// if subtype is not supported by the pin the return value is -1
// if subtype is supported the return value indicates how many other types
// were skipped before we got this one.
public static int IsSubTypeSupported(IPin pPin, Guid subtype)
{
IEnumMediaTypes pEnumTypes;
int cFetched;
int nSkipped = 0;
bool bFound = false;
int hr = pPin.EnumMediaTypes(out pEnumTypes);
if (DsHlp.FAILED(hr))
{
return(-1);
}
IntPtr ptr;
while (pEnumTypes.Next(1, out ptr, out cFetched) == DsHlp.S_OK)
{
AMMediaType mt = (AMMediaType)Marshal.PtrToStructure(ptr, typeof(AMMediaType));
if (mt.subType == subtype)
{
FreeFormatBlock(ptr);
Marshal.FreeCoTaskMem(ptr);
bFound = true;
break;
}
// free the allocated memory
FreeFormatBlock(ptr);
Marshal.FreeCoTaskMem(ptr);
nSkipped++;
}
Marshal.ReleaseComObject(pEnumTypes);
return(bFound ? nSkipped : -1);
}
private static IPin GetPinByMediaType(IGraphBuilder pGraph, PinDirection pinDir, bool bConnected, Guid type, bool isSubType)
{
IEnumFilters pEnumFilters = null;
IBaseFilter pFilter = null;
int cFetched;
int hr = pGraph.EnumFilters(out pEnumFilters);
if (DsHlp.FAILED(hr))
{
return(null);
}
IPin pPin = null;
var found = false;
while ((pEnumFilters.Next(1, out pFilter, out cFetched) == DsHlp.S_OK))
{
pPin = GetPin(pFilter, pinDir, bConnected, 0);
if (pPin != null)
{
if (isSubType && IsSubTypeSupported(pPin, type) == 0)
{
found = true;
}
else if (!isSubType && IsMediaTypeSupported(pPin, type) == 0)
{
found = true;
}
if (!found)
{
Marshal.ReleaseComObject(pPin);
pPin = null;
}
}
Marshal.ReleaseComObject(pFilter);
if (found)
{
break;
}
}
Marshal.ReleaseComObject(pEnumFilters);
return(pPin);
}
/// <summary>
/// Gets the first pin of the specified direction and connection status. You also specify
/// how many matching pins should be skipped before a desired pin is returned.
///
/// 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.
///
/// Leaving the last two parameters at their default
/// values is like saying: "Gimme the first unconnected pin".
/// </summary>
/// <param name="pFilter">Filter</param>
/// <param name="pinDir">Pin direction</param>
/// <param name="bConnected">Whether the returned Pin should be connected to some other pin</param>
/// <param name="nPinsToSkip">How many Pins that match the conditions should be skipped</param>
/// <returns></returns>
public static IPin GetPin(IBaseFilter pFilter, PinDirection pinDir, bool bConnected, int nPinsToSkip)
{
bool bFound = false;
IEnumPins pEnum;
IPin pPin = null;
int cFetched;
int nSkipped = 0;
IPin pConnectedPin = null;
int hr = pFilter.EnumPins(out pEnum);
if (DsHlp.FAILED(hr) || pEnum == null)
{
return(null);
}
while ((pEnum.Next(1, out pPin, out cFetched) == DsHlp.S_OK) && pPin != null)
{
PinDirection PinDirThis;
pPin.QueryDirection(out PinDirThis);
if (pinDir == PinDirThis)
{
hr = pPin.ConnectedTo(out pConnectedPin);
if (pConnectedPin != null)
{
Marshal.ReleaseComObject(pConnectedPin);
pConnectedPin = null;
}
if ((hr == DsHlp.S_OK && bConnected) || ((uint)hr == DsHlp.VFW_E_NOT_CONNECTED && !bConnected))
{
if (nSkipped == nPinsToSkip)
{
bFound = true;
break;
}
else
{
nSkipped++;
}
}
}
Marshal.ReleaseComObject(pPin);
pPin = null;
}
Marshal.ReleaseComObject(pEnum);
return(bFound ? pPin : null);
}
public static int TraceFilterGraph(IGraphBuilder pGraph)
{
IEnumFilters pEnum = null;
IBaseFilter pFilter;
int cFetched;
int hr = pGraph.EnumFilters(out pEnum);
if (DsHlp.FAILED(hr))
{
return(hr);
}
Trace.WriteLine("Tracing filter graph...");
while (pEnum.Next(1, out pFilter, out cFetched) == DsHlp.S_OK)
{
string filterName;
FilterInfo fInfo = new FilterInfo();
hr = pFilter.QueryFilterInfo(out fInfo);
if (DsHlp.FAILED(hr))
{
filterName = "Unknown filter";
}
else
{
filterName = fInfo.achName;
}
// 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);
}
Trace.WriteLine(String.Format("Filter: {0}", filterName));
Trace.Indent();
TraceFilter(pFilter);
Trace.Unindent();
Marshal.ReleaseComObject(pFilter);
}
Marshal.ReleaseComObject(pEnum);
return(DsHlp.S_OK);
}
public static int EnumFilters(IGraphBuilder pGraph, out IEnumerable <string> aFilters) // just getting their names here
{
aFilters = null;
IEnumFilters pEnum = null;
IBaseFilter pFilter;
int cFetched;
int hr = pGraph.EnumFilters(out pEnum);
if (DsHlp.FAILED(hr))
{
return(hr);
}
var result = new List <string>();
while (pEnum.Next(1, out pFilter, out cFetched) == DsHlp.S_OK)
{
FilterInfo fInfo = new FilterInfo();
hr = pFilter.QueryFilterInfo(out fInfo);
if (DsHlp.FAILED(hr))
{
result.Add("Could not get the filter info");
continue; // Maybe the next one will work.
}
result.Add(fInfo.achName);
// 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);
}
Marshal.ReleaseComObject(pFilter);
}
Marshal.ReleaseComObject(pEnum);
aFilters = result;
return(DsHlp.S_OK);
}
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);
}
}