Struggling with this python bit

[Nick Rout]

In the following:

import re

title_re = re.compile(r'(.*?) ((?:\d+x\d+)|(?:\d+\.\d+\.\d+))(.*?) ?\((.*)\)')

m = title_re.match(entry['title'])

What exactly is title_re searching for? And assuming that entry['title'] 
equates to u'Battlestar.Galactica.S03E01E02.HR.HDTV.XviD-SFM' then what should 
end up in m?

Also what should the m.group(1) return?

Answers should be suitable for advanced python idiot (please).