In my personal computing life with a PC, I've tailor-fit my computer to be able to play any video file I've collected over time. And in the years of use, I've garnered a lot of media files, especially videos of family affairs, birthdays, clips from movies and concerts I've downloaded from my camcorders, digital cameras, and the internet.
This large library of videos are something I treasure and would like to keep and re-play over and over, and would like to transfer over to my Mac. Although Mac OS X's QuickTime is a great media player, a substantial amount of my videos were, simply put, unplayable. Some of my videos were set in DivX, while some were set in Windows' proprietary video file format in .wmv (Windows Movie).
I did not want to have to convert all the many videos I already had in my previous computer. And I thought to myself that there had to be codecs out there for Mac that will facilitate native playback for the various video file formats I already have. And at that time, for a new switcher from PC to Mac, I went to search for video codecs.
As I googled away, looking for codecs for QuickTime, I was lucky enough to encounter Perian and Flip4Mac WMV, even luckier upon learning that both are freeware. These two codec packs are very useful install-once-play-everything kind of codecs for the Mac, allowing you to be able to watch virtually any video file right within QuickTime.