Glossary

A-B             C-D             E-L            M-P            R-Z


  A

Access Time
The time needed for the reader to cross the CD gathering information (between 120 and 600 milliseconds, depending on the reader).

A-TIME (Absolute-Time)
The CD coding system includes a clock which monitors recording time and predicts a total.

A/D (analogic/digital)
Conversion of an analogue signal to digital.

ABERL (Atip Burst Error Length)
Number of consecutive ATIP errors. The Orange Book specifies a maximum of 3 (see also, BERL).

ADPCM (Adaptive differential pulsation code modulation)
Audio file compression format used for CD-I or CD-ROM/XA to increase listening time or insert more data. By using this format, up to 16 hours of audio files can be recorded onto one disc (14400 Hertz radio quality).

Artwork
Any design for printing on a CD, DVD, or Blu-ray.

ASCII (American Standard Code for Information Interchange)
Coding for alphanumeric characters used in computing.

ATER (Atip Error Rate)
Number of CRC errors per second in the ATIP. The Orange Book specifies a maximum of 10% error, equivalent to a maximum of 7 errors detected every second.

ATIP (Absolute Time In Pregroove)
Marks the spiral length in time. The different areas have set lengths (The spiral starts at 96:15:00, lead-in area starts at 97:27:55, data starts at 00:00:00, lead out area starts at 74:05:10 end of spiral beyond 76:05:10).

DVD Authoring
The conversion of a high quality digital or analogue video source to a MPEG-2 file for processing by a DVD reader.

  B

BER (Bit Error Rate)
The number of errors divided by number of correct bits. The usual rate for a CD-ROM is 1 per 1012 bits.

BERL (Burst Error Length)
This is the measurement of the quantity of blocks containing type E21 et E31 errors, which generally indicates physical damage. E22 usually indicates the presence of dust, scratches or handling errors. This is an important parameter since it indicates the presence of physical damage with an impact on more than one block of data.

Birefringence
Double light refraction. Certain types of material have this double refraction. The substrate used for CD-Rs has this property, and it is caused by the way the molecules are organized and by the internal tensions created when the disc is molded. Excessive birefringence can cause interference and read errors.

BLER (Block Error Rate)
A measurement of the integrity of data contained on the CD. Error type E11, E21, E31 rate is measured over one second using analysis equipment. An average rate lower than or equal to 220 is considered acceptable in the Yellow Book and Red Book.

Bloc (Block)
The data is organized into blocks on the CD, containing a header, the data, error correction and information checks. This is the minimum logical addressable unit found on a CD, and each one has a logical block number to enable the data to be found.

Books
These summarise the DVD specifications and are marked from A to E depending on the applications they are intended for:
    Book A : DVD-ROM, specifications for read only.
    Book B : DVD-Video, contains video specifications and an Applications specification defining the software and functions built into video readers.
    Book C : DVD-Audio, contains audio specifications and an Applications specification defining the software and functions built into audio readers.
    Book D : DVD-R, specifications for one-time writing and rereading.
    Book E : DVD-E (erasable or re-recordable) and DVD-RAM, contains re-recordable specifications.

Buffer
A temporary storage area to compensate for the difference in speed between the peripherals and ensure a smooth flow of data. A CD CD-Recorder uses from 512 kb to 2 Mb of buffer space.
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