Speech recognition error in Swift 3 & iOS 10 - ios

Question

I'm using an iPhone 6s plus, here is the code for the speech recognition viewcontroller:
import Speech
import UIKit
protocol SpeechRecognitionDelegate: class {
func speechRecognitionComplete(query: String?)
func speechRecognitionCancelled()
}
class SpeechRecognitionViewController: UIViewController, SFSpeechRecognizerDelegate {
var textView: UITextView!
private let speechRecognizer = SFSpeechRecognizer(locale: Locale.init(identifier: "en-US"))
private var recognitionRequest: SFSpeechAudioBufferRecognitionRequest?
private var recognitionTask: SFSpeechRecognitionTask?
private let audioEngine = AVAudioEngine()
private var query: String?
weak var delegate: SpeechRecognitionDelegate?
var isListening: Bool = false
init(delegate: SpeechRecognitionDelegate, frame: CGRect) {
super.init(nibName: nil, bundle: nil)
self.delegate = delegate
self.view.frame = frame
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
enum ErrorMessage: String {
case denied = "To enable Speech Recognition go to Settings -> Privacy."
case notDetermined = "Authorization not determined - please try again."
case restricted = "Speech Recognition is restricted on this device."
case noResults = "No results found - please try a different search."
}
func displayErrorAlert(message: ErrorMessage) {
let alertController = UIAlertController(title: nil,
message: message.rawValue,
preferredStyle: .alert)
let alertAction = UIAlertAction(title: "OK", style: .default, handler: nil)
alertController.addAction(alertAction)
OperationQueue.main.addOperation {
self.present(alertController, animated: true, completion: nil)
}
}
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
speechRecognizer?.delegate = self
//initialize textView and add it to self.view
}
func startListening() {
guard !isListening else {return}
isListening = true
recognitionRequest = SFSpeechAudioBufferRecognitionRequest()
guard let recognitionRequest = recognitionRequest else {
print("SpeechRecognitionViewController recognitionRequest \(self.recognitionRequest)")
return
}
recognitionRequest.shouldReportPartialResults = true
recognitionTask = speechRecognizer?.recognitionTask(with: recognitionRequest, resultHandler: { (result, error) in
var isFinal = false
if result != nil {
self.query = result?.bestTranscription.formattedString
self.textView.text = self.query
isFinal = (result?.isFinal)!
}
if error != nil || isFinal {
print("recognitionTask error = \(error?.localizedDescription)")
self.stopListening()
}
})
let audioSession = AVAudioSession.sharedInstance()
do {
try audioSession.setCategory(AVAudioSessionCategoryRecord)
try audioSession.setMode(AVAudioSessionModeMeasurement)
try audioSession.setActive(true, with: .notifyOthersOnDeactivation)
} catch {
print("Audio session isn't configured correctly")
}
let recordingFormat = audioEngine.inputNode?.outputFormat(forBus: 0)
audioEngine.inputNode?.installTap(onBus: 0, bufferSize: 1024, format: recordingFormat) { (buffer, time) in
self.recognitionRequest?.append(buffer)
}
audioEngine.prepare()
do {
try audioEngine.start()
textView.text = "Listening..."
} catch {
print("Audio engine failed to start")
}
}
func stopListening() {
guard isListening else {return}
audioEngine.stop()
audioEngine.inputNode?.removeTap(onBus: 0)
recognitionRequest = nil
recognitionTask = nil
isListening = false
}
// MARK: SFSpeechRecognizerDelegate
func speechRecognizer(_ speechRecognizer: SFSpeechRecognizer, availabilityDidChange available: Bool) {
if !available {
let alertController = UIAlertController(title: nil,
message: "Speech Recognition is currently unavailable.",
preferredStyle: .alert)
let alertAction = UIAlertAction(title: "OK", style: .default) { (alertAction) in
.self.stopListening()
}
alertController.addAction(alertAction)
present(alertController, animated: true)
}
}
}
This VC is embedded in another viewcontroller.
When a button is tapped in the parent viewcontroller, startListening() is called. When the same button is hit again stopListening() is called.
The first time the speech recognition works just fine. on a second try I get this error (I guess it has to do with grammar loading?):
recognitionTask error = Optional("The operation couldn’t be completed. (kAFAssistantErrorDomain error 209.)")
and speech recognition doesn't works anymore. After 30 seconds I get the timeout error:
Optional(Error Domain=kAFAssistantErrorDomain Code=203 "Timeout" UserInfo={NSLocalizedDescription=Timeout, NSUnderlyingError=0x170446f90 {Error Domain=SiriSpeechErrorDomain Code=100 "(null)"}})
Original code is here SayWhat
What am I missing?

Answer 1

All I had to do was add recognitionRequest?.endAudio() when trying to stop listening:
func stopListening() {
guard isListening else {return}
audioEngine.stop()
audioEngine.inputNode?.removeTap(onBus: 0)
// Indicate that the audio source is finished and no more audio will be appended
recognitionRequest?.endAudio()
recognitionRequest = nil
recognitionTask = nil
isListening = false
}