My guess is you are talking about Tmpg DVD Author 1.6 so you are probably working with a dvd compliant file. So no need to worry about the file extension. What you do need to do is forget DVD Author for the time being if you want to do any editing. The facility does exist in DVD Lab pro but I would never advice you to use(I think even TDA has it). Here's what you do:
- Take the Output of the DVD Recorder and use a seperate editor on the files. You will have to check which editor is compatible with the output of your Panasonic(here is where the extension is important).
The editors which I personally prefer and which do not introduce any sync or any other problems are(in no specific order)
Depending on which is compatible with the O/P of Your Panasonic, use that(check the software's homepages for more info on what files they handle).
NOTE: File extension is the three alphabets following the dot(.) in the name of the file in Windows Explorer.
If none of the editors handle the files. You probable need to convert them into Mpeg2(DVd Compliant) files with something like TmpgEnc Plus or some other encoder.
Hope this helps.
PS: For info after editing the file on how to Burn the file onto a dvd(dvd creation) please read the guides.