You completely lost me at "To do that just Render As ac3 with the stereo template"

Please help :(

File>Render As
File Name: [ Whatever you like]
Save asType: Dolby Digital AC-3
Template: Stereo DVD

click "Custom"
Preprocessing Tab
Line Mode Profile: "None"
RF Mode Profile "None"

Click OK
Click Save

Vegas will renders audio to ac3 for a while.


Now you need to make the mpeg-2 video of the same thing:

File>Render As
File name: [Same as before but with .mpg extension]
Save as File Type: "Main Concept MPEG-2"
Template: "DVD Architect PAL NTSC Video Stream"

Click Save

Vegas renders video to mpeg-2

Start DVDA, Drag mpeg-2 file created in the above into window, DVDA should pickup the ac3 file as being the matching audio file.

The AC3 codec has two templates, 2.0 and 5.1. The 2.0 template renders the smaller file. However, AC3 is a lossy codec. It doesn't have the same "punch" as does PCM.

pelladon,
I keep hearing people saying this but don't quite understand how this conclusion is reached:
Yes, ac3 is a lossy codec, so is mp3.
However ac3 uses floating point values and therefore I assume has much greater dynamic range than PCM (depending on the PCM bit depth).

Certainly ac3 is an output only format like mp3, but I'd suggest PROPERLY encoded ac3 should be far superior to say 16/48 PCM as an output format.
I stress the "properly" because from what I know ac3 is far from goof proof.

uum, farss,

Have you played a music video DVD? Did you listen first to the AC3 soundtrack, then listen to the PCM track? There's a big difference. There's a reason why a lot of music videos have a PCM track.

If AC3 is so good, why the need for dts?

Also, I can clearly hear a difference between a mp3 file and the same PCM. But mp3 sacrifices fidelity for space, which is why we use it.

Thanks so much! So I will get the same audio levels in each channel?

Also, is every DVD player on earth compatabile with this audio? (Unlike mpeg audio)

Also, I want to use DVDLab to make my menus. is there anyway I can save to mpeg2 along with this audio format you decribe?

As far as I'm aware dts is obsolete technology, it's certainly not being used in any new cinemas, they all use Dolby tracks on the film.

I've only got one music video with both ac3 and a PCM track on it, must say I haven't done a comparison. However the ac3 track is 5.1so a lot more data is being muxed in at whatever bitrate it's at.

That still doesn't really resolve the issue though, all it proves is that maybe most ac3 mixes on commercial DVDs aren't too good. Equally likely the decoders aren't up to scratch either.
It doesn't disprove what you're saying either BTW. I'm just by nature very warry of jumping to these sorts of conclusions. There's a big difference between what somethings capable of and how it mostly gets used. I know that most DVD players cannot cope with ac3 at the maximum bitrate, they cannot cope with the mpeg-2 stream at the maximum bitrate either, so most commercial DVDs dumb down both the ac3 bitrate and the mpeg bitrate so they don't have most of the customers bringing the stuff back.

I do a have a DVD with ac3 encoded at the maximum bitrate and the mpeg-2 at the maximum bitrate. I haven't tried the audio through a studio setup to see how it sounds, sounds good on the crappy stuff at hand but that's a pretty poor test, at least on my reference DVD player it doesn't drop out like it does on some players. Much the same goes for the video, most of the players I've run it on it looks just horrid. It's not the fault of mpeg-2 as an encoding system.

So I'm just wondering how much of the flack that ac3 cops is the fault of the system and how much is the fault of how it's used. To illustrate that I'd also mention that I was told by a local projectionist to always go to cinema #7 at ...., because its the only one the local techos hadn't screwed around with the Dolby decoders. I've heard Dolby in a very large cinema that had been setup by Dolby engineers minutes before we were let in, all I can say is it made everything I'd heard in cinemas sound pathetic.

Having said all that, I still use PCM tracks on the DVDs I produce unless space becomes an issue.

wow, how did this thread get off-track???

The original poster was wondering if he could get the same quality of sound that PCM gave him using AC3. But given how AC3 works, you're trying to squeeze a uncompress source into a highly compressed bitrate, and bits have to be dropped.

Dolby has very strong working relationships with the major studios. And if the studios use AC3, the movie chains have no choice but to install AC3 as well. Dolby is really about licensing and marketing, probably moreso then their technology. People forget that Dolby wasn't the first with digital sound in the theaters.

I'm not knocking AC3, but there's always room for improvement...Remember, AC3 is a lossy perceptual codec.

Go to http://www.dolby.com for more details.

DaddyLongLegs,
I am assuming that the music video is short so there is absolutely no reason to use any form of Dolby Digital. It will not improve the sound. You only need it to reduce the size of the audio so you can fit more video.

Just use PCM, it will sound much better.

John