Specifications

Disc Types

AVS4YOU programs currently support three types of optical disc formats that are available for consumer use. This section will better

explain the purpose of these formats and their place in history. With the support of other disc types and formats the corresponding

information will be added.

Compact Discs

Digital Versatile Discs

DVDs of different capacities

DVDs of different medium type

Blu-Ray Discs

Compact Discs

Digital Audio Compact Discs (CD-DA) were first introduced to the consumer audio market in 1980 by Philips and Sony as an alternative

to vinyl records and magnetic tape cassettes. In 1984, Philips and Sony extended the technology to include data storage and retrieval

and introduced a new format: the Data Compact Disc (CD-ROM).

Since then, the Compact Disc has dramatically changed the way that we listen music and handle electronic information. With a

capacity of up to 700 megabytes of computer data or 80 minutes of high quality audio, the Compact Disc has revolutionized the

distribution of every kind of electronic information.

In 1990, Philips and Sony extended the technology again and the Compact Disc became recordable (CD-R). Before the introduction of

the CD-R technology, compact discs were produced in commercial replication plants by stamping the media with a pre-recorded

master. Today, discs are produced in replication plants where large quantities are required. For small production volumes (up to 500

copies or more, depending on your location and manufacturers in your market), it can be significantly less expensive to master your

own discs using commercially available Compact Disc writing drives.

Whether a Compact Disc was stamped at a replication facility or "burned" using a compact disc recorder, it can theoretically be read

any available CD-ROM drive. In reality, some inexpensive media and CD players do not work very well together. Only the physical

composition of a commercially replicated disc and a CD-R disc are different. The former is coated with a reflective layer of aluminum

resulting in a typical silver color. The latter is coated with a reflective layer behind a thin layer of dye (colors can range from blue,

silver, green, and others).

In 1997 Compact Disc ReWritable (CD-RW) - a rewritable optical disc format - was introduced. While a prerecorded compact disc has

its information permanently stamped into its polycarbonate plastic substrate, a CD-RW disc contains a phase-change alloy recording

layer composed of silver, indium, antimony and tellurium. An infra-red laser beam is employed to selectively heat and melt the

crystallized recording layer into an amorphous state or to anneal it at a lower temperature back to its crystalline state. The different

reflectance of the resulting areas make them appear like the pits and lands of a prerecorded CD. A CD-RW recorder can rewrite 700

MB of data to a CD-RW disc roughly 1000 times.

A Compact Disc contain blocks (or sectors) of 2352 bytes each, going from the center hole to the outer diameter. The block at logical

address 0 (beginning of the disc) is located near the center of the disc; the last addressable block (end of the disc) is located near the

outer edge of the disc.

Blank discs are usually available in the following sizes (block sizes approximated).

21 minutes = 94500 blocks

63 minutes = 283500 blocks

74 minutes = 333000 blocks

80 minutes = 360000 blocks

AVS4YOU Programs Help - Appendix

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