Cutting problems with TMPGEnc

[Proch]

I used TMPGEnc to turn a 28GB DV-AVI file into a DVD quality MPEG2 file of around 5GB (5250 bitrate).

Now I want to take this and cut it up before I send it to my DVD burning software. Using TMPGEnc seems to work for the most part, but upon closer observation, it really doesn't. Problem is, the timescale when you play seems to be correct. But if pause and drag the slider somewhere and use the frame advance, the whole thing gets out of sync. What appears to be correct in the editor turns out to be all wrong when you play back the resulting MPEG2 (The beginning is not the location I chose and same with the end) Thus, it's impossible to get the piece I'm looking for with any degree of accuracy.

I've scanned the posts here and haven't really seen anyone complaining of the same thing. I'm using 2.58... Any help would be appreciated.

[theDruid]

Proch,

I'm no expert on this; I only really use MPEG1 and VCD, but whenever I use TMPGEnc to cut a mpg, I always run the resulting file through MPEG Corrector afterwards.

This usually sorts out the header, which means that Nero recognises the file as being compliant (it usually doesn't otherwise, even although the original bigger file was compliant) and also means that the file will rewind and fastforward properly in a player (again, sometimes the cut file doesn't when it's just come out of TMPGEnc).

To be honest, I don't even know if MPEG Corrector works on MPEG2 files, but I think it does. You might want to give it a go and see if it fixes your problem.

There's a link to MPEG Corrector on the Tools page of this site.

cheers,

mcdruid.

PS. When you cut files with TMPGEnc, the start and end points often are not quite where you specified. This is something to do with the way that mpg's are encoded (GOP structure etc.. I think) and there's no way around it as far as I know.

[Proch]

Thanks for the reply. That utility did not work for me. I think it might be only for Mpeg 1.

Here's a real easy way for me to reproduce my problem:
1) Load a VBR MPEG2 into the Cut dialog and double click to play it.
2) Don't press play. Instead, drag the slider halfway,
3) Press Play. Notice that it takes some time to actually catch up and start to play
4) After a few seconds, press Pause.
5) Press the button that is for Frame Advance. Notice how it actually jumps many frames instead of just one. (Like 10 seconds worth in this particular case)

I know that I have used this feature of TMPGEnc before with success. I'm not sure what the factor is that is causing this behavior.

[theDruid]

sorry mate - i'm sure it's not much help, but all i can suggest is that i always try and work out where i'm going to want to cut my mpg using a player before i go into TMPGEnc. I've always found the MPEG tools a bit buggy for searching back and forth in the file (even in MPEG1's).

mcdruid.

[Proch]

Actually, this is exactly what I tried last night. I figured I could find the proper frame using some other player program (I used the Windows Movie Maker that is built into XP) and write them down, then direcly enter the start and end back in TMPGEnc. Wouldn't you know that the same exact problems seem to happen in Windows Movie Maker (Play and Frame advance don't seem to line up).

So I guess the problem is in the MPG itself. Does anyone know how the MPEG2 file format works? How can the file be out of sync like this? Is there a way to fix it?

[KWG22]

Excuse me if I'm showing any ignorance, but my thought was-and I've been working on something similar-was to cut the AVI into the desired files and then encode to MPEG2 with TMPGENC. What are the advantages/disadvantages?

[Proch]

Well, the AVI file is 26 GB and is kind of unruly to work with. Technically, it seems like the AVI would be alot easier to work with... But my original thinking was to reduce first and play with the MPG.