1 /* 2 * Copyright 2016 The WebRTC Project Authors. All rights reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #import <AVFoundation/AVFoundation.h> 12 #import <Foundation/Foundation.h> 13 14 #import "RTCMacros.h" 15 16 NS_ASSUME_NONNULL_BEGIN 17 18 extern NSString *const kRTCAudioSessionErrorDomain; 19 /** Method that requires lock was called without lock. */ 20 extern NSInteger const kRTCAudioSessionErrorLockRequired; 21 /** Unknown configuration error occurred. */ 22 extern NSInteger const kRTCAudioSessionErrorConfiguration; 23 24 @class RTCAudioSession; 25 @class RTCAudioSessionConfiguration; 26 27 // Surfaces AVAudioSession events. WebRTC will listen directly for notifications 28 // from AVAudioSession and handle them before calling these delegate methods, 29 // at which point applications can perform additional processing if required. 30 RTC_OBJC_EXPORT 31 @protocol RTCAudioSessionDelegate <NSObject> 32 33 @optional 34 /** Called on a system notification thread when AVAudioSession starts an 35 * interruption event. 36 */ 37 - (void)audioSessionDidBeginInterruption:(RTCAudioSession *)session; 38 39 /** Called on a system notification thread when AVAudioSession ends an 40 * interruption event. 41 */ 42 - (void)audioSessionDidEndInterruption:(RTCAudioSession *)session 43 shouldResumeSession:(BOOL)shouldResumeSession; 44 45 /** Called on a system notification thread when AVAudioSession changes the 46 * route. 47 */ 48 - (void)audioSessionDidChangeRoute:(RTCAudioSession *)session 49 reason:(AVAudioSessionRouteChangeReason)reason 50 previousRoute:(AVAudioSessionRouteDescription *)previousRoute; 51 52 /** Called on a system notification thread when AVAudioSession media server 53 * terminates. 54 */ 55 - (void)audioSessionMediaServerTerminated:(RTCAudioSession *)session; 56 57 /** Called on a system notification thread when AVAudioSession media server 58 * restarts. 59 */ 60 - (void)audioSessionMediaServerReset:(RTCAudioSession *)session; 61 62 // TODO(tkchin): Maybe handle SilenceSecondaryAudioHintNotification. 63 64 - (void)audioSession:(RTCAudioSession *)session didChangeCanPlayOrRecord:(BOOL)canPlayOrRecord; 65 66 /** Called on a WebRTC thread when the audio device is notified to begin 67 * playback or recording. 68 */ 69 - (void)audioSessionDidStartPlayOrRecord:(RTCAudioSession *)session; 70 71 /** Called on a WebRTC thread when the audio device is notified to stop 72 * playback or recording. 73 */ 74 - (void)audioSessionDidStopPlayOrRecord:(RTCAudioSession *)session; 75 76 /** Called when the AVAudioSession output volume value changes. */ 77 - (void)audioSession:(RTCAudioSession *)audioSession didChangeOutputVolume:(float)outputVolume; 78 79 /** Called when the audio device detects a playout glitch. The argument is the 80 * number of glitches detected so far in the current audio playout session. 81 */ 82 - (void)audioSession:(RTCAudioSession *)audioSession 83 didDetectPlayoutGlitch:(int64_t)totalNumberOfGlitches; 84 85 /** Called when the audio session is about to change the active state. 86 */ 87 - (void)audioSession:(RTCAudioSession *)audioSession willSetActive:(BOOL)active; 88 89 /** Called after the audio session sucessfully changed the active state. 90 */ 91 - (void)audioSession:(RTCAudioSession *)audioSession didSetActive:(BOOL)active; 92 93 /** Called after the audio session failed to change the active state. 94 */ 95 - (void)audioSession:(RTCAudioSession *)audioSession 96 failedToSetActive:(BOOL)active 97 error:(NSError *)error; 98 99 @end 100 101 /** This is a protocol used to inform RTCAudioSession when the audio session 102 * activation state has changed outside of RTCAudioSession. The current known use 103 * case of this is when CallKit activates the audio session for the application 104 */ 105 RTC_OBJC_EXPORT 106 @protocol RTCAudioSessionActivationDelegate <NSObject> 107 108 /** Called when the audio session is activated outside of the app by iOS. */ 109 - (void)audioSessionDidActivate:(AVAudioSession *)session; 110 111 /** Called when the audio session is deactivated outside of the app by iOS. */ 112 - (void)audioSessionDidDeactivate:(AVAudioSession *)session; 113 114 @end 115 116 /** Proxy class for AVAudioSession that adds a locking mechanism similar to 117 * AVCaptureDevice. This is used to that interleaving configurations between 118 * WebRTC and the application layer are avoided. 119 * 120 * RTCAudioSession also coordinates activation so that the audio session is 121 * activated only once. See |setActive:error:|. 122 */ 123 RTC_OBJC_EXPORT 124 @interface RTCAudioSession : NSObject <RTCAudioSessionActivationDelegate> 125 126 /** Convenience property to access the AVAudioSession singleton. Callers should 127 * not call setters on AVAudioSession directly, but other method invocations 128 * are fine. 129 */ 130 @property(nonatomic, readonly) AVAudioSession *session; 131 132 /** Our best guess at whether the session is active based on results of calls to 133 * AVAudioSession. 134 */ 135 @property(nonatomic, readonly) BOOL isActive; 136 /** Whether RTCAudioSession is currently locked for configuration. */ 137 @property(nonatomic, readonly) BOOL isLocked; 138 139 /** If YES, WebRTC will not initialize the audio unit automatically when an 140 * audio track is ready for playout or recording. Instead, applications should 141 * call setIsAudioEnabled. If NO, WebRTC will initialize the audio unit 142 * as soon as an audio track is ready for playout or recording. 143 */ 144 @property(nonatomic, assign) BOOL useManualAudio; 145 146 /** This property is only effective if useManualAudio is YES. 147 * Represents permission for WebRTC to initialize the VoIP audio unit. 148 * When set to NO, if the VoIP audio unit used by WebRTC is active, it will be 149 * stopped and uninitialized. This will stop incoming and outgoing audio. 150 * When set to YES, WebRTC will initialize and start the audio unit when it is 151 * needed (e.g. due to establishing an audio connection). 152 * This property was introduced to work around an issue where if an AVPlayer is 153 * playing audio while the VoIP audio unit is initialized, its audio would be 154 * either cut off completely or played at a reduced volume. By preventing 155 * the audio unit from being initialized until after the audio has completed, 156 * we are able to prevent the abrupt cutoff. 157 */ 158 @property(nonatomic, assign) BOOL isAudioEnabled; 159 160 // Proxy properties. 161 @property(readonly) NSString *category; 162 @property(readonly) AVAudioSessionCategoryOptions categoryOptions; 163 @property(readonly) NSString *mode; 164 @property(readonly) BOOL secondaryAudioShouldBeSilencedHint; 165 @property(readonly) AVAudioSessionRouteDescription *currentRoute; 166 @property(readonly) NSInteger maximumInputNumberOfChannels; 167 @property(readonly) NSInteger maximumOutputNumberOfChannels; 168 @property(readonly) float inputGain; 169 @property(readonly) BOOL inputGainSettable; 170 @property(readonly) BOOL inputAvailable; 171 @property(readonly, nullable) NSArray<AVAudioSessionDataSourceDescription *> *inputDataSources; 172 @property(readonly, nullable) AVAudioSessionDataSourceDescription *inputDataSource; 173 @property(readonly, nullable) NSArray<AVAudioSessionDataSourceDescription *> *outputDataSources; 174 @property(readonly, nullable) AVAudioSessionDataSourceDescription *outputDataSource; 175 @property(readonly) double sampleRate; 176 @property(readonly) double preferredSampleRate; 177 @property(readonly) NSInteger inputNumberOfChannels; 178 @property(readonly) NSInteger outputNumberOfChannels; 179 @property(readonly) float outputVolume; 180 @property(readonly) NSTimeInterval inputLatency; 181 @property(readonly) NSTimeInterval outputLatency; 182 @property(readonly) NSTimeInterval IOBufferDuration; 183 @property(readonly) NSTimeInterval preferredIOBufferDuration; 184 185 /** 186 When YES, calls to -setConfiguration:error: and -setConfiguration:active:error: ignore errors in 187 configuring the audio session's "preferred" attributes (e.g. preferredInputNumberOfChannels). 188 Typically, configurations to preferred attributes are optimizations, and ignoring this type of 189 configuration error allows code flow to continue along the happy path when these optimization are 190 not available. The default value of this property is NO. 191 */ 192 @property(nonatomic) BOOL ignoresPreferredAttributeConfigurationErrors; 193 194 /** Default constructor. */ 195 + (instancetype)sharedInstance; 196 - (instancetype)init NS_UNAVAILABLE; 197 198 /** Adds a delegate, which is held weakly. */ 199 - (void)addDelegate:(id<RTCAudioSessionDelegate>)delegate; 200 /** Removes an added delegate. */ 201 - (void)removeDelegate:(id<RTCAudioSessionDelegate>)delegate; 202 203 /** Request exclusive access to the audio session for configuration. This call 204 * will block if the lock is held by another object. 205 */ 206 - (void)lockForConfiguration; 207 /** Relinquishes exclusive access to the audio session. */ 208 - (void)unlockForConfiguration; 209 210 /** If |active|, activates the audio session if it isn't already active. 211 * Successful calls must be balanced with a setActive:NO when activation is no 212 * longer required. If not |active|, deactivates the audio session if one is 213 * active and this is the last balanced call. When deactivating, the 214 * AVAudioSessionSetActiveOptionNotifyOthersOnDeactivation option is passed to 215 * AVAudioSession. 216 */ 217 - (BOOL)setActive:(BOOL)active error:(NSError **)outError; 218 219 // The following methods are proxies for the associated methods on 220 // AVAudioSession. |lockForConfiguration| must be called before using them 221 // otherwise they will fail with kRTCAudioSessionErrorLockRequired. 222 223 - (BOOL)setCategory:(NSString *)category 224 withOptions:(AVAudioSessionCategoryOptions)options 225 error:(NSError **)outError; 226 - (BOOL)setMode:(NSString *)mode error:(NSError **)outError; 227 - (BOOL)setInputGain:(float)gain error:(NSError **)outError; 228 - (BOOL)setPreferredSampleRate:(double)sampleRate error:(NSError **)outError; 229 - (BOOL)setPreferredIOBufferDuration:(NSTimeInterval)duration error:(NSError **)outError; 230 - (BOOL)setPreferredInputNumberOfChannels:(NSInteger)count error:(NSError **)outError; 231 - (BOOL)setPreferredOutputNumberOfChannels:(NSInteger)count error:(NSError **)outError; 232 - (BOOL)overrideOutputAudioPort:(AVAudioSessionPortOverride)portOverride error:(NSError **)outError; 233 - (BOOL)setPreferredInput:(AVAudioSessionPortDescription *)inPort error:(NSError **)outError; 234 - (BOOL)setInputDataSource:(AVAudioSessionDataSourceDescription *)dataSource 235 error:(NSError **)outError; 236 - (BOOL)setOutputDataSource:(AVAudioSessionDataSourceDescription *)dataSource 237 error:(NSError **)outError; 238 @end 239 240 @interface RTCAudioSession (Configuration) 241 242 /** Applies the configuration to the current session. Attempts to set all 243 * properties even if previous ones fail. Only the last error will be 244 * returned. 245 * |lockForConfiguration| must be called first. 246 */ 247 - (BOOL)setConfiguration:(RTCAudioSessionConfiguration *)configuration error:(NSError **)outError; 248 249 /** Convenience method that calls both setConfiguration and setActive. 250 * |lockForConfiguration| must be called first. 251 */ 252 - (BOOL)setConfiguration:(RTCAudioSessionConfiguration *)configuration 253 active:(BOOL)active 254 error:(NSError **)outError; 255 256 @end 257 258 NS_ASSUME_NONNULL_END 259