Yes. AC-3 Refers specifically to the "Perceptual Encoding" system developed by Dolby Labs to contain 1 to 6 discrete channels of compressed audio within a digital bitstream. The system was called AC-3 long before DVDs, when available only on Laserdisc. "Dolby Digital" was a more descriptive, marketable term, created about 2 years later. If you look at an early DD Laserdisc, like "True Lies" or an early-generation DD decoder like the Pioneer Elite SP-99D (I had one for several years), You will only find "AC-3" as the name for the digital surround system called Dolby Digital today.
Are dolby digital and AC-3 the same?
I'm a bit confused by these 2 terms. I've heard about a difference in bit rates, but that's about all. I currently own a Harman Kardon AVR55 reciever, that does AC-3 decoding, and I would like to use it in my home theater setup. I would like to use the money saved to go out and get 2 additional amps for my system, since the receiver has pre-outs. Also, do most DVD movies come with DD and DTS, or just one of the 2?