44
DVX
Instruction
Manual
QUALITY CONTROL BASICS
WHAT IS DISC QUALITY?
We define disc quality as having every disc work in every drive, every time, with a lifetime appropriate to the
application. You must decide what level of confidence you need for your application. The higher the cost of failure,
the more careful you want to be.
It's Worse Than You Think...
One problem in evaluating disc quality is that discs that appear "good" may not be. All CDs and DVDs have very
powerful error correction built in that hides a multitude of sins. In principle, it is possible to drill a 2mm hole through
the disc and still recover every single bit! However, you wouldn’t want to rely too heavily on having that disc work
reliably. Many people think that just because a disc seems to be readable, it is good. But it actually may be on the
verge of failing.
WHY TEST DISCS?
DVD / CD Duplicators
You can improve profitability and reduce costly problems in your DVD-R / CD-R duplication business. As a disc
duplicator, you are responsible for the quality of your product. Data comparison does not measure disc quality. Just
because you can read it doesn’t mean it’s good. Poor disc quality can cause unreliable operation and short lifetime.
Evaluate and Qualify Recordable Media
- All DVD and CD recordable media are not the same. Compatibility
between writer and media is crucial. Find out which type of media works best with your writers. In addition, anyone
can make a bad batch of media. Localized stamper defects and dye coating problems are not uncommon. Identify bad
batches of media before burning a bunch of bad discs.
Furthermore, you can discover the lowest cost media that meets your quality requirements, providing significant cost
savings.
Detect Media and Recorder Compatibility Problems
- Compatibility between media, writer, and software is necessary
to produce good discs. Certain combinations of write strategy, recording speed, and media type can produce poor
results. Determining the best media to use with a given recorder (or vice versa) is greatly facilitated by testing disc
quality. Identify burners that are failing or about to fail. Discover if the problem is the media or the writer.
Manufacturers
Disc manufacturers must test discs to ensure conformance to standards & license agreements. But of course the main
goal is customer satisfaction. Many replicators have found our products useful for screening discs on the production
line to spot problems before many bad discs are made.
Distributors
Distributors can use disc testing as a way to manage quality variations from vendors, and make sure they get what they
paid for. Although most replicators produce good quality products, bad discs often slip through. Discs that are made
thinner than usual and physical defects such as pit distortion from short manufacturing cycles indicate poor
manufacturing techniques and can result in unusable discs. If you are paying for premium discs, you want to be sure
the quality measures up. In addition, you can avoid returns and unhappy customers.
Studios & publishers
Avoid problems with mastering
-
In the majority of glass mastering systems, uncorrectable errors (referred to as E32;
see discussion below) automatically abort the mastering session, causing costly delays for both the mastering house and
the customer. Most replicators prefer that you be able to demonstrate that your CD-R does not reach this level of error.
Provide confidence in product quality
- When problems occur, they can be resolved more quickly and easily if
publishers know the quality of their discs and have a way to check them. Also, once a product is in the field, fixing a
problem becomes more difficult and expensive. Publishers can avoid returns and maintain a good reputation by
tracking the quality of their discs.
