/// <summary>
/// Pause the audio
/// </summary>
public void Pause()
{
if (m_PlaybackState != PlaybackState.Playing)
{
return;
}
MmResult result;
m_PlaybackState = PlaybackState.Paused; // set this here to avoid a deadlock problem with some drivers
lock (WaveOutLock)
result = WaveInterop.waveOutPause(DeviceHandle);
if (result != MmResult.NoError)
{
throw new MmException(result, nameof(WaveInterop.waveOutPause));
}
}
/// <summary>
/// Resume playing after a pause from the same position
/// </summary>
private void Resume()
{
if (m_PlaybackState != PlaybackState.Paused)
{
return;
}
MmResult result;
lock (WaveOutLock)
result = WaveInterop.waveOutRestart(DeviceHandle);
if (result != MmResult.NoError)
{
throw new MmException(result, nameof(WaveInterop.waveOutRestart));
}
m_PlaybackState = PlaybackState.Playing;
}
private GCHandle hThis; // for the user callback
/// <summary>
/// creates a new wavebuffer
/// </summary>
/// <param name="hWaveOut">WaveOut device to write to</param>
/// <param name="bufferSize">Buffer size in bytes</param>
/// <param name="bufferFillStream">Stream to provide more data</param>
/// <param name="waveOutLock">Lock to protect WaveOut API's from being called on >1 thread</param>
public WaveOutBuffer(IntPtr hWaveOut, Int32 bufferSize, IWaveProvider bufferFillStream, object waveOutLock)
{
this.bufferSize = bufferSize;
buffer = new byte[bufferSize];
hBuffer = GCHandle.Alloc(buffer, GCHandleType.Pinned);
this.hWaveOut = hWaveOut;
waveStream = bufferFillStream;
this.waveOutLock = waveOutLock;
header = new WaveHeader();
hHeader = GCHandle.Alloc(header, GCHandleType.Pinned);
header.dataBuffer = hBuffer.AddrOfPinnedObject();
header.bufferLength = bufferSize;
header.loops = 1;
hThis = GCHandle.Alloc(this);
header.userData = (IntPtr)hThis;
lock (waveOutLock)
{
MmException.Try(WaveInterop.waveOutPrepareHeader(hWaveOut, header, Marshal.SizeOf(header)), "waveOutPrepareHeader");
}
}
/// <summary>
/// Initializes the specified wave provider.
/// </summary>
/// <param name="waveProvider">The wave provider.</param>
/// <exception cref="System.InvalidOperationException">Can't re-initialize during playback</exception>
public void Init(IWaveProvider waveProvider)
{
if (m_PlaybackState != PlaybackState.Stopped)
{
throw new InvalidOperationException("Can't re-initialize during playback");
}
if (DeviceHandle != IntPtr.Zero)
{
// normally we don't allow calling Init twice, but as experiment, see if we can clean up and go again
// try to allow reuse of this waveOut device
// n.b. risky if Playback thread has not exited
DisposeBuffers();
CloseWaveOut();
}
CallbackEvent = new AutoResetEvent(false);
WaveStream = waveProvider;
var bufferSize = waveProvider.WaveFormat.ConvertLatencyToByteSize((DesiredLatency + NumberOfBuffers - 1) / NumberOfBuffers);
MmResult result;
lock (WaveOutLock)
{
result = WaveInterop.waveOutOpenWindow(out DeviceHandle, (IntPtr)DeviceNumber, WaveStream.WaveFormat,
CallbackEvent.SafeWaitHandle.DangerousGetHandle(), IntPtr.Zero, WaveInterop.WaveInOutOpenFlags.CallbackEvent);
}
MmException.Try(result, nameof(WaveInterop.waveOutOpen));
Buffers = new WaveOutBuffer[NumberOfBuffers];
m_PlaybackState = PlaybackState.Stopped;
for (var n = 0; n < NumberOfBuffers; n++)
{
Buffers[n] = new WaveOutBuffer(DeviceHandle, bufferSize, WaveStream, WaveOutLock);
}
}
/// <summary>
/// Stop and reset the WaveOut device
/// </summary>
public void Stop()
{
if (m_PlaybackState != PlaybackState.Stopped)
{
return;
}
// in the call to waveOutReset with function callbacks
// some drivers will block here until OnDone is called
// for every buffer
m_PlaybackState = PlaybackState.Stopped; // set this here to avoid a problem with some drivers whereby
MmResult result;
lock (WaveOutLock)
result = WaveInterop.waveOutReset(DeviceHandle);
if (result != MmResult.NoError)
{
throw new MmException(result, nameof(WaveInterop.waveOutReset));
}
CallbackEvent.Set(); // give the thread a kick, make sure we exit
}