The K-Lite Codec Pack is a collection of codecs and related tools. 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 Full contains even more codecs. It also has encoding support for various formats. This package is for power users and people who do their own encodings.

K-Lite Codec Pack Full Features
It is always very up-to-date with the latest versions of the codecs.
It is very user-friendly and the installation is fully customizable, meaning that you can install only those components that you really want.
It has been very well tested, so that the package doesn't contain any conflicting codecs. It tries to avoid potential problems with existing codecs and even fixes some problems.
It is a very complete package, containing everything you need to play your movies.