|Microsoft DirectX 9.0|
The CreateCategory method adds a new filter category to the registry.
HRESULT CreateCategory( REFCLSID clsidCategory, DWORD dwCategoryMerit, LPCWSTR Description );
[in] Class identifier (CLSID) of the new filter category.
[in] Merit of the category. Categories with higher merit are enumerated first.
[in] Descriptive name for the category.
Returns S_OK if successful, or an HRESULT value indicating the cause of the error.
The filter graph manager initially skips all categories with a merit value less than or equal to MERIT_DO_NOT_USE, to speed up the graph-building process. Filter categories that should not be considered for playback should have a merit of MERIT_DO_NOT_USE or less.
A filter can appear in one or more categories (for example, Video Compressors) to restrict the search space.