Is there an inexpensive way to decompose a video into frames and apply a snapchat-like filter to each frame?
Most motion graphics applications can import most video types and apply filters to them. I believe that Adobe After Effects is available for a subscription (so cheap if you use it only for a month), and Apple's Motion is available for $49 from the Mac App Store.

Or if that's too much, I believe that iMovie is only $15 and has a number of simple snapchat-like filters available.