H.264 vs. Theora vs. MPEG-4 vs. MPEG-2 vs. Dirac
I had no idea of some of these formats. The short answer is that H.264 seems the best. What is even better is there is an open source H.264 encoder! Yes!
Tagged: codec
Windows telling you that you need a codec to play a movie?
Then use this great utility and open that file and it will tell you what codec you need to play it. GSpot Codec Information Appliance