IFilterMapper2 Interface
This interface is an interface for registering and locating DirectShow filters with greater flexibility than IFilterMapper allowed. Applications and filters should use IFilterMapper2 instead of IFilterMapper, although both interfaces can find filters registered with the other interface.
One major change from IFilterMapper to IFilterMapper2 is that IFilterMapper2 provides support for filter categories. A filter can appear in one or more categories (for example, Video Compressors) to restrict the search space. The RegisterFilter method takes a category, and the EnumMatchingFilters method searches across categories.
Other changes include:
- Quicker and easier enumeration of hardware devices such as WDM/PnP
- Registration in one step (previously you had to register pins and media types with separate calls)
- Register and search by mediums (see Kernel Streaming in the NT DDK)
When to Implement
This interface is implemented on the filter graph and is not intended to be implemented by developers.
When to Use
Applications and filters should use IFilterMapper2 when they need to register or unregister filters. IFilterMapper2 should be used instead of IFilterMapper.
Methods in Vtable Order
The following table shows the methods that appear in the Vtable beneath the standard COM methods inherited from IUnknown.
| Method | Description |
|---|---|
| CreateCategory | Adds a new category to the list of filter categories (CLSID_ActiveMovieCategories). |
| UnregisterFilter | Removes the registration of the specified filter from the registry. |
| RegisterFilter | Registers a filter, pins, and media types under a category. |
| EnumMatchingFilters | Provides an enumerator that enumerates registered filters that meet specified requirements. |
Requirements
DirectShow applications and DirectShow filters have different include file and link library requirements. See Setting Up the Build Environment for more information.
OS Versions: Windows CE 2.12 and later. Version 2.12 requires DXPAK 1.0 or later.
See Also
Last updated on Wednesday, April 13, 2005
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