IFilterInfo is an interface that manages information about a filter and provides access to the filter and to the IPinInfo interfaces representing the pins on the filter. It is essentially an IBaseFilter interface that can be accessed through Automation. This was created to provide access to the IBaseFilter methods from Microsoft® Visual Basic® applications without incurring the overhead of Automation in the IBaseFilter interface itself.
When to Implement
This interface is implemented by the filter graph manager for use by Automation client applications, such as Microsoft Visual Basic.
When to Use
Use this interface from an application to retrieve information about a filter and to retrieve individual pin objects in the filter or a collection of all pin objects belonging to the filter. This can be used when adding filters to a filter graph and connecting pins together.
Methods in Vtable Order
| IUnknown methods | Description |
| QueryInterface | Returns pointers to supported interfaces. |
| AddRef | Increments the reference count. |
| Release | Decrements the reference count. |
| IDispatch methods | Description |
| GetTypeInfoCount | Determines whether there is type information available for this dispinterface. |
| GetTypeInfo | Retrieves the type information for this dispinterface if GetTypeInfoCount returned successfully. |
| GetIDsOfNames | Converts text names of properties and methods (including arguments) to their corresponding DISPIDs. |
| Invoke | Calls a method or accesses a property in this dispinterface if given a DISPID and any other necessary parameters. |
| IFilterInfo methods | Description |
| FindPin | Locates a pin and returns an IPinInfo interface. |
| get_Name | Retrieves the filter name. |
| get_VendorInfo | Retrieves a string containing optional information supplied by a vendor about the specified filter. |
| get_Filter | Retrieves the IBaseFilter interface for the filter. |
| get_Pins | Retrieves an IAMCollection interface which provides access to the IPinInfo interfaces for this filter. |
| get_IsFileSource | Determines if the filter is a file source filter. |
| get_Filename | Retrieves the file name associated with the source filter. |
| put_Filename | Sets the file name containing the media source. |
Locates a pin, given an identifier, and returns an IPinInfo interface.
HRESULT FindPin(
BSTR strPinID,
IDispatch **ppUnk
);
Returns an HRESULT value.
This method corresponds to the IBaseFilter::FindPin method. This method is exposed for use by Automation clients and is not expected to be used by C or C++ applications because of performance limitations.
Retrieves the file name associated with the source filter.
HRESULT get_Filename(
BSTR *pstrFilename
);
Returns an HRESULT value.
This method is exposed for use by Automation clients and is not expected to be used by C or C++ applications because of performance limitations.
Retrieves the IBaseFilter interface of the filter.
HRESULT get_Filter(
IUnknown **ppUnk
);
Returns an HRESULT value.
The object that implements IFilterInfo is a wrapper and is not the same COM object as the filter itself. Thus a call to IFilterInfo::QueryInterface for IBaseFilter will fail. The IFilterInfo::get_Filter method allows an application to obtain the filter object itself. This method is exposed for use by Automation clients and is not expected to be used by C or C++ applications because of performance limitations.
Determines if the filter is a file source filter.
HRESULT get_IsFileSource(
LONG *pbIsSource
);
Returns an HRESULT value. Returns OATRUE if filter is a file source filter; otherwise, returns OAFALSE.
This method is exposed for use by Automation clients and is not expected to be used by C or C++ applications because of performance limitations.
Retrieves the filter name.
HRESULT get_Name(
BSTR *strName
);
Returns an HRESULT value.
This method is exposed for use by Automation clients and is not expected to be used by C or C++ applications because of performance limitations.
Retrieves an IAMCollection interface, which provides access to the IPinInfo interfaces for the pins on this filter.
HRESULT get_Pins(
IDispatch **ppUnk
);
Returns an HRESULT value.
This method is exposed for use by Automation clients and is not expected to be used by C or C++ applications because of performance limitations. Visual Basic applications can enumerate the IPinInfo interfaces in the returned IAMCollection object by using the For Each ...Next syntax.
Retrieves a string containing optional information supplied by a vendor about the specified filter.
HRESULT get_VendorInfo(
BSTR *strVendorInfo
);
Returns an HRESULT value.
This method is exposed for use by Automation clients and is not expected to be used by C or C++ applications because of performance limitations.
Sets the file name containing the media source.
HRESULT put_Filename(
BSTR strFilename
);
Returns an HRESULT value.
This method is exposed for use by Automation clients and is not expected to be used by C or C++ applications because of performance limitations.
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