Hello everyone.
There are lots of options when it comes to converting Xvids and DivXs and authoring a DVD with them on.
My question is, which is the best software or method for doing so? I would like the best quality results possible.
Many thanks.
This question has been asked many times 
I personally use ConvertXtoDVD, but it’s not free. For a free option you could give DVDFlick a go.
I think it’ll be trial and error with a few programs to see which one gives results that will suit you.
Just another suggestion: if you must do a lot of these conversions, and if you don’t have a powerful CPU to do the work, an easier solution is buy a standalone able to read also AVI files. There are many models available, not necessarily costly (some are really cheap and can read almost any video format)