This video will show you how to convert a video file either to MP4 (AVC format) or FLV format using a cool freeware named “Any Video Converter”. MP4 (AVC format) and FLV are the 2 main video formats (simple SWF is also supported) which the Studio supports.
You can even convert a non-AVC MP4 video to an AVC MP4 video, add special effects, rotate and crop the video and more.
You can download the software from http://www.any-video-converter.com/products/for_video_free/. When installing it, make sure you install only the software and not other things which come along with it.
Here is another tutorial video you might be interested to watch:
How to convert from one video type to another using ConverterLite (3 minutes tutorial video)