I would appreciate a little advice regarding all in one hifi units which play dvds. some seem to advertise that they are 5.1 dolby units, but when you look at them, the amp seems to be dolby pro-logic only. Does this mean that the DVD player bit has a 5.1 decoder and would produce proper 5.1 sound if connected to the right amp, or will the unit itself actually give 5.1 output as it stands ? I have seen units from Sony, Technics and even Samsung and LG. Any help/thoughts appreciated. cheers.