Kuroyume, thank you for your enthusiasm, but please re-read my initial post.
I stated from the outset, 64 bit (16 X 4 channels).  16 bits per channel, not 64.
16 X 4 = 64.
AKA 64 bit RGB file.
If you go to any high-end 3D package, you will see the option to output various 64 bit RBG formats.

I suppose you would have to investigate the Lightfactory PhotoInside process to totally understand why this is needed, but it has to do with their render-on-the-fly UV mapping process. They give you a 64 bit map (a RGB color gradiant they use to "track" the UV pass), you integrate that into your animation, render as a seperate pass, and hand the various passes of your animation (BG, UV, FG) back to them. A user can then upload a photo, and it will be mapped, on-the-fly, into the animation, thus personalizing it. I hope this clears that up for you :)