CHAPTER 13

DVD Chapter 13
737
During playback in an APS-enabled (Macrovision-enabled) player, the digital-to-analog converter
(DAC) chip inside the player adds the APS signals to the analog output signal being sent to the screen.
These additions to the signal are designed so that they are invisible when viewed on a television or
monitor but cause copies made on most VCRs to appear distorted. Unfortunately, some TVs or other
displays can react to the distortions added to creat a less-than-optimum picture.
APS uses two signal modifications called automatic gain control and colorstripe. The automatic gain
control process consists of pulses placed in the vertical scan interval of the video signal, which TVs
can’t detect but which cause dim and noisy pictures, loss of color, loss of video, tearing, and so on on
a VCR. This process has been used since 1985 on many prerecorded video tapes to prevent copying.
The colorstripe process modifies colorburst information that is also transparent on television displays
but produces lines across the picture when recorded on a VCR.
Note that many older players don’t have the licensed Macrovision circuits and simply ignore the code
to turn on the APS signal modifications. Also, various image stabilizer, enhancer, or copyguard
decoder units are available that can plug in between the player and VCR to remove the APS copyguard
signal and allow a perfect recording to be made.
Adding a DVD Drive to Your System
A DVD drive installs in a manner similar to that of a CD-ROM or any other type of drive. See Chapter
14, “Physical Drive Installation and Configuration,” to learn how to install a 5 1/4-inch DVD drive.
Following are some basic principles to keep in mind when installing a DVD drive:
■ Most DVD drives are ATAPI devices. So, you have the issue of master/slave setups on the dual-connector
40-pin ATA cable. If you’re replacing an old CD-ROM drive, simply note its master/slave
configuration when you remove it from your system, set the new DVD drive the same way,
attach it to the data cable, connect the power, and you’re finished.
■ Many current DVD drives require that you connect them to a busmastering ATA interface. If your drive
requires a busmastering interface, check out the tips later in this chapter.
■ If you want to play DVD movies using your drive, you need an MPEG-2 decoder. This can be either a
card (hardware decoder) or a program (software decoder). If you are using a hardware decoder, it
requires an open PCI expansion slot, as well as an IRQ (interrupt request) resource from your
system. Also, to view the movies on your PC’s display, you must somehow connect the decoder
card to your existing video card. This can be accomplished via an internal connection to the
card, or it can use a loop through connection to the monitor port on the back of the card. Some
video cards include MPEG-2 decoders (players) built in. Table 13.22 compares MPEG decoder
cards to video cards with built-in MPEG players.
Table 13.22 MPEG Decoder Cards Versus Video Cards with MPEG Players
Consideration MPEG Decoder MPEG Player
PCI slot usage One for decoder; one for VGA One slot only
Movie image quality High Varies
Playback speed High Varies
MPEG game compatibility Yes No
Note that as processors have become more powerful, many DVD drives now ship with MPEG-2 software
decoders. These eliminate the need for an MPEG-2 decoder card, and if your processor is fast
enough, it allows for adequate performance when playing DVD video discs. Most of the decoders