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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/time_delta_interpolator.h"
#include <stdint.h>
#include <algorithm>
#include "base/check.h"
#include "base/time/tick_clock.h"
#include "media/base/timestamp_constants.h"
namespace media {
TimeDeltaInterpolator::TimeDeltaInterpolator(const base::TickClock* tick_clock)
: tick_clock_(tick_clock),
interpolating_(false),
upper_bound_(kNoTimestamp),
playback_rate_(0) {
DCHECK(tick_clock_);
}
TimeDeltaInterpolator::~TimeDeltaInterpolator() = default;
base::TimeDelta TimeDeltaInterpolator::StartInterpolating() {
DCHECK(!interpolating_);
reference_ = tick_clock_->NowTicks();
interpolating_ = true;
return lower_bound_;
}
base::TimeDelta TimeDeltaInterpolator::StopInterpolating() {
DCHECK(interpolating_);
lower_bound_ = GetInterpolatedTime();
interpolating_ = false;
return lower_bound_;
}
void TimeDeltaInterpolator::SetPlaybackRate(double playback_rate) {
lower_bound_ = GetInterpolatedTime();
reference_ = tick_clock_->NowTicks();
playback_rate_ = playback_rate;
}
void TimeDeltaInterpolator::SetBounds(base::TimeDelta lower_bound,
base::TimeDelta upper_bound,
base::TimeTicks capture_time) {
DCHECK(lower_bound <= upper_bound);
DCHECK(lower_bound != kNoTimestamp);
lower_bound_ = std::max(base::TimeDelta(), lower_bound);
upper_bound_ = std::max(base::TimeDelta(), upper_bound);
reference_ = capture_time;
}
void TimeDeltaInterpolator::SetUpperBound(base::TimeDelta upper_bound) {
DCHECK(upper_bound != kNoTimestamp);
lower_bound_ = GetInterpolatedTime();
reference_ = tick_clock_->NowTicks();
upper_bound_ = upper_bound;
}
base::TimeDelta TimeDeltaInterpolator::GetInterpolatedTime() {
if (!interpolating_)
return lower_bound_;
int64_t now_us = (tick_clock_->NowTicks() - reference_).InMicroseconds();
now_us = static_cast<int64_t>(now_us * playback_rate_);
base::TimeDelta interpolated_time = lower_bound_ + base::Microseconds(now_us);
if (upper_bound_ == kNoTimestamp)
return interpolated_time;
return std::min(interpolated_time, upper_bound_);
}
} // namespace media
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