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
11 namespace media {
12
13 enum { kPauseDelaySeconds = 10 };
14
AudioRendererMixer(const AudioParameters & input_params,const AudioParameters & output_params,const scoped_refptr<AudioRendererSink> & sink)15 AudioRendererMixer::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
~AudioRendererMixer()28 AudioRendererMixer::~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
AddMixerInput(AudioConverter::InputCallback * input,const base::Closure & error_cb)37 void 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
RemoveMixerInput(AudioConverter::InputCallback * input)52 void 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
Render(AudioBus * audio_bus,int audio_delay_milliseconds)61 int 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
OnRenderError()81 void 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