Aug 5, 2015
So I've got this motherboard (MSI Z77A-G43) and this HTiB (Samsung HT-BD1250) system I got from my aunt & uncle. I've been using it as 2.1 for about a year now but thought it was time to get 5.1 working.

There are images of all the HTBD1250s outputs / inputs in the link and it supposedly supports onboard decoding for Dolby TrueHD and DTS-HD Master Audio.

I'm not sure what this means, but i was wondering if it would work with my motherboards outputs, or if I would have to buy something and in that case, what?

Unfortunately many of these so called "Home Theater" boxes can only decode for the built-in BlueRay/DVD and nothing else.

Look for an HDMI input port on it, or Toslink (optical), either of these port will decode your PC. Without neither ports available, you may as well replace that HTBD with something else.