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.
5 #include "media/audio/virtual_audio_input_stream.h"
10 #include "base/bind.h"
11 #include "base/message_loop/message_loop.h"
12 #include "base/message_loop/message_loop_proxy.h"
13 #include "media/audio/virtual_audio_output_stream.h"
17 // LoopbackAudioConverter works similar to AudioConverter and converts input
18 // streams to different audio parameters. Then, the LoopbackAudioConverter can
19 // be used as an input to another AudioConverter. This allows us to
20 // use converted audio from AudioOutputStreams as input to an AudioConverter.
21 // For example, this allows converting multiple streams into a common format and
22 // using the converted audio as input to another AudioConverter (i.e. a mixer).
23 class LoopbackAudioConverter : public AudioConverter::InputCallback {
25 LoopbackAudioConverter(const AudioParameters& input_params,
26 const AudioParameters& output_params)
27 : audio_converter_(input_params, output_params, false) {}
29 virtual ~LoopbackAudioConverter() {}
31 void AddInput(AudioConverter::InputCallback* input) {
32 audio_converter_.AddInput(input);
35 void RemoveInput(AudioConverter::InputCallback* input) {
36 audio_converter_.RemoveInput(input);
40 virtual double ProvideInput(AudioBus* audio_bus,
41 base::TimeDelta buffer_delay) OVERRIDE {
42 audio_converter_.Convert(audio_bus);
46 AudioConverter audio_converter_;
48 DISALLOW_COPY_AND_ASSIGN(LoopbackAudioConverter);
51 VirtualAudioInputStream::VirtualAudioInputStream(
52 const AudioParameters& params,
53 const scoped_refptr<base::MessageLoopProxy>& worker_loop,
54 const AfterCloseCallback& after_close_cb)
55 : worker_loop_(worker_loop),
56 after_close_cb_(after_close_cb),
58 buffer_(new uint8[params.GetBytesPerBuffer()]),
60 mixer_(params_, params_, false),
61 num_attached_output_streams_(0),
62 fake_consumer_(worker_loop_, params_) {
63 DCHECK(params_.IsValid());
64 DCHECK(worker_loop_.get());
66 // VAIS can be constructed on any thread, but will DCHECK that all
67 // AudioInputStream methods are called from the same thread.
68 thread_checker_.DetachFromThread();
71 VirtualAudioInputStream::~VirtualAudioInputStream() {
74 // Sanity-check: Contract for Add/RemoveOutputStream() requires that all
75 // output streams be removed before VirtualAudioInputStream is destroyed.
76 DCHECK_EQ(0, num_attached_output_streams_);
78 for (AudioConvertersMap::iterator it = converters_.begin();
79 it != converters_.end(); ++it) {
84 bool VirtualAudioInputStream::Open() {
85 DCHECK(thread_checker_.CalledOnValidThread());
86 memset(buffer_.get(), 0, params_.GetBytesPerBuffer());
90 void VirtualAudioInputStream::Start(AudioInputCallback* callback) {
91 DCHECK(thread_checker_.CalledOnValidThread());
93 fake_consumer_.Start(base::Bind(
94 &VirtualAudioInputStream::PumpAudio, base::Unretained(this)));
97 void VirtualAudioInputStream::Stop() {
98 DCHECK(thread_checker_.CalledOnValidThread());
99 fake_consumer_.Stop();
102 void VirtualAudioInputStream::AddOutputStream(
103 VirtualAudioOutputStream* stream, const AudioParameters& output_params) {
104 DCHECK(thread_checker_.CalledOnValidThread());
106 base::AutoLock scoped_lock(converter_network_lock_);
108 AudioConvertersMap::iterator converter = converters_.find(output_params);
109 if (converter == converters_.end()) {
110 std::pair<AudioConvertersMap::iterator, bool> result = converters_.insert(
111 std::make_pair(output_params,
112 new LoopbackAudioConverter(output_params, params_)));
113 converter = result.first;
115 // Add to main mixer if we just added a new AudioTransform.
116 mixer_.AddInput(converter->second);
118 converter->second->AddInput(stream);
119 ++num_attached_output_streams_;
122 void VirtualAudioInputStream::RemoveOutputStream(
123 VirtualAudioOutputStream* stream, const AudioParameters& output_params) {
124 DCHECK(thread_checker_.CalledOnValidThread());
126 base::AutoLock scoped_lock(converter_network_lock_);
128 DCHECK(converters_.find(output_params) != converters_.end());
129 converters_[output_params]->RemoveInput(stream);
131 --num_attached_output_streams_;
132 DCHECK_LE(0, num_attached_output_streams_);
135 void VirtualAudioInputStream::PumpAudio(AudioBus* audio_bus) {
136 DCHECK(worker_loop_->BelongsToCurrentThread());
140 base::AutoLock scoped_lock(converter_network_lock_);
141 mixer_.Convert(audio_bus);
143 audio_bus->ToInterleaved(params_.frames_per_buffer(),
144 params_.bits_per_sample() / 8,
146 callback_->OnData(this,
148 params_.GetBytesPerBuffer(),
149 params_.GetBytesPerBuffer(),
153 void VirtualAudioInputStream::Close() {
154 DCHECK(thread_checker_.CalledOnValidThread());
156 Stop(); // Make sure callback_ is no longer being used.
158 callback_->OnClose(this);
162 // If a non-null AfterCloseCallback was provided to the constructor, invoke it
163 // here. The callback is moved to a stack-local first since |this| could be
164 // destroyed during Run().
165 if (!after_close_cb_.is_null()) {
166 const AfterCloseCallback cb = after_close_cb_;
167 after_close_cb_.Reset();
172 double VirtualAudioInputStream::GetMaxVolume() {
176 void VirtualAudioInputStream::SetVolume(double volume) {}
178 double VirtualAudioInputStream::GetVolume() {
182 void VirtualAudioInputStream::SetAutomaticGainControl(bool enabled) {}
184 bool VirtualAudioInputStream::GetAutomaticGainControl() {