[SlimDX] DirectSound: Capture Microphone Stream With Low Latency Example

using System;using SlimDX;using SlimDX.DirectSound;using SlimDX.Multimedia;using System.IO;using System.Threading;using System.Collections.Generic;namespace CaptureSound{    class Program    {        [System.Runtime.InteropServices.DllImport("user32.dll", CharSet = System.Runtime.InteropServices.CharSet.Auto)]        static extern short GetAsyncKeyState(int key);        const int VK_ESCAPE = 0x1B;        static void Main(string[] args)        {            WaveFormat format = new WaveFormat();            format.FormatTag = WaveFormatTag.Pcm;            format.Channels = 1;            format.BitsPerSample = 16;            format.SamplesPerSecond = 8000;            format.BlockAlignment = (short)(format.BitsPerSample / 8);            format.AverageBytesPerSecond = format.SamplesPerSecond * format.BlockAlignment * format.Channels;            FileStream stream = File.Open("output.raw", FileMode.OpenOrCreate);            SoundBufferDescription primaryBufferDescription = new SoundBufferDescription();            primaryBufferDescription.Format = format;            primaryBufferDescription.Flags = BufferFlags.GlobalFocus;            primaryBufferDescription.SizeInBytes = 2 * format.AverageBytesPerSecond;            // Primary Buffer            DirectSound ds = new DirectSound();            ds.SetCooperativeLevel(System.Diagnostics.Process.GetCurrentProcess().MainWindowHandle, CooperativeLevel.Normal);            // Capture            CaptureBufferDescription captureBufferDescription = new CaptureBufferDescription()            {                Format = format,                BufferBytes = format.AverageBytesPerSecond / 50, // 20ms                WaveMapped = true,                ControlEffects = false,            };            DirectSoundCapture directSoundCapture = new DirectSoundCapture();            CaptureBuffer captureBuffer = new CaptureBuffer(directSoundCapture, captureBufferDescription);            const int bufferPortionCount = 2;            int bufferPortionSize = captureBuffer.SizeInBytes / bufferPortionCount;            List<NotificationPosition> notifications = new List<NotificationPosition>();            for (int i = 0; i < bufferPortionCount; i++)            {                notifications.Add(new NotificationPosition()                {                    Offset = bufferPortionSize - 1 + bufferPortionSize * i,                    Event = new AutoResetEvent(false),                });            }            captureBuffer.SetNotificationPositions(notifications.ToArray());            WaitHandle[] waitHandles = new WaitHandle[notifications.Count];            for (int i = 0; i < notifications.Count; i++)            {                waitHandles = notifications.Event;            }            captureBuffer.Start(true);            byte[] bufferPortion = new byte[bufferPortionSize];            int bufferPortionIndex;            DateTime lastNotificationTime = DateTime.MinValue;            DateTime now;            while (GetAsyncKeyState(VK_ESCAPE) == 0)            {                bufferPortionIndex = WaitHandle.WaitAny(waitHandles);                captureBuffer.Read<byte>(bufferPortion, 0, bufferPortionSize, bufferPortionSize * bufferPortionIndex);                now = DateTime.Now;                System.Diagnostics.Debug.Write(String.Format("{0}\t{1}\n", bufferPortionIndex, (now - lastNotificationTime).Milliseconds));                lastNotificationTime = now;                stream.Write(bufferPortion, 0, bufferPortion.Length);            }            captureBuffer.Stop();            for (int i = 0; i < notifications.Count; i++)            {                notifications.Event.Close();            }            captureBuffer.Dispose();            directSoundCapture.Dispose();            ds.Dispose();            stream.Close();            stream.Dispose();        }    }}