[ae/ca] - add support for fetching the stereo channel layout of a device

4 files changed, 55 insertions, 0 deletions

diff --git a/xbmc/cores/AudioEngine/Sinks/osx/CoreAudioChannelLayout.cpp b/xbmc/cores/AudioEngine/Sinks/osx/CoreAudioChannelLayout.cpp
index 05645c28b4..6ca5df4770 100644
--- a/xbmc/cores/AudioEngine/Sinks/osx/CoreAudioChannelLayout.cpp
+++ b/xbmc/cores/AudioEngine/Sinks/osx/CoreAudioChannelLayout.cpp
@@ -105,6 +105,34 @@ bool CCoreAudioChannelLayout::CopyLayout(AudioChannelLayout& layout)
   return (ret == noErr);
 }
 
+bool CCoreAudioChannelLayout::CopyLayoutForStereo(UInt32 layout[2])
+{
+  enum {
+    kVariableLengthArray_deprecated = 1
+  };
+  
+  free(m_pLayout);
+  m_pLayout = NULL;
+  
+  UInt32 channels = 2;
+  UInt32 size = sizeof(AudioChannelLayout) + (channels - kVariableLengthArray_deprecated) * sizeof(AudioChannelDescription);
+  
+  m_pLayout = (AudioChannelLayout*)malloc(size);
+  m_pLayout->mChannelLayoutTag = kAudioChannelLayoutTag_UseChannelDescriptions;
+  m_pLayout->mNumberChannelDescriptions = 2;//stereo
+
+  AudioChannelDescription desc;
+  desc.mChannelFlags = kAudioChannelFlags_AllOff;
+  memset(desc.mCoordinates, 0, sizeof(desc.mCoordinates));
+
+  desc.mChannelLabel = layout[0];// label for channel 1
+  m_pLayout->mChannelDescriptions[0] = desc;
+
+  desc.mChannelLabel = layout[1];// label for channel 2
+  m_pLayout->mChannelDescriptions[1] = desc;
+  return true;
+}
+
 UInt32 CCoreAudioChannelLayout::GetChannelCountForLayout(AudioChannelLayout& layout)
 {
   UInt32 channels = 0;
diff --git a/xbmc/cores/AudioEngine/Sinks/osx/CoreAudioChannelLayout.h b/xbmc/cores/AudioEngine/Sinks/osx/CoreAudioChannelLayout.h
index cf95c83666..64721c9d4c 100644
--- a/xbmc/cores/AudioEngine/Sinks/osx/CoreAudioChannelLayout.h
+++ b/xbmc/cores/AudioEngine/Sinks/osx/CoreAudioChannelLayout.h
@@ -79,6 +79,7 @@ public:
   operator AudioChannelLayout*() {return m_pLayout;}
 
   bool                CopyLayout(AudioChannelLayout &layout);
+  bool                CopyLayoutForStereo(UInt32 layout[2]);
   static UInt32       GetChannelCountForLayout(AudioChannelLayout &layout);
   static const char*  ChannelLabelToString(UInt32 label);
   static const char*  ChannelLayoutToString(AudioChannelLayout &layout, std::string &str);
diff --git a/xbmc/cores/AudioEngine/Sinks/osx/CoreAudioDevice.cpp b/xbmc/cores/AudioEngine/Sinks/osx/CoreAudioDevice.cpp
index 20b8728996..2fe3bb9b5c 100644
--- a/xbmc/cores/AudioEngine/Sinks/osx/CoreAudioDevice.cpp
+++ b/xbmc/cores/AudioEngine/Sinks/osx/CoreAudioDevice.cpp
@@ -547,6 +547,31 @@ bool CCoreAudioDevice::GetPreferredChannelLayout(CCoreAudioChannelLayout& layout
   return (ret == noErr);
 }
 
+bool CCoreAudioDevice::GetPreferredChannelLayoutForStereo(CCoreAudioChannelLayout &layout)
+{
+  if (!m_DeviceId)
+    return false;
+  
+  AudioObjectPropertyAddress  propertyAddress;
+  propertyAddress.mScope    = kAudioDevicePropertyScopeOutput;
+  propertyAddress.mElement  = 0;
+  propertyAddress.mSelector = kAudioDevicePropertyPreferredChannelsForStereo;
+
+  UInt32 channels[2];// this will receive the channel labels
+  UInt32 propertySize = sizeof(channels);
+
+  OSStatus ret = AudioObjectGetPropertyData(m_DeviceId, &propertyAddress, 0, NULL, &propertySize, &channels);
+  if (ret != noErr)
+    CLog::Log(LOGERROR, "CCoreAudioDevice::GetPreferredChannelLayoutForStereo: "
+              "Unable to retrieve preferred channel layout. Error = %s", GetError(ret).c_str());
+  else
+  {
+    // Copy/generate a layout into the result into the caller's instance
+    layout.CopyLayoutForStereo(channels);
+  }
+  return (ret == noErr);
+}
+
 bool CCoreAudioDevice::GetDataSources(CoreAudioDataSourceList* pList)
 {
   if (!pList || !m_DeviceId)
diff --git a/xbmc/cores/AudioEngine/Sinks/osx/CoreAudioDevice.h b/xbmc/cores/AudioEngine/Sinks/osx/CoreAudioDevice.h
index e95f8c12f1..afe90a14c7 100644
--- a/xbmc/cores/AudioEngine/Sinks/osx/CoreAudioDevice.h
+++ b/xbmc/cores/AudioEngine/Sinks/osx/CoreAudioDevice.h
@@ -61,6 +61,7 @@ public:
   bool          GetMixingSupport();
   bool          SetCurrentVolume(Float32 vol);
   bool          GetPreferredChannelLayout(CCoreAudioChannelLayout &layout);
+  bool          GetPreferredChannelLayoutForStereo(CCoreAudioChannelLayout &layout);
   bool          GetDataSources(CoreAudioDataSourceList *pList);
   Float64       GetNominalSampleRate();
   bool          SetNominalSampleRate(Float64 sampleRate);