There are three or four key compression formats that most people use to compress video (or audio) for playback on the Internet and users will generally use QuickTime, Windows Media Player, RealPlayer or DivX Player to playback your video.
However, it’s not always as simple as this. Some people avoid the mainstream players, as these players require the end-user to register in order to use their software and people see this as an invasion of their privacy. However, some of the freeware and Opensource video players don’t always ship with the relevant codecs. Indeed, if you try and playback a video compressed in the 90’s, you might find it was encoded with an old Intel codec or other popular codecs that have long-since been discontinued.
The K-Lite Codec Pack is a collection of codecs and related tools that will enable you to playback just about any video/audio format you’ll find on the Internet. A codec is short for Compressor-Decompressor. Codecs are needed for encoding and decoding (playing) audio and video. With the K-Lite Codec Pack you should be able to play all the popular movie formats and even some rare formats.
Note: with K-Lite's developers linking directly to the download on our server, and then this being mirrored across the Internet, we've had to take this direct download offline. The download here now links you to the K-Lite download page on their server.