1// Copyright (c) 2012 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/audio_renderer_mixer.h"
6
7#include "base/bind.h"
8#include "base/bind_helpers.h"
9#include "base/logging.h"
10
11namespace media {
12
13enum { kPauseDelaySeconds = 10 };
14
15AudioRendererMixer::AudioRendererMixer(
16    const AudioParameters& input_params, const AudioParameters& output_params,
17    const scoped_refptr<AudioRendererSink>& sink)
18    : audio_sink_(sink),
19      audio_converter_(input_params, output_params, true),
20      pause_delay_(base::TimeDelta::FromSeconds(kPauseDelaySeconds)),
21      last_play_time_(base::TimeTicks::Now()),
22      // Initialize |playing_| to true since Start() results in an auto-play.
23      playing_(true) {
24  audio_sink_->Initialize(output_params, this);
25  audio_sink_->Start();
26}
27
28AudioRendererMixer::~AudioRendererMixer() {
29  // AudioRendererSinks must be stopped before being destructed.
30  audio_sink_->Stop();
31
32  // Ensures that all mixer inputs have stopped themselves prior to destruction
33  // and have called RemoveMixerInput().
34  DCHECK_EQ(mixer_inputs_.size(), 0U);
35}
36
37void AudioRendererMixer::AddMixerInput(AudioConverter::InputCallback* input,
38                                       const base::Closure& error_cb) {
39  base::AutoLock auto_lock(mixer_inputs_lock_);
40
41  if (!playing_) {
42    playing_ = true;
43    last_play_time_ = base::TimeTicks::Now();
44    audio_sink_->Play();
45  }
46
47  DCHECK(mixer_inputs_.find(input) == mixer_inputs_.end());
48  mixer_inputs_[input] = error_cb;
49  audio_converter_.AddInput(input);
50}
51
52void AudioRendererMixer::RemoveMixerInput(
53    AudioConverter::InputCallback* input) {
54  base::AutoLock auto_lock(mixer_inputs_lock_);
55  audio_converter_.RemoveInput(input);
56
57  DCHECK(mixer_inputs_.find(input) != mixer_inputs_.end());
58  mixer_inputs_.erase(input);
59}
60
61int AudioRendererMixer::Render(AudioBus* audio_bus,
62                               int audio_delay_milliseconds) {
63  base::AutoLock auto_lock(mixer_inputs_lock_);
64
65  // If there are no mixer inputs and we haven't seen one for a while, pause the
66  // sink to avoid wasting resources when media elements are present but remain
67  // in the pause state.
68  const base::TimeTicks now = base::TimeTicks::Now();
69  if (!mixer_inputs_.empty()) {
70    last_play_time_ = now;
71  } else if (now - last_play_time_ >= pause_delay_ && playing_) {
72    audio_sink_->Pause();
73    playing_ = false;
74  }
75
76  audio_converter_.ConvertWithDelay(
77      base::TimeDelta::FromMilliseconds(audio_delay_milliseconds), audio_bus);
78  return audio_bus->frames();
79}
80
81void AudioRendererMixer::OnRenderError() {
82  base::AutoLock auto_lock(mixer_inputs_lock_);
83
84  // Call each mixer input and signal an error.
85  for (AudioRendererMixerInputSet::iterator it = mixer_inputs_.begin();
86       it != mixer_inputs_.end(); ++it) {
87    it->second.Run();
88  }
89}
90
91}  // namespace media
92