Gizmodo has a good article up explaining the different video codecs and containers. Its worth the click imo, they do a pretty good job explaining the different file formats and codecs and how it relates to modern technology.
Gizmodo
Okay, so all that stuff up there are industry-wide standard video codecs. On top of all of those, various entities love putting out their own spin on those standards. As we mentioned before, DivX (proprietary) and XviD (open source), for instance, use MPEG-4 Part 2 (more specifically, MPEG-4 ASP) compression, meaning stuff that’ll natively play back MPEG-4 ASP will also play back DivX. Like the Xbox 360, for instance. There are a ton of MPEG-4 ASP-based codecs, actually, like FFmpeg, 3ivx and others, but DivX and XviD are the most common. Same deal with H.264: Some well known codecs that use it are Apple’s Quicktime H.264, x264 and Nero Digital. You’ve also got Windows Media Video (WMV) codecs, which are Microsoft’s proprietary twists on industry standards.