blob: aea174c1114d96d35bcb29543a2ff66b8b0b2adb (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
|
// 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/logging.h"
#include "base/time/tick_clock.h"
#include "media/base/timestamp_constants.h"
namespace media {
TimeDeltaInterpolator::TimeDeltaInterpolator(base::TickClock* tick_clock)
: tick_clock_(tick_clock),
interpolating_(false),
upper_bound_(kNoTimestamp()),
playback_rate_(1.0) {
DCHECK(tick_clock_);
}
TimeDeltaInterpolator::~TimeDeltaInterpolator() {
}
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) {
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_ = tick_clock_->NowTicks();
}
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::TimeDelta::FromMicroseconds(now_us);
if (upper_bound_ == kNoTimestamp())
return interpolated_time;
return std::min(interpolated_time, upper_bound_);
}
} // namespace media
|
