as a new base time for
// the new rate.
if (ticking_) {
base_timestamp_ = CurrentMediaTime_Locked();
reference_time_ = tick_clock_->NowTicks();
}
playback_rate_ = playback_rate;
}
void WallClockTimeSource::SetMediaTime(base::TimeDelta time) {
DVLOG(1) << __FUNCTION__ << "(" << time.InMicroseconds() << ")";
base::AutoLock auto_lock(lock_);
CHECK(!ticking_);
base_timestamp_ = time;
}
base::TimeDelta WallClockTimeSource::CurrentMediaTime() {
base::AutoLock auto_lock(lock_);
return CurrentMediaTime_Locked();
}
bool WallClockTimeSource::GetWallClockTimes(
const std::vector<base::TimeDelta>& media_timestamps,
std::vector<base::TimeTicks>* wall_clock_times) {
base::AutoLock auto_lock(lock_);
DCHECK(wall_clock_times->empty());
if (media_timestamps.empty()) {
wall_clock_times->push_back(reference_time_);
} else {
// When playback is paused (rate is zero), assume a rate of 1.0.
const double playback_rate = playback_rate_ ? playback_rate_ : 1.0;
wall_clock_times->reserve(media_timestamps.size());
for (const auto& media_timestamp : media_timestamps) {
wall_clock_times->push_back(reference_time_ +
(media_timestamp - base_timestamp_) /
playback_rate);
}
}
return playback_rate_ && ticking_;
}
base::TimeDelta WallClockTimeSource::CurrentMediaTime_Locked() {
lock_.AssertAcquired();
if (!ticking_ || !playback_rate_)
return base_timestamp_;
base::TimeTicks now = tick_clock_->NowTicks();
return base_timestamp_ +
base::TimeDelta::FromMicroseconds(
(now - reference_time_).InMicroseconds() * playback_rate_);
}
} // namespace media
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