Thread 1:BAD_EXC_INSTRUCTION (code=EXC_1386_INVOP, subcode=0x0) - swift

Question

My code is posted below, not sure what the issue is but the return errors are listed as above along with fatal error:
unexpectedly found nil while unwrapping an Optional value
I have seen other answers to similar errors, but all of those involve things such as if let, which is not where my error seems to be occurring, the error message is connected to a line near the top that says "audioFile = try AVAudioFile(forReading: recordedAudioURL as URl)"
//
// PlaySoundsViewController+Audio.swift
// PitchPerfect
//
// Copyright © 2016 Udacity. All rights reserved.
//
import UIKit
import AVFoundation
extension PlaySoundsViewController: AVAudioPlayerDelegate {
struct Alerts {
static let DismissAlert = "Dismiss"
static let RecordingDisabledTitle = "Recording Disabled"
static let RecordingDisabledMessage = "You've disabled this app from recording your microphone. Check Settings."
static let RecordingFailedTitle = "Recording Failed"
static let RecordingFailedMessage = "Something went wrong with your recording."
static let AudioRecorderError = "Audio Recorder Error"
static let AudioSessionError = "Audio Session Error"
static let AudioRecordingError = "Audio Recording Error"
static let AudioFileError = "Audio File Error"
static let AudioEngineError = "Audio Engine Error"
}
// raw values correspond to sender tags
enum PlayingState { case Playing, NotPlaying }
// MARK: Audio Functions
func setupAudio() {
// initialize (recording) audio file
do {
audioFile = try AVAudioFile(forReading: recordedAudioURL as URL)
} catch {
showAlert(title: Alerts.AudioFileError, message: String(describing: error))
}
print("Audio has been setup")
}
func playSound(rate: Float? = nil, pitch: Float? = nil, echo: Bool = false, reverb: Bool = false) {
// initialize audio engine components
audioEngine = AVAudioEngine()
// node for playing audio
audioPlayerNode = AVAudioPlayerNode()
audioEngine.attach(audioPlayerNode)
// node for adjusting rate/pitch
let changeRatePitchNode = AVAudioUnitTimePitch()
if let pitch = pitch {
changeRatePitchNode.pitch = pitch
}
if let rate = rate {
changeRatePitchNode.rate = rate
}
audioEngine.attach(changeRatePitchNode)
// node for echo
let echoNode = AVAudioUnitDistortion()
echoNode.loadFactoryPreset(.multiEcho1)
audioEngine.attach(echoNode)
// node for reverb
let reverbNode = AVAudioUnitReverb()
reverbNode.loadFactoryPreset(.cathedral)
reverbNode.wetDryMix = 50
audioEngine.attach(reverbNode)
// connect nodes
if echo == true && reverb == true {
connectAudioNodes(nodes: audioPlayerNode, changeRatePitchNode, echoNode, reverbNode, audioEngine.outputNode)
} else if echo == true {
connectAudioNodes(nodes: audioPlayerNode, changeRatePitchNode, echoNode, audioEngine.outputNode)
} else if reverb == true {
connectAudioNodes(nodes: audioPlayerNode, changeRatePitchNode, reverbNode, audioEngine.outputNode)
} else {
connectAudioNodes(nodes: audioPlayerNode, changeRatePitchNode, audioEngine.outputNode)
}
// schedule to play and start the engine!
audioPlayerNode.stop()
audioPlayerNode.scheduleFile(audioFile, at: nil) {
var delayInSeconds: Double = 0
if let lastRenderTime = self.audioPlayerNode.lastRenderTime, let playerTime = self.audioPlayerNode.playerTime(forNodeTime: lastRenderTime) {
if let rate = rate {
delayInSeconds = Double(self.audioFile.length - playerTime.sampleTime) / Double(self.audioFile.processingFormat.sampleRate) / Double(rate)
} else {
delayInSeconds = Double(self.audioFile.length - playerTime.sampleTime) / Double(self.audioFile.processingFormat.sampleRate)
}
}
// schedule a stop timer for when audio finishes playing
self.stopTimer = Timer(timeInterval: delayInSeconds, target: self, selector: #selector(PlaySoundsViewController.stopAudio), userInfo: nil, repeats: false)
RunLoop.main.add(self.stopTimer!, forMode: RunLoopMode.defaultRunLoopMode)
}
do {
try audioEngine.start()
} catch {
showAlert(title: Alerts.AudioEngineError, message: String(describing: error))
return
}
// play the recording!
audioPlayerNode.play()
}
// MARK: Connect List of Audio Nodes
func connectAudioNodes(nodes: AVAudioNode...) {
for x in 0..<nodes.count-1 {
audioEngine.connect(nodes[x], to: nodes[x+1], format: audioFile.processingFormat)
}
}
func stopAudio() {
if let stopTimer = stopTimer {
stopTimer.invalidate()
}
configureUI(playState: .NotPlaying)
if let audioPlayerNode = audioPlayerNode {
audioPlayerNode.stop()
}
if let audioEngine = audioEngine {
audioEngine.stop()
audioEngine.reset()
}
}
// MARK: UI Functions
func configureUI(playState: PlayingState) {
switch(playState) {
case .Playing:
setPlayButtonsEnabled(enabled: false)
stopplaybackButton.isEnabled = true
case .NotPlaying:
setPlayButtonsEnabled(enabled: true)
stopplaybackButton.isEnabled = false
}
}
func setPlayButtonsEnabled(enabled: Bool) {
snailButton.isEnabled = enabled
chipmunkButton.isEnabled = enabled
rabbitButton.isEnabled = enabled
vaderButton.isEnabled = enabled
echoButton.isEnabled = enabled
reverbButton.isEnabled = enabled
}
func showAlert(title: String, message: String) {
let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
alert.addAction(UIAlertAction(title: Alerts.DismissAlert, style: .default, handler: nil))
self.present(alert, animated: true, completion: nil)
}
}

Answer 1

I was working on the same Udacity course, and I believe this is because the mic is not supported in the iOS 8.0+ simulator. One potential work-around is to drop this line into the viewDidLoad() function in the PlaySoundsViewController:
recordedAudioURL = Bundle.main.url(forResource: "yourSound", withExtension: "mp3")
...and then drag an mp3 named "yourSound.mp3" into your PitchPerfect project. It's a hack but it will stop the crash and allow you to test the audio modification buttons on that mp3, though you need to use an actual iOS device if you want to record your own samples in the app.
EDIT: I went through my entire codebase again and checked my audio settings. On the codebase, I had a method incorrectly placed (prepare for segue) in the PlaySoundsViewController, and for the audio settings, once I set the mic to my cinema display audio, the recording worked in the simulator. Good luck.

Answer 2

I had this same problem and it was because prepare didn't have correct syntax and the audioURL was not being propagated to the PlaySoundViewController.
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "stopRecording" {
let playSoundsVC = segue.destination as! PlaySoundsViewController
let recordedAudioURL = sender as! URL
playSoundsVC.recordedAudioURL = recordedAudioURL
print("setting URL in PlaySoundsViewController")
}
}
fixed it for me.