ActiveAE: Include LFE mixing possibility

We have user without AVR running fullrange speakers. They want the bass of
a 5.1 or 7.1 layout being mixed into FL and FR. This new setting allows
to do so.

15 files changed, 123 insertions, 48 deletions

diff --git a/addons/resource.language.en_gb/resources/strings.po b/addons/resource.language.en_gb/resources/strings.po
index b12f00ede9..abc6949849 100644
--- a/addons/resource.language.en_gb/resources/strings.po
+++ b/addons/resource.language.en_gb/resources/strings.po
@@ -17918,8 +17918,39 @@ msgctxt "#34113"
 msgid "To keep certain AVRs powered we send an inaudible random noise signal. You can disable this setting if you are using headphone or analog output."
 msgstr ""
 
+#. Indicates if Audio Engine should include lfe when downmixing
+#: system/settings/settings.xml
+msgctxt "#34114"
+msgid "Include LFE when downmixing"
+msgstr ""
+
+#. Description of setting with label #34114 "Include LFE when downmixing"
+#: system/settings/settings.xml
+msgctxt "#34115"
+msgid "If enabled, this setting will include lfe channel into the mixing when there is no dedicated LFE output channel available. This only makes sense for full range speakers."
+msgstr ""
+
+#. Description of setting with label #34114 "Include LFE when downmixing"
+#: system/settings/settings.xml
+msgctxt "#34116"
+msgid "Off"
+msgstr ""
+
+#. Description of setting with label #34114 "Include LFE when downmixing"
+#: system/settings/settings.xml
+msgctxt "#34117"
+msgid "50%"
+msgstr ""
+
+#. Description of setting with label #34114 "Include LFE when downmixing"
+#: system/settings/settings.xml
+msgctxt "#34118"
+msgid "100%"
+msgstr ""
+
+
 #empty strings from id 34114 to 34119
-#34114-34119 reserved for future use
+#34119 reserved for future use
 
 #: system/settings/settings.xml
 msgctxt "#34120"
diff --git a/system/settings/settings.xml b/system/settings/settings.xml
index e5bee132ab..6e323fb7ff 100755
--- a/system/settings/settings.xml
+++ b/system/settings/settings.xml
@@ -3259,6 +3259,18 @@
           <default>true</default>
           <control type="toggle" />
         </setting>
+        <setting id="audiooutput.mixsublevel" type="integer" label="34114" help="34115">
+          <level>2</level>
+          <default>0</default>
+          <constraints>
+            <options>
+              <option label="34116">0</option>
+              <option label="34117">50</option>
+              <option label="34118">100</option>
+            </options>
+          </constraints>
+          <control type="list" format="string" />
+        </setting>
       </group>
       <group id="2" label="15108">
         <setting id="audiooutput.guisoundmode" type="integer" label="34120" help="36373">
diff --git a/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAE.cpp b/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAE.cpp
index e7ae140bec..d68de6c6f6 100644
--- a/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAE.cpp
+++ b/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAE.cpp
@@ -1369,7 +1369,8 @@ void CActiveAE::Configure(AEAudioFormat *desiredFmt)
             (*it)->m_inputBuffers->m_format, outputFormat, m_settings.resampleQuality);
         (*it)->m_processingBuffers->ForceResampler((*it)->m_forceResampler);
 
-        (*it)->m_processingBuffers->Create(MAX_CACHE_LEVEL*1000, false, m_settings.stereoupmix, m_settings.normalizelevels);
+        (*it)->m_processingBuffers->Create(MAX_CACHE_LEVEL * 1000, false, m_settings.stereoupmix,
+                                           m_settings.normalizelevels, m_settings.mixSubLevel);
       }
       if (m_mode == MODE_TRANSCODE || m_streams.size() > 1)
         (*it)->m_processingBuffers->FillBuffer();
@@ -1641,7 +1642,9 @@ void CActiveAE::ChangeResamplers()
   std::list<CActiveAEStream*>::iterator it;
   for(it=m_streams.begin(); it!=m_streams.end(); ++it)
   {
-    (*it)->m_processingBuffers->ConfigureResampler(m_settings.normalizelevels, m_settings.stereoupmix, m_settings.resampleQuality);
+    (*it)->m_processingBuffers->ConfigureResampler(
+        m_settings.normalizelevels, m_settings.stereoupmix, m_settings.resampleQuality,
+        m_settings.mixSubLevel);
   }
 }
 
@@ -2666,6 +2669,7 @@ void CActiveAE::LoadSettings()
   m_settings.atempoThreshold = settings->GetInt(CSettings::SETTING_AUDIOOUTPUT_ATEMPOTHRESHOLD) / 100.0;
   m_settings.streamNoise = settings->GetBool(CSettings::SETTING_AUDIOOUTPUT_STREAMNOISE);
   m_settings.silenceTimeoutMinutes = settings->GetInt(CSettings::SETTING_AUDIOOUTPUT_STREAMSILENCE);
+  m_settings.mixSubLevel = settings->GetInt(CSettings::SETTING_AUDIOOUTPUT_MIXSUBLEVEL) / 100.0;
 }
 
 void CActiveAE::ValidateOutputDevices(bool saveChanges)
@@ -3310,13 +3314,9 @@ bool CActiveAE::ResampleSound(CActiveAESound *sound)
   std::unique_ptr<IAEResample> resampler =
       CAEResampleFactory::Create(AERESAMPLEFACTORY_QUICK_RESAMPLE);
 
-  resampler->Init(dst_config, orig_config,
-                  false,
-                  true,
-                  M_SQRT1_2,
-                  outChannels.Count() > 0 ? &outChannels : nullptr,
-                  m_settings.resampleQuality,
-                  false);
+  resampler->Init(dst_config, orig_config, false, true, M_SQRT1_2,
+                  outChannels.Count() > 0 ? &outChannels : nullptr, m_settings.resampleQuality,
+                  false, 0.0f);
 
   dst_samples = resampler->CalcDstSampleCount(sound->GetSound(true)->nb_samples,
                                               m_internalFormat.m_sampleRate,
diff --git a/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAE.h b/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAE.h
index 7c43d2037c..cf74ee52b0 100644
--- a/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAE.h
+++ b/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAE.h
@@ -63,6 +63,7 @@ struct AudioSettings
   double atempoThreshold;
   bool streamNoise;
   int silenceTimeoutMinutes;
+  float mixSubLevel;
 };
 
 class CActiveAEControlProtocol : public Protocol
diff --git a/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEBuffer.cpp b/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEBuffer.cpp
index 8e4d957cea..5ab47edda4 100644
--- a/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEBuffer.cpp
+++ b/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEBuffer.cpp
@@ -144,12 +144,14 @@ CActiveAEBufferPoolResample::~CActiveAEBufferPoolResample()
   Flush();
 }
 
-bool CActiveAEBufferPoolResample::Create(unsigned int totaltime, bool remap, bool upmix, bool normalize)
+bool CActiveAEBufferPoolResample::Create(
+    unsigned int totaltime, bool remap, bool upmix, bool normalize, float sublevel)
 {
   CActiveAEBufferPool::Create(totaltime);
 
   m_remap = remap;
   m_stereoUpmix = upmix;
+  m_mixSubLevel = sublevel;
 
   m_normalize = true;
   if ((m_format.m_channelLayout.Count() < m_inputFormat.m_channelLayout.Count() && !normalize))
@@ -184,13 +186,9 @@ void CActiveAEBufferPoolResample::ChangeResampler()
   srcConfig.bits_per_sample = CAEUtil::DataFormatToUsedBits(m_inputFormat.m_dataFormat);
   srcConfig.dither_bits = CAEUtil::DataFormatToDitherBits(m_inputFormat.m_dataFormat);
 
-  m_resampler->Init(dstConfig, srcConfig,
-                    m_stereoUpmix,
-                    m_normalize,
-                    m_centerMixLevel,
-                    m_remap ? &m_format.m_channelLayout : nullptr,
-                    m_resampleQuality,
-                    m_forceResampler);
+  m_resampler->Init(dstConfig, srcConfig, m_stereoUpmix, m_normalize, m_centerMixLevel,
+                    m_remap ? &m_format.m_channelLayout : nullptr, m_resampleQuality,
+                    m_forceResampler, m_mixSubLevel);
 
   m_changeResampler = false;
 }
@@ -350,7 +348,10 @@ bool CActiveAEBufferPoolResample::ResampleBuffers(int64_t timestamp)
   return busy;
 }
 
-void CActiveAEBufferPoolResample::ConfigureResampler(bool normalizelevels, bool stereoupmix, AEQuality quality)
+void CActiveAEBufferPoolResample::ConfigureResampler(bool normalizelevels,
+                                                     bool stereoupmix,
+                                                     AEQuality quality,
+                                                     float sublevel)
 {
   bool normalize = true;
   if ((m_format.m_channelLayout.Count() < m_inputFormat.m_channelLayout.Count()) && !normalizelevels)
diff --git a/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEBuffer.h b/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEBuffer.h
index 70e51bbd6f..9feff2c558 100644
--- a/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEBuffer.h
+++ b/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEBuffer.h
@@ -78,9 +78,13 @@ public:
   CActiveAEBufferPoolResample(const AEAudioFormat& inputFormat, const AEAudioFormat& outputFormat, AEQuality quality);
   ~CActiveAEBufferPoolResample() override;
   using CActiveAEBufferPool::Create;
-  bool Create(unsigned int totaltime, bool remap, bool upmix, bool normalize = true);
+  bool Create(
+      unsigned int totaltime, bool remap, bool upmix, bool normalize = true, float sublevel = 0.0);
   bool ResampleBuffers(int64_t timestamp = 0);
-  void ConfigureResampler(bool normalizelevels, bool stereoupmix, AEQuality quality);
+  void ConfigureResampler(bool normalizelevels,
+                          bool stereoupmix,
+                          AEQuality quality,
+                          float sublevel);
   float GetDelay();
   void Flush();
   void SetDrain(bool drain);
@@ -107,6 +111,7 @@ protected:
   double m_centerMixLevel = M_SQRT1_2;
   bool m_fillPackets = false;
   bool m_normalize = true;
+  float m_mixSubLevel = 0.0f;
   bool m_changeResampler = false;
   bool m_forceResampler = false;
   AEQuality m_resampleQuality;
diff --git a/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEResampleFFMPEG.cpp b/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEResampleFFMPEG.cpp
index e897cbd3ea..70e946a116 100644
--- a/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEResampleFFMPEG.cpp
+++ b/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEResampleFFMPEG.cpp
@@ -29,8 +29,15 @@ CActiveAEResampleFFMPEG::~CActiveAEResampleFFMPEG()
   swr_free(&m_pContext);
 }
 
-bool CActiveAEResampleFFMPEG::Init(SampleConfig dstConfig, SampleConfig srcConfig, bool upmix, bool normalize, double centerMix,
-                                   CAEChannelInfo *remapLayout, AEQuality quality, bool force_resample)
+bool CActiveAEResampleFFMPEG::Init(SampleConfig dstConfig,
+                                   SampleConfig srcConfig,
+                                   bool upmix,
+                                   bool normalize,
+                                   double centerMix,
+                                   CAEChannelInfo* remapLayout,
+                                   AEQuality quality,
+                                   bool force_resample,
+                                   float sublevel)
 {
   m_dst_chan_layout = dstConfig.channel_layout;
   m_dst_channels = dstConfig.channels;
@@ -78,6 +85,9 @@ bool CActiveAEResampleFFMPEG::Init(SampleConfig dstConfig, SampleConfig srcConfi
     return false;
   }
 
+  if (sublevel > 0.0f)
+    av_opt_set_double(m_pContext, "lfe_mix_level", static_cast<double>(sublevel), 0);
+
   if(quality == AE_QUALITY_HIGH)
   {
     av_opt_set_double(m_pContext, "cutoff", 1.0, 0);
diff --git a/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEResampleFFMPEG.h b/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEResampleFFMPEG.h
index 5fbce373ad..b6a9a03376 100644
--- a/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEResampleFFMPEG.h
+++ b/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEResampleFFMPEG.h
@@ -27,8 +27,15 @@ public:
   const char *GetName() override { return "ActiveAEResampleFFMPEG"; }
   CActiveAEResampleFFMPEG();
   ~CActiveAEResampleFFMPEG() override;
-  bool Init(SampleConfig dstConfig, SampleConfig srcConfig, bool upmix, bool normalize, double centerMix,
-            CAEChannelInfo *remapLayout, AEQuality quality, bool force_resample) override;
+  bool Init(SampleConfig dstConfig,
+            SampleConfig srcConfig,
+            bool upmix,
+            bool normalize,
+            double centerMix,
+            CAEChannelInfo* remapLayout,
+            AEQuality quality,
+            bool force_resample,
+            float sublevel) override;
   int Resample(uint8_t **dst_buffer, int dst_samples, uint8_t **src_buffer, int src_samples, double ratio) override;
   int64_t GetDelay(int64_t base) override;
   int GetBufferedSamples() override;
diff --git a/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAESettings.cpp b/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAESettings.cpp
index 5f9a1fbc75..b7b20ecf3f 100644
--- a/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAESettings.cpp
+++ b/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAESettings.cpp
@@ -52,6 +52,7 @@ CActiveAESettings::CActiveAESettings(CActiveAE &ae) : m_audioEngine(ae)
   settingSet.insert(CSettings::SETTING_AUDIOOUTPUT_PASSTHROUGHDEVICE);
   settingSet.insert(CSettings::SETTING_AUDIOOUTPUT_STREAMSILENCE);
   settingSet.insert(CSettings::SETTING_AUDIOOUTPUT_STREAMNOISE);
+  settingSet.insert(CSettings::SETTING_AUDIOOUTPUT_MIXSUBLEVEL);
   settingSet.insert(CSettings::SETTING_AUDIOOUTPUT_MAINTAINORIGINALVOLUME);
   settingSet.insert(CSettings::SETTING_AUDIOOUTPUT_DTSHDCOREFALLBACK);
   settings->GetSettingsManager()->RegisterCallback(this, settingSet);
diff --git a/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAESink.cpp b/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAESink.cpp
index 700abfcee5..f0cce1885b 100644
--- a/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAESink.cpp
+++ b/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAESink.cpp
@@ -1192,8 +1192,8 @@ void CActiveAESink::GenerateNoise()
   srcConfig.bits_per_sample = CAEUtil::DataFormatToUsedBits(m_sinkFormat.m_dataFormat);
   srcConfig.dither_bits = CAEUtil::DataFormatToDitherBits(m_sinkFormat.m_dataFormat);
 
-  resampler->Init(dstConfig, srcConfig,
-                  false, false, M_SQRT1_2, nullptr, AE_QUALITY_UNKNOWN, false);
+  resampler->Init(dstConfig, srcConfig, false, false, M_SQRT1_2, nullptr, AE_QUALITY_UNKNOWN, false,
+                  0.0);
 
   resampler->Resample(m_sampleOfSilence.pkt->data, m_sampleOfSilence.pkt->max_nb_samples,
                      (uint8_t**)&noise, m_sampleOfSilence.pkt->max_nb_samples, 1.0);
diff --git a/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEStream.cpp b/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEStream.cpp
index bdf65d60ae..bf00b58840 100644
--- a/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEStream.cpp
+++ b/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEStream.cpp
@@ -143,13 +143,9 @@ void CActiveAEStream::InitRemapper()
     srcConfig.bits_per_sample = CAEUtil::DataFormatToUsedBits(m_format.m_dataFormat);
     srcConfig.dither_bits = CAEUtil::DataFormatToDitherBits(m_format.m_dataFormat);
 
-    m_remapper->Init(dstConfig, srcConfig,
-                     false,
-                     false,
-                     M_SQRT1_2,
-                     &remapLayout,
+    m_remapper->Init(dstConfig, srcConfig, false, false, M_SQRT1_2, &remapLayout,
                      AE_QUALITY_LOW, // not used for remapping
-                     false);
+                     false, 0.0f);
 
     // extra sound packet, we can't resample to the same buffer
     m_remapBuffer =
@@ -602,9 +598,10 @@ bool CActiveAEStreamBuffers::HasInputLevel(int level)
     return false;
 }
 
-bool CActiveAEStreamBuffers::Create(unsigned int totaltime, bool remap, bool upmix, bool normalize)
+bool CActiveAEStreamBuffers::Create(
+    unsigned int totaltime, bool remap, bool upmix, bool normalize, float sublevel)
 {
-  if (!m_resampleBuffers->Create(totaltime, remap, upmix, normalize))
+  if (!m_resampleBuffers->Create(totaltime, remap, upmix, normalize, sublevel))
     return false;
 
   if (!m_atempoBuffers->Create(totaltime))
@@ -654,9 +651,12 @@ bool CActiveAEStreamBuffers::ProcessBuffers()
   return busy;
 }
 
-void CActiveAEStreamBuffers::ConfigureResampler(bool normalizelevels, bool stereoupmix, AEQuality quality)
+void CActiveAEStreamBuffers::ConfigureResampler(bool normalizelevels,
+                                                bool stereoupmix,
+                                                AEQuality quality,
+                                                float sublevel)
 {
-  m_resampleBuffers->ConfigureResampler(normalizelevels, stereoupmix, quality);
+  m_resampleBuffers->ConfigureResampler(normalizelevels, stereoupmix, quality, sublevel);
 }
 
 float CActiveAEStreamBuffers::GetDelay()
diff --git a/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEStream.h b/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEStream.h
index 56b9e51f36..e29109fc26 100644
--- a/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEStream.h
+++ b/xbmc/cores/AudioEngine/Engines/ActiveAE/ActiveAEStream.h
@@ -96,10 +96,14 @@ class CActiveAEStreamBuffers
 public:
   CActiveAEStreamBuffers(const AEAudioFormat& inputFormat, const AEAudioFormat& outputFormat, AEQuality quality);
   virtual ~CActiveAEStreamBuffers();
-  bool Create(unsigned int totaltime, bool remap, bool upmix, bool normalize = true);
+  bool Create(
+      unsigned int totaltime, bool remap, bool upmix, bool normalize = true, float sublevel = 0.0f);
   void SetExtraData(int profile, enum AVMatrixEncoding matrix_encoding, enum AVAudioServiceType audio_service_type);
   bool ProcessBuffers();
-  void ConfigureResampler(bool normalizelevels, bool stereoupmix, AEQuality quality);
+  void ConfigureResampler(bool normalizelevels,
+                          bool stereoupmix,
+                          AEQuality quality,
+                          float sublevel);
   bool HasInputLevel(int level);
   float GetDelay();
   void Flush();
diff --git a/xbmc/cores/AudioEngine/Interfaces/AEResample.h b/xbmc/cores/AudioEngine/Interfaces/AEResample.h
index 8b27b32b86..620ce56195 100644
--- a/xbmc/cores/AudioEngine/Interfaces/AEResample.h
+++ b/xbmc/cores/AudioEngine/Interfaces/AEResample.h
@@ -20,8 +20,15 @@ public:
   virtual const char *GetName() = 0;
   IAEResample() = default;
   virtual ~IAEResample() = default;
-  virtual bool Init(SampleConfig dstConfig, SampleConfig srcConfig, bool upmix, bool normalize, double centerMix,
-                    CAEChannelInfo *remapLayout, AEQuality quality, bool force_resample) = 0;
+  virtual bool Init(SampleConfig dstConfig,
+                    SampleConfig srcConfig,
+                    bool upmix,
+                    bool normalize,
+                    double centerMix,
+                    CAEChannelInfo* remapLayout,
+                    AEQuality quality,
+                    bool force_resample,
+                    float sublevel) = 0;
   virtual int Resample(uint8_t **dst_buffer, int dst_samples, uint8_t **src_buffer, int src_samples, double ratio) = 0;
   virtual int64_t GetDelay(int64_t base) = 0;
   virtual int GetBufferedSamples() = 0;
diff --git a/xbmc/cores/paplayer/VideoPlayerCodec.cpp b/xbmc/cores/paplayer/VideoPlayerCodec.cpp
index 0a2468f8ff..1303722908 100644
--- a/xbmc/cores/paplayer/VideoPlayerCodec.cpp
+++ b/xbmc/cores/paplayer/VideoPlayerCodec.cpp
@@ -253,13 +253,8 @@ bool VideoPlayerCodec::Init(const CFileItem &file, unsigned int filecache)
     srcConfig.bits_per_sample = CAEUtil::DataFormatToUsedBits(m_srcFormat.m_dataFormat);
     srcConfig.dither_bits = CAEUtil::DataFormatToDitherBits(m_srcFormat.m_dataFormat);
 
-    m_pResampler->Init(dstConfig, srcConfig,
-                       false,
-                       false,
-                       M_SQRT1_2,
-                       NULL,
-                       AE_QUALITY_UNKNOWN,
-                       false);
+    m_pResampler->Init(dstConfig, srcConfig, false, false, M_SQRT1_2, NULL, AE_QUALITY_UNKNOWN,
+                       false, 0.0f);
 
     m_planes = AE_IS_PLANAR(m_srcFormat.m_dataFormat) ? m_channels : 1;
     m_format = m_srcFormat;
diff --git a/xbmc/settings/Settings.h b/xbmc/settings/Settings.h
index dfc87db9f2..00ab9fb34f 100644
--- a/xbmc/settings/Settings.h
+++ b/xbmc/settings/Settings.h
@@ -397,6 +397,7 @@ public:
   static constexpr auto SETTING_AUDIOOUTPUT_ATEMPOTHRESHOLD = "audiooutput.atempothreshold";
   static constexpr auto SETTING_AUDIOOUTPUT_STREAMSILENCE = "audiooutput.streamsilence";
   static constexpr auto SETTING_AUDIOOUTPUT_STREAMNOISE = "audiooutput.streamnoise";
+  static constexpr auto SETTING_AUDIOOUTPUT_MIXSUBLEVEL = "audiooutput.mixsublevel";
   static constexpr auto SETTING_AUDIOOUTPUT_GUISOUNDMODE = "audiooutput.guisoundmode";
   static constexpr auto SETTING_AUDIOOUTPUT_GUISOUNDVOLUME = "audiooutput.guisoundvolume";
   static constexpr auto SETTING_AUDIOOUTPUT_PASSTHROUGH = "audiooutput.passthrough";