Keeping the menu from a DVD, exchanging just the movie

[misterice]

Hello!

I have the following unusual problem:
I made a DVD with some captured Hi8 Material. I assembled a nice animated menu (with Ulead DVD Workshop), and a bunch of chapters. Everything worked.

But alas, since I did that in the early days of my video career, I am not satisfied anymore with the main movie quality: the video turns out to be too dark and the audio isn’t perfectly in sync.

Unfortunately, since I don’t have the raw files on my hard disk anymore, I want to recapture the movie (and post-process it properly this time).

Is there a way to:
- reuse the menu from the DVD (I’d have to rip it from the old DVD somehow since the original DVD Workshop files were lost)
- reuse the chapter points (it was a recorded live concert, so finding the marks again is boring
- …and quasi exchange just the movie.

The movie was captured analogue, so, since I have to capture and encode it again, it won’t be the same exact size, and the I-frames will be in another position.

Any help, ideas or suggestions are appreciated!

[Baldrick]

you maybe could use pgcedit, like https://www.videohelp.com/guides.php?guideid=711&howtoselect=6;34#711

but I would reauthor everything.

[jeanl]

It can be done, but the difficulty will be to preserve the chapter points because they're needed when you remux the audio/video to create the VOBs (chapter points are primarily defined in the vob files).
I would extract the chapter points in your main movie using IFOEdit (see this guide for an example). Then re-capture your movie, re-edit it, and use either muxman or IFOEdit to remux everything together, using the cell times you saved (as described in the guide). After than you can reconnect everything using for example PgcEdit...

jeanl

[misterice]

Thanks for your suggestions!

I wonder if, when I extract the chapter points from the old DVD, I can use them on the recaptured movie? AFAIK you can add chapters only at I-frames, and these will, due to the analogue recapture, almost certainly be at another positions (unlike when shaving off bitrate with, say DVD Shrink)? Or am I wrong?

[jeanl]

You're right, but it's even worse than that! You get I-frames about every 0.4s so it wouldn't be too bad if you were off by 0.2 s (or would it?). You can only put chapters at cell boundaries (in other words, the VOB/CELL ID inside the VOB file must change at a chapter boundary). This means you have to set that right when you do your remuxing, so the VOB/CELL IDs change at the right point. As far as I know, there's no way to do that after the fact (i.e., mux your VOB without cell times, then modify it to put chapter points where you want them). This would be very useful, and I know it's on vobblanker's author's todo list, but I wouldn't wait for that!
So you have to remux with the chapter points extracted from the original. Of course, they might be slightly off to the next I-frame... But that might be a minor poblem....
Also, it depends on how you capture. If you capture to avi, there's no notion of I-frame, so you're OK. It's when you encode into MPEG2 that you get I-frames. Some encoders let you place I-frames at specific times (TMPGenc I think lets you do that), others puts them automatically at scene changes (which might or might not be good for you)...
Jeanl