Before watch Blu-ray Movie on your MacBook Pro 10.8, you need Download Mac Blu-ray Player. After you move it to application folder to finish the installation. Run Mac Blu-ray Play Now like this.
This is very important part when setting output of the sound , because generally you can use headphones and soundspeaker with our Mac only 3.5mm headphone jack.
So when you have integrated amplifier can receive optical input and D / A functions with digital decoding , you can check the top " Use S / PDIF when available " ( When the optical fiber is available with optical output ).
In this way you can through it to submit DTS 5.1 audio signal to your Power Amplifier.