/// <summary>
/// Gets the first pin of the specified direction that supports specified media types.
///
/// If this function finds a matching pin, it returns an IPin interface pointer
/// with an outstanding reference count. The caller is responsible for releasing the interface.
/// </summary>
/// <param name="pFilter">Filter</param>
/// <param name="pinDir">Pin direction</param>
/// <param name="mediaTypes">Supported media types</param>
/// <param name="searchConnected">Search connected pins in addition to disconnected ones</param>
/// <param name="disconnect">Disconnect a connected pin if it satifies the conditions and return it</param>
/// <returns></returns>
public static IPin GetPin(IBaseFilter pFilter, PinDirection pinDir, Guid[] mediaTypes, bool searchConnected, bool disconnect)
{
IPin pPin = null;
int nSkip = 0;
while ((pPin = GetPin(pFilter, pinDir, false, nSkip)) != null)
{
if (mediaTypes.Any(t => IsMediaTypeSupported(pPin, t) == 0))
{
break;
}
nSkip++;
Marshal.ReleaseComObject(pPin);
pPin = null;
}
if (pPin == null && searchConnected)
{
// let's try connected pins
nSkip = 0;
while ((pPin = GetPin(pFilter, pinDir, true, nSkip)) != null)
{
if (mediaTypes.Any(t => IsMediaTypeSupported(pPin, t) == 0))
{
if (disconnect)
{
FilterInfo fInfo = new FilterInfo();
var hr = pFilter.QueryFilterInfo(out fInfo);
if (DsHlp.SUCCEEDED(hr))
{
// The FILTER_INFO structure holds a pointer to the Filter Graph
// Manager, with a reference count that must be released.
if (fInfo.pGraph != null)
{
Disconnect(fInfo.pGraph, pPin);
Marshal.ReleaseComObject(fInfo.pGraph);
}
}
}
break;
}
nSkip++;
Marshal.ReleaseComObject(pPin);
pPin = null;
}
}
return(pPin);
}
public static Guid GetMediaType(IPin pPin)
{
Guid mediaType = Guid.Empty;
IEnumMediaTypes pEnumTypes;
int cFetched;
int hr = pPin.EnumMediaTypes(out pEnumTypes);
if (DsHlp.SUCCEEDED(hr))
{
IntPtr ptr;
if (pEnumTypes.Next(1, out ptr, out cFetched) == DsHlp.S_OK)
{
AMMediaType mt = (AMMediaType)Marshal.PtrToStructure(ptr, typeof(AMMediaType));
mediaType = mt.majorType;
// free the allocated memory
FreeFormatBlock(ptr);
Marshal.FreeCoTaskMem(ptr);
}
Marshal.ReleaseComObject(pEnumTypes);
}
return(mediaType);
}
public static void RemoveRedundantFilters(IBaseFilter sourceFilter, IGraphBuilder graphBuilder)
{
IEnumFilters pEnumFilters = null;
IBaseFilter pFilter = null;
int cFetched;
int hr;
bool bCallAgain = false;
// get information about the source filter (its name)
FilterInfo fSourceInfo = new FilterInfo();
if (sourceFilter != null)
{
hr = sourceFilter.QueryFilterInfo(out fSourceInfo);
if (DsHlp.SUCCEEDED(hr))
{
if (fSourceInfo.pGraph != null)
{
Marshal.ReleaseComObject(fSourceInfo.pGraph);
}
}
else
{
fSourceInfo.achName = null;
}
}
// let's start enumerating filters
hr = graphBuilder.EnumFilters(out pEnumFilters);
if (DsHlp.FAILED(hr))
{
return;
}
while ((pEnumFilters.Next(1, out pFilter, out cFetched) == DsHlp.S_OK))
{
FilterInfo fInfo = new FilterInfo();
hr = pFilter.QueryFilterInfo(out fInfo);
if (DsHlp.FAILED(hr))
{
Marshal.ReleaseComObject(pFilter);
continue; // don't touch this one
}
// The FILTER_INFO structure holds a pointer to the Filter Graph
// Manager, with a reference count that must be released.
if (fInfo.pGraph != null)
{
Marshal.ReleaseComObject(fInfo.pGraph);
}
if (fInfo.achName == null || fSourceInfo.achName == null)
{
Marshal.ReleaseComObject(pFilter);
continue;
}
if (fInfo.achName == fSourceInfo.achName) // source filter
{
Marshal.ReleaseComObject(pFilter);
continue;
}
IPin pPin = DsUtils.GetPin(pFilter, PinDirection.Input, true, 0);
if (pPin == null)
{
// this filter does not have connected input pins
graphBuilder.RemoveFilter(pFilter);
Marshal.ReleaseComObject(pFilter);
bCallAgain = true;
break;
}
else
{
// this filter is connected, let's try another one
Marshal.ReleaseComObject(pPin);
Marshal.ReleaseComObject(pFilter);
}
}
Marshal.ReleaseComObject(pEnumFilters);
if (bCallAgain)
{
RemoveRedundantFilters(sourceFilter, graphBuilder);
}
}