/// <summary>
/// Cleans up any resources being used.
/// </summary>
public void Dispose()
{
if (m_IsDisposed)
{
return;
}
m_IsDisposed = true;
lock (m_pPlayItems) {
try {
// If playing, we need to reset wav device first.
WavMethods.waveOutReset(m_pWavDevHandle);
// If there are unprepared wav headers, we need to unprepare these.
foreach (PlayItem item in m_pPlayItems)
{
WavMethods.waveOutUnprepareHeader(m_pWavDevHandle, item.HeaderHandle.AddrOfPinnedObject(), Marshal.SizeOf(item.Header));
item.Dispose();
}
// Close output device.
WavMethods.waveOutClose(m_pWavDevHandle);
m_pOutDevice = null;
m_pWavDevHandle = IntPtr.Zero;
m_pPlayItems = null;
m_pWaveOutProc = null;
} catch {
}
}
}
/// <summary>
/// Default constructor.
/// </summary>
/// <param name="outputDevice">Output device.</param>
/// <param name="samplesPerSec">Sample rate, in samples per second (hertz). For PCM common values are
/// 8.0 kHz, 11.025 kHz, 22.05 kHz, and 44.1 kHz.</param>
/// <param name="bitsPerSample">Bits per sample. For PCM 8 or 16 are the only valid values.</param>
/// <param name="channels">Number of channels.</param>
/// <exception cref="ArgumentNullException">Is raised when <b>outputDevice</b> is null.</exception>
/// <exception cref="ArgumentException">Is raised when any of the aruments has invalid value.</exception>
public WaveOut(WavOutDevice outputDevice, int samplesPerSec, int bitsPerSample, int channels)
{
if (outputDevice == null)
{
throw new ArgumentNullException("outputDevice");
}
if (samplesPerSec < 8000)
{
throw new ArgumentException("Argument 'samplesPerSec' value must be >= 8000.");
}
if (bitsPerSample < 8)
{
throw new ArgumentException("Argument 'bitsPerSample' value must be >= 8.");
}
if (channels < 1)
{
throw new ArgumentException("Argument 'channels' value must be >= 1.");
}
m_pOutDevice = outputDevice;
m_SamplesPerSec = samplesPerSec;
m_BitsPerSample = bitsPerSample;
m_Channels = channels;
m_BlockSize = m_Channels * (m_BitsPerSample / 8);
m_pPlayItems = new List <PlayItem>();
// Try to open wav device.
WAVEFORMATEX format = new WAVEFORMATEX();
format.wFormatTag = WavFormat.PCM;
format.nChannels = (ushort)m_Channels;
format.nSamplesPerSec = (uint)samplesPerSec;
//1秒钟数据量（字节/秒）= (采样频率（Hz）*采样位数（bit）*声道数)/ 8
//换算成20ms的数据量则再除50
format.nAvgBytesPerSec = (uint)((m_SamplesPerSec * m_Channels * (m_BitsPerSample / 8))) / 50;
format.nBlockAlign = (ushort)m_BlockSize;
format.wBitsPerSample = (ushort)m_BitsPerSample;
format.cbSize = 0;
m_MinBuffer = (int)format.nAvgBytesPerSec * 10;
// We must delegate reference, otherwise GC will collect it.
m_pWaveOutProc = new waveOutProc(this.OnWaveOutProc);
int result = WavMethods.waveOutOpen(out m_pWavDevHandle, m_pOutDevice.Index, format, m_pWaveOutProc, 0, WavConstants.CALLBACK_FUNCTION);
if (result != MMSYSERR.NOERROR)
{
throw new Exception("Failed to open wav device, error: " + result.ToString() + ".");
}
}
