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      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() = 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_
     70