/// <summary>
/// Initializes the direct sound.
/// </summary>
private void InitializeDirectSound()
{
// We will have 2 buffers: one for immediate audio out rendering, and another where we will
// feed the samples. We will copy audio data from the back buffer into the immediate render
// buffer. We first open the DirectSound driver, create the buffers and start the playback!
// Open DirectSound
DirectSoundDriver = null;
var createDriverResult = NativeMethods.DirectSoundCreate(ref DeviceId, out DirectSoundDriver, IntPtr.Zero);
if (DirectSoundDriver == null || createDriverResult != 0)
{
return;
}
// Set Cooperative Level to PRIORITY (priority level can call the SetFormat and Compact methods)
DirectSoundDriver.SetCooperativeLevel(NativeMethods.GetDesktopWindow(),
DirectSound.DirectSoundCooperativeLevel.Normal);
// Fill BufferDescription for immediate, rendering buffer
var renderBuffer = new DirectSound.BufferDescription
{
Size = Marshal.SizeOf <DirectSound.BufferDescription>(),
BufferBytes = 0,
Flags = DirectSound.DirectSoundBufferCaps.PrimaryBuffer,
Reserved = 0,
FormatHandle = IntPtr.Zero,
AlgorithmId = Guid.Empty
};
// Create the Render Buffer (Immediate audio out)
DirectSoundDriver.CreateSoundBuffer(renderBuffer, out var audioRenderBuffer, IntPtr.Zero);
AudioRenderBuffer = audioRenderBuffer as DirectSound.IDirectSoundBuffer;
// Play & Loop on the render buffer
AudioRenderBuffer?.Play(0, 0, DirectSound.DirectSoundPlayFlags.Looping);
// A frame of samples equals to Desired Latency
SamplesFrameSize = MillisToBytes(DesiredLatency);
var waveFormatHandle = GCHandle.Alloc(WaveFormat, GCHandleType.Pinned);
// Fill BufferDescription for sample-receiving back buffer
var backBuffer = new DirectSound.BufferDescription
{
Size = Marshal.SizeOf <DirectSound.BufferDescription>(),
BufferBytes = (uint)(SamplesFrameSize * 2),
Flags = DirectSound.DirectSoundBufferCaps.GetCurrentPosition2
| DirectSound.DirectSoundBufferCaps.ControlNotifyPosition
| DirectSound.DirectSoundBufferCaps.GlobalFocus
| DirectSound.DirectSoundBufferCaps.ControlVolume
| DirectSound.DirectSoundBufferCaps.StickyFocus
| DirectSound.DirectSoundBufferCaps.GetCurrentPosition2,
Reserved = 0,
FormatHandle = waveFormatHandle.AddrOfPinnedObject(),
AlgorithmId = Guid.Empty
};
// Create back buffer where samples will be fed
DirectSoundDriver.CreateSoundBuffer(backBuffer, out audioRenderBuffer, IntPtr.Zero);
AudioBackBuffer = audioRenderBuffer as DirectSound.IDirectSoundBuffer;
waveFormatHandle.Free();
// Get effective SecondaryBuffer size
var bufferCapabilities = new DirectSound.BufferCaps {
Size = Marshal.SizeOf <DirectSound.BufferCaps>()
};
AudioBackBuffer?.GetCaps(bufferCapabilities);
NextSamplesWriteIndex = 0;
SamplesTotalSize = bufferCapabilities.BufferBytes;
Samples = new byte[SamplesTotalSize];
Debug.Assert(SamplesTotalSize == (2 * SamplesFrameSize), "Invalid SamplesTotalSize vs SamplesFrameSize");
// Create double buffering notifications.
// Use DirectSoundNotify at Position [0, 1/2] and Stop Position (0xFFFFFFFF)
var notifier = audioRenderBuffer as DirectSound.IDirectSoundNotify;
FrameStartEventWaitHandle = new EventWaitHandle(false, EventResetMode.AutoReset);
FrameEndEventWaitHandle = new EventWaitHandle(false, EventResetMode.AutoReset);
PlaybackEndedEventWaitHandle = new EventWaitHandle(false, EventResetMode.AutoReset);
PlaybackWaitHandles = new WaitHandle[] { FrameStartEventWaitHandle, FrameEndEventWaitHandle, PlaybackEndedEventWaitHandle, CancelEvent };
var notificationEvents = new[]
{
CreatePositionNotification(FrameStartEventWaitHandle, 0),
CreatePositionNotification(FrameEndEventWaitHandle, (uint)SamplesFrameSize),
CreatePositionNotification(PlaybackEndedEventWaitHandle, 0xFFFFFFFF)
};
notifier?.SetNotificationPositions((uint)notificationEvents.Length, notificationEvents);
}
/// <summary>
/// Initializes the direct sound.
/// </summary>
private void InitializeDirectSound()
{
// Open DirectSound
DirectSoundDriver = null;
NativeMethods.DirectSoundCreate(ref DeviceId, out DirectSoundDriver, IntPtr.Zero);
if (DirectSoundDriver == null)
{
return;
}
// Set Cooperative Level to PRIORITY (priority level can call the SetFormat and Compact methods)
DirectSoundDriver.SetCooperativeLevel(NativeMethods.GetDesktopWindow(),
DirectSound.DirectSoundCooperativeLevel.DSSCL_PRIORITY);
// -------------------------------------------------------------------------------------
// Create PrimaryBuffer
// -------------------------------------------------------------------------------------
// Fill BufferDescription for PrimaryBuffer
var bufferDesc = new DirectSound.BufferDescription();
bufferDesc.Size = Marshal.SizeOf(bufferDesc);
bufferDesc.BufferBytes = 0;
bufferDesc.Flags = DirectSound.DirectSoundBufferCaps.DSBCAPS_PRIMARYBUFFER;
bufferDesc.Reserved = 0;
bufferDesc.FormatHandle = IntPtr.Zero;
bufferDesc.AlgorithmId = Guid.Empty;
// Create PrimaryBuffer
DirectSoundDriver.CreateSoundBuffer(bufferDesc, out object soundBufferObj, IntPtr.Zero);
AudioPlaybackBuffer = soundBufferObj as DirectSound.IDirectSoundBuffer;
// Play & Loop on the PrimarySound Buffer
AudioPlaybackBuffer.Play(0, 0, DirectSound.DirectSoundPlayFlags.DSBPLAY_LOOPING);
// -------------------------------------------------------------------------------------
// Create SecondaryBuffer
// -------------------------------------------------------------------------------------
// A frame of samples equals to Desired Latency
SamplesFrameSize = MillisToBytes(DesiredLatency);
// Fill BufferDescription for SecondaryBuffer
var bufferDesc2 = new DirectSound.BufferDescription();
bufferDesc2.Size = Marshal.SizeOf(bufferDesc2);
bufferDesc2.BufferBytes = (uint)(SamplesFrameSize * 2);
bufferDesc2.Flags = DirectSound.DirectSoundBufferCaps.DSBCAPS_GETCURRENTPOSITION2
| DirectSound.DirectSoundBufferCaps.DSBCAPS_CTRLPOSITIONNOTIFY
| DirectSound.DirectSoundBufferCaps.DSBCAPS_GLOBALFOCUS
| DirectSound.DirectSoundBufferCaps.DSBCAPS_CTRLVOLUME
| DirectSound.DirectSoundBufferCaps.DSBCAPS_STICKYFOCUS
| DirectSound.DirectSoundBufferCaps.DSBCAPS_GETCURRENTPOSITION2;
bufferDesc2.Reserved = 0;
var handleOnWaveFormat = GCHandle.Alloc(WaveFormat, GCHandleType.Pinned); // Ptr to waveFormat
bufferDesc2.FormatHandle = handleOnWaveFormat.AddrOfPinnedObject(); // set Ptr to waveFormat
bufferDesc2.AlgorithmId = Guid.Empty;
// Create SecondaryBuffer
DirectSoundDriver.CreateSoundBuffer(bufferDesc2, out soundBufferObj, IntPtr.Zero);
AudioBackBuffer = soundBufferObj as DirectSound.IDirectSoundBuffer;
handleOnWaveFormat.Free();
// Get effective SecondaryBuffer size
var dsbCaps = new DirectSound.BufferCaps();
dsbCaps.Size = Marshal.SizeOf(dsbCaps);
AudioBackBuffer.GetCaps(dsbCaps);
NextSamplesWriteIndex = 0;
SamplesTotalSize = dsbCaps.BufferBytes;
Samples = new byte[SamplesTotalSize];
Debug.Assert(SamplesTotalSize == (2 * SamplesFrameSize), "Invalid SamplesTotalSize vs SamplesFrameSize");
// -------------------------------------------------------------------------------------
// Create double buffering notification.
// Use DirectSoundNotify at Position [0, 1/2] and Stop Position (0xFFFFFFFF)
// -------------------------------------------------------------------------------------
var notify = soundBufferObj as DirectSound.IDirectSoundNotify;
FrameEventWaitHandle1 = new EventWaitHandle(false, EventResetMode.AutoReset);
FrameEventWaitHandle2 = new EventWaitHandle(false, EventResetMode.AutoReset);
EndEventWaitHandle = new EventWaitHandle(false, EventResetMode.AutoReset);
var notifies = new DirectSound.DirectSoundBufferPositionNotify[3];
notifies[0] = new DirectSound.DirectSoundBufferPositionNotify
{
Offset = 0,
NotifyHandle = FrameEventWaitHandle1.SafeWaitHandle.DangerousGetHandle()
};
notifies[1] = new DirectSound.DirectSoundBufferPositionNotify
{
Offset = (uint)SamplesFrameSize,
NotifyHandle = FrameEventWaitHandle2.SafeWaitHandle.DangerousGetHandle()
};
notifies[2] = new DirectSound.DirectSoundBufferPositionNotify
{
Offset = 0xFFFFFFFF,
NotifyHandle = EndEventWaitHandle.SafeWaitHandle.DangerousGetHandle()
};
notify.SetNotificationPositions(3, notifies);
}
