/// <summary>
/// Suggests an appropriate PCM format that the compressed format can be converted
/// to in one step
/// </summary>
/// <param name="compressedFormat">The compressed format</param>
/// <returns>The PCM format</returns>
public static WaveFormat SuggestPcmFormat(WaveFormat compressedFormat)
{
// create a PCM format
WaveFormat suggestedFormat = new WaveFormat(compressedFormat.SampleRate, 16, compressedFormat.Channels);
//MmException.Try(AcmInterop.acmFormatSuggest(IntPtr.Zero, compressedFormat, suggestedFormat, Marshal.SizeOf(suggestedFormat), AcmFormatSuggestFlags.FormatTag), "acmFormatSuggest");
IntPtr suggestedFormatPointer = WaveFormat.MarshalToPtr(suggestedFormat);
IntPtr compressedFormatPointer = WaveFormat.MarshalToPtr(compressedFormat);
try
{
MmResult result = AcmInterop.acmFormatSuggest(IntPtr.Zero, compressedFormatPointer, suggestedFormatPointer, Marshal.SizeOf(suggestedFormat), AcmFormatSuggestFlags.FormatTag);
suggestedFormat = WaveFormat.MarshalFromPtr(suggestedFormatPointer);
MmException.Try(result, "acmFormatSuggest");
}
finally
{
Marshal.FreeHGlobal(suggestedFormatPointer);
Marshal.FreeHGlobal(compressedFormatPointer);
}
return(suggestedFormat);
}
/// <summary>
/// Creates a new ACM stream to convert one format to another, using a
/// specified driver identified 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.acmStreamOpen(out streamHandle, driverHandle,
sourceFormatPointer, sourceFormatPointer, waveFilter, IntPtr.Zero, IntPtr.Zero, AcmStreamOpenFlags.None), "acmStreamOpen");
}
finally
{
Marshal.FreeHGlobal(sourceFormatPointer);
}
//MmException.Try(AcmInterop.acmStreamOpen(out streamHandle, driverHandle,
// sourceFormat, sourceFormat, waveFilter, IntPtr.Zero, IntPtr.Zero, AcmStreamOpenFlags.NonRealTime), "acmStreamOpen");
streamHeader = new AcmStreamHeader(streamHandle, sourceBufferSize, SourceToDest(sourceBufferSize));
}