录音波naudio库-音质差

Question

我正在使用naudio (使用教程)来学习音频编程。我的程序(C# .net winForms)中有录制和停止按钮。代码如下所示：

    NAudio.Wave.WaveIn sourceStream = null;
    NAudio.Wave.WaveFileWriter waveWriter = null;

    private void RecordButton_Click(object sender, EventArgs e)
    {
        int deviceNumber = 0;
        sourceStream = new NAudio.Wave.WaveIn();
        sourceStream.DeviceNumber = deviceNumber;
        sourceStream.WaveFormat = new NAudio.Wave.WaveFormat(44100, NAudio.Wave.WaveIn.GetCapabilities(deviceNumber).Channels);

        sourceStream.DataAvailable += new EventHandler<NAudio.Wave.WaveInEventArgs>(sourceStream_DataAvailable);
        waveWriter = new NAudio.Wave.WaveFileWriter("d:\\a.wav", sourceStream.WaveFormat);

        sourceStream.StartRecording();
    }

    private void sourceStream_DataAvailable(object sender, NAudio.Wave.WaveInEventArgs e)
    {
        if (waveWriter == null) return;

        waveWriter.WriteData(e.Buffer, 0, e.BytesRecorded);
        waveWriter.Flush();
    }

    private void StopButton_Click(object sender, EventArgs e)
    { 
            waveWriter.Dispose();
            waveWriter = null;       
    }

它可以工作，但wave文件质量不好-在我录制的声音中有很小的间隙。我希望采样率为44100 Hz，采样格式为16位。

Answer 1

我不能准确地复制您发现的内容，但我确实注意到DataAvailable事件没有为其他操作留下太多阻塞空间。一个简单的Thread.Sleep(100);会停止应用程序。

假设您的持续写入(和刷新)可能会导致这个问题，我实现了一个简单的Queue，它保留要写入的字节，并使用线程池中的线程进行实际写入。

DataAvailable事件现在看起来如下所示：

    Queue<byte[]> writebuffer = new Queue<byte[]>();

    private void sourceStream_DataAvailable(object sender, NAudio.Wave.WaveInEventArgs e)
    {
        if (waveWriter == null) return;

        byte[] realbytes = new byte[e.BytesRecorded];
        Array.Copy(e.Buffer, realbytes, e.BytesRecorded);
        writebuffer.Enqueue(realbytes);
    }

就在StartRecording调用之后，我将读取队列并将数据写入流的任务排入队列。如果我在那里添加一个延迟，应用程序就不会再停滞。

ThreadPool.QueueUserWorkItem((s) =>
{
    var keeprunning = true;
    sourceStream.RecordingStopped += (rss, rse) => { keeprunning = false; };
    while(keeprunning)
    {
        if (writebuffer.Count==0)
        {
                Thread.Sleep(0);
        }
        else
        { 
            var buf = writebuffer.Dequeue();
            waveWriter.Write(buf,0,buf.Length);
            // Thread.Sleep(100); // for testing 
        }
    }
    waveWriter.Dispose();
    waveWriter = null;
});

Answer 2

我也遇到过这个问题。解决方案是从使用WaveIn录制切换到WasapiCapture。设置和使用几乎相同，但质量要好得多。试试这个：

public class Recorder
{
    public string _outputFolder { get; set; }
    public string _outputFilePath { get; set; }
    public WasapiCapture _capture { get; set; }
    public WaveFileWriter _writer { get; set; }

    public Recorder()
    {
        _outputFolder = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "NAudio");
        Directory.CreateDirectory(_outputFolder);
        _outputFilePath = Path.Combine(_outputFolder, "recorded.wav");
    }

    public void StartRecording()
    {
        _capture = new WasapiCapture();
        _capture.ShareMode = AudioClientShareMode.Shared;
        _capture.WaveFormat = new WaveFormat(44100, 32, 1);

        _writer = new WaveFileWriter(_outputFilePath, _capture.WaveFormat);

        _capture.DataAvailable += _capture_DataAvailable;
        _capture.RecordingStopped += _capture_RecordingStopped; ;

        _capture.StartRecording();
    }

    public void StopRecording()
    {
        _capture.StopRecording();
    }

    private void _capture_DataAvailable(object sender, WaveInEventArgs e)
    {
        _writer.Write(e.Buffer, 0, e.BytesRecorded);
    }

    private void _capture_RecordingStopped(object sender, StoppedEventArgs e)
    {
        _writer?.Dispose();
        _writer = null;
        _capture.Dispose();
        _capture = null;
    }

}