Difference in VTS_C_ADT and VTS_PGCITI tables

[blutach]

A couple of DVDs I have load into VobBlanker (http://jsoto.posunplugged.com/vobblanker.htm) with an error saying there is a difference between the entry sector shown in these two tables.

Essentially VTS_C_ADT shows the start of the cell but the PGC decides to enter several sectors later.

Anyone know if this is illegal to have the entry point sector point into the middle of the cell instead of the start?

As I said, VobBlanker complains but DVD Remake Pro (http://www.dimadsoft.com/dvdremakepro/index.php) does not.

Note: The cells are not interleaved/angles.

Thanks in advance.

Regards

[Sir Didymus]

Hi Blutach!

I have seen other times this type of mistakes (as intentional disruption, intended as a copy protection trick) ... some time ago there was some interesting discussions in the italian doom9 forum about...

I am almost sure verifiers should complain about - but never performed this simple check...

What I can say for sure is that other DVD manipulation applications, apart VobBlanker, complain a lot about, but all of the standalones I tried use the tables in the PGC, playing the titles, apparently, without any issue...

Cheers,
SD

[bigotti5]

Verifiers complains about that.....Interra classifies as minor error

[r0lZ]

... but all of the standalones I tried use the tables in the PGC, playing the titles, apparently, without any issue...
Hum, I'm not sure.

There is a well known old trick to skip a studio logo at the beginning of the movie. It consists of altering the start VOBU sector number in the cell table, to point to another nav pack, later in the same cell. Unfortunately, my Sony hangs sometimes (but not always :confused:) when the cell is played. Maybe it's because the multiplex is not suitable to enter the cell at this point, but that means that at least this kind of trick must be used with care.
However, if a similar method is used to protect some commercial DVDs, I suppose it is possible to do it harmlessly. I'm interested to know what are the conditions to do it without problem. If it's possible, I'll add a function in PgcEdit to modify the VOBU sector numbers of the cell table in a safe way.

[blutach]

Thanks to all for their answers to this.

That old trick was very nice, r0lZ, but I think the two entry sectors were matched when you did it (I may be wrong since it has been some time since I did this due to the ease of use of PgcEdit (http://www.videohelp.com/~r0lZ/pgcedit/index.html)'s kill playback :))

Here, we are only talking about the mismatch. It is seen regularly on ARccOS DVDs, but who knows if it is compliant (or if SONY/Macrovision care)? BTW: Most titles with these cells in them are unplayed.

My standalones (including 2 SONYs) are also OK with it.

Regards

[Sir Didymus]

Hum, I'm not sure.

There is a well known old trick to skip a studio logo at the beginning of the movie. It consists of altering the start VOBU sector number in the cell table, to point to another nav pack, later in the same cell. Unfortunately, my Sony hangs sometimes (but not always :confused:) when the cell is played....


I see...
But here the situation is the opposite: I am very curious to see what happen to your Sony if you take a regular DVD, and just scramble the VTS_C_ADT with random values...

I guess it will play ok...

;)

Edit - spelling...

[r0lZ]

Probably, yes.

BTW, I wonder why there is a VTS_C_ADT table. I can't imagine when it is needed by the player, since the cells that are played are also always defined in the PGCs.
I even wonder if it is possible to remove that table completely. Of course, it's certainly illegal, but I'm almost sure the players will continue to work as before.

[blutach]

I suspect the players simply acknowledge sectors, not VCIDs. This was exemplified in Seinfeld Season 4, Disk 4, where we saw many of the ARccOS cells, some of which were played, with the same VCID but different entry sectors.

Regards

[jsoto]

Probably, yes.

BTW, I wonder why there is a VTS_C_ADT table. I can't imagine when it is needed by the player, since the cells that are played are also always defined in the PGCs.
I even wonder if it is possible to remove that table completely. Of course, it's certainly illegal, but I'm almost sure the players will continue to work as before.
In an ILV VOB, the pointers in PGC are not enough. The player needs the pointers to each part of the cell currently played, and they are in VTS_C_ADT. However, these pointers can be calculated from the internal VOB ones, thought...
jsoto

[r0lZ]

Thanks, jsoto. I didn't thought at that. But again, I'm almost sure the player will use the info in the VOB rather than the IFO table.

[jeanl]

I agree with r0lZ, I think the player go for the most direct info and ignore the rest. This means, use internal VOB pointers for ILVUs (why try to get them from the C_ADT, when you have them right there, when you need them - with a flag to warn you in advance you'll need to skip ahead), and also ignore the VCID entirely during playback!!! We've seen several DVDs where the VCID changes in the middle of a cell, but playback sails right through it (in other words, the players only look at the Entry and Last VOBU LBAs, and seem to completely ignore the VCIDs either in the PGCs or in the VOB!). I'm sure this is not legit though.

We had a previous thread about this very issue. I'm trying to look for it, mpucoder had some interesting stuff to say...
Edit: Here it is:
http://forum.doom9.org/showthread.php?t=103233&goto=nextoldest
jeanl

[blutach]

It makes sense for players to look in the VOBs. I guess the behaviour is the same in cases where there are ILVUs compared with those which simply have the mismatch I referred to (no ILVUs).

Interesting find jeanl.

Regards

[jinjin_jp]

I searched info about ARccOS and RipGuard and found two patents from MACROVISION.
patent_1 (http://v3.espacenet.com/family?DB=EPODOC&IDX=JP2005332568&F=8&OREQ=0&textdoc=TRUE)and patent_2 (http://v3.espacenet.com/family?DB=EPODOC&IDX=JP2005251379&F=8&OREQ=0&textdoc=TRUE)
Written in these, VTS_C_ADT and VTS_PGCITI tables and ILVU. (I'm reading these days, but can't understand.)
Is there any info in these patents?

[jinjin_jp]

Essentially VTS_C_ADT shows the start of the cell but the PGC decides to enter several sectors later.
There is the info from fengtao.
He explains "it's legal to use a part of Vob/Cell in PGC" in post #25 of http://forum.digital-digest.com/showthread.php?t=70483&page=2.

Regards.