RTCAudioSession Class Reference

Inherits from NSObject
Conforms to RTCAudioSessionActivationDelegate
Declared in RTCAudioSession.h
RTCAudioSession_old.h

Overview

Proxy class for AVAudioSession that adds a locking mechanism similar to AVCaptureDevice. This is used to that interleaving configurations between WebRTC and the application layer are avoided.

RTCAudioSession also coordinates activation so that the audio session is activated only once. See |setActive:error:|.

Other Methods

  session

Convenience property to access the AVAudioSession singleton. Callers should not call setters on AVAudioSession directly, but other method invocations are fine.

@property (nonatomic, readonly) AVAudioSession *session

Discussion

Convenience property to access the AVAudioSession singleton. Callers should not call setters on AVAudioSession directly, but other method invocations are fine.

Declared In

RTCAudioSession.h

  isActive

Our best guess at whether the session is active based on results of calls to AVAudioSession.

@property (nonatomic, readonly) BOOL isActive

Discussion

Our best guess at whether the session is active based on results of calls to AVAudioSession.

Declared In

RTCAudioSession.h

  isLocked

Whether RTCAudioSession is currently locked for configuration.

@property (nonatomic, readonly) BOOL isLocked

Discussion

Whether RTCAudioSession is currently locked for configuration.

Declared In

RTCAudioSession.h

  useManualAudio

If YES, WebRTC will not initialize the audio unit automatically when an audio track is ready for playout or recording. Instead, applications should call setIsAudioEnabled. If NO, WebRTC will initialize the audio unit as soon as an audio track is ready for playout or recording.

@property (nonatomic, assign) BOOL useManualAudio

Discussion

If YES, WebRTC will not initialize the audio unit automatically when an audio track is ready for playout or recording. Instead, applications should call setIsAudioEnabled. If NO, WebRTC will initialize the audio unit as soon as an audio track is ready for playout or recording.

Declared In

RTCAudioSession.h

  isAudioEnabled

This property is only effective if useManualAudio is YES. Represents permission for WebRTC to initialize the VoIP audio unit. When set to NO, if the VoIP audio unit used by WebRTC is active, it will be stopped and uninitialized. This will stop incoming and outgoing audio. When set to YES, WebRTC will initialize and start the audio unit when it is needed (e.g. due to establishing an audio connection). This property was introduced to work around an issue where if an AVPlayer is playing audio while the VoIP audio unit is initialized, its audio would be either cut off completely or played at a reduced volume. By preventing the audio unit from being initialized until after the audio has completed, we are able to prevent the abrupt cutoff.

@property (nonatomic, assign) BOOL isAudioEnabled

Discussion

This property is only effective if useManualAudio is YES. Represents permission for WebRTC to initialize the VoIP audio unit. When set to NO, if the VoIP audio unit used by WebRTC is active, it will be stopped and uninitialized. This will stop incoming and outgoing audio. When set to YES, WebRTC will initialize and start the audio unit when it is needed (e.g. due to establishing an audio connection). This property was introduced to work around an issue where if an AVPlayer is playing audio while the VoIP audio unit is initialized, its audio would be either cut off completely or played at a reduced volume. By preventing the audio unit from being initialized until after the audio has completed, we are able to prevent the abrupt cutoff.

Declared In

RTCAudioSession.h

  inputDataSource 

NSArray<AVAudioSessionDataSourceDescription *> * inputDataSources;
@property (readonly, nullable) AVAudioSessionDataSourceDescription *inputDataSource

Discussion

NSArray<AVAudioSessionDataSourceDescription *> * inputDataSources;

Declared In

RTCAudioSession_old.h

  outputDataSource 

NSArray<AVAudioSessionDataSourceDescription *> * outputDataSources;
@property (readonly, nullable) AVAudioSessionDataSourceDescription *outputDataSource

Discussion

NSArray<AVAudioSessionDataSourceDescription *> * outputDataSources;

Declared In

RTCAudioSession_old.h

+ sharedInstance

Default constructor.

+ (instancetype)sharedInstance

Discussion

Default constructor.

Declared In

RTCAudioSession.h

– addDelegate:

Adds a delegate, which is held weakly.

- (void)addDelegate:(id<RTCAudioSessionDelegate>)delegate

Discussion

Adds a delegate, which is held weakly.

Declared In

RTCAudioSession.h

– removeDelegate:

Removes an added delegate.

- (void)removeDelegate:(id<RTCAudioSessionDelegate>)delegate

Discussion

Removes an added delegate.

Declared In

RTCAudioSession.h

– lockForConfiguration

Request exclusive access to the audio session for configuration. This call will block if the lock is held by another object.

- (void)lockForConfiguration

Discussion

Request exclusive access to the audio session for configuration. This call will block if the lock is held by another object.

Declared In

RTCAudioSession.h

– unlockForConfiguration

Relinquishes exclusive access to the audio session.

- (void)unlockForConfiguration

Discussion

Relinquishes exclusive access to the audio session.

Declared In

RTCAudioSession.h

– setActive:error:

If |active|, activates the audio session if it isn’t already active. Successful calls must be balanced with a setActive:NO when activation is no longer required. If not |active|, deactivates the audio session if one is active and this is the last balanced call. When deactivating, the AVAudioSessionSetActiveOptionNotifyOthersOnDeactivation option is passed to AVAudioSession.

- (BOOL)setActive:(BOOL)active error:(NSError **)outError

Discussion

If |active|, activates the audio session if it isn’t already active. Successful calls must be balanced with a setActive:NO when activation is no longer required. If not |active|, deactivates the audio session if one is active and this is the last balanced call. When deactivating, the AVAudioSessionSetActiveOptionNotifyOthersOnDeactivation option is passed to AVAudioSession.

Declared In

RTCAudioSession.h

Configuration Methods

– setConfiguration:error:

Applies the configuration to the current session. Attempts to set all properties even if previous ones fail. Only the last error will be returned. |lockForConfiguration| must be called first.

- (BOOL)setConfiguration:(RTCAudioSessionConfiguration *)configuration error:(NSError **)outError

Discussion

Applies the configuration to the current session. Attempts to set all properties even if previous ones fail. Only the last error will be returned. |lockForConfiguration| must be called first.

Declared In

RTCAudioSession.h

– setConfiguration:active:error:

Convenience method that calls both setConfiguration and setActive. |lockForConfiguration| must be called first.

- (BOOL)setConfiguration:(RTCAudioSessionConfiguration *)configuration active:(BOOL)active error:(NSError **)outError

Discussion

Convenience method that calls both setConfiguration and setActive. |lockForConfiguration| must be called first.

Declared In

RTCAudioSession.h