directsoundsink: add support for ac-3 over spdif
directsoundsink: add support for ac-3 over spdif

freedesktop-unofficial-mirror/gstreamer-sdk__gst-plugins-good,freedesktop-unofficial-mirror/gstreamer-sdk__gst-plugins-good,freedesktop-unofficial-mirror/gstreamer-sdk__gst-plugins-good,freedesktop-unofficial-mirror/gstreamer-sdk__gst-plugins-good