Chapters don't jive with ChapterExtractor

[FamousPerson]

LIGHTNING UK:

Sorry if this has already been addressed, but I couldn't find anything on it in 5 mins of searching...

I recently started using DVDDecrypter's IFO mode (always used FILE mode before) and found the auto creation of chapter lists for Maestro and CCE especially handy. However, I noticed that the chapters are not the same as ChapterExtracter creates. They are always several frames different.

Am I missing a setting somewhere?

BTW, I'm using NTSC

[LIGHTNING UK!]

Now I know ChapterExtractor was the first program to do this kinda stuff, but that doesnt mean its the best. Back when i implemented the feature, I looked at the ChapterExtractor code, and I think mine is more accurate. That said, on the dvds ive tested, both have come out exactly the same.

[FamousPerson]

I must have something set wrong then, because I experience this problem with every single DVD. Here's an example from Minority Report (NTSC):

ChapterExtractor:

chapter=0:
chapter=12085:
chapter=26494:
chapter=38017:
chapter=44326:
chapter=53382:
chapter=66664:
chapter=76624:
chapter=92778:
chapter=99266:
chapter=107613:
chapter=116993:
chapter=125115:
chapter=138242:
chapter=147847:
chapter=157922:
chapter=171833:
chapter=178007:
chapter=195889:
chapter=204745:
chapter=218117:
chapter=227533:
chapter=239176:
chapter=243627:
chapter=(this chap removed because I checked the box)


DVD Decrypter:

chapter=0:
chapter=12097:
chapter=26520:
chapter=38055:
chapter=44370:
chapter=53435:
chapter=66730:
chapter=76700:
chapter=92870:
chapter=99365:
chapter=107720:
chapter=117110:
chapter=125240:
chapter=138380:
chapter=147995:
chapter=158080:
chapter=172005:
chapter=178185:
chapter=196085:
chapter=204950:
chapter=218335:
chapter=227760:
chapter=239415:
chapter=243870:
chapter=261100:


Any ideas?

[LIGHTNING UK!]

Perhaps its just a ntsc thing. I wonder if chapterextractor uses 29.97 fps for its calculation and not 30 as it says in the ifo file.
Of course which way is right is anyones guess. The vob might well be 29.97, but if the ifo works in terms of 25 fps and 30fps, which way is correct?!

[FamousPerson]

Originally posted by LIGHTNING UK!
Perhaps its just a ntsc thing. I wonder if chapterextractor uses 29.97 fps for its calculation and not 30 as it says in the ifo file.
Of course which way is right is anyones guess. The vob might well be 29.97, but if the ifo works in terms of 25 fps and 30fps, which way is correct?!
I'm not sure - but I've been using the ChapterExtractor output because the end resulting chapter locations seem to be in places that are more likely where a chapter point should be (scene change, etc).

I haven't actually compared the final to the original, though. I can if you like.

[FamousPerson]

Originally posted by LIGHTNING UK!
Perhaps its just a ntsc thing. I wonder if chapterextractor uses 29.97 fps for its calculation and not 30 as it says in the ifo file.
Of course which way is right is anyones guess. The vob might well be 29.97, but if the ifo works in terms of 25 fps and 30fps, which way is correct?!
I've done some further investigation - yes, that is indeed the difference!

If you take DVD Decrypter's number, multiply it by .999 (29.97/30), and then always ROUND UP, you get ChapterExtractor's number.

[[Toff]]

ChapterXtractor is not well tested (by me) with NTSC content or for DVD authoring. So ChapterXtractor is probably wrong.
29.97 or 30 ? ChatpterXtractor use what is in the "FPS rate" combo box. For NTSC it use 29.97 if I remember well.
There is no real drop frame mode.

EDIT : FamousPerson is ChatpterXtractor ok ? what is needed to correct it ?

[FamousPerson]

Originally posted by [Toff]
FamousPerson is ChatpterXtractor ok ? what is needed to correct it ?
Actually, as I say above, I think ChapterXtractor produces more accurate chapter points. I will test it for sure tonight.

[FamousPerson]

OK, I tested it on Back to the Future. ChapterXtractor's output jived with the original disc.

Lightning, it must be the 29.97 vs 30 fps thing.

[LIGHTNING UK!]

So we're saying I just need ot use 29.97 where the ifo says 30?
Thats simple enough.

Will that then cover all films, or do I need to do the 'FILM' setting too - 24fps is that? The IFO only specifies 25 or 30 FPS so that might be tricky to do automatically.

[FamousPerson]

Well, DVDs can only come in two speeds, 25 or 30, right? (PAL or NTSC). I would think if you used 29.97 instead of 30 that would fix it all.

(Actually, I think NTSC is really always 29.96987. I got this number from CCE)