AC-3 VS
AC-3 VS is Dolby Virtual Surround AC-3.
AC-3 VS uses the way you ears work to generate a surround sound feeling from a 2CH signal. This permits you to convert 5.1 AC3 audio that you might find on a DVD to AC-3 VS, dropping the bitrate to 192kbit/s while still maintaining a surround feeling and superior quality.