Are AC3 files completely lossless?

[Laz]

Are AC3 files full 100% quality straight from the DVD?
Ive been ripping some ac3's from DVD's and they seem to be too small.

[scharfis_brain]

AC3 is a lossy audiocompressionformat like MP3 or others. It just supports multichannel-audio (5.1).

AC3 can have different bitrates, too. Most common are IMO 384 - 512 kbps.

And even 512kbps-Audio will have less than the half size then AudioCD-PCM-Audio.

[Laz]

I see.
But are they the best quality audio that I can get from a DVD?

also. Would the 2channel audio (ac3 track) from A Concert DVD be better than the audio from the concert CD?? What about the 6channel track from the DVD downmixed to stero?

I assume after a conversion to 200kbps Ogg Vorbis, they will be the same?
thanks

[jggimi]

Laz,

There are many different types of audio streams available within the DVD standard. For example, you asked: ... are they the best quality audio that I can get from a DVD? Actually, uh ... no. AC3 is Dolby Digital; streams in Digital Theatre Sound (DTS) are considered by many to be better; DTS is a format used in some DVDs. (Until very recently, there were no software decoders available for DTS; one was just announced, apparently; see the 4/28 News at www.doom9.org for more info.)

Other high quality soundtrack formats are possible, such as Linear PCM (WAV).

In the DVD Basics section of www.doom9.org you can find a link to The Official DVD FAQ (http://www.thedigitalbits.com/officialfaq.html), where much, much, much more information on audio streams for DVD can be found.

[Laz]

thanks, checking the FAQ out now :)