A DVD player supports 16 locations that DVD-Video program material on a DVD-compliant
disc can have access to. Each location is an unsigned 16-bit quantity (or 2 bytes of
storage, corresponding to the decimal value range 0-65535). These locations are known
as the general parameter registers, or GPRMs.
Each GPRM contains a value that can be modified under program control to create
complex branching in the playback of your DVD project. GPRMs can store values read
from the system parameter registers (SPRMs)
. GPRMs values can be calculated during
playback, and the appropriate navigation decisions are taken based upon the
computed result. GPRMs can be used as time counters to trigger certain events
when an assigned timeout expires.
The DVD player clears the contents of all GPRMs registers to 0 when the user
removes a DVD disc from the player.
Typical usage for GPRMs
Depending upon the value of a specified GPRM, playback is returned to a particular
submenu of the VTS, instead of to the root menu, when the Menu button is pressed
on the remote control. This is more intuitive to most users, since he/she would want
repeated access to the selected submenu which corresponds to the video material he/she
wants to see, and not to have to cycle it again through the root menu.
A GPRM can be used as time counters to "time out" a video or menu display. For
example, the display of the root menu can be set to expire after a defined interval.
If the user does not press any key on his or her remote control after the timeout
expires, the playback of the movie begins automatically.
GPRMs can be used to hold the results of interactive scoring tests or games that a
user takes after viewing training DVD videos. If the result is high enough, the user
can advance to the next play level.
Select the default audio language based upon region setting or parental level.
Highlight the button of the current audio language.
Set parental level.
Provide and control access by prompting for passwords.
GPRMs can be used to perform the timing of an event, such as the length of time
a user takes to respond to a set of multiple choice questions. Depending upon the
time and the set limit of the time, the player can then take the user to a specific
video segment or another display level.
Create hidden highlight buttons that appear only when the user makes certain
selections in a certain predefined sequence.
Most standard arithmetic and logical operations on digital computers are supported
by the GPRMs registers (see the Set GPRM Operations