Fatal error: AudioKit: Could not start engine. AudioKit.start() - audiokit

Question

import UIKit
import Photos
import AudioKit
import AudioKitUI
class VoicesController: CaptureContentController {
#IBOutlet weak var nodeOutputPlot: AKNodeOutputPlot!
#IBOutlet weak var recordButton: UIButton!
#IBAction func recordButtonAction(_ sender: UIButton, forEvent event: UIEvent) {
guard let phase = event.allTouches?.first?.phase else {
return
}
if phase == .began {
try? nodeRecorder.record()
}
if phase == .ended {
nodeRecorder.stop()
try? audioPlayer.reloadFile()
let fileName = NSUUID().uuidString + ".wav"
audioPlayer.audioFile.exportAsynchronously(name: fileName, baseDir: .documents, exportFormat: .wav, callback: { [weak self] (audioFile, error) in
if let error = error {
print(#line, error)
return
}
// // FIXME:
// if let url = audioFile?.avAsset.url {
// _ = PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: url)!
// // creationRequest.location
// }
if let fileName = audioFile?.avAsset.url.lastPathComponent {
let asset = VPFAsset()
asset.mediaType = .audio
asset.urlString = fileName
asset.thumbUrlString = ""
self?.captureDelegate?.append(asset)
}
})
}
}
var audioPlayer: AKAudioPlayer!
var nodeRecorder: AKNodeRecorder!
var micMixer: AKMixer!
var mainMixer: AKMixer!
var booster: AKBooster!
var moogLadder: AKMoogLadder!
let microphone = AKMicrophone()
#objc func didBecomeActive(_ notification: Notification) {
AudioKit.start()
}
#objc func willResignActive(_ notification: Notification) {
AudioKit.stop()
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
AKAudioFile.cleanTempDirectory()
AKSettings.bufferLength = .medium
do {
try AKSettings.setSession(category: .playAndRecord)
} catch {
print(error)
}
AKSettings.defaultToSpeaker = true
nodeOutputPlot.node = microphone
micMixer = AKMixer(microphone)
booster = AKBooster(micMixer)
booster.gain = 0
nodeRecorder = try? AKNodeRecorder(node: micMixer)
if let audioFile = nodeRecorder.audioFile {
audioPlayer = try? AKAudioPlayer(file: audioFile)
audioPlayer.completionHandler = {
print(#line)
}
}
moogLadder = AKMoogLadder(audioPlayer)
mainMixer = AKMixer(moogLadder, booster)
AudioKit.output = mainMixer
AudioKit.start()
NotificationCenter.default
.addObserver(self, selector: #selector(didBecomeActive), name: .UIApplicationDidBecomeActive, object: nil)
NotificationCenter.default
.addObserver(self, selector: #selector(willResignActive), name: .UIApplicationWillResignActive, object: nil)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
deinit {
print("deinit VoicesController")
AudioKit.stop()
NotificationCenter.default
.removeObserver(self)
}
}
Hello, my English is not good, I am a Chinese, I really like AudioKit, because it is convenient, but in the recent system update, I encountered a crashes, but not always crashes, it seems that only collapse once, After that no crashes, I made a screenshot, because the system does not always update, hoping to get help，thank you very much，I am a novice, please advise
这是截图
Thread 1: Fatal error: AudioKit: Could not start engine. error: Error Domain=com.apple.coreaudio.avfaudio Code=-10875 "(null)" UserInfo={failed call=err = AUGraphParser::InitializeActiveNodesInOutputChain(ThisGraph, kOutputChainOptimizedTraversal, *GetOutputNode(), isOutputChainActive)}.

Answer 1

In the latest develop branch (not yet released), you have to wrap AudioKit.start() in a do try catch block
do {
try AudioKit.start()
} catch {
AKLog("Something went wrong.")
}
All of the examples included with AudioKit show how to implement this change.