1// Copyright 2014 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "media/base/wall_clock_time_source.h"
6
7#include "base/logging.h"
8#include "base/time/default_tick_clock.h"
9
10namespace media {
11
12WallClockTimeSource::WallClockTimeSource()
13    : tick_clock_(new base::DefaultTickClock()),
14      ticking_(false),
15      playback_rate_(1.0f) {
16}
17
18WallClockTimeSource::~WallClockTimeSource() {
19}
20
21void WallClockTimeSource::StartTicking() {
22  DVLOG(1) << __FUNCTION__;
23  base::AutoLock auto_lock(lock_);
24  DCHECK(!ticking_);
25  ticking_ = true;
26  reference_wall_ticks_ = tick_clock_->NowTicks();
27}
28
29void WallClockTimeSource::StopTicking() {
30  DVLOG(1) << __FUNCTION__;
31  base::AutoLock auto_lock(lock_);
32  DCHECK(ticking_);
33  base_time_ = CurrentMediaTime_Locked();
34  ticking_ = false;
35  reference_wall_ticks_ = tick_clock_->NowTicks();
36}
37
38void WallClockTimeSource::SetPlaybackRate(float playback_rate) {
39  DVLOG(1) << __FUNCTION__ << "(" << playback_rate << ")";
40  base::AutoLock auto_lock(lock_);
41  // Estimate current media time using old rate to use as a new base time for
42  // the new rate.
43  if (ticking_) {
44    base_time_ = CurrentMediaTime_Locked();
45    reference_wall_ticks_ = tick_clock_->NowTicks();
46  }
47
48  playback_rate_ = playback_rate;
49}
50
51void WallClockTimeSource::SetMediaTime(base::TimeDelta time) {
52  DVLOG(1) << __FUNCTION__ << "(" << time.InMicroseconds() << ")";
53  base::AutoLock auto_lock(lock_);
54  CHECK(!ticking_);
55  base_time_ = time;
56}
57
58base::TimeDelta WallClockTimeSource::CurrentMediaTime() {
59  base::AutoLock auto_lock(lock_);
60  return CurrentMediaTime_Locked();
61}
62
63base::TimeDelta WallClockTimeSource::CurrentMediaTimeForSyncingVideo() {
64  return CurrentMediaTime();
65}
66
67void WallClockTimeSource::SetTickClockForTesting(
68    scoped_ptr<base::TickClock> tick_clock) {
69  tick_clock_.swap(tick_clock);
70}
71
72base::TimeDelta WallClockTimeSource::CurrentMediaTime_Locked() {
73  lock_.AssertAcquired();
74  if (!ticking_)
75    return base_time_;
76
77  base::TimeTicks now = tick_clock_->NowTicks();
78  return base_time_ +
79         base::TimeDelta::FromMicroseconds(
80             (now - reference_wall_ticks_).InMicroseconds() * playback_rate_);
81}
82
83}  // namespace media
84