Add basic resample support to WASAPIAudioInputStream.

media/audio/win/audio_low_latency_input_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 AudioInputStream for Windows using Windows Core Audio
 // WASAPI for low latency capturing.
 //
 // Overview of operation:
 //
 // - An object of WASAPIAudioInputStream is created by the AudioManager
@@ skipping 57 matching lines @@
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/threading/non_thread_safe.h"
 #include "base/threading/platform_thread.h"
 #include "base/threading/simple_thread.h"
 #include "base/win/scoped_co_mem.h"
 #include "base/win/scoped_com_initializer.h"
 #include "base/win/scoped_comptr.h"
 #include "base/win/scoped_handle.h"
 #include "media/audio/agc_audio_stream.h"
+#include "media/base/audio_converter.h"
 #include "media/base/audio_parameters.h"
 #include "media/base/media_export.h"
 
 namespace media {
 
+class AudioBlockFifo;
 class AudioBus;
 class AudioManagerWin;
 
 // AudioInputStream implementation using Windows Core Audio APIs.
 class MEDIA_EXPORT WASAPIAudioInputStream
     : public AgcAudioStream<AudioInputStream>,
       public base::DelegateSimpleThread::Delegate,
+      public AudioConverter::InputCallback,
       NON_EXPORTED_BASE(public base::NonThreadSafe) {
  public:
   // The ctor takes all the usual parameters, plus |manager| which is the
   // the audio manager who is creating this object.
   WASAPIAudioInputStream(AudioManagerWin* manager,
                          const AudioParameters& params,
                          const std::string& device_id);
 
   // The dtor is typically called by the AudioManager only and it is usually
   // triggered by calling AudioInputStream::Close().
@@ skipping 18 matching lines @@
   // Issues the OnError() callback to the |sink_|.
   void HandleError(HRESULT err);
 
   // The Open() method is divided into these sub methods.
   HRESULT SetCaptureDevice();
   HRESULT GetAudioEngineStreamFormat();
   bool DesiredFormatIsSupported();
   HRESULT InitializeAudioEngine();
   void ReportOpenResult() const;
 
+  // AudioConverter::InputCallback implementation.
+  double ProvideInput(AudioBus* audio_bus, uint32_t frames_delayed) override;
+
   // Used to track down where we fail during initialization which at the
   // moment seems to be happening frequently and we're not sure why.
   // The reason might be expected (e.g. trying to open "default" on a machine
   // that has no audio devices).
   // Note: This enum is used to record a histogram value and should not be
   // re-ordered.
   enum StreamOpenResult {
     OPEN_RESULT_OK = 0,
     OPEN_RESULT_CREATE_INSTANCE = 1,
     OPEN_RESULT_NO_ENDPOINT = 2,
     OPEN_RESULT_NO_STATE = 3,
     OPEN_RESULT_DEVICE_NOT_ACTIVE = 4,
     OPEN_RESULT_ACTIVATION_FAILED = 5,
     OPEN_RESULT_FORMAT_NOT_SUPPORTED = 6,
     OPEN_RESULT_AUDIO_CLIENT_INIT_FAILED = 7,
     OPEN_RESULT_GET_BUFFER_SIZE_FAILED = 8,
     OPEN_RESULT_LOOPBACK_ACTIVATE_FAILED = 9,
     OPEN_RESULT_LOOPBACK_INIT_FAILED = 10,
     OPEN_RESULT_SET_EVENT_HANDLE = 11,
     OPEN_RESULT_NO_CAPTURE_CLIENT = 12,
     OPEN_RESULT_NO_AUDIO_VOLUME = 13,
-    OPEN_RESULT_MAX = OPEN_RESULT_NO_AUDIO_VOLUME
+    OPEN_RESULT_OK_WITH_RESAMPLING = 14,
+    OPEN_RESULT_MAX = OPEN_RESULT_OK_WITH_RESAMPLING
   };
 
   // Our creator, the audio manager needs to be notified when we close.
   AudioManagerWin* const manager_;
 
   // Capturing is driven by this thread (which has no message loop).
   // All OnData() callbacks will be called from this thread.
   std::unique_ptr<base::DelegateSimpleThread> capture_thread_;
 
   // Contains the desired audio format which is set up at construction.
@@ skipping 66 matching lines @@
   // the whole system.
   base::win::ScopedComPtr<IAudioEndpointVolume> system_audio_volume_;
 
   // The audio engine will signal this event each time a buffer has been
   // recorded.
   base::win::ScopedHandle audio_samples_ready_event_;
 
   // This event will be signaled when capturing shall stop.
   base::win::ScopedHandle stop_capture_event_;
 
-  // Extra audio bus used for storage of deinterleaved data for the OnData
-  // callback.
-  std::unique_ptr<media::AudioBus> audio_bus_;
-
   // Never set it through external API. Only used when |device_id_| ==
   // kLoopbackWithMuteDeviceId.
   // True, if we have muted the system audio for the stream capturing, and
   // indicates that we need to unmute the system audio when stopping capturing.
   bool mute_done_ = false;
 
+  // Used for the captured audio on the callback thread.
+  std::unique_ptr<AudioBlockFifo> fifo_;
+
+  // If the caller requires resampling (should only be in exceptional cases and
+  // ideally, never), we support using an AudioConverter.
+  std::unique_ptr<AudioConverter> converter_;
+  std::unique_ptr<AudioBus> convert_bus_;
+  bool imperfect_buffer_size_conversion_ = false;
+
   DISALLOW_COPY_AND_ASSIGN(WASAPIAudioInputStream);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_WIN_AUDIO_LOW_LATENCY_INPUT_WIN_H_