You can use converters to do this job, such as Aimersoft video converter, fully support convert MPEG files into AVI format. Know more from here: http://www.aimersoft.com/video-converter.html#161
And some video editing software own the converting functionality as well. I would like to recommend you AviDemux or mpeg video wizard.
Video Convertr to convert avi mpeg
To convert you MPG video files to AVI, it is easy, just use MPEG to AVI program, you can search it via google by using the keywords "mpeg to avi, mpeg to divx, mpeg to xvid". or just go to its official site here: http://www.008soft.com/mpeg-to-avi.htm
No, Windows Media Center does not convert AVI files to DVD format. However, it is capable of playing most AVI files.
What do you use to convert? I always use mpeg video wizard DVD to convert video files to avi format and the quality is almost as the same as the original one because of the smart rendering technical of this software.
The most common video format (in my opinion) that is used in Windows Movie Maker is either .avi or .mpeg.
I usually use imoviesoft total video converter, it can convert almost any video format with excellent conversion speed and quality, such as converting WMV to MP4, WMV to MPEG, MKV to AVI, WMV to AVI, AVI to MPEG, etc.. Furthermore, it can easily convert video files to popular audio files like converting WMV to MP3, AVI to WMA, MKV to AAC, MP4 to MP3, etc. You can have a try! Good luck!
Try MPEG Video Wizard DVD to convert video files to .avi extension or convert .avi video file to other formats, such as mpeg 2, mp4, etc. I like UM video converter
RMVB is quite an outdated format. If you want to change your RMVB videos to AVI or MPEG files, you can try some video converters like the Free HD Video Converter Factory, or use the VLC media player to play/convert files. These are the easiest programs to transfer your RMVB files.
Though Apple TV can stream your video files from computers, it has video format limitation. It only support H.264 or MPEG-4 video format. If you attempt to sync unsupported video format like AVI to Apple TV, it will draw an error message from iTunes. In order to stream AVI video files to Apple TV successfully, we need to convert these AVI movies to a format compatible with iTunes and Apple TV The following will introduce a step by step guide on how to convert AVI to Apple TV supported format on Mac or Windows at http://ipad2software.blogspot.com/2012/03/how-to-convert-and-stream-avi-to-apple.html
If using Need4Free 3GP Converter 8.0, you can convert dvd, mp4, mpeg, mov, wmv, and avi to a 3gp file format. This software will not convert copy protected files. This converter is available for free at Need4Video's website.
AVI, MPEG, and WMA
PowerPoint only accepts .avi,.asf and .mpeg video formats.