Volume button now controls media volume for WebAudio.

Today, WebAudio uses the OpenSL ES low-latency audio backend in media/audio but the stream type is always communication mode (which is OK for WebRTC but not for WebAudio).

This patch ensures that:

- Only switch to system-wide Communication mode when a low-latency input stream is created (e.g. from getUserMedia).
- Opens the native output stream in Media mode if system mode is Media and in Communication mode if system mode is Communication.

To summarize: an application which renders WebAudio audio should now be able to see the default media volume icon and change the volume accordingly.

TEST=http://chromium.googlecode.com/svn/trunk/samples/audio/shiny-drum-machine.html
BUG=342114

Review URL: https://codereview.chromium.org/173503003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252341 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 36 insertions, 28 deletions

diff --git a/media/audio/android/audio_manager_android.cc b/media/audio/android/audio_manager_android.cc
index a8d81c7..273a741 100644
--- a/media/audio/android/audio_manager_android.cc
+++ b/media/audio/android/audio_manager_android.cc
@@ -45,7 +45,8 @@ AudioManager* CreateAudioManager(AudioLogFactory* audio_log_factory) {
 }
 
 AudioManagerAndroid::AudioManagerAndroid(AudioLogFactory* audio_log_factory)
-    : AudioManagerBase(audio_log_factory) {
+    : AudioManagerBase(audio_log_factory),
+      communication_mode_is_on_(false) {
   SetMaxOutputStreamsAllowed(kMaxOutputStreams);
 
   j_audio_manager_.Reset(
@@ -123,17 +124,8 @@ AudioParameters AudioManagerAndroid::GetInputStreamParameters(
 AudioOutputStream* AudioManagerAndroid::MakeAudioOutputStream(
     const AudioParameters& params,
     const std::string& device_id) {
-  bool had_no_streams = HadNoAudioStreams();
   AudioOutputStream* stream =
       AudioManagerBase::MakeAudioOutputStream(params, std::string());
-
-  // The audio manager for Android creates streams intended for real-time
-  // VoIP sessions and therefore sets the audio mode to MODE_IN_COMMUNICATION.
-  // If a Bluetooth headset is used, the audio stream will use the SCO
-  // channel and therefore have a limited bandwidth (8-16kHz).
-  if (stream && had_no_streams)
-    SetCommunicationAudioModeOn(true);
-
   {
     base::AutoLock lock(streams_lock_);
     streams_.insert(static_cast<OpenSLESOutputStream*>(stream));
@@ -144,7 +136,7 @@ AudioOutputStream* AudioManagerAndroid::MakeAudioOutputStream(
 
 AudioInputStream* AudioManagerAndroid::MakeAudioInputStream(
     const AudioParameters& params, const std::string& device_id) {
-  bool had_no_streams = HadNoAudioStreams();
+  bool has_no_input_streams = HasNoAudioInputStreams();
   AudioInputStream* stream =
       AudioManagerBase::MakeAudioInputStream(params, device_id);
 
@@ -152,18 +144,15 @@ AudioInputStream* AudioManagerAndroid::MakeAudioInputStream(
   // VoIP sessions and therefore sets the audio mode to MODE_IN_COMMUNICATION.
   // If a Bluetooth headset is used, the audio stream will use the SCO
   // channel and therefore have a limited bandwidth (8kHz).
-  if (stream && had_no_streams)
+  if (stream && has_no_input_streams) {
+    communication_mode_is_on_ = true;
     SetCommunicationAudioModeOn(true);
+  }
   return stream;
 }
 
 void AudioManagerAndroid::ReleaseOutputStream(AudioOutputStream* stream) {
   AudioManagerBase::ReleaseOutputStream(stream);
-
-  // Restore the audio mode which was used before the first communication-
-  // mode stream was created.
-  if (HadNoAudioStreams())
-    SetCommunicationAudioModeOn(false);
   base::AutoLock lock(streams_lock_);
   streams_.erase(static_cast<OpenSLESOutputStream*>(stream));
 }
@@ -173,14 +162,16 @@ void AudioManagerAndroid::ReleaseInputStream(AudioInputStream* stream) {
 
   // Restore the audio mode which was used before the first communication-
   // mode stream was created.
-  if (HadNoAudioStreams())
+  if (HasNoAudioInputStreams()) {
+    communication_mode_is_on_ = false;
     SetCommunicationAudioModeOn(false);
+  }
 }
 
 AudioOutputStream* AudioManagerAndroid::MakeLinearOutputStream(
     const AudioParameters& params) {
   DCHECK_EQ(AudioParameters::AUDIO_PCM_LINEAR, params.format());
-  return new OpenSLESOutputStream(this, params);
+  return new OpenSLESOutputStream(this, params, SL_ANDROID_STREAM_MEDIA);
 }
 
 AudioOutputStream* AudioManagerAndroid::MakeLowLatencyOutputStream(
@@ -188,7 +179,12 @@ AudioOutputStream* AudioManagerAndroid::MakeLowLatencyOutputStream(
     const std::string& device_id) {
   DLOG_IF(ERROR, !device_id.empty()) << "Not implemented!";
   DCHECK_EQ(AudioParameters::AUDIO_PCM_LOW_LATENCY, params.format());
-  return new OpenSLESOutputStream(this, params);
+
+  // Set stream type which matches the current system-wide audio mode used by
+  // the Android audio manager.
+  const SLint32 stream_type = communication_mode_is_on_ ?
+      SL_ANDROID_STREAM_VOICE : SL_ANDROID_STREAM_MEDIA;
+  return new OpenSLESOutputStream(this, params, stream_type);
 }
 
 AudioInputStream* AudioManagerAndroid::MakeLinearInputStream(
@@ -270,8 +266,8 @@ AudioParameters AudioManagerAndroid::GetPreferredOutputStreamParameters(
       sample_rate, bits_per_sample, buffer_size, AudioParameters::NO_EFFECTS);
 }
 
-bool AudioManagerAndroid::HadNoAudioStreams() {
-  return output_stream_count() == 0 && input_stream_count() == 0;
+bool AudioManagerAndroid::HasNoAudioInputStreams() {
+  return input_stream_count() == 0;
 }
 
 // static
diff --git a/media/audio/android/audio_manager_android.h b/media/audio/android/audio_manager_android.h
index ac67d08..b65e593 100644
--- a/media/audio/android/audio_manager_android.h
+++ b/media/audio/android/audio_manager_android.h
@@ -65,7 +65,7 @@ class MEDIA_EXPORT AudioManagerAndroid : public AudioManagerBase {
       const AudioParameters& input_params) OVERRIDE;
 
  private:
-  bool HadNoAudioStreams();
+  bool HasNoAudioInputStreams();
   void Init();
   void Close();
   void SetCommunicationAudioModeOn(bool on);
@@ -90,6 +90,10 @@ class MEDIA_EXPORT AudioManagerAndroid : public AudioManagerBase {
   // lock is used to guard access to |streams_|.
   base::Lock streams_lock_;
 
+  // Enabled when first input stream is created and set to false when last
+  // input stream is destroyed. Also affects the stream type of output streams.
+  bool communication_mode_is_on_;
+
   DISALLOW_COPY_AND_ASSIGN(AudioManagerAndroid);
 };
 
diff --git a/media/audio/android/opensles_output.cc b/media/audio/android/opensles_output.cc
index b71680f..41c03c7 100644
--- a/media/audio/android/opensles_output.cc
+++ b/media/audio/android/opensles_output.cc
@@ -20,8 +20,10 @@
 namespace media {
 
 OpenSLESOutputStream::OpenSLESOutputStream(AudioManagerAndroid* manager,
-                                           const AudioParameters& params)
+                                           const AudioParameters& params,
+                                           SLint32 stream_type)
     : audio_manager_(manager),
+      stream_type_(stream_type),
       callback_(NULL),
       player_(NULL),
       simple_buffer_queue_(NULL),
@@ -30,7 +32,8 @@ OpenSLESOutputStream::OpenSLESOutputStream(AudioManagerAndroid* manager,
       started_(false),
       muted_(false),
       volume_(1.0) {
-  DVLOG(2) << "OpenSLESOutputStream::OpenSLESOutputStream()";
+  DVLOG(2) << "OpenSLESOutputStream::OpenSLESOutputStream("
+           << "stream_type=" << stream_type << ")";
   format_.formatType = SL_DATAFORMAT_PCM;
   format_.numChannels = static_cast<SLuint32>(params.channels());
   // Provides sampling rate in milliHertz to OpenSLES.
@@ -248,11 +251,11 @@ bool OpenSLESOutputStream::CreatePlayer() {
           player_object_.Get(), SL_IID_ANDROIDCONFIGURATION, &player_config),
       false);
 
-  SLint32 stream_type = SL_ANDROID_STREAM_VOICE;
+  // Set configuration using the stream type provided at construction.
   LOG_ON_FAILURE_AND_RETURN(
       (*player_config)->SetConfiguration(player_config,
                                          SL_ANDROID_KEY_STREAM_TYPE,
-                                         &stream_type,
+                                         &stream_type_,
                                          sizeof(SLint32)),
       false);
 
diff --git a/media/audio/android/opensles_output.h b/media/audio/android/opensles_output.h
index 623b019..b0b678c 100644
--- a/media/audio/android/opensles_output.h
+++ b/media/audio/android/opensles_output.h
@@ -28,7 +28,8 @@ class OpenSLESOutputStream : public AudioOutputStream {
   static const int kMaxNumOfBuffersInQueue = 2;
 
   OpenSLESOutputStream(AudioManagerAndroid* manager,
-                       const AudioParameters& params);
+                       const AudioParameters& params,
+                       SLint32 stream_type);
 
   virtual ~OpenSLESOutputStream();
 
@@ -77,6 +78,10 @@ class OpenSLESOutputStream : public AudioOutputStream {
 
   AudioManagerAndroid* audio_manager_;
 
+  // Audio playback stream type.
+  // See SLES/OpenSLES_Android.h for details.
+  SLint32 stream_type_;
+
   AudioSourceCallback* callback_;
 
   // Shared engine interfaces for the app.