most of my laserdiscs have digital audio tracks on them, many of them with DTS sound as well as the dolby progic( some have AC-3 also )

has anyone tried capturing the audio portion of a laserdisc using a sound card with an optical or coaxial digital input, instead fo the analog RCA connectors? I imagien it would improve the sound somewhat. i wonder what kind of A/V Sync issues one would run into if attempting this..