What are AC3 files???

[mtrichardson]

i am a little confused.... I have been making DVDs with Sonic DVDit. I have now changed and using DVDLab and Nero to burn. i seem to be having Audio Issues with my surround system and what to learn more about how to use AC3 audio files.....
Can anyone explain to me what they are and how to use them????

[Vejita-sama]

That a loo to the left under What is DVDR and also at:

http://www.doom9.org/audio-guides.htm

AC3 file are compressed audio files that can contain mono, stereo, Dolby Surround, Dolby Digital or DTS audio (5.1). The DVD standard calls for either ac3 or PCM (uncompressed wav) audio. MP2 audio streams at not supported by the NTSC DVD standard (but are part of the PAL DVD Standard). Hence, a few NTSC standalones can't play mp2 audio (most can).

[Heavensent]

ac3 files are files that are encoded for 5.1 sound systems
(5 speakers and 1 sub).
you need a receiver that can decode dolby surround ac3 sound to enjoy the full surround.
most dvd's movies come with an ac3 dolby audio track.
ac3 files are highly compressed to save space on the dvd for the video.

there is a way to encode a regular wav file into ac3 track using besweet
you can use this to create a dvd with ac3 by yourself.

you will need a dvd authoring program that can handle ac3 audio.
i dont remember which one supports it, but the guys here will probably
know for sure.

if you need to know more about ac3 just go to dolby's site.

[mtrichardson]

ac3 files are files that are encoded for 5.1 sound systems
(5 speakers and 1 sub).
you need a receiver that can decode dolby surround ac3 sound to enjoy the full surround.
most dvd's movies come with an ac3 dolby audio track.
ac3 files are highly compressed to save space on the dvd for the video.

there is a way to encode a regular wav file into ac3 track using besweet
you can use this to create a dvd with ac3 by yourself.

you will need a dvd authoring program that can handle ac3 audio.
i dont remember which one supports it, but the guys here will probably
know for sure.

if you need to know more about ac3 just go to dolby's site.

That is whre my question lies......
I have a full surround system and DVD movies work great! and when I made DVDs on Sonic DVDit, my decoder (audio system) would make the audio to Prologic. Now when I use DVDlab and NERO, my system can't decode it and no audio comes through..... So, if I make an AC3 file and put it in DVDLab and attach it to my project,,,,, after compling will the audio work?

[Vejita-sama]

It should work yes, but we don't actually know what the problem is. As I said the DVD standard calls for either AC3 or PCM audio (mp2 is not supported even thou most NTSC standalones will play it anyway). This is one of those 'test it out and report' back situations really

[housepig]

ac3 files are files that are encoded for 5.1 sound systems (5 speakers and 1 sub).

sure about that?

from the Glossary:

AC3
See Dolby Digital. A .ac3 file is a Dolby Digital audio file.

Dolby Digital
Dolby's best-known digital system, is used to provide multichannel surround sound in cinemas from 35 mm film, and in the home from laser discs, DVDs, and digital broadcast television, cable, and satellite systems. It enables the transmission and storage of up to five full-range audio channels, plus a low-frequency effects channel (LFE), in less space than is required for just one linear PCM-coded channel on a compact disc. Dolby.

AC3 can be plain old stereo as well....

[mtrichardson]

OK,, i tried that,,, I made the AC3 file,,,, (just as directed, per this site) and then imported into DVDLab..... attached it to my project and complied the files.....
I went to NERO to burn and it shows that there is nothing in the Audio_ts file, but I have it use all the Video_ts files (IFO, VOB, BUP)... aftering burning the video looks fine, but NO AUDIO......
I don't know if I don't have teh right settings on DVDLab, or NERO... please advise!!!

[Heavensent]

housepig said :

Quote:
Dolby Digital
Dolby's best-known digital system, is used to provide multichannel surround sound in cinemas from 35 mm film, and in the home from laser discs, DVDs, and digital broadcast television, cable, and satellite systems. It enables the transmission and storage of up to five full-range audio channels, plus a low-frequency effects channel (LFE), in less space than is required for just one linear PCM-coded channel on a compact disc. Dolby.

good point.

but most 2 channels ac3 files that you DO encounter, comes from a 5.1 ac3 (downmixing)
and thats why i didnt get into it.

i havent encounterd a commercial dvd made with 2 channels ac3, im not saying that they dont exist, but you dont see them that often.

bottom line - you are right.
no harm done i hope...

[housepig]

no harm done i hope...

not at all! I just wanted to point that out, because most of my AC3 work is done with stereo captures, not ripped files, so all of mine is AC3 2-channel.

I wanted to make sure the original poster knew that it could be plain stereo, not necessarily 5.1

although a quick trip to the Glossary at upper left could have shown him that...