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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_AUDIO_MAC_AUDIO_SYNCHRONIZED_MAC_H_ | |
6 #define MEDIA_AUDIO_MAC_AUDIO_SYNCHRONIZED_MAC_H_ | |
7 | |
8 #include <AudioToolbox/AudioToolbox.h> | |
9 #include <AudioUnit/AudioUnit.h> | |
10 #include <CoreAudio/CoreAudio.h> | |
11 | |
12 #include "base/compiler_specific.h" | |
13 #include "base/synchronization/lock.h" | |
14 #include "media/audio/audio_io.h" | |
15 #include "media/audio/audio_parameters.h" | |
16 #include "media/base/audio_fifo.h" | |
17 | |
18 namespace media { | |
19 | |
20 class AudioManagerMac; | |
21 | |
22 // AudioSynchronizedStream allows arbitrary combinations of input and output | |
23 // devices running off different clocks and using different drivers, with | |
24 // potentially differing sample-rates. It implements AudioOutputStream | |
25 // and shuttles its synchronized I/O data using AudioSourceCallback. | |
26 // | |
27 // It is required to first acquire the native sample rate of the selected | |
28 // output device and then use the same rate when creating this object. | |
29 // | |
30 // ............................................................................ | |
31 // Theory of Operation: | |
32 // . | |
33 // INPUT THREAD . OUTPUT THREAD | |
34 // +-----------------+ +------+ . | |
35 // | Input AudioUnit | --> | | . | |
36 // +-----------------+ | | . | |
37 // | FIFO | . | |
38 // | | +-----------+ | |
39 // | | -----> | Varispeed | | |
40 // | | +-----------+ | |
41 // +------+ . | | |
42 // . | +-----------+ | |
43 // . OnMoreIOData() --> | Output AU | | |
44 // . +-----------+ | |
45 // | |
46 // The input AudioUnit's InputProc is called on one thread which feeds the | |
47 // FIFO. The output AudioUnit's OutputProc is called on a second thread | |
48 // which pulls on the varispeed to get the current input data. The varispeed | |
49 // handles mismatches between input and output sample-rate and also clock drift | |
50 // between the input and output drivers. The varispeed consumes its data from | |
51 // the FIFO and adjusts its rate dynamically according to the amount | |
52 // of data buffered in the FIFO. If the FIFO starts getting too much data | |
53 // buffered then the varispeed will speed up slightly to compensate | |
54 // and similarly if the FIFO doesn't have enough data buffered then the | |
55 // varispeed will slow down slightly. | |
56 // | |
57 // Finally, once the input data is available then OnMoreIOData() is called | |
58 // which is given this input, and renders the output which is finally sent | |
59 // to the Output AudioUnit. | |
60 // | |
61 class AudioSynchronizedStream : public AudioOutputStream { | |
62 public: | |
63 // The ctor takes all the usual parameters, plus |manager| which is the | |
64 // the audio manager who is creating this object. | |
65 AudioSynchronizedStream(AudioManagerMac* manager, | |
66 const AudioParameters& params, | |
67 AudioDeviceID input_id, | |
68 AudioDeviceID output_id); | |
69 | |
70 virtual ~AudioSynchronizedStream(); | |
71 | |
72 // Implementation of AudioOutputStream. | |
73 virtual bool Open() OVERRIDE; | |
74 virtual void Close() OVERRIDE; | |
75 virtual void Start(AudioSourceCallback* callback) OVERRIDE; | |
76 virtual void Stop() OVERRIDE; | |
77 | |
78 virtual void SetVolume(double volume) OVERRIDE; | |
79 virtual void GetVolume(double* volume) OVERRIDE; | |
80 | |
81 OSStatus SetInputDeviceAsCurrent(AudioDeviceID input_id); | |
82 OSStatus SetOutputDeviceAsCurrent(AudioDeviceID output_id); | |
83 AudioDeviceID GetInputDeviceID() { return input_info_.id_; } | |
84 AudioDeviceID GetOutputDeviceID() { return output_info_.id_; } | |
85 | |
86 bool IsRunning(); | |
87 | |
88 private: | |
89 // Initialization. | |
90 OSStatus CreateAudioUnits(); | |
91 OSStatus SetupInput(AudioDeviceID input_id); | |
92 OSStatus EnableIO(); | |
93 OSStatus SetupOutput(AudioDeviceID output_id); | |
94 OSStatus SetupCallbacks(); | |
95 OSStatus SetupStreamFormats(); | |
96 void AllocateInputData(); | |
97 | |
98 void ComputeThruOffset(); | |
99 | |
100 // Handlers for the AudioUnit callbacks. | |
101 OSStatus HandleInputCallback(AudioUnitRenderActionFlags* io_action_flags, | |
102 const AudioTimeStamp* time_stamp, | |
103 UInt32 bus_number, | |
104 UInt32 number_of_frames, | |
105 AudioBufferList* io_data); | |
106 | |
107 OSStatus HandleVarispeedCallback(AudioUnitRenderActionFlags* io_action_flags, | |
108 const AudioTimeStamp* time_stamp, | |
109 UInt32 bus_number, | |
110 UInt32 number_of_frames, | |
111 AudioBufferList* io_data); | |
112 | |
113 OSStatus HandleOutputCallback(AudioUnitRenderActionFlags* io_action_flags, | |
114 const AudioTimeStamp* time_stamp, | |
115 UInt32 bus_number, | |
116 UInt32 number_of_frames, | |
117 AudioBufferList* io_data); | |
118 | |
119 // AudioUnit callbacks. | |
120 static OSStatus InputProc(void* user_data, | |
121 AudioUnitRenderActionFlags* io_action_flags, | |
122 const AudioTimeStamp* time_stamp, | |
123 UInt32 bus_number, | |
124 UInt32 number_of_frames, | |
125 AudioBufferList* io_data); | |
126 | |
127 static OSStatus VarispeedProc(void* user_data, | |
128 AudioUnitRenderActionFlags* io_action_flags, | |
129 const AudioTimeStamp* time_stamp, | |
130 UInt32 bus_number, | |
131 UInt32 number_of_frames, | |
132 AudioBufferList* io_data); | |
133 | |
134 static OSStatus OutputProc(void* user_data, | |
135 AudioUnitRenderActionFlags* io_action_flags, | |
136 const AudioTimeStamp* time_stamp, | |
137 UInt32 bus_number, | |
138 UInt32 number_of_frames, | |
139 AudioBufferList* io_data); | |
140 | |
141 // Our creator. | |
142 AudioManagerMac* manager_; | |
143 | |
144 // Pointer to the object that will provide the audio samples. | |
145 AudioSourceCallback* source_; | |
146 | |
147 // Values used in Open(). | |
148 AudioDeviceID input_id_; | |
149 AudioDeviceID output_id_; | |
150 | |
151 // The input AudioUnit renders its data here. | |
152 AudioBufferList* input_data_; | |
153 | |
154 class AudioDeviceInfo { | |
155 public: | |
156 AudioDeviceInfo() | |
157 : id_(kAudioDeviceUnknown), | |
scherkus (not reviewing)
2012/09/13 13:06:03
should be indented by two more spaces
Chris Rogers
2012/09/15 00:06:08
Done.
| |
158 is_input_(false), | |
159 buffer_size_frames_(0) {} | |
160 void Initialize(AudioDeviceID inID, bool isInput); | |
161 bool IsInitialized() const { return id_ != kAudioDeviceUnknown; } | |
162 | |
163 AudioDeviceID id_; | |
164 bool is_input_; | |
165 UInt32 buffer_size_frames_; | |
166 }; | |
167 | |
168 AudioDeviceInfo input_info_; | |
169 AudioDeviceInfo output_info_; | |
170 | |
171 // Used for input to output buffering. | |
172 AudioFifo fifo_; | |
173 | |
174 // Protect FIFO access. | |
175 // TODO(crogers): the correct solution is to make AudioFifo thread-safe. | |
176 // This lock is just a stop-gap, and is not good since it can cause glitches | |
177 // if the lock is contended. | |
178 base::Lock fifo_lock_; | |
179 | |
180 bool is_fifo_initialized_; | |
181 double fifo_rate_compensation_; | |
182 double output_sample_rate_; | |
183 | |
184 // AudioUnits. | |
185 AudioUnit input_unit_; | |
186 AudioUnit varispeed_unit_; | |
187 AudioUnit output_unit_; | |
188 | |
189 // Initial latency estimation. | |
190 double first_input_time_; | |
191 double first_output_time_; | |
192 double in_to_out_sample_offset_; | |
193 | |
194 bool is_running_; | |
195 UInt32 hardware_buffer_size_; | |
scherkus (not reviewing)
2012/09/13 13:06:03
any chance we can swap UInt32 for int, size_t, uin
Chris Rogers
2012/09/15 00:06:08
Removed here and in a few other places. But there
| |
196 int channels_; | |
197 | |
198 DISALLOW_COPY_AND_ASSIGN(AudioSynchronizedStream); | |
199 }; | |
200 | |
201 } // namespace media | |
202 | |
203 #endif // MEDIA_AUDIO_MAC_AUDIO_SYNCHRONIZED_MAC_H_ | |
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