start method

Future<void> start()

Opens audio input stream and sends audio frames to Picovoice. Throws a PvAudioException if there was a problem starting the audio engine. Throws a PvError if an instance of Picovoice could not be created.

Implementation

Future<void> start() async {
  if (_picovoice != null) {
    return;
  }

  _picovoice = await Picovoice.create(
      _keywordPath, _wakeWordCallback, _contextPath, _inferenceCallback,
      porcupineSensitivity: _porcupineSensitivity,
      rhinoSensitivity: _rhinoSensitivity,
      porcupineModelPath: _porcupineModelPath,
      rhinoModelPath: _rhinoModelPath);

  if (_voiceProcessor == null) {
    throw new PvError("flutter_voice_processor not available.");
  }
  _removeVoiceProcessorListener =
      _voiceProcessor!.addListener((buffer) async {
    // cast from dynamic to int array
    List<int> picovoiceFrame;
    try {
      picovoiceFrame = (buffer as List<dynamic>).cast<int>();
    } on Error {
      PvError castError = new PvError(
          "flutter_voice_processor sent an unexpected data type.");
      _errorCallback == null
          ? print(castError.message)
          : _errorCallback!(castError);
      return;
    }

    // process frame with Picovoice
    try {
      _picovoice?.process(picovoiceFrame);
    } on PvError catch (error) {
      _errorCallback == null ? print(error.message) : _errorCallback!(error);
    }
  });

  if (await _voiceProcessor?.hasRecordAudioPermission() != null) {
    try {
      // create picovoice
      await _voiceProcessor!.start();
    } on PlatformException {
      throw new PvAudioException(
          "Audio engine failed to start. Hardware may not be supported.");
    }
  } else {
    throw new PvAudioException(
        "User did not give permission to record audio.");
  }
}