Divx Networks released Divx 5.0 today....
DivX 5.0 raises the bar for video technologies everywhere with a universal architecture, increased optimizations and encoding performance, significantly improved visual quality, MPEG-4 compatibility including a new MPEG-4 based DivX file format, a complete command line interface for advanced users, and a host of other improvements that will appear to novice and power users alike.
Notable features include backward compatability, MPEG-4 Compatability, MPEG-4 based file format, and a Mac OS Alpha build... "making it the first publicly distributed MPEG-4 compatible technology available on Mac OS that is capable of playing back MPEG-4 Simple Profile and MPEG-4 Advanced Simple Profile video"
The Mac OS based encoder is "right around the corner".