What is the best software to convert .mpeg video files to .avi files?
.mpeg to .avi conversion is very popular these days and almost any converter application has this feature to convert from .mpeg/.mpg to avi. These two formats are the most widespread when it comes to video content. I recommend using VirtualDub application because it's free and it does its job according to the request you're having.
To achieve your goal please follow these simple steps:
File > Open > Browse to your file
Audio > Full processing mode
File > Save as AVI...
I would like to recommend this one - Video Converter Ultimate.
It is competible with 150+ media format, including MP4, AVI, etc. It can easily convert the video between them.