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Subject: AC3 encoding in 1.0 (Mono)
Posted by: Lyris
Date: 2/15/2008 8:14:44 AM

Hey everyone,

I've asked Sony this question and have been told it's not possible, but was wondering if anyone had any other solutions that might work.

Basically, I'm working on a DVD of a film that was originally recorded in Mono and would like to present the audio on the final disc as such.

Although Vegas' AC3 encoder has all sorts of options alongside the common Stereo and 5.1 options, when I tell it I'd like to encode in 1.0/Mono, after clicking OK, Vegas "buts in" and tells me that I can't do this because that setting doesn't match the current project setting (which is Stereo, because there's no option for Mono in Vegas).

Does anyone have any alternative recommendations for including a Mono AC3 track on my DVD? Using Stereo (sending the same mono signal out of the Left and Right speakers) is not only incorrect for the film, but wastes disc space.

Many thanks

Subject: RE: AC3 encoding in 1.0 (Mono)
Reply by: Kennymusicman
Date: 2/15/2008 12:22:27 PM

Ok..

I think you've done this bit already, but...
In vegas, when you render to AC3, are you using the pro option? If so, you can click on custom and under audio service, specify audio coding mode 1/0 (C) - rendered ok for me, but plays in dual mono (see below)

However, my main question would be why?.
You target of delivery will do changes anyway- for example.
If you play a mono file on a stereo system, it will likely convert into dual-mono and play 2/0 (dual mono anyway).
If you play mono on mono system, you get mono.
If you play mono on 5.1 system, you either get dual mono, or centre speaker.

If you play dual mono on stereo system, you get dual mono
If you play on mono system, you get mono (pot. buss summing - make sure levels are not above -6dB)
If on 5.1, you get dual mono, or centre pan depending on setup

So why not simply use dual-mono? the size cost is not a lot for a typical film-length featurette.

If setup is pro-logic, then mon, or dual mono would be panned centrally anyway due to phase demuxing.

Just a thought or two..

[edit: forgot to add - 'net shows lots of people having problems with mono ac3, and thus this could be a problematic can-of-worms anyways]

Message last edited on 2/15/2008 12:24:38 PM by Kennymusicman.
Subject: RE: AC3 encoding in 1.0 (Mono)
Reply by: Lyris
Date: 2/19/2008 2:00:36 AM

Hi Kenny

Thanks for that - I've found the problem. Having the project audio type set to Stereo locks the option out, but if I specify a 5.1 project, I can render 1.0 audio.

The reason was mainly because that this is a Mono film, and we wanted people to see that we'd included the original audio track without any attempts at altering it (the center speaker playback was also an issue). As you say, though, we'll need to thoroughly investigate the compatibility.

Many thanks!

Subject: RE: AC3 encoding in 1.0 (Mono)
Reply by: Lyris
Date: 3/29/2008 7:06:46 PM

Quick update: it turns out that DVD Architect can only support Stereo or 5.1 AC3 tracks. So, it looks like we'll promote this as a "Dual Mono" release.

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