K-Lite Mega Codec Pack is a free software bundle which includes the K-Lite Codec Pack Full and Real Alternative. Codec is short for Compressor-Decompressor. Codecs are needed for encoding and decoding (playing) audio and video. The K-Lite Codec Pack is designed as a user-friendly solution for playing all your movie files. With the K-Lite Codec Pack you should be able to play all the popular movie formats and even some rare formats.

The K-Lite Codec Pack has a couple of major advantages compared to other codec packs:

It is updated frequently. So it is always up-to-date with the newest and/or best components.
All components have been carefully selected for specific purposes. It is not just a random bunch of stuff thrown together.
It is very user-friendly and easy to use.
Works great with Windows Media Player and Windows Media Center. But also with all other DirectShow players, such as Media Player Classic, BS.Player, ZoomPlayer, and others.
The installation is fully customizable, meaning that you are able to install just those components that you really want.
The pack has many options, which allows you to tweak it to your own specific needs and preferences.
Uninstallation removes everything that was installed by the pack. Including all registry keys. All changes are properly undone.
It is extremely easy to make a fully customized unattended installation with the integrated wizard.
It does not contain any codecs or filters that are known to be bad, buggy or unstable. In fact, the installer is able to detect and disable several known troublemakers.
It tries to avoid potential conflicts with other codecs installed on your computer. The installer is able to detect and remove over 100 different codec and filter packs.
The installer is able to detect broken codecs and filters on your system, and helps you to remove them.
It is a very complete package, containing everything you need to play your movies.
The pack has options to activate thumbnail generation in Windows Explorer for several popular video file formats, which are by default not thumbnailed in Explorer.
The pack automatically configures Media Center to recognize all common audio and video file formats, so that such files show up in your media library.
This pack has a huge user base. This means that problems are found and resolved quickly.
There are different variants of the pack. From very small to large.
The pack is suitable for both novice and expert users.