[AE] Allow sink to decide how or if it can be suspended

xbmc/cores/AudioEngine/Engines/SoftAE/SoftAE.cpp

@@ -1017,34 +1017,8 @@ void CSoftAE::Run()
         restart = true;
     }
 
-    if (m_playingStreams.empty() && m_playing_sounds.empty() && m_streams.empty() && 
-       !m_softSuspend && !g_advancedSettings.m_streamSilence)
-    {
-      m_softSuspend = true;
-      m_softSuspendTimer = XbmcThreads::SystemClockMillis() + 10000; //10.0 second delay for softSuspend
-    }
-
-    unsigned int curSystemClock = XbmcThreads::SystemClockMillis();
-
-    /* idle while in Suspend() state until Resume() called */
-    /* idle if nothing to play and user hasn't enabled     */
-    /* continuous streaming (silent stream) in as.xml      */
-    while ((m_isSuspended || (m_softSuspend && (curSystemClock > m_softSuspendTimer))) &&
-            m_running     && !m_reOpen      && !restart)
-    {
-      if (m_sink)
-      {
-        /* take the sink lock */
-        CExclusiveLock sinkLock(m_sinkLock);
-        //m_sink->Drain(); TODO: implement
-        m_sink->Deinitialize();
-        delete m_sink;
-        m_sink = NULL;
-      }
-      if (!m_playingStreams.empty() || !m_playing_sounds.empty() || !m_sounds.empty())
-        m_softSuspend = false;
-      m_wake.WaitMSec(SOFTAE_IDLE_WAIT_MSEC);
-    }
+    /* Handle idle or forced suspend */
+    ProcessSuspend();
 
     /* if we are told to restart */
     if (m_reOpen || restart || !m_sink)
@@ -1405,3 +1379,51 @@ inline void CSoftAE::RemoveStream(StreamList &streams, CSoftAEStream *stream)
     m_streamsPlaying = !m_playingStreams.empty();
 }
 
+inline void CSoftAE::ProcessSuspend()
+{
+  bool sinkIsSuspended = false;
+
+  if (m_playingStreams.empty() && m_playing_sounds.empty() && 
+     !m_softSuspend && !g_advancedSettings.m_streamSilence)
+  {
+    m_softSuspend = true;
+    m_softSuspendTimer = XbmcThreads::SystemClockMillis() + 10000; //10.0 second delay for softSuspend
+  }
+
+  unsigned int curSystemClock = XbmcThreads::SystemClockMillis();
+
+  /* idle while in Suspend() state until Resume() called */
+  /* idle if nothing to play and user hasn't enabled     */
+  /* continuous streaming (silent stream) in as.xml      */
+  while ((m_isSuspended || (m_softSuspend && (curSystemClock > m_softSuspendTimer))) &&
+          m_running     && !m_reOpen)
+  {
+    if (m_sink && !sinkIsSuspended)
+    {
+      /* put the sink in Suspend mode */
+      CExclusiveLock sinkLock(m_sinkLock);
+      if (!m_sink->SoftSuspend())
+      {
+        sinkIsSuspended = false; //sink cannot be suspended
+        m_softSuspend   = false; //break suspend loop
+        break;
+      }
+      else
+        sinkIsSuspended = true; //sink has suspended processing
+      sinkLock.Leave();
+    }
+
+    /* idle for platform-defined time */
+    m_wake.WaitMSec(SOFTAE_IDLE_WAIT_MSEC);
+
+    /* check if we need to resume for stream or sound */
+    if (!m_isSuspended && (!m_playingStreams.empty() || !m_playing_sounds.empty()))
+    {
+      m_reOpen = !m_sink->SoftResume(); // sink returns false if it requires reinit
+      sinkIsSuspended = false; //sink processing data
+      m_softSuspend   = false; //break suspend loop
+      break;
+    }
+  }
+}
+

xbmc/cores/AudioEngine/Engines/SoftAE/SoftAE.h

@@ -120,6 +120,8 @@ class CSoftAE : public IThreadedAE
   bool SetupEncoder(AEAudioFormat &format);
   void Deinitialize();
 
+  inline void ProcessSuspend(); /* enter suspend state if nothing to play and sink allows */
+
   inline void GetDeviceFriendlyName(std::string &device);
 
   IAESink *GetSink(AEAudioFormat &desiredFormat, bool passthrough, std::string &device);
@@ -133,9 +135,10 @@ class CSoftAE : public IThreadedAE
   bool m_stereoUpmix;
 
   /* internal vars */
-  bool             m_running, m_reOpen, m_isSuspended;
-  bool             m_softSuspend;      /* latches after last stream or sound played for timer below */
-  unsigned int     m_softSuspendTimer; /* time in milliseconds to hold sink open before soft suspend */
+  bool             m_running, m_reOpen;
+  bool             m_isSuspended;      /* engine suspended by external function to release audio context */
+  bool             m_softSuspend;      /* latches after last stream or sound played for timer below for idle */
+  unsigned int     m_softSuspendTimer; /* time in milliseconds to hold sink open before soft suspend for idle */
   CEvent           m_reOpenEvent;
   CEvent           m_wake;
 

xbmc/cores/AudioEngine/Interfaces/AESink.h

@@ -87,5 +87,17 @@ class IAESink
     This method sets the volume control, volume ranges from 0.0 to 1.0.
   */
   virtual void  SetVolume(float volume) {};
+
+  /*
+    Requests sink to prepare itself for a suspend state
+    @return false if sink cannot be suspended
+  */
+  virtual bool SoftSuspend() {return false;};
+
+  /*
+    Notify sink to prepare to resume processing after suspend state
+    @return false if sink must be reinitialized
+  */
+  virtual bool SoftResume() {return false;};
 };
 

xbmc/cores/AudioEngine/Sinks/AESinkALSA.cpp

@@ -489,9 +489,6 @@ unsigned int CAESinkALSA::AddPackets(uint8_t *data, unsigned int frames, bool ha
   if (!m_pcm)
     return 0;
 
-  if (snd_pcm_state(m_pcm) == SND_PCM_STATE_PREPARED)
-    snd_pcm_start(m_pcm);
-
   int ret;
 
   ret = snd_pcm_avail(m_pcm);
@@ -520,6 +517,9 @@ unsigned int CAESinkALSA::AddPackets(uint8_t *data, unsigned int frames, bool ha
     }
   }
 
+  if ( ret > 0 && snd_pcm_state(m_pcm) == SND_PCM_STATE_PREPARED)
+    snd_pcm_start(m_pcm);
+
   return ret;
 }
 

xbmc/cores/AudioEngine/Sinks/AESinkWASAPI.cpp

@@ -331,7 +331,8 @@ void CAESinkWASAPI::Deinitialize()
   {
     try
     {
-    m_pAudioClient->Stop();
+    m_pAudioClient->Stop();  //stop the audio output
+    m_pAudioClient->Reset(); //flush buffer and reset audio clock stream position
     }
     catch (...)
     {
@@ -537,6 +538,27 @@ unsigned int CAESinkWASAPI::AddPackets(uint8_t *data, unsigned int frames, bool
   return NumFramesRequested;
 }
 
+bool CAESinkWASAPI::SoftSuspend()
+{
+  /* Sink has been asked to suspend output - we release audio   */
+  /* device as we are in exclusive mode and thus allow external */
+  /* audio sources to play. This requires us to reinitialize    */
+  /* on resume.                                                 */
+
+  Deinitialize();
+
+  return true;
+}
+
+bool CAESinkWASAPI::SoftResume()
+{
+  /* Sink asked to resume output. To release audio device in    */
+  /* exclusive mode we release the device context and therefore */
+  /* must reinitialize. Return false to force re-init by engine */
+
+  return false;
+}
+
 void CAESinkWASAPI::EnumerateDevicesEx(AEDeviceInfoList &deviceInfoList)
 {
   IMMDeviceEnumerator* pEnumerator = NULL;

xbmc/cores/AudioEngine/Sinks/AESinkWASAPI.h

@@ -43,6 +43,8 @@ class CAESinkWASAPI : public IAESink
     virtual double       GetCacheTime                ();
     virtual double       GetCacheTotal               ();
     virtual unsigned int AddPackets                  (uint8_t *data, unsigned int frames, bool hasAudio);
+    virtual bool         SoftSuspend                 ();
+    virtual bool         SoftResume                  ();
     static  void         EnumerateDevicesEx          (AEDeviceInfoList &deviceInfoList);
 private:
     bool         InitializeExclusive(AEAudioFormat &format);
@@ -70,6 +72,7 @@ class CAESinkWASAPI : public IAESink
 
     bool                m_running;
     bool                m_initialized;
+    bool                m_isSuspended;    /* sink is in a suspended state - release audio device */
     bool                m_isDirty;        /* sink output failed - needs re-init or new device */
 
     unsigned int        m_uiBufferLen;    /* wasapi endpoint buffer size, in frames */