Windows 7 Codec Pack - Version 4.0.1 The Windows 7 Codec Pack is a simple to install package of codecs/filters/splitters used for playing back music and movie files. After installation you will be able to play 99.9% of files on the internet. Also included in the package are a number of encoder codec's, allowing you to encode files in formats such as DivX. XviD, x264 and many more in your favourite encoding application.