About the K-Lite Codec Pack
The K-Lite Codec Pack is a collection of DirectShow filters, VFW/ACM codecs, and tools. Codecs and DirectShow filters are needed for encoding and decoding audio and video formats. The K-Lite Codec Pack is designed as a user-friendly solution for playing all your audio and movie files. With the K-Lite Codec Pack you should be able to play all the popular audio and video formats and even several less common formats.

The pack supports playback of a few more audio and video formats.
You get better video quality when you use MPC-HC in combination with madVR. This is an advanced video renderer that is included in the codec pack.
You get more frequent updates of MPC-HC. The pack includes stable development builds of MPC-HC and LAV Filters. This means you will get access to the latest improvements and fixes much sooner.
The pack provides additional functionality that is not directly related to playback. For example video thumbnail generation in Windows Explorer, and display of MKV file properties in Windows Explorer.
Codecs are available to other applications as well (if you want). It is also possible to install the codecs just for MPC-HC.
Advantages of the codec pack compared to using VLC Player:

You get better video quality when you use MPC-HC in combination with madVR (an advanced video renderer).
The pack provides additional functionality that is not directly related to playback. For example video thumbnail generation in Windows Explorer, and display of MKV file properties in Windows Explorer.
The pack provides more hardware acceleration options.
Better support for MKV files.
Better performance for rendering SSA/ASS subtitles.
MPC-HC loads much faster than VLC.
MPC-HC provides a better user interface (in our opinion).
Codecs are also available to other applications.

Back-up Link: K-Lite Codec Pack 1646