Ac3?

This maybe stupid but wtf is AC3 Encoded Movies? They are much bigger files.
is it a better sound quality or summit
thanks

AC3 is Dolby Digital Surround Sound.
5.1 channels: center, front left, front right, rear left, rear right and the .1 is for the subwoofer.

Useless unless you have a soundcard or home stereo with 5.1 decoding capability.