Which Option for Digital Output on WD Live?

Hello, Which setting is better ? Digital Passing True or Digital Passing Optical only ? I have now sound true a Optical cable, but I wonder if I must set it on Optical Only ?

What is the use of Medialibre ? When I set that off, what happens then ?

I know this is out off topic, but sometimes I cannot find, where I can set a new question on/in the Topic ?

Hope for a answer, You all ! Have helped me a lot ! Greetings from Holland

S/PDIF digital output needs to be configured on the settings as digital surround sound is only available when using the S/PDIF interface (Optical). You can select Digital with No HDMI.