This title template includes a Drop Zone and Blend Mode to be a self-contained effect. The video, photo, graphic you place in the Drop Zone will fill only inside the text. Drop Zone positioning and scale are published, as well as the text layer's Blend Mode setting (defaults to Stencil Luma).
Comes with it's own built-in Drop Shadow and all standard controls, as the Blend Mode won't let the normal FCP X title drop shadow work properly.
Yeah, I did
a tutorial about this
that includes a bunch of other compositing techniques in it, also. But I figured the basic video-inside-of-text should just be super simple and be available as a template. So, there you have it. Simple, but effective.