Blending CG and Video

I'm not sure if CGCookie already has course material on this, but I couldn't find anything relevant to the kind of stuff I'm wanting to do. It's easier to show you an example of my goals than explain it, so here you are:

First, the end result of a fantastic piece of work made by some really dedicated Zelda fans. https://youtu.be/vbMQfaG6lo8

Then they were kind enough to upload a 'behind the scenes' video. https://www.youtube.com/watch?v=eQC7ZQcyPoY

Around the 1m mark on the second video I believe is the best example of what I'm wanting to do. I want to blend high quality video environments with my CG creations. In this example, they took some LEDs and used them to capture the reflected light from the CG fairies, then they overlaid the CG on top (Instead of trying to recreate accurate lighting effects in blender itself)

Where would I even start for this kind of thing? I've got the equipment to do it, just not the know-how.