Command line video to SWF or FLV converter

Can anyone point me to a command line video to SWF or FLV converter? I have a client I'm developing an app for that wants to create an interface for playing videos through.

One part of the app is the setup, where my client chooses AVI files to include in the project. I was thinking of doing this in VB.NET in either a windows form app or a web app and calling some sort of command line converter to convert the files to SWF or FLV once he commits the AVI's to the project. Then the setup app will write the paths and such to an XML file so that the Flash front-end app can retrieve them later.

The resulting file just needs to be able to be loaded externally from my Flash app running on a DVD-ROM disc.

So yeah... any good command line converters that are inexpensive? I can't see paying $2990 for GeoVid's just for one project.