Is there an online video converter? Does anyone know of any services that will convert a large video (1gb+)? 
I've a bunch of files I'm looking to convert from mkv to mp4's. I'm on an older Mac and I've looked at some sites like video toolbox but they limit to 600mb. I'm willing to pay.
How old of a Mac? MPEG Streamclip is a great option.


  This free software requires at least Mac OS X 10.2 (Jaguar) and QuickTime 6. It is also compatible with Mac OS X 10.3.x (Panther), Mac OS X 10.4.x (Tiger), Mac OS X 10.5.x (Leopard), Mac OS X 10.6.x (Snow Leopard), OS X Lion, and QuickTime 7. It works with PowerPC and Intel based Macs.


Unless you are living the the Stone Age and have a Mac running 10.1 or lower, you'll be fine. 

You can batch convert files by going to List>Batch List:



You'll be presented with a screen like this:



You can add files from there and convert them.