What is AC3 sound?

[msfox]

Is AC3 sound the older stereo Dolby prologic?

Thanks,

Mike

[AntnyMD]

AC3 is the standard audio format in DVD and HDTV. It can deliver monaural sound up through 6 channels of discrete audio (the sixth being a LFE channel, for bass).

[msfox]

Thanks for the reply. Then what sound do I get when I rip a DVD? I know it is 2 channel,
but is it surround?

[patrickm]

AC3=Dolby Digital.

they carry exactly the same info, the naming convention is just a technicality. try http://www.dolby.com for more info.

the 2ch DD (AC3) can be formatted in Dolby Surround (for a Pro-Logic decoder), but i think it depends on the movie. what you want to do if it's not is to downmix the 5.1 AC3 into a stereo mix, or simply rip the PCM soundtrack, which should be that already.

[AntnyMD]

Two-channel Dolby Digital (DD 2.0) can also be a straight stereo mix, so you have to pay attention to how it sounds in your 5.1 "home theater" setup. For most films made after like 1975, the 2.0 sound on the DVD is either the old "Dolby Stereo" mix or the "Dolby Surround" found on VHS cassettes.

Dolby Pro-Logic is the digital version of Dolby Surround. Dolby Pro-Logic is usually labeled on DVDs as "Dolby Surround" but in actuality will trigger your Dolby Digital receiver into either a 2.1 or 3.1 mode.

The PCM soundtracks on DVDs, in addition to being a waste of space, are usually found on music videos, and are the stereo mix you hear on MTV. Some music videos actually remix the songs for Dolby Digital 5.1, which is a neat, rarely-discussed feature ... you essentially get fresh audio mixes without paying extra money. I have rented a few music videos, though, with new DD5.1 audio mixes and the lip-synch is terrible. I'd say that's happened on maybe three DVDs out of 40 or 50.