I would like to take existing VOBs from DVDs I have already created, edit them (just cut and merge) and author them without re-encoding.

I have tried the trial version of ULEAD DVD Workshop, and if you change the filename extension from .vob to .mpg, it will accept the file. However, this version re-encodes everything.

Before I pay for the updated version, can it use existing VOBs without having to re-encode? Is there another method to use instead?