Ways to output 5.1 audio to an OPPO 105 from the Mac

I'm downloading high resolution music which is sometimes in a 5.1 surround format. Once the music is downloaded to the Mac (mid 2011) I want to send it to my OPPO blu ray machine because it has excellent DACs. The OPPO essentially takes the digital output of the computer and translates it for the rest of the analog music chain. The least amount of processing of the signals is preferable so I'm looking at options for how to get the digital audio files from the Mac to the OPPO. Thanks.