Add Mac OS X synchronized audio I/O back-end

media/audio/mac/audio_manager_mac.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <CoreAudio/AudioHardware.h>
 
 #include <string>
 
+#include "base/command_line.h"
 #include "base/mac/mac_logging.h"
 #include "base/mac/scoped_cftyperef.h"
 #include "base/sys_string_conversions.h"
 #include "media/audio/mac/audio_input_mac.h"
 #include "media/audio/mac/audio_low_latency_input_mac.h"
 #include "media/audio/mac/audio_low_latency_output_mac.h"
 #include "media/audio/mac/audio_manager_mac.h"
 #include "media/audio/mac/audio_output_mac.h"
+#include "media/audio/mac/audio_synchronized_mac.h"
+#include "media/audio/mac/audio_unified_mac.h"
 #include "media/base/limits.h"
+#include "media/base/media_switches.h"
 
 namespace media {
 
 // Maximum number of output streams that can be open simultaneously.
 static const int kMaxOutputStreams = 50;
 
 static bool HasAudioHardware(AudioObjectPropertySelector selector) {
   AudioDeviceID output_device_id = kAudioObjectUnknown;
   const AudioObjectPropertyAddress property_address = {
     selector,
     kAudioObjectPropertyScopeGlobal,            // mScope
     kAudioObjectPropertyElementMaster           // mElement
   };
   size_t output_device_id_size = sizeof(output_device_id);
   OSStatus err = AudioObjectGetPropertyData(kAudioObjectSystemObject,
                                             &property_address,
                                             0,     // inQualifierDataSize
                                             NULL,  // inQualifierData
                                             &output_device_id_size,
                                             &output_device_id);
   return err == kAudioHardwareNoError &&
       output_device_id != kAudioObjectUnknown;
 }
 
+// Returns if the default input device is the same as the default output.

[scherkus (not reviewing), 2012/09/17 23:07:17]

Returns... true? :)

[Chris Rogers, 2012/09/18 00:22:36]

Done.

+static bool HasUnifiedDefaultIO() {
+  AudioDeviceID input_id, output_id;
+
+  AudioObjectPropertyAddress pa;
+  pa.mSelector = kAudioHardwarePropertyDefaultInputDevice;
+  pa.mScope = kAudioObjectPropertyScopeGlobal;
+  pa.mElement = kAudioObjectPropertyElementMaster;
+  UInt32 size = sizeof(input_id);
+
+  // Get the default input.
+  OSStatus result = AudioObjectGetPropertyData(
+      kAudioObjectSystemObject,
+      &pa,
+      0,
+      0,
+      &size,
+      &input_id);
+
+  if (result != noErr)
+    return false;
+
+  // Get the default output.
+  pa.mSelector = kAudioHardwarePropertyDefaultOutputDevice;
+  result = AudioObjectGetPropertyData(
+      kAudioObjectSystemObject,
+      &pa,
+      0,
+      0,
+      &size,
+      &output_id);
+
+  if (result != noErr)
+    return false;
+
+  return input_id == output_id;
+}
+
 static void GetAudioDeviceInfo(bool is_input,
                                media::AudioDeviceNames* device_names) {
   DCHECK(device_names);
   device_names->clear();
 
   // Query the number of total devices.
   AudioObjectPropertyAddress property_address = {
     kAudioHardwarePropertyDevices,
     kAudioObjectPropertyScopeGlobal,
     kAudioObjectPropertyElementMaster
@@ skipping 191 matching lines @@
 
 AudioOutputStream* AudioManagerMac::MakeLinearOutputStream(
     const AudioParameters& params) {
   DCHECK_EQ(AudioParameters::AUDIO_PCM_LINEAR, params.format());
   return new PCMQueueOutAudioOutputStream(this, params);
 }
 
 AudioOutputStream* AudioManagerMac::MakeLowLatencyOutputStream(
     const AudioParameters& params) {
   DCHECK_EQ(AudioParameters::AUDIO_PCM_LOW_LATENCY, params.format());
+
+  // TODO(crogers): remove once we properly handle input device selection.
+  if (CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kEnableWebAudioInput)) {
+    if (HasUnifiedDefaultIO()) {
+      return new AudioHardwareUnifiedStream(this, params);
+    } else {

[scherkus (not reviewing), 2012/09/17 23:07:17]

nit: no need for else due to early return

[Chris Rogers, 2012/09/18 00:22:36]

Done.

+      // kAudioDeviceUnknown translates to "use default" here.
+      return new AudioSynchronizedStream(this,
+                                         params,
+                                         kAudioDeviceUnknown,
+                                         kAudioDeviceUnknown);
+    }
+  }
+
   return new AUAudioOutputStream(this, params);
 }
 
 AudioInputStream* AudioManagerMac::MakeLinearInputStream(
     const AudioParameters& params, const std::string& device_id) {
   DCHECK_EQ(AudioParameters::AUDIO_PCM_LINEAR, params.format());
   return new PCMQueueInAudioInputStream(this, params);
 }
 
 AudioInputStream* AudioManagerMac::MakeLowLatencyInputStream(
     const AudioParameters& params, const std::string& device_id) {
   DCHECK_EQ(AudioParameters::AUDIO_PCM_LOW_LATENCY, params.format());
   // Gets the AudioDeviceID that refers to the AudioOutputDevice with the device
   // unique id. This AudioDeviceID is used to set the device for Audio Unit.
   AudioDeviceID audio_device_id = GetAudioDeviceIdByUId(true, device_id);
   AudioInputStream* stream = NULL;
   if (audio_device_id != kAudioObjectUnknown)
     stream = new AUAudioInputStream(this, params, audio_device_id);
 
   return stream;
 }
 
 AudioManager* CreateAudioManager() {
   return new AudioManagerMac();
 }
 
 }  // namespace media