DirectShow

DirectShow

DirectShow (formerly ActiveMovie) is a multimedia architecture developed by Microsoft. It is part of Windows 98, Windows 2000, Windows XP and Internet Explorer, and available separately for free download from Microsoft (as part of DirectX).

DirectShow divides the processing of multimedia tasks such as video playback into a set of steps known as filters. Filters have a number of input and output pins which connect them together. The generic design of the connection mechanism means that filters can be connected in many different ways to achieve different tasks, and developers can add their own effects or other filters at any stage in the graph. DirectShow filter graphs are widely used in video playback (in which the filters will provide steps such as file parsing, video and audio de-multiplexing, decompressing and rendering) as well as being used for video and audio recording and editing. Interactive tasks such as DVD navigation are also successfully based on DirectShow.

To get started on developing a DirectShow filter, try the filter wizard for Visual Studio from John McAleely. This is way of creating a Visual C++ project for a DirectShow filter. It will create the code for a filter with no pins. This can then be modified by you to add pin and other code to create a useful filter.

More on DirectShow

An overview of the DirectShow filter architecture
The filter graph manager and plug-in distributors
How the filtergraph manager builds graphs
Media types
Data transports
A technical Q & A for developers

Related Topics

WDM Streaming: a kernel-mode equivalent of DirectShow
Video Capture overview
Microsoft's DirectX site
The Component Object Model that underlies DirectShow