Original Chapter Points – How to extract accurately?

[grannyGeek]

I demuxed a dvd using DvdDecrypter, and used ChapterXtractor to generate a list of original chapter points (from the IFO file) for re-authoring.
But the re-authored dvd chapter points were not at original times.

So, I did some comparative tests.
I get conflicting information, depending on how I obtain the chapter points.

1. Dvd Decrypter chapter lists and ChapterXtractor chapter lists agree with each other.
2. ChapterEdit and my eyeballs using VdubMpeg2 agree with each other, and with PowerDVD playing the original disk.

Sources #1 and #2 do not agree with each other.

Starting off, #2 times are a few frames later than #1 times.
By the end of the 80+ minute video, #2 times are five seconds later than #1 times.
With a longer video, time drift is even more extreme by the end.
I'm attaching a visual aid to compare a couple of the chapters.

This is a minor matter indeed, but I am hoping for some input to ease my curiosity.

What do YOU do when you want to use original chapter points?
What would you recommend for me?

Hoping for some input from you puzzle freaks ---
granny –
just another puzzled freak . . . . . :P

[Pinstripes23]

Personally I use pgcdemux to extract the celltimes.txt of the original chapter points. These can be used with authoring software like muxman, ifoedit, and rejig. DVDlab pro can import these also.

[grannyGeek]

Hey Pinstripes23, thank you for responding.
I will give pgcDemux a try.

[borax]

The frames/times are based on either 30 fps or 29.97 fps. This accounts for (most of) the differences. But it seems to depend on the authoring program, which version to use... I'm struggling with this matter myself. To make things worse, chapters may only be set at GOP boundaries (usually, but not necessarily I-frames). I have not found a 100% solution for this problem yet.
PAL is so much easier in this case!

[Alex_ander]

If you plan reauthoring, TDA imports a DVD source by tracks with accurate original chapter points for each track, with ability to cut-edit. It's fast, reliable and doesn't need demuxing at importing a track (the streams are read/rewritten just at creating output folders). So if you don't need DTS or subtitles this is a very good choice.

[grannyGeek]

@ borax -
That makes sense (30 vs 29.97).

Dvd Decrypter's lists are designated for specific authoring apps (Scenarist, etc)
But I'm using DvdAuthorGui, and I don't think anything generates lists designed for it specifically.



@ Alex_ander
Thank you for the suggestion about TDA. It seems to be very well thought of around here.
I am going to check out the TDA demo soon.


In this particular project, I had to demux; the audio needed editing, but not the video.

I ended up authoring a chapterless dvd using Quenc, and then added the chapters using ChapterEdit, having already noted the times from the source disk.
When I previously used ChapterEdit to revise existing chapter points on a completed dvd, there would be a slight playback pause at each chapter stop.
But using it to create new points on a chapterless dvd, it worked just fine for me this time.