I do a lot of video editing for Inglewood Church and have recently shifted to Mac for both editing and presentation duties. Before that I was moving between both PC and Mac platforms.
However even now with just Mac, I am always on the lookout for video converters that work. Often the good ones are the ones that cost you.
But get in quick, Macx Video Pro Convertor is available for the next day or so for free, make sure you download it, install it, and then grab the free authentication code off the website and register.
By the way, if you are still stuck in a Windows world, they also have a PC version for free as well.