audio_capturer_source.h revision 3551c9c881056c480085172ff9840cab31610854 
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
16namespace 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.
21class 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(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