Tough cell change skipping problem on a DVD

[eatcaramels]

Hi folks,

I've been trying different ways to rebuild a movie, but after running through DVDRebuilder, I get video skipping at the cell transitions. Usually the first cell change (from 1 to 2), and at some other cell changes afterwards. The movie plays perfectly in the final state that I want it in (from HDD), so it's definitely the rebuild that is bringing out the skipping.

Process:
RipIt4Me
-There's no ARccOS or anything like that for this DVD
VOBBlanker (2.1.1.0)
-I don't want the first part of the first cell. I've tried cut, and split then blank, but neither fixes the skipping
-Tried with and without "Use blank cells in unreferenced middle ones"
-Haven't tried "Fix always VOB SYNCI/SRI Pointers in titles"
DVDRemakePro (3.5.3)
-Repalce moving menu with my own fabricated still (from a muxman VOB)
DVDRebuilder (0.98.1)
-HC Encoder (19.1)
-Best quality, Steal 25%
-Tried *CLOSEDGOPs in the hc.ini, but am skeptical it was honored by the scripts DVDRB ran.

Loading the result into PGCEdit and VOBBlanker both show that the cell flags go something like:
2, 8, 8, 8..., 2, 8, 8, 8...
As a last-ditch effort, I tried forcing the offending cell's flags to have "STC (SCR) discontinuity", and that didn't work either.
Tried loading and running the result through VOBBlanker (without blanking) and DVDShrink (without compression) to see if it would correct the problem, but it never did.
Finally tried rebuilding the timecode in PGCEdit, but didn't work again.

Next thing I'll try tomorrow is to switch menu substitution and blanking in my process, but I've lost confidence that I'll stumble upon a fix after as many rebuilds as I've put into this one.

Any ideas or suggestions are welcome!

[blutach]

First thing jdobbs will tell you is before you blame DVD Rebuilder, don't do any pre-processing. Post process, but not pre.

Chances are that your cuts in VobBlanker have caused the cell joints to become non-seamless. On a stand-alone player, this might cause little pauses but not skipping video.

However, if it is terribly pronounced with skipping, it is probably a burning/media issue.

Regards

[eatcaramels]

Thanks Blu.

This isn't a standalone or media/burning problem because I can get it to play with the skips straight from hard drive. Maybe I should describe the skip just in case that will help - video stutters into last frames of the cell, audio continues for most of a second then stops, video restarts a few frames later, audio restarts, and playback is normal again.

I was very careful with the words I used so as to make sure I didn't blame DVDRebuilder. DVDRB is handling things in a way I wish it didn't, but I know it's because of a situation I created with my manipulations.

I understand the reasons to post-process instead of pre-, but I I'm trying to avoid it for 2 reasons:

1. I want to use the extra space from the menus and other video in the parts that I'm keeping.
2. I don't want to manually calculate how many MB over target I can go, use RBOpt to tweak, then remove the content later, especially since I was hoping to use 1-click mode.

Is it known that VOBBlanker break something specific, and if I used DVDRebuilder Pro for blanking and stilling menus, it would work correctly?

I guess I would like to know which programs are most likely to cause which types of problems, so I can chart out a process that's least likely to be problematic.

[blutach]

No, VobBlanker won't break something specific, but if you do cut at an Open GOP, there's a chance of a decoding error. This should not last for more than a whole GOP though (1/2 second), since the next GOP gets a brand new I-frame to start life off with. Audio delays and such can mean cuts in the middle of a movie can get out of sync. I ALWAYS have Fix VOB SYNCI/SRI pointers on when cutting - yes, it might take a while longer, but it's safer.

Since you are getting an issue after your preprocessing but before Rebuilder, there's clearly an error there (unless the rip also exhibited this effect, in which case try to rip it again).

As for RBOpt, that is a bit obsolete. Use the new beta previewer, which is just tremendous.

Regards

[eatcaramels]

Thanks again blu.

To clarify, the skipping happens only after running Rebuilder. I verified non-skipping playback at every step of the way. That means after rip, after blanking, and after menu substitution, and all the modifications before rebuilder result in a non-skipping video (in PowerDVD6 from HDD).

Until now I've only used SYNCI/SRI of VOBBlanker when I thought there would be a problem (I was thinking "first do no harm"), but I'll gladly make it standard practice. In fact, I'll try that out right now and get another rebuild done.

There's definitely an open GOP that I'm slicing, but it's at the beginning of the first cell, so it's probably not causing the cell transition troubles.

Thanks for the suggestion of the previewer too.

[eatcaramels]

I ran a rebuild where SYNCI/SRI was enabled for the blanking, but that didn't fix it either.

The skips for the last rebuild happen at cell transitions
1-2, 3-4, 4-5, 9-10, 11-12, which are all in the first VOB of the main movie.

I'm starting to think that whenever this happens, I should give up on recoding and just transcode

[blutach]

Time to post your Rebuilder logs and INI files please.

Regards

[eatcaramels]

Woohoo!

I finally got a rebuild that worked without skips!

Used DVDRemakePro (instead of VOBBlanker) to blank everything except for the intro of the first cell. Then encoded with Rebuilder. Lastly used VOBBlanker to remove the intro part of the first cell.

It's possible that the lesson of the day is if you want to pre-process, then don't cut from cells with VOBBlanker (maybe don't use VOBBlanker). But, it's also possible that I've stumbled upon an issue either with VOBBlanker's output, or with the way DVDRebuilder handles processed input.

I'm sure I can recreate the behavior, so if I put more hours of rebuilding to generate "good" and "bad" logs from DVDRebuilder, would someone want to look at it as a possible bug, or would I be wasting my time? I want to help make our tools better, but I don't want to be on the wrong end of the stick because you think "don't pre-process" is the only way to go.

[blutach]

Remember, if you cut with VobBlanker you need to rebuild the time map - use PgcEdit for this. jsoto is working on fixing this.

It, might be related to this issue (don't think so, though).

Anyways, glad you got it sorted out.

Regards