Basically K-Lite Codec Pack is a pack that contains a video player and a lot of video codes, so you can watch almost all different videos out in the internet. This software can also play all kind of different format videos, like Windows Media Player format, QuickTime format, Real Player format, HD format, etc. In other words, one player rules all the other players. By the way, this player uses less ram than all other players.
K-Lite Mega Codec Pack is a collection of codecs, DirectShow filters and tools. Codecs and DirectShow filters are needed for encoding and decoding (playing) audio and video formats. The K-Lite Mega Codec Pack is designed as an user-friendly solution for playing all your movie files. With K-Lite Codec Pack you should be able to play all the popular audio and video formats and even some rare formats.