This is a perfectly good question. If you google it you'll get a hundred different solutions...some of them very complicated...requiring multiple steps and reassembling video and audio. Surveying the group, with their favorite solutions IS legitimate and doesn't deserve a "use the search engine" answer.

Personally, I like the simple solution. I use FairUseWizard; MS Windows, try to buy ware. It does the job simply, albiet slowly. You can even leave all the settings on the default, if I recall. Mplayer plays the Divx results just fine. I liked it enough to upgrade to the full version which lets you further optimize the file size by trimming off starting and ending credits. One caveat, the author, is totally unresponsive to help, but there is a forum should answer most of your questions.
http://www.fairusewizard.com/lang_en...t_edition.html