Thanks I found it via Google after posting here.

It would certainly do the job but for a one off need at present, as I don't know how many of these type of short features I'll be mixing, it makes things relatively unprofitable. By the time I convert $495US to $AUS I'm looking at around $650.00

The audio post budget for this short is so low I'm doing it more out of interest that income. Subsidising this project from my other work.

Anyone have any other suggestions?

Regards
Steve

You can make a 5.1 .ac3 file from Vegas, not a problem as long as you have any version of DVD Architect (Pro- DVDA Pro gets you the AC3 encoder). You can use that .ac3 file for your DVD surround soundtrack.

"Lt-Rt mix for Digibeta "- sounds like for this all you need is a stereo file. If what actually mean they want to encode 5.1 as Dolby E (5.1 printed to a stereo digibeta track pair), talk to the facililty doing the layback- they'll have special requirements for this since it will need to run through their hardware. The delivery requyirement for you could be as simple as 6 separate mono wav files, one for each channel from the 5.1 mixer (which Vegas will let you render).

Thanks for the reply.
What is generally called an Lt/Rt mix , as opposed to an Lo/Ro mix which is straight stereo, is a Dolby Surround or, as the consumer knows it, Dolby Prologic mix.

Dolby E, which is a transport medium used on AES-EBU digital channels, is a way of encoding up to eight discreet tracks into a stereo digital pair. These may contain a 5.1 mix as well as an Lt/Rt downmix or any other combination of tracks as desired.

What the client wants is 6 mono waves making up the basis of a 5.1 mix for later Dolby Digital encoding for film, an AC3 for DVD veiwing which I can produce out of Vegas and a Dolby Surround (Lt/Rt mix) for the main stereo pair (tracks 1 & 2 ) on the digibeta. This will give a Prologic decode into Left, Centre, Right and mono surround if decoded by a proligic capable decoder as found in most home theatre set ups.

My concern is, given the budget this project DOES NOT possess, the layback to Digibeta may be as crude as replay from the AVID it was edited on in the editing suite only with my mix replacing their edited audio. Hence the need to encode the Lt/Rt myself.... but we'll see.

Thanks again for your input

Regards
Stephen Hope
new Hope Media

Hi Steve,

not sure if it's any help but Audiobrien (ex David+John) have a Prologic Encoder AND Digibeta. If you talk to Jeremy and mention my name they may be able to do a deal for you

Phil

I don't know of anything that can enable you to do this in Vegas.

But it can be done separately using a little free command line application called Azid.exe which you can download from the Doom9 website at www.doom9.org

Azid will take your 5.1 AC3 file as input and allow you to export a downmixed version as a WAV file in a variety of formats, including Dolby Surround, Dolby Pro Logic, and Dolby Pro Logic II. (These are not officially sanctioned, certificated, etc, by Dolby Labs - it is a free app after all - but they seem to work just fine when presented to a Dolby Surround decoder.)

Azid can be a bit of a pain to use as a command line app, so various people have written GUIs to allow it to be used more easily. The one I use is a GUI called BeSweetGUI which is a GUI for the other well known audio command line tool BeSweet as well as a GUI for Azid. They can both be found on the Doom9 website as well.

Mark

Mark

Thanks for the info on that... a very interesting piece of software.
My only concern is that it seems on first glance only to produce the Prologic encode out of exisitng AC3 files which are data compressed.

For general use on multimedia or domestic use I wouldn't be too concerned but I'd be a bit reticent to lay that audio back onto a digibeta which at some time may end up being broadcast and re-encoded into a stereo AC3 file for digital TV transmision thereby doubling the data compression of the transmitted signal.

I don't think I'd want to hear the resultant audio even though the output of Azid may sound fine by itself.

Still I think the BeSweet and Azid utilities are a great find for other use.

I think I'll be looking to other methods that allow encoding the Rt/Lt from the uncompressed wave files I'll be outputting from Vegas for the film Dolby Digital encode.

Thanks again

Steve

I think if you look at the customizable settings for the AC3 encoder in Vegas, you will find options for Lt/Rt and Lo/Ro encoding that should give you what you want without having to get the other software programs mentioned in this thread.

Yes, fair point about the Lt/Rt WAV being created from a lossily-compressed source when it may end up being lossily compressed again. You could of course do a test re-compress (in Vegas) of the Lt/Rt WAV to a 2.0 AC3 file and see if you find the quality of the compressed-uncompressed-recompressed audio that results to be acceptable.

But other than azid I don't know of any cheap/free way to achieve your object. There is a free LCRS encoder VST plugin available from here but it is weird thing that has (up to) eight inputs and two outputs and is really only intended for use in the master section of Cubase/Nuendo. I don't think it can be used in Vegas (though I must admit I haven't tried) but perhaps it can be made to work.

Mark

Mark

Thanks for the help, I'll check out the VST plugin.

pmooney
"the customizable settings for the AC3 encoder in Vegas, you will find options for Lt/Rt and Lo/Ro"

Thanks for the reply but those settings refer to how Dolby Digital downmixes on systems without 5.1 monitoring. For example when you play a DVD with a 5.1 sound track on a system with only a Prologic decoder, if the Lt/Rt setting has been enabled the end user will get a Dolby Surround decoded mix or if Lo/Ro is selected they get stereo.

The problem is that on a Digibeta the tracks won't be Dolby Digital (AC3) so I can't make use of the AC3 encoder in Vegas.

I could make an AC3 track and replay it through a system requiring it to downmix re-recording it as a stereo track but I end up with a lossy quality audio track on the Digibeta, similar to what AZID which mark suggested would create.

I do appreciate the replies though.

Regards
Steve

I've just tested the output of a 5.1 mix I've been doing in Vegas 7.

I've discovered that if I render out a WAVE file and select the stereo downmix from the Surround Master when you enable multichannel mapping in the Render dialogue box the resultant stereo wave file decodes as Dolby Surround (Prologic) when played into a Dolby Prologic amplifier.

It's not an official Dolby Surround (Prologic) encoder but it definitely works.

The piece I rendered had a phone ring slowly moving from the Surround Right through Front right to Front Centre in the 5.1 mix as the camera slowly tracked around to centre on the phone.

(Excuse the Aussie/English spelling of 'center' it's what we do)

In the stereo downmix it decodes as Prologic which only has a mono surround.

So it started with Front Right + Surround and as the panning took it to full front right and then centre the ringing slowly disappeared out of the surround speakers meanwhile the atmosphere tracks I had mixed into the front and surround speakers remained in place.

This effectively eliminates my need for a Dolby Surround encoder for the Lt/Rt mix required for Digibeta layback as Vegas appears to be doing the job itself in the downmix.

I'd appreciate any feedback if any of you have tried this yourselves as the was just a test of the first two minutes of a 30 minute mix.

Regards
New Hope Media

I'll post any other findings I can but it was a reasonable result