S/PDIF (Sony/Philips Digital Interface) is an audio transfer format interface. It transfers digital audio signals from one device to another without the need to first convert to an analog signal
Stop leaving negative comments just because you have limited understanding, SPDIF passes through the sound signal the way it is, and it's up to your AV to figure it out and what to do with it, if its 5.1, 7.1, or whatever This is not a converter, if you need such then install ffdshow with ac3 filter on your pc first and make it convert to proper signal before passing it through to your AV, or just use analog output