PGC command table

[Romzess]

Hi,
Sometimes to get rid of some Vts_XX_X.vob files doesn't help. Specially if those files (for example warning FBI and etc.) are before main movie. In this case my standalone player usualy freezes (Software players-no problems). In this situation best way - to edit PGC command table. As far as i know DVD player start read disk from VIDEO_TS/VMGM_MAT/First Play PGS and .....
All Ifo files contains VTS-PGCITI/VTS_PGC_x and VTS_PGCI_UT/PGC-MENU_x where situated PGC commands.
Usually it looks like:
1.Pre command Set GPreg<6> mov (set-val) <1000>
2.Pre command Set GPreg<7> mov(set-val) <1>
3.Pre command Jump to TitleSet(vts):1,Title(ttn):1,root-menu or
(CallSS VMGM) Call VMG PGC:7 [Resume Cell:1] or
(Jump TT) Jump To title:2

With commands Jump and Call a little clear. When I change this volumes to exist titles, my standalone player understand it perfectly.

But still not clear - what is GPreg parameters and for what it change. May be anybody knows about it or find some articles on this matter?
:confused:

[Derrow]

GPreg stands for Gerneral Purpose register.

The means, it's just an memory place, where you can place some own values.
Authoring tools use them to save some values, which audio stream has been selected, or wich button has been pressed, or which title-set has just been displayed and so on.