Starting an IFOedited disk at chapter 'n'

[rusty.hill]

I thought I could use IFOedit to edit the Pre command table to add a second pre command to get the disk to start at, say, chapter 3 instead of ch.1 but I can't get it to work.

Any advice pls?


TiA
Rusty
(The reason is that I am reediting a DVD+RW from a Philips 880 and want to loose the tail of the preceeding tv show and the movie really starts at ch 2.)

[mpucoder]

You didn't say what PGC. If it is the First Play, change the command to go where you want. It probably already is a jump command, and, just like "real" computer programs, once you jump the rest does not get executed.

[rusty.hill]

HI MPUCODER,

Thanks for the feedback. Doh! I should have realised that 'jump' is just like any assembler code... thanks!

To recap, (idiot mode ON), as you guessed, there is only one PGC for the disk, with 17 chapters.

So If I edit VIDEO_TS.IFO, I find '(Jump_TT) Jump to Title 1'under 'first play pgc'

If I want the disk in fact to start with chapter 2, say, then I replace this with '(Jump_VTS_PTT) Jump to Chapter 2'...?

(I'm at work so can't try this now..) But if this is right how does the disk know it's 'title 1' that 'chapetr 2' refers to?

Thanks for yr help - and how's Darrow? - still Stateside?

brgds

Rusty

[mpucoder]

You're right, First Play can only jump to the title, not a particular chapter. In that case (unless you want to remove the chapter) you would modify the title PGC pre commands to start the title at chapter 2. There are 4 possible commands, listed best to worst:
20 05 00 00 00 00 0x xx LinkPTTN (xxx = chapter number)
20 06 00 00 00 00 00 xx LinkPGN (xx = program number)
20 07 00 00 00 00 00 xx LinkCN (xx = cell number)
20 01 00 00 00 00 00 02 LinkNextCell - will start at cell 2

[rusty.hill]

Mpucoder,

Thanks - I'll try tonight...

Thanks,

Rusty

[riprazor]

Rusty, I would also suggest that you take a look at some of 2Cool's guides. He has an enormous amount of information on using IFOEDIT to manipulate chapters, eliminate unwanted information, all while keep the format of the disc legal and avoiding illegal instructions.

Regards,
Riprazor

[rusty.hill]

Thanks - anyone can find them at:

http://forum.doom9.org/showthread.php?s=&postid=242410post#242410

Rusty

[rusty.hill]

OK, Thanks for the help, but I think I'm stuffed. The title PGC does not have a pre command block in it, and with IFOEdit I can't see how one could insert one.

So that, I think, rules out leaving the disk IFO intact (with Jump_TT) and playing with VTS_01_0.IFO.

2Cools suggests changing the start value of Cell 1 in the program IFO from it's normal '0' to some largeer value which is at the desired 'in' point. This seems to work (at least in emulation mode) but I wonder if it's fully 'legal'?

Also, it alters the VTS sectors which worries me a little - I know IFOEdit corrects this --....

(Tough for me that IFOEdit DVD play has never worked on my kit or I could find the required sector from that I guess...)

Thanks again,

Rusty

[mpucoder]

No, it's not legal, and will cause problems. Also IfoEdit and IfoUpdate will correct the start point based on the VobID and CellID in the vob files.

Right click on "Size of Command table in bytes" and select "add pre command".

[rusty.hill]

Thanks, - the problem is that the IFO relating to the program VOBs (as opposed to the disk IFO) does not have a PGC command table in it and IFOEDIT 0.96B1 won't let me insert one. (Probably quite correctly, as there are no sectors available for it..?)

VTS_01_0.IFO

VTS_PGCITI/VTS_PGC_1
----------------------------------------------------------------------

PGC (program chain):
[00000002] Number of Programs 67 [43]
[00000003] Number of Cells 67 [43]
[00000004] Playback time (BCD) 20972385 [01400361]
Playback time (hh:mm:ss.frame) 01:40:03.21 / 25 fps
[00000008] Prohibited user operations 0 [00000000]
[0000000c] Audio stream 1 status 32768 [8000]
Audio stream 1 uses stream nr.: 0


{deleted stuff}


[000000dd] Color 14 Y Cr CB 0 0 0 [00 00 00 ]
[000000e1] Color 15 Y Cr CB 0 0 0 [00 00 00 ]

[000000e4] PGC Command Table start byte 0 [0000]
[000000e6] PGC Program Map start byte 236 [00ec]
[000000e8] Cell Playback Information Table start byte 304 [0130]
[000000ea] Cell Position Information Table start byte 1912 [0778]

There is no PGC Command Table

PGC Program Map:
[000000ec] Program_1: Entry cell number 1 [01]
[000000ed] Program_2: Entry cell number 2 [02]
----------------------------------------------------------------------
I agree that it's essential to keep the IFO legal so setting 'start' address to be other than zero is not good news.

Am I missing something obvious or do you have any suggestions?

Thanks

Rusty.

[mpucoder]

OK, just went through this myself using 0.95 -
If there is no command table right click on the line that says "There is no PGC Command Table" and select "add PreCommand". This will create a command table with one pre command, a NOP. Now, since the command you want isn't one of the ones in the edit drop box, double click the NOP, and a hex editor will open up for those 8 bytes.
You could use Jump_VTS_PTT from the drop box, but it requires the title number, we want to use Link, as it is relative to the current title.

[rusty.hill]

Thanks again, yes, you'r quite correct. In pre 0.95 it seems this right click was missing but is in 0.95 & 0.96b1.

Incidentally, I was getting round the problem by using TMPEG DVD Author which lets one cut top & tails from VOBs. Again, not sure if the resultant structure is legal, but I think the TMPEG guy is usually quite smart.

I'll post back after some more tests and thanks again.

brdgs

Rusty

[rusty.hill]

MPUCODER,

Thanks for all yr help. It works!

1) There seem to be two 'good' ways to achieve the ability to start the disk at, say, chapter 2.

2) Use IFOEDIT 0.9x or better to edit or add a PRE COMMAND and hex edit the value of the chapter in as Mpucoder details above. This works fine, is quick to do and legal. The down side is that the 'unrequired' material remains on the disk and can be accessed by manually selecting, say, Ch 1 via the DVD remote control.

3) Use TMPEGAuthor to edit the VOBs and remove the unwanted material. This takes longer, as the VOBs are written out but not too long. Is it legal? I'm not sure. The resultant IFOs look OK and the VOB structure seems good but as I don't know what TMPEGAuthor is actually doing I can't be sure.

Thanks again for the help - excellent example of Doom's forum!

brgds

Rusty