I have XBMC under xp64 with a hd3450 video card run to a SONY with HDMI the audio plays with XBMC sound effect and with music but when a movie playes back it says unable to initalise sound and I get no sound.
Fixed it.. Had to have the realtek hd audio drivers installed, not supplied with the video card Now why they are not with the card is a mystery. I found the answer on another forum .