XviD is a continuation of Project Mayo and aims to develope a high quality open-source MPEG-4 codec. As you may already know, XviD comes from the same open-source project that was the basis for DivX 4.x/5.x, but instead of going all commercial, XviD remains open-source. The quality of the codec is extremely good, and encoding speed is very fast as well, so it is at least worth a try.

Xvid is an open-source research project focusing on video compression and is a collaborative development effort. All code is released under the terms of the GNU GPL license. Learn more.