DirectShow (http://msdn.microsoft.com/library/default.asp?url=/library/en-us/directx9_c/directX/htm/directshow.asp), formerly Active Movie, is a component of the Microsoft DirectX 8+ (http://www.microsoft.com/directx/) family of multi-media APIs.

It is characterized by streams of data that are represented and controlled by a graph of data filters.

Filters can have input and output "pins" that permit their interconnection. Pins are typed so that only legal interconnections are permitted.

A filter graph may represent data moving through memory, data moving through hardware, or a combination of the two.

DirectShow is closely associated with the new WindowsDriverModel (WDM) supported in Windows98 and WindowsNT 5.0.

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'''From DirectX FAQ''' (http://www.microsoft.com/windows/directx/default.aspx?url=/windows/directx/productinfo/faq/):

Q: In earlier versions of DirectX, I had to install DirectX Media. Do I still need it?

A: No, not with DirectX 9.0. The key part of DirectX Media for video capture, Microsoft DirectShow(R), has been integrated into DirectX.


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Some resources for developers:
* For ones starting out, play around with the graphedit utility.  You won't learn any programming, but you'll learn how filter graphs work - which are by far the most complicated (i.e. convoluted) part of DS.
* Look at the DirectShowEncoder sample over at CodeProject.com
* Pay close attention to the asyncfilter sample in the latest directx sdk and the way it renders the memory

An interesting tidbit is that most of the API still has ActiveMovie remnants around it (AMMediaStream, AM_TRUE etc.).

--RyanNorton