How to Create a DirectShow Filter DLL

[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

This article describes how to implement a component as a dynamic-link library (DLL) in Microsoft DirectShow. This article is a continuation from How to Implement IUnknown, which describes how to implement the IUnknown interface by deriving your component from the CUnknown base class.

This article contains the following sections.

• Class Factories and Factory Templates
• Factory Template Array
• DLL Functions

Registering a DirectShow filter (as opposed to a generic COM object) requires some additional steps that are not covered in this article. For information on registering filters, see How to Register DirectShow Filters.

Related topics

DirectShow and COM