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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 // AudioOutputMixer is a class that implements browser-side audio mixer. | |
6 // AudioOutputMixer implements both AudioOutputDispatcher and | |
7 // AudioSourceCallback interfaces. | |
8 | |
9 #ifndef MEDIA_AUDIO_AUDIO_OUTPUT_MIXER_H_ | |
10 #define MEDIA_AUDIO_AUDIO_OUTPUT_MIXER_H_ | |
11 | |
12 #include <map> | |
13 | |
14 #include "base/basictypes.h" | |
15 #include "base/memory/ref_counted.h" | |
16 #include "base/memory/scoped_ptr.h" | |
17 #include "base/memory/weak_ptr.h" | |
18 #include "base/synchronization/lock.h" | |
19 #include "base/timer.h" | |
20 #include "media/audio/audio_io.h" | |
21 #include "media/audio/audio_manager.h" | |
22 #include "media/audio/audio_output_dispatcher.h" | |
23 #include "media/audio/audio_parameters.h" | |
24 | |
25 class MEDIA_EXPORT AudioOutputMixer | |
26 : public AudioOutputDispatcher, | |
27 public AudioOutputStream::AudioSourceCallback { | |
28 public: | |
29 AudioOutputMixer(AudioManager* audio_manager, | |
30 const AudioParameters& params, | |
31 const base::TimeDelta& close_delay); | |
32 | |
33 // AudioOutputDispatcher interface. | |
34 virtual bool OpenStream() OVERRIDE; | |
35 virtual bool StartStream(AudioOutputStream::AudioSourceCallback* callback, | |
36 AudioOutputProxy* stream_proxy) OVERRIDE; | |
37 virtual void StopStream(AudioOutputProxy* stream_proxy) OVERRIDE; | |
38 virtual void StreamVolumeSet(AudioOutputProxy* stream_proxy, | |
39 double volume) OVERRIDE; | |
40 virtual void CloseStream(AudioOutputProxy* stream_proxy) OVERRIDE; | |
41 virtual void Shutdown() OVERRIDE; | |
42 | |
43 // AudioSourceCallback interface. | |
44 virtual uint32 OnMoreData(AudioOutputStream* stream, | |
45 uint8* dest, | |
46 uint32 max_size, | |
47 AudioBuffersState buffers_state) OVERRIDE; | |
48 virtual void OnError(AudioOutputStream* stream, int code) OVERRIDE; | |
49 virtual void WaitTillDataReady() OVERRIDE; | |
50 | |
51 private: | |
52 friend class base::RefCountedThreadSafe<AudioOutputMixer>; | |
53 virtual ~AudioOutputMixer(); | |
54 | |
55 // Called by |close_timer_|. Closes physical stream. | |
56 void ClosePhysicalStream(); | |
57 | |
58 // The |lock_| must be acquired whenever we modify |proxies_| in the audio | |
59 // manager thread or accessing it in the hardware audio thread. Read in the | |
60 // audio manager thread is safe. | |
61 base::Lock lock_; | |
62 | |
63 // List of audio output proxies. | |
64 // For every proxy we store aux structure containing data necessary for | |
65 // mixing. | |
66 struct ProxyData { | |
67 int pending_bytes; | |
68 }; | |
69 typedef std::map<AudioOutputProxy*, ProxyData> ProxyMap; | |
vrk (LEFT CHROMIUM)
2012/04/06 23:37:05
This is closer to what I was thinking, but now tha
enal1
2012/04/16 22:01:35
Done.
| |
70 ProxyMap proxies_; | |
71 | |
72 // Physical stream for this mixer. | |
73 scoped_ptr<AudioOutputStream> physical_stream_; | |
74 | |
75 // Temporary buffer used when mixing. Allocated in the constructor | |
76 // to avoid constant allocation/deallocation in the callback. | |
77 scoped_array<uint8> mixer_data_; | |
78 | |
79 // Used to post delayed tasks to ourselves that we cancel inside Shutdown(). | |
80 base::WeakPtrFactory<AudioOutputMixer> weak_this_; | |
81 base::DelayTimer<AudioOutputMixer> close_timer_; | |
82 | |
83 DISALLOW_COPY_AND_ASSIGN(AudioOutputMixer); | |
84 }; | |
85 | |
86 #endif // MEDIA_AUDIO_AUDIO_OUTPUT_MIXER_H_ | |
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