User blog comment:Zolnir/60 Frames Per Second/@comment-24620600-20141213095451/@comment-10380701-20141213095947

By default, RWBY is 30/48 fps. (Unsure, as the 1080p episodes I downloaded from the site are faster than the youtube ones, but not as fast as the 60 fps ones)

I think it's a mix of him combining two frames and adding the new frame in-between, thus doubling the length of the scene, followed by speeding it up to make it look 60fps.

But don't quote me on this, as I'm only really saying it based on what one of the render methods of Sony Vegas can do.