I'm having some weird issues related to getting surround sound from my Xbox One's optical out.
I have the audio settings as: HDMI audio - uncompressed stereo (HDMI connected straight to TV), Optical out - Bitstream (goes to 5.1 surround AVR), Bitstream format - Dolby Digital
My first problem is that there is almost no sound in the surround channels. I have my surround system calibrated to equal levels all around (tested w/ separate Blu-ray player). I've tried a handful of XBO games (Witcher 3, ACIV: Black Flag, AC: Unity, Batman: Arkham Knight), and none of them have much of anything going on in the surround channels beyond basic ambient sounds, and even those are at very low volume. This is odd, as ACIV: BF had amazing surround when I played it on my 360. I remember being able to hear the game dialog circle around me as I rotated the camera on 360. On XBO, dialog just dies whenever a character isn't in the L/C/R channels.
It's as if the XBO is outputting upsampled 2-channel 'virtual' surround as a DD 5.1 signal - but why one earth would it do that?
Then I tried watching a DVD on the XBO, and ran the on-disc 'THX optimizer', which seems to confirm my above suspicion. There was no discrete 5.1-ch separation; the left and right surround channels bleed into the fronts, and they're not even close to the same volume. They're down at least 6-10 dB.
What the heck is the XBO doing in its surround mixing, and how do I fix it? At this point it sounds dramatically worse than the 360 it replaced...