DVD Demystified

Essentials of DVD Production
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After emulation testing, output to DVD-R for testing on standard players
and on other PCs. Test as many players as you can, and test with as many
of the popular PC hardware and software decoders as you can. However,
keep in mind that DVD-Rs don’t play properly in all players, and can even
cause spurious errors. Reserve some of this matrix testing time for replicated
check discs. Consider sending the DVD-R to a verification service or
running it through verification software or hardware. If the video has
Closed Captions, connect a player to a TV with a Closed Caption decoder
and make sure they appear correctly.
When you are sure everything works, send the DLT off to the replicator
and request check discs. Check discs are a short replication run from the
stamping master. A check disc is essentially the same as a final massproduced
disc. If you approve the check disc, the replicator can use the existing
master for the full replication run. Most replicators provide one round
of check discs for free as part of their replication service. However, they may
charge a fee if you find errors and have to send in a new DLT for another set
of check discs. Unless you have thoroughly tested with DVD-Rs and are
comfortable with the potential of having thousands of shiny coasters at
your disposal, don’t skip the check disc step. If you are making a dual-layer
disc, check discs are indispensable since you can’t fully test with a DVD-R.
You can break the disc into smaller parts to check on DVD-R, but you can’t
test layer changes and full navigation.
Tips and Tricks The following tips may help your testing and quality
control be more affective and efficient:
■ Test on a cheap TV. Most of the production process is done with highend,
high-quality video equipment, but many of your customers will
watch your work on a cheap, old television. Make sure that details of
video and graphics, menu highlights, and so on are not lost on the
average viewer.
■ It’s almost impossible to test all the permutations of a highly
interactive disc; try to break things down into testable subsections.
■ If you have computer software that can mount a formatted DVD image
file from DLT or a hard drive, mount the volume for more thorough
emulation. This will find file system errors that normal emulation will
not find.
■ If you put computer applications or large amounts of computer data on
the disc, use a checksum program to verify the accuracy of the original
data against DVD-Rs, DLTs, check discs, and final discs. A file-compare
program such as windiff is also useful for verifying filenames and data