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/audio_renderer_sink.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   // Attempts to switch the audio output device.
  38   // Once the attempt is finished, |callback| is invoked with the
  39   // result of the operation passed as a parameter. The result is a value from
  40   // the media::SwitchOutputDeviceResult enum.
  41   // There is no guarantee about the thread where |callback| will
  42   // be invoked, so users are advised to use media::BindToCurrentLoop() to
  43   // ensure that |callback| runs on the correct thread.
  44   // Note also that copy constructors and destructors for arguments bound to
  45   // |callback| may run on arbitrary threads as |callback| is moved across
  46   // threads. It is advisable to bind arguments such that they are released by
  47   // |callback| when it runs in order to avoid surprises.
  48   virtual void SwitchOutputDevice(
  49       const std::string& device_id,
  50       const GURL& security_origin,
  51       const media::SwitchOutputDeviceCB& callback) = 0;
  52
  53   // Time stamp that reflects the current render time. Should not be updated
  54   // when paused.
  55   virtual base::TimeDelta GetCurrentRenderTime() const = 0;
  56
  57   // Returns true if the implementation is a local renderer and false
  58   // otherwise.
  59   virtual bool IsLocalRenderer() const = 0;
  60
  61  protected:
  62   friend class base::RefCountedThreadSafe<MediaStreamAudioRenderer>;
  63
  64   virtual ~MediaStreamAudioRenderer() {}
  65 };
  66
  67 }  // namespace content
  68
  69 #endif  // CONTENT_PUBLIC_RENDERER_MEDIA_STREAM_AUDIO_RENDERER_H_