AVAudioEngine inputNode installTap crash when restarting recording : <p>I am implementing Speech Recognition in my app. When I first present the view controller with the speech recognition logic, everything works fine. However, when I try present the view controller again, I get the following crash:</p>

<pre><code>ERROR:    [0x190bf000] &gt;avae&gt; AVAudioNode.mm:568: CreateRecordingTap: required condition is false: IsFormatSampleRateAndChannelCountValid(format)
*** Terminating app due to uncaught exception 'com.apple.coreaudio.avfaudio', reason: 'required condition is false: IsFormatSampleRateAndChannelCountValid(format)'
</code></pre>

<p>Here is the code used for starting and stopping recording:</p>

<pre><code>@available(iOS 10.0, *)
extension DictationViewController {

fileprivate func startRecording() throws {
    guard let recognizer = speechRecognizer else {
        debugLog(className, message: "Not supported for the device's locale")
        return
    }

    guard recognizer.isAvailable else {
        debugLog(className, message: "Recognizer is not available right now")
        return
    }

    mostRecentlyProcessedSegmentDuration = 0
    guard let node = audioEngine.inputNode else {
        debugLog(className, message: "Could not get an input node")
        return
    }

    let recordingFormat = node.outputFormat(forBus: 0)
    node.installTap(onBus: 0, bufferSize: 1024, format: recordingFormat) { [weak self] (buffer, _) in
        self?.request.append(buffer)
    }

    audioEngine.prepare()
    try audioEngine.start()

    recognitionTask = recognizer.recognitionTask(with: request, resultHandler: {/***/})
}

fileprivate func stopRecording() {
    audioEngine.stop()
    audioEngine.inputNode?.removeTap(onBus: 0)
    request.endAudio()
    recognitionTask?.cancel()
}

}
</code></pre>

<p><code>startRecording()</code> is called in viewDidLoad once we have requested authorization. <code>stopRecording()</code> is called when the view controller is dismissed.</p>

<p>Please assist. I'm struggling to find a solution to this crash</p>
