Always need a VMG title number for a TTN?

[blutach]

On some recently released ARccOS DVDs, some TTNs (albeit uncalled) have no title in VMG associated with them. Note TTNs 2-16 in the attached.

http://img178.imageshack.us/img178/2489/03162007000314kr8.png

Just wondering if this is legal. Wouldn't surprise me if it isn't given all the shenanigans that has been going on lately.

Regards

[mpucoder]

It's allowed but discouraged.

Until just now I had not thought about it, but this gives a way to have more than 99 titles on a DVD. Only 99 can be indexed and reachable from the title menu (VMGM), but each of those 99 could lead to a seperate VTS, each of which contains 98 additional titles reachable only from within the VTS.

Reminds me of the early days of CD when sub tracks were implemented. That concept was not popular enough, so modern players no longer support it. I have only one player left that can select and display track and sub track

[blutach]

Thanks as always mpucoder. Yes, I have seen some ARccOS DVDs with 99 titles and some "unnamed" TTNs, and also wondered if Jump to TTN x in this VTS commands could be implemented.

Regards

[r0lZ]

Only 99 can be indexed and reachable from the title menu (VMGM), but each of those 99 could lead to a seperate VTS, each of which contains 98 additional titles reachable only from within the VTS.
Interesting!

But in this case, what is supposed to be in SPRM 4 (and shown in the led display of the player)? The last visited Title?

Also, mpucoder, can you confirm that it is necessary to have at least one Title per VTS? It is theoretically possible to reach the TTNs via the VTSM menu, so, technically, no Titles at all are necessary.

[EDIT] Mkisofs can't create the ISO if there are no title at all in a VTS. It complains about a negative VTS sector pointer, probably because the pointer to the start of the VOB file is missing in VTS_TT_SRPT.

[mpucoder]

Good question about what's in SPRM 4, probably the old "unpredictable results" answer since this is not an intended use.

Every VTS must have at least one title, file VTS_xx_1.VOB is not optional. Also every VTS needs at least one entry in TT_SRPT, this is how the player locates the ifo file for the VTS.

[blutach]

I saw a disk the other day without a title in the VTS (it was naturally unreferenced). I believe there was a VOB but no title in the IFO. This was simply an authoring error as the DVD was released in 2001.

This DVD in fact led to this discussion.

Regards

[r0lZ]

Thanks for the reply, mpucoder.

Currently, the trace in PgcEdit leaves what was previously in GPRM 4. I suppose that's what a real player does.

After having analysed the problem with the DVD blu is talking about, I have modified PgcEdit to create a new Title in VMG_TT_SRPT for each "unnamed" TTN, but there is an important risk to exceed the limit of 99 titles. Therefore, I'll change that again to create only one Title per VTS, and only when there are no titles at all in the VTS.

[blutach]

Thanks r0lZ.

Regards

[Robotik]

i've had a dvd recently that had the same structure. the bonus features had one title for each category, one title for previews, one title for 'making of' featurettes, etc. the only problem was that search didn't function.

But in this case, what is supposed to be in SPRM 4 (and shown in the led display of the player)? The last visited Title?

well the desktop player was a bit confused. first it showed the title number of the last preceding pgc that had a title number, then after a second or so it switched to show the TTN number. iirc the software player showed the title number of the last preceding pgc that had a title number, so in blutach's example TTN 1-16 are all title 32. but if e.g. TTN 10 was title 33, then TTN 1-9 were title 32, and TTN 10-16 were title 33.

[r0lZ]

That's probably not the same thing.

They are not-one_sequential titles, made of several PGCs. All PGCs in the title pertain really to the same title. They have the same TTN number. Not-one_sequential titles cannot have a time map, and therefore you cannot use the search function.

On the other hand, what we call here "unnamed titles" are different TTNs without title numbers at all. Such an unnamed title is made of only one TTN, and can have a time map.

For example, in PgcEdit, when you see something like that:
VTST 1, 1, TTN 1, Title 1
VTST 1, 2, TTN 1
Title 1 is not a one_sequential title, because it is made of PGCs 1 and 2. This situation is very frequent, especially in the bonuses and games.

Here, TTN 1 is a regular title, but TTN 2 has no title number, and is therefore an "unnamed title".
VTST 1, 1, TTN 1, Title 1
VTST 1, 2, TTN 2

[bigotti5]

On the other hand, what we call here "unnamed titles" are different TTNs without title numbers at all. Such an unnamed title is made of only one TTN, and can have a time map.

Just to increase confusion - an unnamed title can not be marked as one_sequential because there is no entry in TT_SRPT...

Verifiers are nonacceding

Philips complains about unnamed titles with an ERROR 5613 - VTS_TTN (2) from VTS 2 not found in VMGI for VTSI

Interra does not complain about it

[Robotik]

i can't remember what it was, but once i used a program that referred to these as 'TTNs belonging to the same title' or something similar. i mean the TTNs between two titles belong to the previous title. of course they might be wrong, or i might have misunderstood it, or just getting confused over the time.

[r0lZ]

Just to increase confusion - an unnamed title can not be marked as one_sequential because there is no entry in TT_SRPT...
Right.
It's another good reason to avoid using them.

Anyway, remember that blutach has started this thread because we've found a commercial DVD with just one unnamed title in a VTS. This title is never called explicitly, therefore it's obviously an authoring bug. I'm almost sure this happens never in good DVDs, except perhaps for some forms of copy protection. This discussion is really theoretical!
BTW, the original thread about this strange DVD is here (http://forum.digital-digest.com/showthread.php?t=79000), at DVF.

[blutach]

If I may go on with something very interesting that mpucoder said.

Also every VTS needs at least one entry in TT_SRPT, this is how the player locates the ifo file for the VTS.This raises the question about what filesystems are for. Some (intentionally) corrupt DVDs have emerged lately from Europe where both ISO9660 and UDF1.02 are corrupt, making the DVD impossible to play on a PC. I am almost certain this is not legal as people are complaining they can not play their DVDs on Media Centre PC etc.

But, taking the cue from mpucoder, does the (presumably only standalone) player simply only need to find VIDEO_TS.IFO (these seem to be OK) and locate other IFOs from the Titleset Starting Sector in VMG_TT_SRPT? If so, why have a filesystem with any files in it at all other VIDEO_TS.IFO?

Regards

[mpucoder]

Right, hardware players do not use the file system except to locate VIDEO_TS.IFO, after that everything they need is in the ifo files. This is also why DVD-Video cannot be burned as data, if it were the files would most likely not be in the correct locations as specified in the ifo's. There are three orders the files could be in (all wrong) - sorted alphabetically, sorted by date/time (the last file written by any authoring app is VIDEO_TS.IFO because the values needed by this file aren't known until all titlesets are muxed), or system order (the order the files appear in the directory, usually the order written, but not always)

[blutach]

Right, hardware players do not use the file system except to locate VIDEO_TS.IFO, after that everything they need is in the ifo files. This is also why DVD-Video cannot be burned as data, if it were the files would most likely not be in the correct locations as specified in the ifo's. There are three orders the files could be in (all wrong) - sorted alphabetically, sorted by date/time (the last file written by any authoring app is VIDEO_TS.IFO because the values needed by this file aren't known until all titlesets are muxed), or system order (the order the files appear in the directory, usually the order written, but not always)So, if I understand, the player looks for the IFO (perhaps looking for DVDVIDEO-VTS in the process) in the Titleset starting sector and uses the tables there to decide where the IFO infomation ends and the VOBs start. The rest of the info is totally redundant!

But how then do people who buy a DVD with corrupt filesystems actually play them on licensed (software) players that do use the filesystem to find files? That's why I think these disks must be illegal to the spec.

As always, thanks mpucoder for clearing up murky waters.

Regards

[mpucoder]

I would agree with that, at least the micro-udf file system is mandatory. Corrupting it would make the disk non-compliant. Anybody know any titles and regions?

re the other thread: I just checked my 2001 region 1 Crouching Tiger Hidden Dragon and it does not have anything unusual.

[blutach]

The three ones to date have been released by minor houses in Germany.


Silent Hill (only UDF was corrupt on this one)
Das Parfum (both FS corrupt)
Wer frueher stirbt, ist laenger tot (both corrupt)
Regards

[mpucoder]

These are all region 2?

[blutach]

Yes. And the Crouching Tiger poor authoring was for a Greek version where no VMG title number at all was declared for VTS 2.

Regards

[r0lZ]

I've made a little DVD to test the bahaviour of my players with those "unnamed titles".
The first TTN has a title number. The 2nd one is unnamed. TTN 1 leads to TTN 2.

Software players:

IfoEdit complains about an "illegal command" and stops when playing TTN 2.

MPC hangs when playing TTN 2.

M$ Media Player 10 plays Title 1 again and again. Seems it refuses to play TTN 2, but I don't understand why it returns to title 1. If I use the menu to play TTN 2 directly, it stops immediately.

Hardware players:

My cheap XiRON recorder plays correctly both titles. When Title 1 is played before TTN 2, it displays 00 as the title number when playing TTN 2, but when TTN 2 is played immediately, it displays 01!

My cheap KISS plays both TTNs without problem. It displays Title 0 when playing TTN 2.

My Sony plays both titles without problem. It displays nothing when playing TTN 2. The chapter number isn't displayed neither.

Conclusion: those unnamed titles might be legal, but, IMO, they should be "highly discouraged"!

For ppl interested, I join the test DVD.

[jeanl]

@r0lZ: amazing! So you were right. It's quite risky to have these unnamed TTNs... That's a good thing to know.

@mpucoder: The one file that's not directly pointed to by the IFO is the BUP file... The IFOs point to the last sector of the BUP, but you'd have to know its size to go back to its beginning... You can probably assume that it's the same size as the IFO (should be) I guess. But all this is a bit contorted!
Jeanl

[blutach]

jeanl has hit upon a good point. How to find the BUP if the IFO is damaged/scratched?

And r0lZ, those tests are all over the place, but it seems the software players have the most trouble. PowerDVD plays TTN 1 twice (button 1) and stops immediately on button 2. Showtime (button 1) is fine first time around. The second it plays blackness, probably because of SPRM 4 (it shows title 0). Button 2 shows the menu (without highlights in 16:9) for 10 seconds. I wonder if Jump to TTN2 in the VTS works better in the titles domain (which would explain why button 2 is hopeless) - trouble is it is not an entry point for a title, of course.

Regards

[r0lZ]

@r0lZ: amazing! So you were right. It's quite risky to have these unnamed TTNs... That's a good thing to know.Well, yes and no. If the unnamed TTN is never called, I guess it's safe!
And as the user cannot jump to the title with the remote, it is even not necessary to set the Title Play PUO to ensure the user cannot call it manually.

@blutach:
Even more strange. Seems all soft players have their own way to crash when playing those unnamed TTNs!