DVD player w/ decoding, or go external?

I use the same system for audio and video. Since I use it mostly for high quality stereo, for video I've got an older (cheap) Pro Logic processor, with built in amps for surround and center channel. The front RCA outputs go into one of the inputs on my preamp, which then drives the main amp and the subwoofer amp. Now I want to go DVD, but to take full advantage, I need a DTS, DD decoder. Ideally I would get a new preamp/processor with analog bypass so as to still deliver good stereo, but no money. So, in an effort to do this on the cheap, here's the stupid question: can the built in decoder on a so-equipped DVD player be used with out a processor? Or is just a decoder as opposed to a processor? Do the DVD players with built in decoding have any volume control, or processing/channel management? I'm thinking the only way I can do this is to get an outboard processor (Technics SH-AC500D comes to mind) to replace my Pro Logic processor, but if you guys have better information, please let me know. Also, suggestions for outboard processors (DTS and DD). Thanks in advance.
I'm unaware of any DVD player w/ decoding and a volume control, so there's no way to control the volume even if you were to be able to get the connections worked out. There's no way to use it with your existing processor unless it has a six-analog-channel input, which I doubt it does. There are lots of inexpensive processor / receivers that would make the whole thing relatively painless - Kenwood makes a lot of well-reviewed budget receivers.
Hello Sun, You might want to check with www.Vantas.com. They have a couple of processors made for set-ups with either 2-channel stereo or existing Pro-logic set-ups. Decent prices, decent reviews. Good Luck!