DirectShow is a part of the Operating System that controls how Audio and Video content is played.
DirectShow is built on a Filter (Think "Plug-In") infrastructure. There are several types of filters:
Source Filters. Filters that read the file data either off your local drives, from a network or from a capture device.
Parsing Filters. Filters that take the data and Parse it. For example the MPEG Splitter filter takes
the Audio and Video streams and splits them into separate streams.
Decoder Filters. Filters that take a compressed or encrypted data and extract it into raw Video, Audio or Text data.
Transform Filters. Filters that manipulate data. These can include sharpening and other processing effects.
Rendering Filters. These are filters that display the RAW data on a device. Video Renderers render to your
monitor for example.
Zoom Player is based on DirectShow technology. It uses the DirectShow infrastructure to play Media and DVD data.
To do this, your system must have pre-installed Filters that take care of the decoding and rendering of the
media you are trying to Play. By default DirectShow attempts to automatically construct a Filter Graph to play
any Media or DVD content. Zoom Player can manipulate DirectShow into reconstructing the Automated Filter Graph
in a way more suited to your system.
For information on configuring your system as stable playback environment, read this article.