AVAudio Class Reference

Core Audio capture class for macOS audio input and system-wide audio tapping. Provides functionality for both microphone capture via AVFoundation and system-wide audio capture via Core Audio taps (requires macOS 14.0+). More...

#include <src/platform/macos/av_audio.h>

Inheritance diagram for AVAudio:

Collaboration diagram for AVAudio:

Instance Methods
(void)	- cleanupAudioBuffer
	Cleans up and deallocates the audio buffer resources.
(void)	- cleanupSystemTapContext:
	Cleans up system tap resources in a safe, ordered manner.
(OSStatus)	- createAggregateDeviceWithTapDescription:sampleRate:frameSize:
	Creates an aggregate device with the specified tap description and audio parameters.
(nullable CATapDescription *)	- createSystemTapDescriptionForChannels:
	Creates a Core Audio tap description for system audio capture.
(void)	- initializeAudioBuffer:
	Initializes the circular audio buffer for the specified number of channels.
(int)	- initializeSystemTapContext:frameSize:channels:
	Initializes the system tap context with specified audio parameters.
(int)	- setupMicrophone:sampleRate:frameSize:channels:
	Sets up microphone capture using AVFoundation framework.
(int)	- setupSystemTap:frameSize:channels:
	Sets up system-wide audio tap for capturing all system audio. Requires macOS 14.0+ and appropriate permissions.

Class Methods
(nullable AVCaptureDevice *)	+ findMicrophone:
	Find a specific microphone device by name.
(NSArray< NSString * > *)	+ microphoneNames
	Get names of all available microphone devices.
(NSArray< AVCaptureDevice * > *)	+ microphones
	Get all available microphone devices on the system.

Public Attributes
TPCircularBuffer	audioSampleBuffer
	Shared circular buffer for both audio capture paths.
dispatch_semaphore_t	audioSemaphore
	Real-time safe semaphore for signaling audio sample availability.

Properties
AVCaptureSession *	audioCaptureSession
	AVFoundation capture session for microphone input.
AVCaptureConnection *	audioConnection
	Audio connection within the capture session.
BOOL	hostAudioEnabled
	Whether host audio playback should be enabled (affects tap mute behavior)

Detailed Description

Core Audio capture class for macOS audio input and system-wide audio tapping. Provides functionality for both microphone capture via AVFoundation and system-wide audio capture via Core Audio taps (requires macOS 14.0+).

Method Documentation

cleanupSystemTapContext:

- (void) cleanupSystemTapContext:

(nullable id)

tapDescription

Cleans up system tap resources in a safe, ordered manner.

Parameters

tapDescription

Optional tap description object to release (can be nil)

createAggregateDeviceWithTapDescription:sampleRate:frameSize:

- (OSStatus) createAggregateDeviceWithTapDescription:		(CATapDescription *)	tapDescription
sampleRate:		(UInt32)	sampleRate
frameSize:		(UInt32)	frameSize

Creates an aggregate device with the specified tap description and audio parameters.

Parameters

tapDescription	Core Audio tap description for system audio capture
sampleRate	Target sample rate in Hz
frameSize	Number of frames per buffer

Returns

OSStatus indicating success (noErr) or error code

createSystemTapDescriptionForChannels:

- (CATapDescription *) createSystemTapDescriptionForChannels:

(UInt8)

channels

Creates a Core Audio tap description for system audio capture.

Parameters

channels

Number of audio channels to configure the tap for

Returns

CATapDescription object on success, nil on failure

findMicrophone:

+ (nullable AVCaptureDevice *) findMicrophone:

(nullable NSString *)

name

Find a specific microphone device by name.

Parameters

name	The name of the microphone to find (nullable - will return nil if name is nil)

Returns

AVCaptureDevice object if found, nil otherwise

initializeAudioBuffer:

- (void) initializeAudioBuffer:

(UInt8)

channels

Initializes the circular audio buffer for the specified number of channels.

Parameters

channels

Number of audio channels to configure the buffer for

initializeSystemTapContext:frameSize:channels:

- (int) initializeSystemTapContext:		(UInt32)	sampleRate
frameSize:		(UInt32)	frameSize
channels:		(UInt8)	channels

Initializes the system tap context with specified audio parameters.

Parameters

sampleRate	Target sample rate in Hz
frameSize	Number of frames per buffer
channels	Number of audio channels

Returns

0 on success, -1 on failure

microphoneNames

+ (NSArray< NSString * > *) microphoneNames

Get names of all available microphone devices.

Returns

Array of NSString objects with microphone device names

microphones

+ (NSArray< AVCaptureDevice * > *) microphones

Get all available microphone devices on the system.

Returns

Array of AVCaptureDevice objects representing available microphones

setupMicrophone:sampleRate:frameSize:channels:

- (int) setupMicrophone:		(nullable AVCaptureDevice *)	device
sampleRate:		(UInt32)	sampleRate
frameSize:		(UInt32)	frameSize
channels:		(UInt8)	channels

Sets up microphone capture using AVFoundation framework.

Parameters

device	The AVCaptureDevice to use for audio input (nullable - will return error if nil)
sampleRate	Target sample rate in Hz
frameSize	Number of frames per buffer
channels	Number of audio channels (1=mono, 2=stereo)

Returns

0 on success, -1 on failure

setupSystemTap:frameSize:channels:

- (int) setupSystemTap:		(UInt32)	sampleRate
frameSize:		(UInt32)	frameSize
channels:		(UInt8)	channels

Sets up system-wide audio tap for capturing all system audio. Requires macOS 14.0+ and appropriate permissions.

Parameters

sampleRate	Target sample rate in Hz
frameSize	Number of frames per buffer
channels	Number of audio channels

Returns

0 on success, -1 on failure

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The documentation for this class was generated from the following files:

• src/platform/macos/av_audio.h
• src/platform/macos/av_audio.mm