Windows 8.1 unable to play Music or the Audio from videos through Optical Out

I am having an issue with my audio output, where any music file, and the audio side of videos are not being played through my optical audio output. I am running a Realtek HD Audio device built on Revision 1.0 on a GA-P55A-UD6 Gigabyte Board, which runs through it's optical output to an Astro A40 Mixamp, which does some upscaling before sending it to the headset.

Now, notification sounds, and sounds/videos/music played through the browser or programs like Skype or games are working fine. This seems to specifically effect Foobar2000 and Media Player Classic.

I have updated these two programs to their latest revisions, in addition to the soundcard drivers to no avail, and searching the error code thrown by Foobar2000:

Unrecoverable playback error: The parameter is incorrect. (0x80070057)

through Google returns not very helpful results, other than the one potentially mentioning DRM. This issue I am having a very hard time resolving, and am wondering if anyone here has experienced similar issues after updating.