/// <summary>
/// Creates a new ACM stream to convert one format to another. Note that
/// not all conversions can be done in one step
/// </summary>
/// <param name="sourceFormat">The source audio format</param>
/// <param name="destFormat">The destination audio format</param>
public AcmStream(WaveFormat sourceFormat, WaveFormat destFormat)
{
try
{
streamHandle = IntPtr.Zero;
this.sourceFormat = sourceFormat;
int sourceBufferSize = Math.Max(65536, sourceFormat.AverageBytesPerSecond);
sourceBufferSize -= (sourceBufferSize % sourceFormat.BlockAlign);
IntPtr sourceFormatPointer = WaveFormat.MarshalToPtr(sourceFormat);
IntPtr destFormatPointer = WaveFormat.MarshalToPtr(destFormat);
try
{
MmException.Try(AcmInterop.acmStreamOpen2(out streamHandle, IntPtr.Zero, sourceFormatPointer, destFormatPointer, null, IntPtr.Zero, IntPtr.Zero, AcmStreamOpenFlags.NonRealTime), "acmStreamOpen");
}
finally
{
Marshal.FreeHGlobal(sourceFormatPointer);
Marshal.FreeHGlobal(destFormatPointer);
}
int destBufferSize = SourceToDest(sourceBufferSize);
streamHeader = new AcmStreamHeader(streamHandle, sourceBufferSize, destBufferSize);
driverHandle = IntPtr.Zero;
}
catch
{
// suppress the finalise and clean up resources
Dispose();
throw;
}
}
/// <summary>
/// Frees resources associated with this ACM Stream
/// </summary>
protected virtual void Dispose(bool disposing)
{
if (disposing)
{
// Free other state (managed objects).
if (streamHeader != null)
{
streamHeader.Dispose();
streamHeader = null;
}
}
// Free your own state (unmanaged objects).
if (streamHandle != IntPtr.Zero)
{
MmResult result = AcmInterop.acmStreamClose(streamHandle, 0);
streamHandle = IntPtr.Zero;
if (result != MmResult.NoError)
{
throw new MmException(result, "acmStreamClose");
}
}
// Set large fields to null.
if (driverHandle != IntPtr.Zero)
{
AcmInterop.acmDriverClose(driverHandle, 0);
driverHandle = IntPtr.Zero;
}
}
/// <summary>
/// Creates a new ACM stream to convert one format to another, using a
/// specified driver identifier and wave filter
/// </summary>
/// <param name="driverId">the driver identifier</param>
/// <param name="sourceFormat">the source format</param>
/// <param name="waveFilter">the wave filter</param>
public AcmStream(IntPtr driverId, WaveFormat sourceFormat, WaveFilter waveFilter)
{
int sourceBufferSize = Math.Max(16384, sourceFormat.AverageBytesPerSecond);
this.sourceFormat = sourceFormat;
sourceBufferSize -= (sourceBufferSize % sourceFormat.BlockAlign);
MmException.Try(AcmInterop.acmDriverOpen(out driverHandle, driverId, 0), "acmDriverOpen");
IntPtr sourceFormatPointer = WaveFormat.MarshalToPtr(sourceFormat);
try
{
MmException.Try(AcmInterop.acmStreamOpen2(out streamHandle, driverHandle,
sourceFormatPointer, sourceFormatPointer, waveFilter, IntPtr.Zero, IntPtr.Zero, AcmStreamOpenFlags.NonRealTime), "acmStreamOpen");
}
finally
{
Marshal.FreeHGlobal(sourceFormatPointer);
}
streamHeader = new AcmStreamHeader(streamHandle, sourceBufferSize, SourceToDest(sourceBufferSize));
}