C#中使用DirectSound来获取麦克音量

　　大家好,我最近在做一个程序需要使用DirectSound, 当用户说话时我要开始录音,当用户说完了自动停止录音,然后这样循环下去.

　　现在的问题是如何知道用户是否在说话.请下看下以下代码:

        private void RecordCapturedData()

        {

            byte[] CaptureData = null;

            int ReadPos;

            int CapturePos;

            int LockSize;

            mRecBuffer.GetCurrentPosition(out CapturePos, out ReadPos);

            LockSize = ReadPos - mNextCaptureOffset;

            if (LockSize < 0)

                LockSize += mBufferSize;

            LockSize -= (LockSize % mNotifySize);

            if (0 == LockSize)

                return;

            CaptureData = (byte[])mRecBuffer.Read(mNextCaptureOffset, typeof(byte), LockFlag.None, LockSize);

            mNextCaptureOffset += CaptureData.Length;

            mNextCaptureOffset %= mBufferSize;

            //check state

            if (state == State.Recording || state == State.PreRecording)

            {

                secondBuffer.Add(CaptureData);

            }           

        }

　　上面的代码是C# DirectSound的捕获到数据后的处理方法.也就是说,麦克风得到的信号转换成数字信号,在程序里变为一个byte[]数组放到缓存区,然后我可以一个一个的从缓冲区里得到这个byte[]对象,以前我在这里提问过,一些朋友说计算这个byte[]的平均值或方差可以得到用户说话的音量,可是效果不理想.有时好用有时不好用.

　　所以来到这里请大家帮忙!是否有办法通过计算缓冲区得到的byte[]数据来得到麦克音量,或通过其他API(最好是DirectSound的)能知道用户当前的说话的音量大小.无论你能否帮上忙，先谢谢你!


以下的信息或许会有帮助:

1.我找到的声音探测的软件(含源码)，不过功能太复杂了,不容易分离出来,并且使用的不是DirectSound如果用他的整个程序得重写.
http://www.dreamincode.net/forums/showtopic38890.htm

2.我已经完成的不带自动探测声音的录音的源代码

public class Recorder

    {

        //由于长度限制,变量略

          public void Initialize()

        {

            // Create capture buffer.

            CreateCaptureBuffer();

            // Create notification system.

            InitNotifications();

            mRecBuffer.Start(true);

        }

        public void Dispose()

        {

            // Close notification

            if (null != mNotificationEvent)

                mNotificationEvent.Set();

            // Stop recording

            mRecBuffer.Stop();

        }

  

       

               #endregion

        #region Initialize Recorder

        public Recorder()

        {

            InitCaptureDevice();

            mWavFormat = CreateWaveFormat();     

            buffDes = new BufferDescription();

            buffDes.GlobalFocus = true;

            buffDes.ControlVolume = true;

            buffDes.ControlPan = true;            

            secDev = new Device();

            bufferStates = new List<int>();

        }

        private void RecordCapturedData()

        {

            byte[] CaptureData = null;

            int ReadPos;

            int CapturePos;

            int LockSize;

            mRecBuffer.GetCurrentPosition(out CapturePos, out ReadPos);

            LockSize = ReadPos - mNextCaptureOffset;

            if (LockSize < 0)

                LockSize += mBufferSize;

            LockSize -= (LockSize % mNotifySize);

            if (0 == LockSize)

                return;

            CaptureData = (byte[])mRecBuffer.Read(mNextCaptureOffset, typeof(byte), LockFlag.None, LockSize);

            mNextCaptureOffset += CaptureData.Length;

            mNextCaptureOffset %= mBufferSize;

            //check state

            if (state == State.Recording || state == State.PreRecording)

            {

                secondBuffer.Add(CaptureData);

            }           

        }

        private void CreateCaptureBuffer()

        {

            CaptureBufferDescription bufferdescription = new CaptureBufferDescription();

            if (null != mNotify)

            {

                mNotify.Dispose();

                mNotify = null;

            }

            if (null != mRecBuffer)

            {

                mRecBuffer.Dispose();

                mRecBuffer = null;

            }

            // set notification's size: 1 second

            mNotifySize = (1024 > mWavFormat.AverageBytesPerSecond / 8) ? 1024 : (mWavFormat.AverageBytesPerSecond / 8);

            mNotifySize -= mNotifySize % mWavFormat.BlockAlign;

            // set size of buffer

            mBufferSize = mNotifySize * cNotifyNum;



            bufferdescription.BufferBytes = mBufferSize;

            bufferdescription.Format = mWavFormat;



            mRecBuffer = new CaptureBuffer(bufferdescription, mCapDev);

            mNextCaptureOffset = 0;

        }

        private bool InitNotifications()

        {

            if (null == mRecBuffer)

            {

                MessageBox.Show("Record buffer is not found!");

                return false;

            }

            mNotificationEvent = new AutoResetEvent(false);

            if (null == mNotifyThread)

            {

                mNotifyThread = new Thread(new ThreadStart(WaitThread));

                mNotifyThread.Start();

            }

            BufferPositionNotify[] PositionNotify = new BufferPositionNotify[cNotifyNum + 1];

            for (int i = 0; i < cNotifyNum; i++)

            {

                PositionNotify[i].Offset = (mNotifySize * i) + mNotifySize - 1;

                PositionNotify[i].EventNotifyHandle = mNotificationEvent.Handle;

            }

            mNotify = new Notify(mRecBuffer);

            mNotify.SetNotificationPositions(PositionNotify, cNotifyNum);



            return true;

        }

        private bool InitCaptureDevice()

        {

            CaptureDevicesCollection devices = new CaptureDevicesCollection();

            Guid deviceGuid = Guid.Empty;

            if (devices.Count > 0)

                deviceGuid = devices[0].DriverGuid;

            else

            {

                MessageBox.Show("No device to capture wave!");

                return false;

            }

            try

            {

                mCapDev = new Capture(deviceGuid);

            }

            catch (DirectXException e)

            {

                MessageBox.Show(e.ToString());

                return false;

            }

            return true;

        }

        private WaveFormat CreateWaveFormat()

        {

            WaveFormat format = new WaveFormat();

            format.FormatTag = WaveFormatTag.Pcm;   // PCM

            format.SamplesPerSecond = 16000;        // 16KHz

            format.BitsPerSample = 16;              // 16Bit

            format.Channels = 1;                    // Mono

            format.BlockAlign = (short)(format.Channels * (format.BitsPerSample / 8));

            format.AverageBytesPerSecond = format.BlockAlign * format.SamplesPerSecond;

            return format;



        }

        private void WaitThread()

        {

            while (true)

            {

                // waiting for notification

                mNotificationEvent.WaitOne(Timeout.Infinite, true);

                // process data captured

                RecordCapturedData();

            }

        }

        #endregion

    }