K-Lite Codec Pack is a collection of codecs and related tools. Codecs are required to encode and/or decode (play) audio and video. K-Lite Codec pack gives you the ability to play 99% of all the movies that you download from the Internet.
There are several different variants of the K-Lite Codec Pack. Ranging from a very small bundle that contains only the most essential decoders to a large and more comprehensive bundle. The global differences between the 5 variants can be found here.
Download K-Lite Codec Pack here