Microsoft DirectX 9.0

Providing a Custom Video Resizer

Note   This feature requires DirectX 9.0 or later.

When DirectShow Editing Services (DES) resizes a video source clip, the default behavior is a StretchBlt, which is fast but not anti-aliased. You can change the resizing behavior by implementing a custom resizer as a DirectShow transform filter. The filter must expose the IResize interface, which enables DES to specify the input and output video size. For information about writing a transform filter, see Writing Transform Filters. The CTransformFilter base class is recommended as the starting point. When you implement the filter, note the following:

To use the resizer filter, the filter must be registered as a COM object on the user's system. Before the application renders the video project, query the Render Engine for the IRenderEngine2 interface and call IRenderEngine2::SetResizerGUID with the CLSID of the resizer filter.