Hi, as other threads have already discussed, I'd like to record audio from a keyboard extension.
The keyboard has been granted both full access and microphone access. Nonetheless whenever I attempt to start a recording from my keyboard, it fails to start with the following error:
Recording failed to start: Error Domain=com.apple.coreaudio.avfaudio Code=561145187 "(null)" UserInfo={failed call=err = PerformCommand(*ioNode, kAUStartIO, NULL, 0)}
This is the code I am using:
import Foundation
import AVFoundation
protocol AudioRecordingServiceDelegate: AnyObject {
func audioRecordingDidStart()
func audioRecordingDidStop(withAudioData: Data?)
func audioRecordingPermissionDenied()
}
class AudioRecordingService {
weak var delegate: AudioRecordingServiceDelegate?
private var audioEngine: AVAudioEngine?
private var audioSession: AVAudioSession?
private var isRecording = false
private var audioData = Data()
private let targetFormat = AVAudioFormat(commonFormat: .pcmFormatInt16,
sampleRate: 16000,
channels: 1,
interleaved: false)!
private func setupAudioSession() throws {
let session = AVAudioSession.sharedInstance()
try session.setCategory(.playAndRecord, mode: .spokenAudio,
options: [.mixWithOthers, .allowBluetooth, .defaultToSpeaker])
try session.setPreferredIOBufferDuration(0.005)
try session.setActive(true, options: .notifyOthersOnDeactivation)
audioSession = session
}
func checkMicrophonePermission(completion: @escaping (Bool) -> Void) {
switch AVAudioApplication.shared.recordPermission {
case .granted:
completion(true)
case .denied:
delegate?.audioRecordingPermissionDenied()
completion(false)
case .undetermined:
AVAudioApplication.requestRecordPermission { [weak self] granted in
if !granted {
self?.delegate?.audioRecordingPermissionDenied()
}
completion(granted)
}
@unknown default:
delegate?.audioRecordingPermissionDenied()
completion(false)
}
}
func toggleRecording() {
if isRecording {
stopRecording()
} else {
checkMicrophonePermission { [weak self] granted in
if granted {
self?.startRecording()
}
}
}
}
private func startRecording() {
guard !isRecording else { return }
do {
try setupAudioSession()
audioEngine = AVAudioEngine()
guard let engine = audioEngine else { return }
let inputNode = engine.inputNode
let inputFormat = inputNode.inputFormat(forBus: 0)
audioData.removeAll()
guard let converter = AVAudioConverter(from: inputFormat, to: targetFormat) else {
print("Failed to create audio converter")
return
}
inputNode.installTap(onBus: 0, bufferSize: 1024, format: inputFormat) { [weak self] buffer, _ in
guard let self = self else { return }
let frameCount = AVAudioFrameCount(Double(buffer.frameLength) * 16000.0 / buffer.format.sampleRate)
guard let outputBuffer = AVAudioPCMBuffer(pcmFormat: self.targetFormat,
frameCapacity: frameCount) else { return }
outputBuffer.frameLength = frameCount
var error: NSError?
converter.convert(to: outputBuffer, error: &error) { _, outStatus in
outStatus.pointee = .haveData
return buffer
}
if error == nil, let channelData = outputBuffer.int16ChannelData {
let dataLength = Int(outputBuffer.frameLength) * 2
let data = Data(bytes: channelData.pointee, count: dataLength)
self.audioData.append(data)
}
}
engine.prepare()
try engine.start()
isRecording = true
delegate?.audioRecordingDidStart()
} catch {
print("Recording failed to start: \(error)")
stopRecording()
}
}
private func stopRecording() {
audioEngine?.inputNode.removeTap(onBus: 0)
audioEngine?.stop()
isRecording = false
let finalData = audioData
audioData.removeAll()
delegate?.audioRecordingDidStop(withAudioData: finalData)
try? audioSession?.setActive(false, options: .notifyOthersOnDeactivation)
}
deinit {
if isRecording {
stopRecording()
}
}
}
Granting the deprecated "Inter-App Audio" capability did not solve the problem either.
Is recording audio from a keyboard extension even possible in general? If so, how do I fix it?
Related threads:
https://developer.apple.com/forums/thread/108055
https://developer.apple.com/forums/thread/742601