I've been looking for a solution to cut parts of MPEG's (like remove beginning and end of a video file) easily. I tried some softwares to re-edit the MPEGs and some of them you have to re-encode. I discovered something that might help some people (sorry if this is too obvious or has already been discussed on another topic, just wanted to share a tip since reading these forums have helped me a lot on authoring).

Import your movies on TMPGEnc DVD Author and create a Track for each movie. After imported, use the "Cut / Edit" button and select Start and Ending Points. Do any kind of menu, and "Begin Output".

Get into DVDLab and Import the VOBs that you created with TMPGEnc DVD Author and use the features of authoring with DVDLab without having trouble editing every MPEG with other software.

Hope this helps
Diogo