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Dolby Pro-Logic Encoding/Decoding

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Hi everyone. I've looked at various guides, forums, and so forth, and I've found some useful stuff, but so far I haven't found a straightforward answer to the following:

1. How do you encode a stereo WAV that is Pro-Logic (or PL2) compatible with something like Vegas or BeSweet (without having to buy a $600 plugin), using 4 or 5 tracks as a base? I know you dump "Front right" into the right and "Front Left" into left, but I'm confused about the volumes, the scaling, phase inversion, directional steering and so forth. I realize that no matter what you do, it's matrixed and you're going to lose some info upon decoding, but I'd love to be able to encode a stereo file with the surround info in it.

2. Is there any easy method for Dolby Pro-Logic or Pro-Logic II playback on a PC (from a matrixed stereo file)? For instance, you're watching the 2006 Star Wars DVD's on your PC through a set of USB 5.1 surround sound headphones. Is there any inexpensive method or program where you could listen to the matrixed surround in realtime? Or not in realtime? In other words, is there a program where you can put a matrixed stereo file in and get 4 or 5 separate channels out? Obviously this would vary from decoder to decoder, but is there a way to do it?

Thanks so much! I've been looking everywhere for this info,

-TM

Episode II: Shroud of the Dark Side

Emperor Jar-Jar
“Back when we made Star Wars, we just couldn’t make Palpatine as evil as we intended. Now, thanks to the miracles of technology, it is finally possible. Finally, I’ve created the movies that I originally imagined.” -George Lucas on the 2007 Extra Extra Special HD-DVD Edition

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check out the info on http://www.dtsac3.com
and
www.doom9.net
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1. You can use BeSweet to convert a 6-channel AC3 file into a 2-channel surround encoded file; it's probably possible to use a multichannel WAV instead of AC3 as the source if you wish. You can choose between the "surround" or "surround 2" downmix mode; the latter supposedly being more compatible with DPL II decoders. In realtime, AC3Filter can do the same thing.
(Both these programs are free; the downmix algorithm is not officially Dolby licensed but works just fine.)

2. Yes, popular software DVD players (PowerDVD, WinDVD) include a software DPL II decoder (although it's normally only the "deluxe" or "platinum" versions of such players). If you actually want to process a 2-channel file to get 5/6 separate channels, there are several guides over at the doom9 forums.

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Thanks a lot for that advice, Moth3r.

So I started up BeSweet and muxed my six mono WAV files into a single 5.1 WAV file. So far so good.

Then, I found out that it seems BeSweet can't downmix a 5.1 WAV to a matrixed stereo WAV. Apparently it has to be an AC3 track?

All I want to do is get a PCM stereo track that can be decoded into surround- I don't want to convert it to AC3 at any point in the process and lose quality. Do you know if there's any way that this could be done?

Thanks so much!

Episode II: Shroud of the Dark Side

Emperor Jar-Jar
“Back when we made Star Wars, we just couldn’t make Palpatine as evil as we intended. Now, thanks to the miracles of technology, it is finally possible. Finally, I’ve created the movies that I originally imagined.” -George Lucas on the 2007 Extra Extra Special HD-DVD Edition

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Yes, you're right. BeSweet uses the azid.dll to decode and downmix AC3 files.

If your source is a multichannel WAV, you probably need to have a play with the 6ch to 2ch Downmix plugin for BeSweet:
http://besweet.notrace.dk/plug-ins.htm

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The good news: I finally got to work. BeSweet downmixed the 5.1 WAV into a 2-channel WAV
The bad news: The audio quality is hideous. I can barely even recognize it from my original sound. I went to doom9 to check it out, and apparently this is a glitch.

So I guess I have to find another way. But thanks anyway, Moth3r

Episode II: Shroud of the Dark Side

Emperor Jar-Jar
“Back when we made Star Wars, we just couldn’t make Palpatine as evil as we intended. Now, thanks to the miracles of technology, it is finally possible. Finally, I’ve created the movies that I originally imagined.” -George Lucas on the 2007 Extra Extra Special HD-DVD Edition