SpeechKit所需条件为假：IsFormatSampleRateAndChannelCountValid（format）

Question

我们已为口述实现了SpeechKit。它的工作正常，但有时会导致某些用户崩溃。当用户单击以开始录制音频引擎时。

代码：

    if recognitionTask != nil {
        recognitionTask?.cancel()
        recognitionTask = nil
    }

    let node = audioEngine.inputNode
    let recordingFormat = node.outputFormat(forBus: 0)
    node.installTap(onBus: 0, bufferSize: 1024, format: recordingFormat) { buffer, _ in
        self.request.append(buffer)
    }
    audioEngine.prepare()
    do {
        try audioEngine.start()
    } catch {
        self.sendAlert(message: "There has been an audio engine error.")
        return print(error)
    }

    guard let myRecognizer = SFSpeechRecognizer() else {
        self.sendAlert(message: "Speech recognition is not supported for your current locale.")
        return
    }

    if !myRecognizer.isAvailable {
        self.sendAlert(message: "Speech recognition is not currently available. Check back at a later time.")
        // Recognizer is not available right now
        return
    }

    recognitionTask = speechRecognizer?.recognitionTask(with: request, resultHandler: { result, error in
    //Code here
    })

错误：

  

致命异常：com.apple.coreaudio.avfaudio所需条件为   false：IsFormatSampleRateAndChannelCountValid（format）