Implementation of 'AudioContext.getOutputTimestamp' method

third_party/WebKit/Source/platform/audio/AudioDestination.h

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 64 matching lines @@
 
   virtual void start();
   virtual void stop();
   bool isPlaying() { return m_isPlaying; }
 
   float sampleRate() const { return m_sampleRate; }
 
   // WebAudioDevice::RenderCallback
   void render(const WebVector<float*>& sourceData,
               const WebVector<float*>& audioData,
-              size_t numberOfFrames) override;
+              size_t numberOfFrames,
+              double delay,
+              double delayTimestamp,
+              size_t priorFramesSkipped) override;

[Raymond Toy, 2016/11/04 17:51:40]

Can we document what these three parameters really mean?

[Mikhail, 2016/11/28 15:15:59]

Done.

 
   // AudioSourceProvider
   void provideInput(AudioBus*, size_t framesToProcess) override;
 
   static float hardwareSampleRate();
 
   // maxChannelCount() returns the total number of output channels of the audio
   // hardware.  A value of 0 indicates that the number of channels cannot be
   // configured and that only stereo (2-channel) destinations can be created.
   // The numberOfOutputChannels parameter of AudioDestination::create() is
   // allowed to be a value: 1 <= numberOfOutputChannels <= maxChannelCount(),
   // or if maxChannelCount() equals 0, then numberOfOutputChannels must be 2.
   static unsigned long maxChannelCount();
 
  private:
   AudioIOCallback& m_callback;
   unsigned m_numberOfOutputChannels;
   RefPtr<AudioBus> m_inputBus;
   RefPtr<AudioBus> m_renderBus;
   float m_sampleRate;
   bool m_isPlaying;
   std::unique_ptr<WebAudioDevice> m_audioDevice;
   size_t m_callbackBufferSize;
 
   std::unique_ptr<AudioFIFO> m_inputFifo;
   std::unique_ptr<AudioPullFIFO> m_fifo;
+
+  size_t m_framesElapsed;
+  AudioIOPosition m_outputPosition;
+  base::TimeTicks m_outputPositionReceivedTimestamp;
 };
 
 }  // namespace blink
 
 #endif  // AudioDestination_h