Switch to STA mode for audio thread and WASAPI I/O streams.

media/audio/win/audio_low_latency_output_win.h

 // 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.
 
 // Implementation of AudioOutputStream for Windows using Windows Core Audio
 // WASAPI for low latency rendering.
 //
 // Overview of operation and performance:
 //
 // - An object of WASAPIAudioOutputStream is created by the AudioManager
@@ skipping 139 matching lines @@
   bool started() const { return render_thread_.get() != NULL; }
 
  private:
   // DelegateSimpleThread::Delegate implementation.
   virtual void Run() override;
 
   // Core part of the thread loop which controls the actual rendering.
   // Checks available amount of space in the endpoint buffer and reads
   // data from the client to fill up the buffer without causing audio
   // glitches.
-  bool RenderAudioFromSource(UINT64 device_frequency);
+  bool RenderAudioFromSource(UINT64 device_frequency,
+                             IAudioClient* thread_audio_client,
+                             IAudioRenderClient* thread_audio_render_client,
+                             IAudioClock* thread_audio_clock);
 
   // Called when the device will be opened in exclusive mode and use the
   // application specified format.
   // TODO(henrika): rewrite and move to CoreAudioUtil when removing flag
   // for exclusive audio mode.
   HRESULT ExclusiveModeInitialization(IAudioClient* client,
                                       HANDLE event_handle,
                                       uint32* endpoint_buffer_size);
 
   // If |render_thread_| is valid, sets |stop_render_event_| and blocks until
   // the thread has stopped.  |stop_render_event_| is reset after the call.
   // |source_| is set to NULL.
   void StopThread();
 
+  // Handles sharing of COM pointers between the audio and render threads.  The
+  // marshal method must be called on the audio manager thread, while unmarshal
+  // must be called on |render_thread_|.
+  bool MarshalComPointers();
+  bool UnmarshalComPointers(
+      base::win::ScopedComPtr<IAudioClient>* audio_client,
+      base::win::ScopedComPtr<IAudioRenderClient>* audio_render_client,
+      base::win::ScopedComPtr<IAudioClock>* audio_clock);
+
   // Contains the thread ID of the creating thread.
   base::PlatformThreadId creating_thread_id_;
 
   // Our creator, the audio manager needs to be notified when we close.
   AudioManagerWin* manager_;
 
   // Rendering is driven by this thread (which has no message loop).
   // All OnMoreData() callbacks will be called from this thread.
   scoped_ptr<base::DelegateSimpleThread> render_thread_;
 
@@ skipping 29 matching lines @@
   // Valid values are AUDCLNT_SHAREMODE_SHARED and AUDCLNT_SHAREMODE_EXCLUSIVE
   // where AUDCLNT_SHAREMODE_SHARED is the default.
   AUDCLNT_SHAREMODE share_mode_;
 
   // Counts the number of audio frames written to the endpoint buffer.
   UINT64 num_written_frames_;
 
   // Pointer to the client that will deliver audio samples to be played out.
   AudioSourceCallback* source_;
 
+  // ------------------------------------------------------
+  // Warning: COM pointers must be marshaled from the audio thread to be used
+  // on any other thread. Do not use any of these interfaces on a thread other
+  // than the audio thread.  See MarshalComPointers() and UnmarshalComPointers()
+  // for marshaling pointers to the render thread.
+
+  // Stream into which the COM pointers below are marshaled so that they can
+  // be used on another thread.
+  base::win::ScopedComPtr<IStream> com_stream_;
+
+  // Windows Audio Session API (WASAPI) interfaces.
+
   // An IAudioClient interface which enables a client to create and initialize
   // an audio stream between an audio application and the audio engine.
   base::win::ScopedComPtr<IAudioClient> audio_client_;
 
   // The IAudioRenderClient interface enables a client to write output
   // data to a rendering endpoint buffer.
   base::win::ScopedComPtr<IAudioRenderClient> audio_render_client_;
 
+  base::win::ScopedComPtr<IAudioClock> audio_clock_;
+  // ------------------------------------------------------
+
   // The audio engine will signal this event each time a buffer becomes
   // ready to be filled by the client.
   base::win::ScopedHandle audio_samples_render_event_;
 
   // This event will be signaled when rendering shall stop.
   base::win::ScopedHandle stop_render_event_;
 
   // Container for retrieving data from AudioSourceCallback::OnMoreData().
   scoped_ptr<AudioBus> audio_bus_;
 
-  base::win::ScopedComPtr<IAudioClock> audio_clock_;
-
   DISALLOW_COPY_AND_ASSIGN(WASAPIAudioOutputStream);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_WIN_AUDIO_LOW_LATENCY_OUTPUT_WIN_H_