This blog – has links to various codec downloads. (Looks entertaining)
Has the following links on this page.
Ah Ha – Found some-thing that has eluded me, … #3:-Comment re-pasted below
DivX® 7 for Windows is a free download that provides everything you need to enjoy high-quality digital videos on your computer, including HD H.264 (.mkv) videos with AAC audio and videos created using all previous versions of DivX technology.
Use any good search engine