Naudio将麦克风录制X秒

Question

目前我可以使用Naudio.dll记录麦克风输入，如下所示：

public void recordInput()
{
    Console.WriteLine("Now recording...");
    waveSource = new WaveIn();
    waveSource.WaveFormat = new WaveFormat(16000, 1);
    waveSource.DataAvailable += new EventHandler<WaveInEventArgs>(waveSource_DataAvailable);
    waveSource.RecordingStopped += new EventHandler<StoppedEventArgs>(waveSource_RecordingStopped);
    //string tempFile = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString() + ".wav");
    string tempFile = Path.Combine(@"C:UsersNickDesktop",  "test.wav");

    waveFile = new WaveFileWriter(tempFile, waveSource.WaveFormat);
    waveSource.StartRecording();
    myTimer.Interval = 5000;
    myTimer.Tick += new EventHandler(myTimer_Tick);
    myTimer.Start();
}

目前，我使用事件处理程序等待5秒，然后在Tick上停止录制。然而，这会造成问题，因为我在等待录制任务在我调用的代码的主要部分完成时遇到了问题：

    public string voiceToText()
    {
        recordInput();
        //Somehow wait here until record is done then proceed.
        convertToFlac();
        return "done";

    }

我试着把Naudio放在线程中并使用waitOne();，但waveSource.StartRecording();放在事件处理程序中并给线程一个预期。我也尝试过使用Thread.Sleep(5000)，并在线程结束后停止录制，但由于某种原因，音频只录制了前500毫秒的音频。

我对c#还很陌生，不完全理解线程，所以欢迎任何帮助或单独的方法。

Answer 1

我知道这是一个老话题，但这里有一些我为我的一个项目制作的代码，它可以录制x秒的音频（它使用NAudio.Lame将波形文件转换为mp3）：

public class Recorder
{
    /// <summary>
    /// Timer used to start/stop recording
    /// </summary>
    private Timer _timer;
    private WaveInEvent _waveSource;
    private WaveFileWriter _waveWriter;
    private string _filename;
    private string _tempFilename;
    public event EventHandler RecordingFinished;
    /// <summary>
    /// Record from the mic
    /// </summary>
    /// <param name="seconds">Duration in seconds</param>
    /// <param name="filename">Output file name</param>
    public void RecordAudio(int seconds, string filename)
    {
        /*if the filename is empty, throw an exception*/
        if (string.IsNullOrEmpty(filename))
            throw new ArgumentNullException("The file name cannot be empty.");
        /*if the recording duration is not > 0, throw an exception*/
        if (seconds <= 0)
            throw new ArgumentNullException("The recording duration must be a positive integer.");
        _filename = filename;
        _tempFilename = $"{Path.GetFileNameWithoutExtension(filename)}.wav";
        _waveSource = new WaveInEvent
        {
            WaveFormat = new WaveFormat(44100, 1)
        };
        _waveSource.DataAvailable += DataAvailable;
        _waveSource.RecordingStopped += RecordingStopped;
        _waveWriter = new WaveFileWriter(_tempFilename, _waveSource.WaveFormat);
        /*Start the timer that will mark the recording end*/
        /*We multiply by 1000 because the Timer object works with milliseconds*/
        _timer = new Timer(seconds * 1000);
        /*if the timer elapses don't reset it, stop it instead*/
        _timer.AutoReset = false;
        /*Callback that will be executed once the recording duration has elapsed*/
        _timer.Elapsed += StopRecording;
        /*Start recording the audio*/
        _waveSource.StartRecording();
        /*Start the timer*/
        _timer.Start();
    }
    /// <summary>
    /// Callback that will be executed once the recording duration has elapsed
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void StopRecording(object sender, ElapsedEventArgs e)
    {
        /*Stop the timer*/
        _timer?.Stop();
        /*Destroy/Dispose of the timer to free memory*/
        _timer?.Dispose();
        /*Stop the audio recording*/
        _waveSource.StopRecording();
    }
    /// <summary>
    /// Callback executed when the recording is stopped
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void RecordingStopped(object sender, StoppedEventArgs e)
    {
        _waveSource.DataAvailable -= DataAvailable;
        _waveSource.RecordingStopped -= RecordingStopped;
        _waveSource?.Dispose();
        _waveWriter?.Dispose();
        /*Convert the recorded file to MP3*/
        ConvertWaveToMp3(_tempFilename, _filename);
        /*Send notification that the recording is complete*/
        RecordingFinished?.Invoke(this, null);
    }
    /// <summary>
    /// Callback executed when new data is available
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    private void DataAvailable(object sender, WaveInEventArgs e)
    {
        if (_waveWriter != null)
        {
            _waveWriter.Write(e.Buffer, 0, e.BytesRecorded);
            _waveWriter.Flush();
        }
    }
    /// <summary>
    /// Converts the recorded WAV file to MP3
    /// </summary>
    private void ConvertWaveToMp3(string source, string destination)
    {
        using (var waveStream = new WaveFileReader(source))
        using(var fileWriter = new LameMP3FileWriter(destination, waveStream.WaveFormat, 128))
        {
            waveStream.CopyTo(fileWriter);
            waveStream.Flush();
        }
        /*Delete the temporary WAV file*/
        File.Delete(source);
    }
}

以下是如何在代码中使用它：

        var rec = new Recorder();
        /*This line allows us to be notified when the recording is complete and the callback 'OnRecordingFinished' will be executed*/
        rec.RecordingFinished += OnRecordingFinished;
        rec.RecordAudio(seconds, recPath);
    private void OnRecordingFinished(object sender, RecordingContentArgs e)
    {
        //Put your code here to process the audio file

    }

Answer 2

如果您不是在Windows窗体或WPF应用程序中运行，那么您应该使用WaveInEvent，这样就可以设置一个后台线程来处理回调。WaveIn的默认构造函数使用Windows消息。