Prism is the most stable and comprehensive multi-format video converter available and is very easy to use.

Features:

Adjust Video Settings Easily
Prism lets you set compression/encoder rates, resolution and frame rate of output files. Prism supports everything from HD to high compression for smaller files. You can even set a specific size for output files.

Convert Many Video Formats
Prism converts avi, mpg, vob, asf, wmv, mp4 and all video formats that have a DirectShow based codec. If you can play the video file using Windows Media Player, you can convert it using Prism. Video formats supported by Prism.

Preview Before Converting Videos
Preview original videos and what the video output results will be before converting to ensure effect settings including video rotation and captions are set up correctly.

Direct DVD Converting
Convert from DVDs by simply adding the DVD, selecting the format and clicking convert.

Get it Free. A free version is available for non-commercial use only. The free video converter supports fewer encoding formats for home use. You can download the free version here.

Requirements:
OS X 10.4 - 10.8
Intel