About DVD Player Registers
Each DVD player has two types of memory registers: General Purpose Register Memories
(GPRMs, also known as variables) and System Parameter Register Memories (SPRMs).
Scripts interact with these registers to determine DVD player settings (such as language
and parental control) and to control various aspects of disc playback.
Scripts use GPRMs as temporary storage, or “scratch pads,” while executing their
commands. DVD Studio Pro provides access to eight 16-bit GPRM registers, designated
GPRM 0 through GPRM 7 (though they can be renamed). DVD Studio Pro includes the
ability to partition seven of these registers into multiple smaller registers. For example,
you can partition GPRM3 into four 4-bit registers. Each register is independent of the
others, and all are cleared whenever a disc is inserted into the DVD player. The registers
can be used as storage locations or as countdown timers.
In contrast, SPRMs have rigidly defined functions. There are 24 of them, designated SPRM
0 through SPRM 23. See
System Parameter Register Memories Details
for a detailed listing
of their functions.
Scripts spend a lot of time copying values from an SPRM to a GPRM, extracting information
from the values (for example, determining the language setting), and then acting on that
information (selecting the proper audio stream to play). Extracting the information can
be challenging, requiring a bit of skill and programming knowledge.