I am sure I was previously getting Dolby Digital on, at least, many of the HD channels. Now my surround sound system is not detecting DD5.1 at all just pro-logic. Using optical connection. Currently Film4 HD indicating only pro-logic, If I press info and go to sound, It shows 1. MPEG1, 2 Dolby Digital but making the change makes no difference. Maybe a reboot would fix it but I have other recordings going on?