What is DirectShow Decoder?

by David Kennedy

DirectShow is an editing and diagnostic tool used by Microsoft to check media files. It is a programming feature added to Windows operating systems and is often used by Windows Media Player and Windows Media Player Classic. Third-party software and programs may also use DirectShow. DirectShow can playback videos, capture them, and analyze live videos. Microsoft lets the user install video components and files without updating the direct show video application.


A direct show decoder is a filter, or a codec, the component in the filter graph that decodes a video stream. The filter graph shows all codecs in operation. Each codec takes data and processes the data before moving it to the next codec. All of the filters are independent components that work together. Codecs are registered with Windows, and solving media file problems becomes easy when the files are seen as streams of data.

Fast Video Indexer

This program creates an index of pictures from video files. By default, AVI and VFW files are selected. Fast video indexer uses DirectShow to decode the video file and then uses a codec to set up the video frames viewable as pictures. Fast video indexer needs the appropriate codec for each type of media file that isn't AVI or VFW. So, an MKV codec is needed to run an MKV file.

Other File Types

Video file formats are how data streams are organized. The format AVI is different than VFW. This is due to the algorithm used to compress the data. Video data decoding is how the different filters separate the data. There can be different filters for splitters and for the decoding of the video and audio streams. Each of these is a codec.

Other Media Players

Other popular media players are Quick Time and RealMedia. Unfortunately, Quick Time is not supported by DirectShow but can still use it. Downloading the right filters will set up Quick Time with DirectShow. RealMedia is the same way, also not supported by DirectShow by default. If the right filters are downloaded, RealMedia can also have access to fast video indexer, giving it the ability separate videos into pictures. With the addition of Windows Vista, DVD and MPEG now support DirectShow filters.

K-Lite Codec Pack

The K-Lite Codec Pack is a collection of codecs and tools. These are third-party tools designed to make using DirectShow easier. There are many types of codec packs, and most are available free over the Internet. Different codec packs may come with different files, and having one may not mean you can play every form of media. However, some codec packs are not compatible with others and may ask that you remove previous codecs first.

About the Author

David Kennedy attended Purdue University in West Lafayette, Indiana. After graduating with a Bachelors of Arts in creative writing, he has continued his writing career through online freelance work with Demand Studios. Kennedy writes informational articles related to health, medicine, industry, computers and education.