Xcode 8.0 beta3 AVAudioRecorder(url,setting) error catch - "Error Domain=NSOSStatusErrorDomain Code=-50 "(null)"" - avaudiorecorder

Question

I'm trying to record the voice of the user and change it to a text data. I used AVAudioRecorder to record the sound and SpeechKit to change it to text which is included in iOS 10. When user touches down the button record starts and stops when button is touched up. But when I initialize the AVAudioRecorder using do catch syntax, error occurs and fails.
I added the appropriate frameworks(Speech, AVFoundation).
import UIKit
import Speech
import AVFoundation
class SearchViewController: UIViewController, CLLocationManagerDelegate, AVAudioRecorderDelegate {
var audioRecorder = AVAudioRecorder()
let recordSettings = [AVSampleRateKey : String(NSNumber(value: Float(44100.0))),
AVFormatIDKey : String(kAudioFileCAFType),
AVNumberOfChannelsKey : String(NSNumber(value: 2))]
#IBAction func recordButtonDown(_ sender: AnyObject) {
print("recordButtonDown")
self.audioPlayer.play()
sleep(1)
let fileManager = FileManager.default
let paths = fileManager.urlsForDirectory(.documentDirectory, inDomains: .userDomainMask)
var audioURL = paths[0] as NSURL
audioURL = audioURL.appendingPathComponent("soundForMapSearch.caf", isDirectory: false)!
do {
self.audioRecorder = try AVAudioRecorder(url: soundFileURL as URL, settings: self.recordSettings)
self.audioRecorder.delegate = self
self.audioRecorder.prepareToRecord()
self.audioRecorder.record()
} catch (let error) {
print("Error: \(error)")
}
}
#IBAction func recordButtonUp(_ sender: AnyObject) {
self.audioRecorder.stop()
}
override func viewDidLoad() {
super.viewDidLoad()
do {
try audioSession.setCategory(AVAudioSessionCategoryPlayAndRecord)
try audioSession.setActive(true)
audioSession.requestRecordPermission({ (recordPermission) in
})
} catch {
print("record initiallizing failed")
}
And on the line
self.audioRecorder = try AVAudioRecorder(url: soundFileURL as URL, settings: self.recordSettings)
error occurs at catch
Error: Error Domain=NSOSStatusErrorDomain Code=-50 "(null)"
is printed. I searched for this error and code=-50 means the NSURL object is invalid. How can I solve this error?

Answer 1

my working code
let recordingName = "recording1" + ".m4a"
let pathArray = [dirPath, recordingName]
print(pathArray)
let filePath = NSURL.fileURL(withPathComponents: pathArray)
print(filePath)
do{
let session = AVAudioSession.sharedInstance()
try! session.setCategory(AVAudioSessionCategoryPlayAndRecord)
} catch {
assertionFailure("AVAudioSession setup error: \(error)")
}
let recordSettings: [String: AnyObject] = [
AVFormatIDKey: NSNumber(value: kAudioFormatMPEG4AAC),
AVSampleRateKey: 44100.0,
AVNumberOfChannelsKey: 1,
]
try! audioRecorder = AVAudioRecorder(url: filePath!, settings: recordSettings)
audioRecorder.delegate = self
audioRecorder.isMeteringEnabled = true
audioRecorder.prepareToRecord()
audioRecorder.record()