media/base/audio_capturer_source.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 MEDIA_BASE_AUDIO_CAPTURER_SOURCE_H_
   6 #define MEDIA_BASE_AUDIO_CAPTURER_SOURCE_H_
   7
   8 #include <string>
   9 #include <vector>
  10 #include "base/basictypes.h"
  11 #include "base/memory/ref_counted.h"
  12 #include "media/audio/audio_parameters.h"
  13 #include "media/base/audio_bus.h"
  14 #include "media/base/media_export.h"
  15
  16 namespace media {
  17
  18 // AudioCapturerSource is an interface representing the source for
  19 // captured audio.  An implementation will periodically call Capture() on a
  20 // callback object.
  21 class AudioCapturerSource
  22     : public base::RefCountedThreadSafe<media::AudioCapturerSource> {
  23  public:
  24   class CaptureCallback {
  25    public:
  26     // Callback to deliver the captured data from the OS.
  27     virtual void Capture(const AudioBus* audio_source,
  28                          int audio_delay_milliseconds,
  29                          double volume,
  30                          bool key_pressed) = 0;
  31
  32     // Signals an error has occurred.
  33     virtual void OnCaptureError(const std::string& message) = 0;
  34
  35    protected:
  36     virtual ~CaptureCallback() {}
  37   };
  38
  39   // Sets information about the audio stream format and the device
  40   // to be used. It must be called before any of the other methods.
  41   // The |session_id| is used by the browser to identify which input device to
  42   // be used. For clients who do not care about device permission and device
  43   // selection, pass |session_id| using
  44   // AudioInputDeviceManager::kFakeOpenSessionId.
  45   virtual void Initialize(const AudioParameters& params,
  46                           CaptureCallback* callback,
  47                           int session_id) = 0;
  48
  49   // Starts the audio recording.
  50   virtual void Start() = 0;
  51
  52   // Stops the audio recording. This API is synchronous, and no more data
  53   // callback will be passed to the client after it is being called.
  54   virtual void Stop() = 0;
  55
  56   // Sets the capture volume, with range [0.0, 1.0] inclusive.
  57   virtual void SetVolume(double volume) = 0;
  58
  59   // Enables or disables the WebRtc AGC control.
  60   virtual void SetAutomaticGainControl(bool enable) = 0;
  61
  62  protected:
  63   friend class base::RefCountedThreadSafe<AudioCapturerSource>;
  64   virtual ~AudioCapturerSource() {}
  65 };
  66
  67 }  // namespace media
  68
  69 #endif  // MEDIA_BASE_AUDIO_CAPTURER_SOURCE_H_