LaCie 400USB user manual About DVD/CD Available Capacity

LaCie d2 DVD±RW Drive	Helpful Technical Information
User Manual	page 25

4.3. About DVD/CD Available Capacity

There are important factors to consider when record- ing video, audio or data to CD or DVD discs. The DVD media specification provides for two physical sizes: 4.7” (12cm) and 3.1” (8cm) (both are .47” (1.2cm) thick). DVD discs are single-sided and can have one (SL) or two (DL) layers of data.

The amount of data or video that a disc can hold are dependent upon factors such as the amount of audio and the degree of compression of the data, video or audio.

When media companies reference the amount of data that a disc can hold, they represent the total amount in terms of gigabytes (GB), or a billion bytes (1000 x 1000 x 1000 bytes). This number, though, is not the way in which a computer addresses the data; to a computer the value is binary and larger than a billion bytes – 1,073,741,824 (1024 x 1024 x 1024 bytes).