content/renderer/media/renderer_webaudiodevice_impl.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CONTENT_RENDERER_MEDIA_RENDERER_WEBAUDIODEVICE_IMPL_H_
   6 #define CONTENT_RENDERER_MEDIA_RENDERER_WEBAUDIODEVICE_IMPL_H_
   7
   8 #include "base/cancelable_callback.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "base/threading/thread_checker.h"
  11 #include "media/audio/audio_parameters.h"
  12 #include "media/base/audio_renderer_sink.h"
  13 #include "third_party/WebKit/public/platform/WebAudioDevice.h"
  14 #include "third_party/WebKit/public/platform/WebVector.h"
  15
  16 namespace base {
  17 class SingleThreadTaskRunner;
  18 }
  19
  20 namespace media {
  21 class AudioOutputDevice;
  22 class NullAudioSink;
  23 }
  24
  25 namespace content {
  26
  27 class RendererWebAudioDeviceImpl
  28     : public blink::WebAudioDevice,
  29       public media::AudioRendererSink::RenderCallback {
  30  public:
  31   RendererWebAudioDeviceImpl(const media::AudioParameters& params,
  32                              blink::WebAudioDevice::RenderCallback* callback,
  33                              int session_id);
  34   virtual ~RendererWebAudioDeviceImpl();
  35
  36   // blink::WebAudioDevice implementation.
  37   virtual void start();
  38   virtual void stop();
  39   virtual double sampleRate();
  40
  41   // AudioRendererSink::RenderCallback implementation.
  42   int Render(media::AudioBus* dest, int audio_delay_milliseconds) override;
  43
  44   void OnRenderError() override;
  45
  46  private:
  47   const media::AudioParameters params_;
  48
  49   // Weak reference to the callback into WebKit code.
  50   blink::WebAudioDevice::RenderCallback* const client_callback_;
  51
  52   // To avoid the need for locking, ensure the control methods of the
  53   // blink::WebAudioDevice implementation are called on the same thread.
  54   base::ThreadChecker thread_checker_;
  55
  56   // When non-NULL, we are started.  When NULL, we are stopped.
  57   scoped_refptr<media::AudioOutputDevice> output_device_;
  58
  59   // ID to allow browser to select the correct input device for unified IO.
  60   int session_id_;
  61
  62   // Timeticks when the silence starts.
  63   base::TimeTicks first_silence_time_ ;
  64
  65   // TaskRunner to post callbacks to the render thread.
  66   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
  67
  68   // A fake audio sink object that consumes data when long period of silence
  69   // audio is detected. This object lives on the render thread.
  70   scoped_refptr<media::NullAudioSink> null_audio_sink_;
  71
  72   // Whether audio output is directed to |null_audio_sink_|.
  73   bool is_using_null_audio_sink_;
  74
  75   // First audio buffer after silence finishes. We store this buffer so that
  76   // it can be sent to the |output_device_| later after switching from
  77   // |null_audio_sink_|.
  78   scoped_ptr<media::AudioBus> first_buffer_after_silence_;
  79
  80   bool is_first_buffer_after_silence_;
  81
  82   // A cancelable task that is posted to start the |null_audio_sink_| after a
  83   // period of silence. We do this on android to save battery consumption.
  84   base::CancelableClosure start_null_audio_sink_callback_;
  85
  86   DISALLOW_COPY_AND_ASSIGN(RendererWebAudioDeviceImpl);
  87 };
  88
  89 }  // namespace content
  90
  91 #endif  // CONTENT_RENDERER_MEDIA_RENDERER_WEBAUDIODEVICE_IMPL_H_