BLANK MEDIA

Blank media DVDs are available in many different formats.

“DVD-R,” for DVD-Recordable (sometimes spoken as “DVD minus R”) is a writing format for the storage of data according to DVD specifications so as to be playable on any compliant DVD player. DVD-R media can only be written to once, up to 4.7GB’s worth of data. Two versions of DVD-R blank media exist: one for professional content developers used to make master discs that serve as models to be mass-produced by postproduction facilities, and the more common one commercially available for general use.

“DVD+R” (usually spoken as “DVD plus R”) is another recordable format which stores data according to official DVD specifications for playback on compliant DVD players. The “+” simply refers to the method used to follow disc tracks: “-” uses Constant Linear Velocity (CLV) for disc rotation, while “+” can use CLV or Constant Angular Velocity (CAV), which allows for easier data access. DVD+R also provides for lossless linking of new data added by multiple recording sessions.

“DVD-RAM,” for Random Access Memory, is a rewritable format, meaning data can be recorded and erased up to a hundred thousand times. DVD-RAM blank media utilize phase-change data layers and can function as virtual hard disks.

“DVD-RW” (“DVD minus RW”) stands for DVD-ReWritable, and is similar to DVD-RAM except that it uses a sequential read-write method more akin to a phonograph than a hard disk. It can also only be rewritten to about a thousand times.

“DVD+RW” (“DVD plus RW”) is very similar to DVD-RW, but uses a different technique to track the laser around the disc while writing data. DVD-RWs use CLV while DVD+RWs can use either CLV or CAV for disc rotation, with CAV providing easier access to the data. DVD+RW media also allows for lossless linking of new data inserted by multiple recording sessions.

“BD-R” refers to Blu-ray Disc Recordable media that can be written to only once using the Blu-ray Disc standard, allowing 25GB of capacity for single-layer discs and 50GB of capacity on dual-layer discs.

“BD-RE” media are discs that can be written to using Blu-ray Disc specifications many times. Available in capacities of 25GB and 50GB for the standard 12cm disc, the latest versions can be found in a smaller 8cm size for use with camcorders.