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1 /*
2  * Copyright (C) 2009 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #ifndef ANDROID_AUDIOPOLICYINTERFACE_H
18 #define ANDROID_AUDIOPOLICYINTERFACE_H
19 
20 #include <media/AudioSystem.h>
21 #include <media/ToneGenerator.h>
22 #include <utils/String8.h>
23 
24 #include <hardware_legacy/AudioSystemLegacy.h>
25 #include <hardware/audio_policy.h>
26 
27 namespace android_audio_legacy {
28     using android::Vector;
29     using android::String8;
30     using android::ToneGenerator;
31 
32 // ----------------------------------------------------------------------------
33 
34 // The AudioPolicyInterface and AudioPolicyClientInterface classes define the communication interfaces
35 // between the platform specific audio policy manager and Android generic audio policy manager.
36 // The platform specific audio policy manager must implement methods of the AudioPolicyInterface class.
37 // This implementation makes use of the AudioPolicyClientInterface to control the activity and
38 // configuration of audio input and output streams.
39 //
40 // The platform specific audio policy manager is in charge of the audio routing and volume control
41 // policies for a given platform.
42 // The main roles of this module are:
43 //   - keep track of current system state (removable device connections, phone state, user requests...).
44 //   System state changes and user actions are notified to audio policy manager with methods of the AudioPolicyInterface.
45 //   - process getOutput() queries received when AudioTrack objects are created: Those queries
46 //   return a handler on an output that has been selected, configured and opened by the audio policy manager and that
47 //   must be used by the AudioTrack when registering to the AudioFlinger with the createTrack() method.
48 //   When the AudioTrack object is released, a putOutput() query is received and the audio policy manager can decide
49 //   to close or reconfigure the output depending on other streams using this output and current system state.
50 //   - similarly process getInput() and putInput() queries received from AudioRecord objects and configure audio inputs.
51 //   - process volume control requests: the stream volume is converted from an index value (received from UI) to a float value
52 //   applicable to each output as a function of platform specific settings and current output route (destination device). It
53 //   also make sure that streams are not muted if not allowed (e.g. camera shutter sound in some countries).
54 //
55 // The platform specific audio policy manager is provided as a shared library by platform vendors (as for libaudio.so)
56 // and is linked with libaudioflinger.so
57 
58 
59 //    Audio Policy Manager Interface
60 class AudioPolicyInterface
61 {
62 
63 public:
~AudioPolicyInterface()64     virtual ~AudioPolicyInterface() {}
65     //
66     // configuration functions
67     //
68 
69     // indicate a change in device connection status
70     virtual status_t setDeviceConnectionState(audio_devices_t device,
71                                           AudioSystem::device_connection_state state,
72                                           const char *device_address) = 0;
73     // retrieve a device connection status
74     virtual AudioSystem::device_connection_state getDeviceConnectionState(audio_devices_t device,
75                                                                           const char *device_address) = 0;
76     // indicate a change in phone state. Valid phones states are defined by AudioSystem::audio_mode
77     virtual void setPhoneState(int state) = 0;
78     // force using a specific device category for the specified usage
79     virtual void setForceUse(AudioSystem::force_use usage, AudioSystem::forced_config config) = 0;
80     // retrieve current device category forced for a given usage
81     virtual AudioSystem::forced_config getForceUse(AudioSystem::force_use usage) = 0;
82     // set a system property (e.g. camera sound always audible)
83     virtual void setSystemProperty(const char* property, const char* value) = 0;
84     // check proper initialization
85     virtual status_t initCheck() = 0;
86 
87     //
88     // Audio routing query functions
89     //
90 
91     // request an output appropriate for playback of the supplied stream type and parameters
92     virtual audio_io_handle_t getOutput(AudioSystem::stream_type stream,
93                                         uint32_t samplingRate,
94                                         audio_format_t format,
95                                         audio_channel_mask_t channelMask,
96                                         AudioSystem::output_flags flags,
97                                         const audio_offload_info_t *offloadInfo) = 0;
98     // indicates to the audio policy manager that the output starts being used by corresponding stream.
99     virtual status_t startOutput(audio_io_handle_t output,
100                                  AudioSystem::stream_type stream,
101                                  audio_session_t session = AUDIO_SESSION_NONE) = 0;
102     // indicates to the audio policy manager that the output stops being used by corresponding stream.
103     virtual status_t stopOutput(audio_io_handle_t output,
104                                 AudioSystem::stream_type stream,
105                                 audio_session_t session = AUDIO_SESSION_NONE) = 0;
106     // releases the output.
107     virtual void releaseOutput(audio_io_handle_t output) = 0;
108 
109     // request an input appropriate for record from the supplied device with supplied parameters.
110     virtual audio_io_handle_t getInput(int inputSource,
111                                     uint32_t samplingRate,
112                                     audio_format_t format,
113                                     audio_channel_mask_t channelMask,
114                                     AudioSystem::audio_in_acoustics acoustics) = 0;
115     // indicates to the audio policy manager that the input starts being used.
116     virtual status_t startInput(audio_io_handle_t input) = 0;
117     // indicates to the audio policy manager that the input stops being used.
118     virtual status_t stopInput(audio_io_handle_t input) = 0;
119     // releases the input.
120     virtual void releaseInput(audio_io_handle_t input) = 0;
121 
122     //
123     // volume control functions
124     //
125 
126     // initialises stream volume conversion parameters by specifying volume index range.
127     virtual void initStreamVolume(AudioSystem::stream_type stream,
128                                       int indexMin,
129                                       int indexMax) = 0;
130 
131     // sets the new stream volume at a level corresponding to the supplied index for the
132     // supplied device. By convention, specifying AUDIO_DEVICE_OUT_DEFAULT means
133     // setting volume for all devices
134     virtual status_t setStreamVolumeIndex(AudioSystem::stream_type stream,
135                                           int index,
136                                           audio_devices_t device) = 0;
137 
138     // retrieve current volume index for the specified stream and the
139     // specified device. By convention, specifying AUDIO_DEVICE_OUT_DEFAULT means
140     // querying the volume of the active device.
141     virtual status_t getStreamVolumeIndex(AudioSystem::stream_type stream,
142                                           int *index,
143                                           audio_devices_t device) = 0;
144 
145     // return the strategy corresponding to a given stream type
146     virtual uint32_t getStrategyForStream(AudioSystem::stream_type stream) = 0;
147 
148     // return the enabled output devices for the given stream type
149     virtual audio_devices_t getDevicesForStream(AudioSystem::stream_type stream) = 0;
150 
151     // Audio effect management
152     virtual audio_io_handle_t getOutputForEffect(const effect_descriptor_t *desc) = 0;
153     virtual status_t registerEffect(const effect_descriptor_t *desc,
154                                     audio_io_handle_t io,
155                                     uint32_t strategy,
156                                     audio_session_t session,
157                                     int id) = 0;
158     virtual status_t unregisterEffect(int id) = 0;
159     virtual status_t setEffectEnabled(int id, bool enabled) = 0;
160 
161     virtual bool isStreamActive(int stream, uint32_t inPastMs = 0) const = 0;
162     virtual bool isStreamActiveRemotely(int stream, uint32_t inPastMs = 0) const = 0;
163     virtual bool isSourceActive(audio_source_t source) const = 0;
164 
165     //dump state
166     virtual status_t    dump(int fd) = 0;
167 
168     virtual bool isOffloadSupported(const audio_offload_info_t& offloadInfo) = 0;
169 };
170 
171 
172 // Audio Policy client Interface
173 class AudioPolicyClientInterface
174 {
175 public:
~AudioPolicyClientInterface()176     virtual ~AudioPolicyClientInterface() {}
177 
178     //
179     // Audio HW module functions
180     //
181 
182     // loads a HW module.
183     virtual audio_module_handle_t loadHwModule(const char *name) = 0;
184 
185     //
186     // Audio output Control functions
187     //
188 
189     // opens an audio output with the requested parameters. The parameter values can indicate to use the default values
190     // in case the audio policy manager has no specific requirements for the output being opened.
191     // When the function returns, the parameter values reflect the actual values used by the audio hardware output stream.
192     // The audio policy manager can check if the proposed parameters are suitable or not and act accordingly.
193     virtual audio_io_handle_t openOutput(audio_module_handle_t module,
194                                          audio_devices_t *pDevices,
195                                          uint32_t *pSamplingRate,
196                                          audio_format_t *pFormat,
197                                          audio_channel_mask_t *pChannelMask,
198                                          uint32_t *pLatencyMs,
199                                          audio_output_flags_t flags,
200                                          const audio_offload_info_t *offloadInfo = NULL) = 0;
201     // creates a special output that is duplicated to the two outputs passed as arguments. The duplication is performed by
202     // a special mixer thread in the AudioFlinger.
203     virtual audio_io_handle_t openDuplicateOutput(audio_io_handle_t output1, audio_io_handle_t output2) = 0;
204     // closes the output stream
205     virtual status_t closeOutput(audio_io_handle_t output) = 0;
206     // suspends the output. When an output is suspended, the corresponding audio hardware output stream is placed in
207     // standby and the AudioTracks attached to the mixer thread are still processed but the output mix is discarded.
208     virtual status_t suspendOutput(audio_io_handle_t output) = 0;
209     // restores a suspended output.
210     virtual status_t restoreOutput(audio_io_handle_t output) = 0;
211 
212     //
213     // Audio input Control functions
214     //
215 
216     // opens an audio input
217     virtual audio_io_handle_t openInput(audio_module_handle_t module,
218                                         audio_devices_t *pDevices,
219                                         uint32_t *pSamplingRate,
220                                         audio_format_t *pFormat,
221                                         audio_channel_mask_t *pChannelMask) = 0;
222     // closes an audio input
223     virtual status_t closeInput(audio_io_handle_t input) = 0;
224     //
225     // misc control functions
226     //
227 
228     // set a stream volume for a particular output. For the same user setting, a given stream type can have different volumes
229     // for each output (destination device) it is attached to.
230     virtual status_t setStreamVolume(AudioSystem::stream_type stream, float volume, audio_io_handle_t output, int delayMs = 0) = 0;
231 
232     // invalidate a stream type, causing a reroute to an unspecified new output
233     virtual status_t invalidateStream(AudioSystem::stream_type stream) = 0;
234 
235     // function enabling to send proprietary informations directly from audio policy manager to audio hardware interface.
236     virtual void setParameters(audio_io_handle_t ioHandle, const String8& keyValuePairs, int delayMs = 0) = 0;
237     // function enabling to receive proprietary informations directly from audio hardware interface to audio policy manager.
238     virtual String8 getParameters(audio_io_handle_t ioHandle, const String8& keys) = 0;
239 
240     // request the playback of a tone on the specified stream: used for instance to replace notification sounds when playing
241     // over a telephony device during a phone call.
242     virtual status_t startTone(ToneGenerator::tone_type tone, AudioSystem::stream_type stream) = 0;
243     virtual status_t stopTone() = 0;
244 
245     // set down link audio volume.
246     virtual status_t setVoiceVolume(float volume, int delayMs = 0) = 0;
247 
248     // move effect to the specified output
249     virtual status_t moveEffects(audio_session_t session,
250                                      audio_io_handle_t srcOutput,
251                                      audio_io_handle_t dstOutput) = 0;
252 
253 };
254 
255 extern "C" AudioPolicyInterface* createAudioPolicyManager(AudioPolicyClientInterface *clientInterface);
256 extern "C" void destroyAudioPolicyManager(AudioPolicyInterface *interface);
257 
258 
259 }; // namespace android
260 
261 #endif // ANDROID_AUDIOPOLICYINTERFACE_H
262