RTCAudioSession.h

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/*
 *  Copyright 2016 The WebRTC Project Authors. All rights reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#import <AVFoundation/AVFoundation.h>
#import <Foundation/Foundation.h>

NS_ASSUME_NONNULL_BEGIN

extern NSString * const kRTCAudioSessionErrorDomain;
extern NSInteger const kRTCAudioSessionErrorLockRequired;

@class RTCAudioSession;

// Surfaces AVAudioSession events. WebRTC will listen directly for notifications
// from AVAudioSession and handle them before calling these delegate methods,
// at which point applications can perform additional processing if required.
@protocol RTCAudioSessionDelegate <NSObject>

- (void)rtcaudioSessionDidBeginInterruption:(RTCAudioSession *)session;

- (void)rtcaudioSessionDidEndInterruption:(RTCAudioSession *)session
                   shouldResumeSession:(BOOL)shouldResumeSession;

- (void)rtcaudioSessionDidChangeRoute:(RTCAudioSession *)session
           reason:(AVAudioSessionRouteChangeReason)reason
    previousRoute:(AVAudioSessionRouteDescription *)previousRoute;

- (void)rtcaudioSessionMediaServicesWereLost:(RTCAudioSession *)session;

- (void)rtcaudioSessionMediaServicesWereReset:(RTCAudioSession *)session;

// TODO(tkchin): Maybe handle SilenceSecondaryAudioHintNotification.

@end

@interface RTCAudioSession : NSObject

@property(nonatomic, readonly) AVAudioSession *session;

@property(nonatomic, readonly) BOOL isActive;
@property(nonatomic, readonly) BOOL isLocked;

// Proxy properties.
@property(readonly) NSString *category;
@property(readonly) AVAudioSessionCategoryOptions categoryOptions;
@property(readonly) NSString *mode;
@property(readonly) BOOL secondaryAudioShouldBeSilencedHint;
@property(readonly) AVAudioSessionRouteDescription *currentRoute;
@property(readonly) NSInteger maximumInputNumberOfChannels;
@property(readonly) NSInteger maximumOutputNumberOfChannels;
@property(readonly) float inputGain;
@property(readonly) BOOL inputGainSettable;
@property(readonly) BOOL inputAvailable;
@property(readonly, nullable) NSArray* inputDataSources;
@property(readonly, nullable)
  AVAudioSessionDataSourceDescription *inputDataSource;
@property(readonly, nullable) NSArray* outputDataSources;
@property(readonly, nullable)
    AVAudioSessionDataSourceDescription *outputDataSource;
@property(readonly) double sampleRate;
@property(readonly) NSInteger inputNumberOfChannels;
@property(readonly) NSInteger outputNumberOfChannels;
@property(readonly) float outputVolume;
@property(readonly) NSTimeInterval inputLatency;
@property(readonly) NSTimeInterval outputLatency;
@property(readonly) NSTimeInterval IOBufferDuration;

+ (instancetype)sharedInstance;

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

- (void)lockForConfiguration;
- (void)unlockForConfiguration;

- (BOOL)setActive:(BOOL)active
            error:(NSError **)outError;
- (BOOL)setActive:(BOOL)active
            withOptions:(AVAudioSessionSetActiveOptions)options
            error:(NSError **)outError;

// The following methods are proxies for the associated methods on
// AVAudioSession. |lockForConfiguration| must be called before using them
// otherwise they will fail with kRTCAudioSessionErrorLockRequired.

- (BOOL)setCategory:(NSString *)category
        withOptions:(AVAudioSessionCategoryOptions)options
              error:(NSError **)outError;
- (BOOL)setMode:(NSString *)mode error:(NSError **)outError;
- (BOOL)setInputGain:(float)gain error:(NSError **)outError;
- (BOOL)setPreferredSampleRate:(double)sampleRate error:(NSError **)outError;
- (BOOL)setPreferredIOBufferDuration:(NSTimeInterval)duration
                               error:(NSError **)outError;
- (BOOL)setPreferredInputNumberOfChannels:(NSInteger)count
                                    error:(NSError **)outError;
- (BOOL)setPreferredOutputNumberOfChannels:(NSInteger)count
                                     error:(NSError **)outError;
- (BOOL)overrideOutputAudioPort:(AVAudioSessionPortOverride)portOverride
                          error:(NSError **)outError;
- (BOOL)setPreferredInput:(AVAudioSessionPortDescription *)inPort
                    error:(NSError **)outError;
- (BOOL)setInputDataSource:(AVAudioSessionDataSourceDescription *)dataSource
                     error:(NSError **)outError;
- (BOOL)setOutputDataSource:(AVAudioSessionDataSourceDescription *)dataSource
                      error:(NSError **)outError;

@end

NS_ASSUME_NONNULL_END