Apple DVD Studio Pro 4 - Manual (Page 499)

Exit Pre-Script Command
A pre-script executes as soon as an element is selected. Depending on the purpose of
the pre-script, you will often want to have that element display as normal once the
pre-script is finished running. The exit pre-script command provides a way to end a
pre-script and display the element as normal.
Note: When a script is run as a pre-script, it reacts differently to having a Nop as the last
command line. With a regular script, if the last command line is a Nop and the script
encounters it while running, the script stops and the title will no longer play. With a
pre-script, if the last command is a Nop, it is treated as if it were an exit pre-script
command, and the element the pre-script is assigned to displays as normal.
Jump Indirect Command
With the normal jump command, you must specify an element (menu, track, story,
slideshow, or script) to jump to, even when using the GPRM Based Button setting.
The jump indirect command provides a way to jump to an element that is entirely
determined by a value stored in a GPRM. For example, you could have a script that uses
the set command write the current menu’s value to a GPRM, and then later on have a
second script use the jump indirect command to jump to that same menu by reading
that GPRM.
Note: You can only select from the 16-bit GPRM registers.
System Parameter Register Memories List
Each DVD player operates internally via a group of system parameter registers (System
Parameter Register Memories, or SPRMs). The status of player operation (which DVD track
is playing, what language is being used, and so on) can be read by script commands that
access the SPRM status registers.
The following list describes the system parameters that can be read by a script:
• SPRM 0: Menu language description code; DVD player setup by user
• SPRM 1: Current audio stream number; set by user or program
• SPRM 2: Current subtitle stream number; set by user or program
• SPRM 3: Current angle number; set by user or program
• SPRM 4: Current playing title number (Title); set by DVD player
499 Chapter 20 Creating Scripts