Trouble trimming last milliseconds off

[Mapilowee]

Hi all,

I have a series of videos with durations ranging from 5:00:01 to 5:00:03. I've been trying to trim the last milliseconds off to 5:00:00 using the video duration tool in VideoStudio 6. Whenever I try to reduce the time, it goes from 5:00:02 and jumps to 4:59:29. The videos are 29.97 fps NTSC MPEGs.

I used to be able to trim down to 5:00:00, but when I patched the program to 6.02, this issue started happening. Is there a way to uninstall the patch w/o reinstalling the program? (I don't know where the program CD is anymore).

Thanks for your help!

[DVDDoug]

Whenever I try to reduce the time, it goes from 5:00:02 and jumps to 4:59:29. The videos are 29.97 fps NTSC MPEGs.

This is due to the MPEG structure.

The MPEG is encoded as Groups Of Pictures (GOPs) The GOP typically consists of 12 to 15 frames, which works-out to about half a second.

The GOP starts-out with an I-Frame, which is a full image. P-Frames or B-Frames follow, which essentially contain the differences/changes from the I-Frame.

Generally, edits need to start on an I-Frame. You would think that you could throw-away extra P or B frames at the end, but maybe this confuses the encoder/decoder.... I dunno...

I used to be able to trim down to 5:00:00, but when I patched the program to 6.02, this issue started happening.

Maybe you were working with a different file format. Or, you may have just been lucky, with the GOP ending at 5:00:00. (On average, you should get lucky once out of every 15 files. )