DivX Convert replaces Dr. DivX in version 6.x or newer of the DivX Codec. Dr. DivX is now an open source software, more information here
From the Official Site :
DivX Plus™ Converter lets you create high-quality DivX® and DivX Plus videos in one simple step, but it offers much more than basic file conversion. The latest version of our video converter has been redesigned so it's easier to customize settings like file size and audio tracks or subtitles. Additionally, DivX Plus output (.mkv) is now free so you can always create MKV files with advanced features. (Converting files to DivX Mobile profile on up to DivX HD 1080p profile requires unlocking the DivX Pro features.)
Convert your videos to DivX or MKV in one step
Create high definition MKV videos for free
Backup personal DVDs with the additional MPEG-2/DVD Plug-in
The "DivX Codec" is a copyright of DivX, Inc. All Rights Reserved. DIVX® is a trademark of DivX, Inc.