Introduction
There are now two different types of DVD Recordable (DVD-R) media: DVD-R for Authoring
and DVD-R for General. It is important to understand how these two formats differ, and just as
importantly, how they are alike. In a nutshell, it is important to match the correct type of DVD-R
media with the specific DVD-R recorders, but after recording, either type can be used for
playback on any playback device that supports DVD-R.
Background
DVD-R is an official member of the DVD Forum's family of formats. Its write-once
characteristic allows users to make their won DVD discs, very similar to how CD-Rs are
recorded. As with CD-R, playback compatibility is one of DVD-R's most important attributes -
nearly all existing DVD video players and DVD-ROM drives will play one or both of the two
available disc capacities (3.95 or 4.7 billion bytes). Another key feature is the security inherent in
DVD-R's write-once nature - no one can accidentally erase valuable information once it's been
recorded. And because at least one media manufacturer (Pioneer) specifies a 100-year life
expectancy of recorded DVD-R discs, the format is well suited for long-term archival
applications.
Until early 2001, DVD-R was used primarily in professional applications such as video authoring
and storage of imaging data. For DVD authoring users, DVD-R allows testing and approval of
finished titles prior to mass production, and can even be used by some replicators as the final
program source in place of DLT tape. In many cases, recorded DVD-R discs are the finished
product when only a few discs are needed for deployment in vertical applications such as
museums or videowalls in retail stores. In medical environments, x-rays, CT-scans and
ultrasound video images are stored in automated DVD-R library systems to provide physicians
much faster access to information as well as better reliability than tape solutions. In the banking
industry, the format is used for storage and retrieval of checks and credit card receipt images
generated each day in retail transactions.
During this initial three-year period, the underlying technology of these professional applications
employed 635 nanometer (nm) lasers for writing information to 3.95 and 4.7 GB DVD-R discs.
This technology has allowed DVD-R products to become vital and dependable components of
many DVD authoring suites and library systems around the world.
Two Formats for Two Markets: Professional and Consumer
To support consumer applications for DVD-R, the DVD Forum determined that another type of
DVD-R media was necessary. The newest member of the DVD-R family uses a recording
wavelength of 650nm, and discs are recorded on different drives than the existing 635nm format.
This new format is called "DVD-R for General", because it is aimed at a broad base of
applications. Meanwhile, the existing 635 nm format has been renamed "DVD-R for Authoring"
to reflect its use in professional applications.