If I buy a blu ray player, will the audio work with my existing environment? I have a Yamaha home theater receiver that is about 8 years old (read: no HDMI). It supports DD 5.1 and DTS which I connect my DVD player and xbox through an optical connection. Will I need to upgrade my receiver if I get a blu ray player, or can I get a BR player with optical audio output that will support what I have? I would be connecting the BR to my TV via HDMI if that matters?