Shawn King's post | Latest updates on Sulia
HandBrakeBatch review: Easy-does-it batch video conversion.
There are an insane number of video formats available - some play on your Mac but not your iPhone. Some can be watched via the Apple TV but not on your iPad. I can't tell you how many billions of computer cycles I've wasted converting videos to and from various formats.
Macworld has a review of a free app that can help. http://www.macworld.com/article/2049117/handbrakebatch-review-easy-does-it-batch-video-conversion.html