/// <summary>
/// retrieves the media type that was set for an output stream, if any
/// </summary>
/// <param name="outputStreamIndex">Output stream index</param>
/// <returns>DMO Media Type or null if no more available</returns>
public DmoMediaType GetOutputCurrentType(int outputStreamIndex)
{
DmoMediaType mediaType;
int hresult = mediaObject.GetOutputCurrentType(outputStreamIndex, out mediaType);
if (hresult == HResult.S_OK)
{
// this frees the format (if present)
// we should therefore come up with a way of marshaling the format
// into a completely managed structure
DmoInterop.MoFreeMediaType(ref mediaType);
return(mediaType);
}
else
{
if (hresult == (int)DmoHResults.DMO_E_TYPE_NOT_SET)
{
throw new InvalidOperationException("Media type was not set.");
}
else
{
throw Marshal.GetExceptionForHR(hresult);
}
}
}
/// <summary>
/// Tests if the specified Wave Format is supported for output
/// n.b. may need to set the input type first
/// </summary>
/// <param name="outputStreamIndex">Output stream index</param>
/// <param name="waveFormat">Wave format</param>
/// <returns>True if supported</returns>
public bool SupportsOutputWaveFormat(int outputStreamIndex, WaveFormat waveFormat)
{
DmoMediaType mediaType = CreateDmoMediaTypeForWaveFormat(waveFormat);
bool supported = SetOutputType(outputStreamIndex, mediaType, DmoSetTypeFlags.DMO_SET_TYPEF_TEST_ONLY);
DmoInterop.MoFreeMediaType(ref mediaType);
return(supported);
}
/// <summary>
/// Helper function to make a DMO Media Type to represent a particular WaveFormat
/// </summary>
private DmoMediaType CreateDmoMediaTypeForWaveFormat(WaveFormat waveFormat)
{
DmoMediaType mediaType = new DmoMediaType();
int waveFormatExSize = Marshal.SizeOf(waveFormat); // 18 + waveFormat.ExtraSize;
DmoInterop.MoInitMediaType(ref mediaType, waveFormatExSize);
mediaType.SetWaveFormat(waveFormat);
return(mediaType);
}
/// <summary>
/// Set output type to the specified wave format
/// n.b. may need to set input type first
/// </summary>
/// <param name="outputStreamIndex">Output stream index</param>
/// <param name="waveFormat">Wave format</param>
public void SetOutputWaveFormat(int outputStreamIndex, WaveFormat waveFormat)
{
DmoMediaType mediaType = CreateDmoMediaTypeForWaveFormat(waveFormat);
bool succeeded = SetOutputType(outputStreamIndex, mediaType, DmoSetTypeFlags.None);
DmoInterop.MoFreeMediaType(ref mediaType);
if (!succeeded)
{
throw new ArgumentException("Media Type not supported");
}
}
private static IEnumerable <DmoDescriptor> GetDmos(Guid category)
{
IEnumDmo enumDmo;
int hresult = DmoInterop.DMOEnum(ref category, DmoEnumFlags.None, 0, null, 0, null, out enumDmo);
Marshal.ThrowExceptionForHR(hresult);
Guid guid;
int itemsFetched;
IntPtr namePointer;
do
{
enumDmo.Next(1, out guid, out namePointer, out itemsFetched);
if (itemsFetched == 1)
{
string name = Marshal.PtrToStringUni(namePointer);
Marshal.FreeCoTaskMem(namePointer);
yield return(new DmoDescriptor(name, guid));
}
} while (itemsFetched > 0);
}
/// <summary>
/// Gets the DMO Media Output type
/// </summary>
/// <param name="outputStream">The output stream</param>
/// <param name="outputTypeIndex">Output type index</param>
/// <returns>DMO Media Type or null if no more available</returns>
public DmoMediaType?GetOutputType(int outputStream, int outputTypeIndex)
{
try
{
DmoMediaType mediaType;
int hresult = mediaObject.GetOutputType(outputStream, outputTypeIndex, out mediaType);
if (hresult == HResult.S_OK)
{
// this frees the format (if present)
// we should therefore come up with a way of marshaling the format
// into a completely managed structure
DmoInterop.MoFreeMediaType(ref mediaType);
return(mediaType);
}
}
catch (COMException e)
{
if (e.GetHResult() != (int)DmoHResults.DMO_E_NO_MORE_ITEMS)
{
throw;
}
}
return(null);
}
