Here's the method I use to analyze a music track and animate characters to hit the beats. In this instance I'm animating Legos dancing up a storm. Methods described can be applied to setups from a DSLR using Dragonframe to an app on a phone.

Be sure to check out my other stop motion tutorials covering explosions, cut-out animation, lip sync, clay animation effects, animating toys, and of course, a good hard punch to the face.