Absolutely not. They are same and you need only one. So you just need a proper video converting software to solve your problem. just convert AVI to Divx. And your source file will not changed. I know some video converter.
If u need , here is the link:
http://videoconverterfactory.com/free-hd-video-converter/ it is free hd video converter factory
http://www.xisoft.com/video-converter.html it fees.
http://www.leowe.com/leawo-video-converter/ it also fees.
All they can solve your problem. I think you can try the first one, it is free,and quality is good.