16x9 AVI source to letterbox DVD. HELP!!!

[obidan]

Hi,
I'm using roxio dvd builder 6 to burn out some cartoons, and am having a problem. The source AVIs are 704x396 pixels, and I would like to burn them so that they disply ala "widescreen letterbox", whereas roxio just smashes them into a standard 4:3 aspect ratio. No cropping, though, a THOROUGHLY distorted image. What can I do to add the "black bars" to the top/bottom of the source avi so roxio doesn't smoosh it?
Thanks,
ObiDan

[obidan]

Moving forward... VirtualDub!

So I found VirtualDub on sourceforge, and it does EVERYTHING I need it to.
Except for ONE little issue...
When I resize my 704x396 video (approx 100mb) to a 640x480 letterboxed avi, IT WANTS TO MAKE THE FILE 30 GIGABYTES!!!
WHAT IS UP WITH THAT?!?!?

[obidan]

Problem solved... kinda.

So apparently VirtualDub wasn't using a codec. Got that fixed. But now I have to double process every video I want to put on DVD: First, get the letterbox fixed right and THEN go through the mpeg compression to burn it. Sigh.
Anyone have any better ideas? I wish I could just tell roxio to leave it 16x9 and let my dvd player letterbox it for me.
Any help?!?

[mattgrant]

Why don't you let Roxio burn make it 4:3? The distorted image is anamorphic or Full Height 16:9. That's how commercial DVDs are. When you play it back in your DVD player your TV will either auto switch it, or you just manually select widescreen.

If you have a 16:9 TV then it should fit it perfectly, and if you have a 4:3 TV then it should put the black bars in itself.