Kirisute Gomen intro

Mr. Serpent

I've always had some trouble figuring out what's doing what (on the drums of course) during the KG intro.

*It may be a bit hard to tell on youtube, the album version is much clearer, from about 0:16 to 0:53*

I just can't seem to decipher it (probably due to the fact I'm not really a drummer), so, I was wondering if anyone can tell me which one it is...or if I'm completely wrong.

Is it constant double bass, with tom rolls, or constant toms with double bass?
Any help would be appreciated, I doubt I have the correct terminology either but I put it as best I can.