What are you outputting the sound to? You have four options really: S/PDIF over HDMI where you get 2 channel LPCM or DTS/AC3, 7.1 LPCM at limited resolutions, full 7.1 LPCM, and full bitstreaming.
If you're just doing this to a TV rather than an HDMI amp then you don't need to go to any lengths.