如何在Windows 8中获取麦克风音量

Question

我想从windows 8中记录麦克风数据中获得音量级别。

microphone = Microphone.Default;
microphone.BufferDuration = TimeSpan.FromMilliseconds(150);
microphone.BufferReady += microphone_BufferReady;

private void microphone_BufferReady(object sender, EventArgs e)
{
      // Get buffer from microphone and add to collection
      int size = microphone.GetSampleSizeInBytes(microphone.BufferDuration);
      byte[] buffer = new byte[size];
      int bytes = microphone.GetData(buffer);
      MicrophoneDuration += microphone.GetSampleDuration(size);
      bufferCollection.Add(buffer);
      //Get the volume of microphone
      MicrophoneVolume = GetMicrophoneVolume(buffer);
}

/// <summary>
/// Get the microphone volume, from 0 up to 100.
/// 
/// The sum of data[i] square divided by the total length of the data.
/// volume = sum(data[i] * data[i])/Length/10000
/// </summary>
/// <param name="data"></param>
/// <returns></returns>
public static double GetMicrophoneVolume(byte[] data)
{
    double value = 0;

    for (int i = 0; i < data.Length; i++)
    {
        value += data[i] * data[i];
    }
    return ConvertTo(value / data.Length / 10000);
}

/// <summary>
///  x/100 = value/MaxiMicrophoneVolume/// </summary>
/// <param name="value"></param>
/// <returns></returns>
private static double ConvertTo(double value)
{
    if (value > MaxiMicrophoneVolume)
        value = MaxiMicrophoneVolume;
    if (value < 0)
        value = 0;

    return (100 * value) / MaxiMicrophoneVolume;
}

但是在这种方法中，体积取决于data[]中每个数据的和。在开始时，当和低时，当我们大声说话时，和是大的，但是当声音变小时，和没有变化，所以由GetMicrophoneVolume计算的体积没有变化。

有人知道如何正确获得麦克风音量吗？

还是我的解决方案有什么问题？

另外，为什么当声音变小时，数据的总和不减少呢？

更好的解决这个问题的方法将会受到极大的赞赏。

Answer 1

谢谢各位，我终于找到了一个由均方根计算出来的解决方案

/// <summary>
/// Detecting volume changes, the RMS Mothod.
/// 
/// RMS(Root mean square)
/// </summary>
/// <param name="data">RAW datas</param>
/// <returns></returns>
public static void MicrophoneVolume(byte[] data)
{
    //RMS Method
    double rms = 0;
    ushort byte1 = 0;
    ushort byte2 = 0;
    short value = 0;
    int volume = 0;
    rms = (short)(byte1 | (byte2 << 8));

    for (int i = 0; i < data.Length - 1; i += 2)
    {
        byte1 = data[i];
        byte2 = data[i + 1];

        value = (short)(byte1 | (byte2 << 8));
        rms += Math.Pow(value, 2);
    }

    rms /= (double)(data.Length / 2);
    volume = (int)Math.Floor(Math.Sqrt(rms));
}