Tool for deleting PGC cells

[vertical]

Hi,

Looking for a way how to handle audio synch problem, I’ve found the following post at Doom9 http://forum.doom9.org/showthread.php?t=115197&highlight=audio+synch+problem

The author advises to check PGC cells in order to determine whether they contain audio or are just a trash.

Could somebody please advise what tool can be used to this and to remove the unused cells if required?

What would be the experts' opinion whether the method can fix progressive audio synch problems?

Thank you!

[manono]

Could somebody please advise what tool can be used to this and to remove the unused cells if required?

FixVTS. Or you can decrypt in the first place using RipIt4Me, which also uses FixVTS to "clean up" the DVD. Or you can (I think) "Process" the entire thing through VobBlanker at default settings, as mentioned in the final post in that thread to which you linked.

What would be the experts' opinion whether the method can fix progressive audio synch problems?

I don't know what you did to introduce the progressive audio asynch, so I have no idea what has to be done to fix it. You get this not after just decrypting, but encoding and authoring, right?

[vertical]

manono, thank you!

Progressive audio synch is porbably the most annoying thing I have to deal with. I get it (or rather I notice it in simulation or edit&cut mode) pretty often while muxing audio with video with TDA (the video is always NTSC DVD that I get either from AVI or PAL DVD).

I check the audio running time and it is unchanged. I check m2v running time and it is unchanged. I do not get where it comes from.

My understanding was that audio synch problem has to be fixed during authring stage (muxing audio and m2v) but FixVTS works with VOBs only. Does it mean that if I get audio synch problem, I can put the DVD through FixVTS and it will fix audio synch?

Can PGC Edit be used for the same purpose?

Can you advise something about such tools as HypercubeTimeStretcherInstaller; AVI-Mux_GUI; DVD2DVDR with regard to the same asynch problem? Are they useful?

[manono]

Does it mean that if I get audio synch problem, I can put the DVD through FixVTS and it will fix audio synch?

Nope, it means that if it's caused by one or another of the newer protection schemes, it'll be corrected at the very beginning.

If it's caused by something you did during one of your PAL->NTSC or AVI->DVD conversions, then I don't want to touch it. It also means that the thread to which you linked has nothing to do with your particular problem. Sorry.

[jeanl]

manono, in fact FixVTS will not remove PGC cells... It will remove cells from the VOB file if they're not referenced.
The solution to the poster's question is:
- Use PGCEdit to remove the first few cells in your PGC (the ones that don't have audio).
- Then run FixVTS on that VTS to remove the corresponding cells from the VOB file.

But simpler yet would be to use RipIt4Me in movie-only mode, which does all this automatically.
jeanl

[manono]

OK, thanks for the correction, jeanl. I guess I'm a bit unsure of the distinction between unreferenced cells and PGC cells.

As it turns out, though, none of this had anything to do with vertical's problem, as he often gets asynched audio, not because of protections on DVDs, but when doing PAL->NTSC conversions.

[jeanl]

The terminology is very very confusing. Cell is used to describe the parts of a PGC (as defined in the IFOs), but also to describe units in the VOB files (vob cells are composed of multiple smaller units called VOBUs etc). FixVTS scans the vob file, finding vob cells, and checks whether the vob cells are "referenced" in the IFO (i.e., there is a PGC cell that uses that vob cell). If not, it's removed from the vob file. Confusing? Yes!
But you're right, PAL->NTSC conversion has nothing to do with that, I'm guessing...
jeanl

[vertical]

Hi,

Can you please advise a guide or forum thread that describes how to determine the cells that have no audio?

I browsed numerous PGC guides on Doom9 forums, read the PGCEditor manual, browsed through the links on PGCEditor Home Web page but could not find anything on the subject.

Thanks!

[manono]

If you have the DVD, decrypt using RipIt4Me, as stated. You can check in DVD Decrypter by setting it up in IFO Mode and decrypting by cell.

If you have the files on the hard drive, unless and until jeanl comes back with a better method, you can demux the cell(s) using PGCDemux and check if an audio track came with it.

[jeanl]

There's no easy answer to your question, unless you know what you're looking for. The thread you link to in your original post is probably about a protected DVD where the first cells are unused, and normally skipped during playback. This isn't about PAL->NTSC conversion. Now, I'm not sure where your out-of-sync problem is, but I can answer your question about determining which cells should be removed.
If you open your DVD with PGCEdit, and locate your movie (that's the longest PGC), then double-click on that PGC, you'll see a list of all the cells in that PGC. One way to see whether cells are useless is to see whether they have a chapter associated with them (PTT) or are very short. If your DVD is indeed protected, the first few cells will not have chapters (except for the first one), and will be fairly short (a few seconds). The first useful cell will be several seconds long. Also, you can preview each cell with the little arrow at the far right of each cell row, this will show you whether the cell contains useful video or just crap...
But RipIt4Me does all this automatically for you (in movie-only mode), so that would be my preferred route if I were you.
Jeanl

[vertical]

Jeanl,

Thank you!

[vertical]

Hi,

I am trying to remove useless cells from a DVD with PGCEdit. I am doing this for the first time and would appreciate advice as I am not quite sure.

I opened the DVD in PGCEditor and after double clicking VTST 1.1..., I got PGC.

I checked the cells by clicking the small arrow against each cell. I could not preview the first 13 cells as the button "Play" cannot be clicked.

The button works starting with cell 14.1. When I click the arrow against the cell, the movie starts playing from the beginning.

Should I delete all first 13 cells? I am not sure whether it is OK to delete so many cells. Thanks.

[Bjs]

Nope , audio sync problem's cannot be fixed as mentioned by other's using tool's mentioned .

To fix the audio issue will required the title vob to be reathoured .
Use pgcdemux to demux the title vob only to a new folder .

You will need to export a celltime's text ... possibly pgcedit may be capable of doing this , but ...

Open the main title's ifo in ifoedit , then click on vts_pgciti , followed by the plus symbol , and click on the listed pgc for title .
Now go to Tool's , and choose Save celltimes to file .

You will need this when you remux using rejig to reset the chapter information within the title ... of course you could use other tool's to perform this fuction , but rejig dose it simple , and produce's less issue's when it come's down to nstc and pal format's .

When using rejig to remux it , set the audio delay to a closer match to bring the audio in sync .

--------------

Then we come down to audio sync that get's worse the longer it play's .

You will need to follow the advice as outlined above , and require syncview .

Syncview allow's you to readjust the audio , and output as you go ... otherwise , you may cause issue's with previous fixed point's .

You might find it easier if the audio file is converted to wav first , and of course there are other method's using audacity or an avisynth script ... use besweet to convert audio back to ac3 .

[vertical]

Thank you!

I will definitely give it a try as I am sick and tired of the problem and cannot find a relaible way to fix it. Not sure I will be able to do all the operations as it is complicated for my level of knowledge.

Is there anything good in removing useless cells from DVD with PGCEdit?

[jeanl]

vertical, you can definitely try the PGCEdit's way, but remember to process the result with FixVTS afterwards (because otherwise, the unused cells are not removed from the VOB).
Indeed, your PGC is protected, and there's a host of tiny cells before the actual movie, that's a definite pattern.
You can safely remove them. Then save the DVD, fire up FixVTS, process the VTS in question (drag and drop VTS_01_1.VOB for example), in-place (to save time), with the option "remove unreferenced cells" on. (all options on in fact).
This will leave you with a VOB file that starts with the movie (instead of the first crappy cells), and this might simply make it work.
It should take less than 5minutes to do the entire thing. If that fails, you could try bsj's suggestion (but I'm not sure why he's so sure this won't work, as it has for many many many people).
jeanl

[vertical]

jeanl, thank you!

[Bjs]

vertical :

What would be the experts' opinion whether the method can fix progressive audio synch problems?

jeanl :

(but I'm not sure why he's so sure this won't work, as it has for many many many people)

The problem can appear in the actual title , which cannot simply have the audio shifted without reauthoring process being involved .

Audio constantly out can be simply reprocessed via reauthoring to reset the amount of audio shift , either + or - value's being used to make the required , correct , alignment adjustment.

Where audio sync is not constant , then the same process is required , but the audio need's more attention and reprocessing to correct it's alignment for the entire title's video source .

There are time's when this other simple trick might work , but is not guaranteed .

vertical :

I get it (or rather I notice it in simulation or edit&cut mode) pretty often while muxing audio with video with TDA

And bingo ... there's that dirty word again ... Tda ... it suck's ... there are better tool's than this .

Try ulead videostudio 9 SE (buy the SE edition in ebay for $25au or less) ... dose a hell of a lot more , and better at performing the conversion's .

[vertical]

Thank you!