public void Stop()
{
if (IntPtr.Zero == _hWaveout)
{
return;
}
_started = false;
int result = Native.waveOutReset(_hWaveout);
System.Diagnostics.Debug.Assert(result == Native.MMSYSERR_NOERROR);
ReleaseBuffers();
result = Native.waveOutClose(_hWaveout);
System.Diagnostics.Debug.Assert(result == Native.MMSYSERR_NOERROR);
_gchThis.Free();
_hWaveout = IntPtr.Zero;
_callback = null;
_fmt = null;
}
public bool Start(WinMMAudioRenderCallback callback, int sampleRate, int channels, int bitsPerSample)
{
if (null == callback)
{
return(false);
}
if ((0 == sampleRate) || (0 == channels) || (0 == bitsPerSample))
{
return(false);
}
// only mono and stereo are supported
if (channels > 2)
{
return(false);
}
Stop();
_callback = callback;
_fmt = new Native.WAVEFORMATEX();
_fmt.wFormatTag = Native.WAVE_FORMAT_PCM;
_fmt.nChannels = (short)channels;
_fmt.nSamplesPerSec = sampleRate;
_fmt.nBlockAlign = (short)((bitsPerSample >> 3) * channels);
_fmt.nAvgBytesPerSec = _fmt.nBlockAlign * sampleRate;
_fmt.wBitsPerSample = (short)bitsPerSample;
_fmt.cbSize = (short)Marshal.SizeOf(_fmt);
_gchThis = GCHandle.Alloc(this);
int result = Native.waveOutOpen(out _hWaveout, Native.WAVE_MAPPER, _fmt, _waveOutProc, (IntPtr)_gchThis, Native.CALLBACK_FUNCTION);
if (result != Native.MMSYSERR_NOERROR)
{
_gchThis.Free();
_hWaveout = IntPtr.Zero;
return(false);
}
_started = true;
_totalDuration = 0;
CreateBuffers(5, _fmt.nBlockAlign * (_fmt.nSamplesPerSec / 50)); // 5 buffers, 20ms each buffer
result = Native.waveOutPause(_hWaveout);
System.Diagnostics.Debug.Assert(result == Native.MMSYSERR_NOERROR);
// write the empty buffers
for (int i = 0; i < _buffers.Count; i++)
{
WaveOutBuffer buffer = _buffers[i];
buffer._hdr.dwBufferLength = 0;
result = Native.waveOutWrite(_hWaveout, buffer._gchHdr.AddrOfPinnedObject(), Marshal.SizeOf(buffer._hdr));
System.Diagnostics.Debug.Assert(Native.MMSYSERR_NOERROR == result);
}
result = Native.waveOutRestart(_hWaveout);
System.Diagnostics.Debug.Assert(result == Native.MMSYSERR_NOERROR);
return(true);
}
