Amon Amarth Cello/double bass?

I have no idea what this guy tries to do here.
That could be a bad dobblebase in the background. But it could be a fast played cello aswell, sounds pretty strange to me in any case.
 
All played on cello, good for him, but I don't really like it. Sound sloppy.
I do recognized the song (eventually), but maybe he should practice some more...
 
hmm...if he does the "doublebass" sound also with the cello then I think thats the reaseon why it sounds so strange ^^

first I had absolutely no idea wchich song he plays...but I recognised the song/melody when he played "normal" for the refrain ;)