content/public/renderer/media_stream_audio_renderer.h

   1 // Copyright 2013 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_PUBLIC_RENDERER_MEDIA_STREAM_AUDIO_RENDERER_H_
   6 #define CONTENT_PUBLIC_RENDERER_MEDIA_STREAM_AUDIO_RENDERER_H_
   7
   8 #include <string>
   9
  10 #include "base/callback.h"
  11 #include "base/memory/ref_counted.h"
  12 #include "base/time/time.h"
  13 #include "media/base/output_device.h"
  14 #include "url/gurl.h"
  15
  16 namespace content {
  17
  18 class MediaStreamAudioRenderer
  19     : public base::RefCountedThreadSafe<MediaStreamAudioRenderer> {
  20  public:
  21   // Starts rendering audio.
  22   virtual void Start() = 0;
  23
  24   // Stops rendering audio.
  25   virtual void Stop() = 0;
  26
  27   // Resumes rendering audio after being paused.
  28   virtual void Play() = 0;
  29
  30   // Temporarily suspends rendering audio. The audio stream might still be
  31   // active but new audio data is not provided to the consumer.
  32   virtual void Pause() = 0;
  33
  34   // Sets the output volume.
  35   virtual void SetVolume(float volume) = 0;
  36
  37   // Returns a pointer to the internal output device.
  38   // The pointer is not to be owned by the caller and is valid only during
  39   // the lifetime of the MediaStreamAudioRenderer.
  40   // It can be null, which means that access to the output device is not
  41   // supported.
  42   virtual media::OutputDevice* GetOutputDevice() = 0;
  43
  44   // Time stamp that reflects the current render time. Should not be updated
  45   // when paused.
  46   virtual base::TimeDelta GetCurrentRenderTime() const = 0;
  47
  48   // Returns true if the implementation is a local renderer and false
  49   // otherwise.
  50   virtual bool IsLocalRenderer() const = 0;
  51
  52  protected:
  53   friend class base::RefCountedThreadSafe<MediaStreamAudioRenderer>;
  54
  55   virtual ~MediaStreamAudioRenderer() {}
  56 };
  57
  58 }  // namespace content
  59
  60 #endif  // CONTENT_PUBLIC_RENDERER_MEDIA_STREAM_AUDIO_RENDERER_H_