SPDIF Not outputing or showing up
I have an Asus p5n-e SLI motherboard that has a SPDIF output onboard. I have been trying to watch some 720p files off my computer such as the latest battlestar galactica but no voices are coming through the centre channel. I have a RCA cable run from my computer to my reciever. The onboard sound software is the "realtek HD audio manager" and when I click on the mixer tab the SPDIF shows no option to control the volume of that as if there was nothing plugged into it, but there is. I have tried unplugging and plugging the RCA jack back in, but it doesn't pick it up. If I watch something that is not in HD in windows media player, the voices come through. This could be something to do with some codecs I need to get the 5.1 digital out, or maybe some new type of software being used in the movie file itself. The KM player I am using is playing the picture, and the background sound, but not the voices. I have tested my stereo speakers with the reciever to make sure all speakers are hooked up correctly. The problem seems to be on the computer end of things.
Any help or suggestions would be appreciated.