DVD glossary
- Birefringence
Optical distortion caused by different indices
of refraction for separate directions of polarization, often caused by stress
in the optical medium. Produced during CD or DVD injection molding by
shrinkage, flow lines, and inclusions in the substrate. Usually more severe
near the outer diameter.
- Bit
One binary information element having the value
ZERO or ONE.
- Bit Error Rate (BER)
Probability that a read bit does not match the
written bit.
- Block
Group of contiguous recorded characters treated
as a unit and containing one or more logical records. A logical block contains
512x28 bytes, where n is an integer (0, 1, 2, ...) Normally used to
characterize a DVD ECC block or a CD subcode block, or section, but can also
refer to a CD frame.
- Block Error Rate (BLER)
Number of blocks, each containing one or more
erroneous bits, per unit of time (usually seconds).
- Blue Book
Proprietary Philips/Sony specification (blue
cover) for Enhanced Music CD.
- Bump
Exposed area on the master viewed from the
entrance surface. Also used to designate indentations caused by foreign matter
during molding.
- Burst
Contiguous error groups usually caused by a
large tangential physical defect. ISO burst limit for CD is less than seven
successive frames, each containing two or more successive error bytes.
- Burst Cutting Area (BCA)
Optional annular area on a DVD disc near lead-in
containing low reflectance radial stripes of encoded content provider
information.
- Byte
Contiguous set of eight data bits, represented
by an equal or greater number of channel or recorded bits.
B-frame
Bi-directional frame. The frame in an MPEG sequence created by comparing the
difference between the current frame and the frames before and after it.
Bandwidth
(1) The amount of data that can be transferred or processed per unit of time.
(2) The range of frequencies a device operates within. The wider the bandwidth,
the better the performance. Bandwidth is measured in kHz.
Bass
Frequencies in the lower part of the audio spectrum (20 Hz - 160 Hz).
Bi-directional Prediction
A form of compression in which the codec uses information not only from frames
that have already been decompressed, but also from frames yet to come. The codec
looks in two directions: ahead as well as back. This helps avoid large spikes in
data rate caused by scene changes or fast movement, improving image quality.
Bit
A binary digit that indicates 0 for "off" and 1 for "on."
Bitmap
An array of pixels.
Bits
per Pixel
The number of bits used to represent the color information of a pixel. 1 bit per
pixels allows using only 2 colors (usually black and white), 24 bits are used
for True Color images (more than 16,7 million colors).
Bit
Rate
An indication of the amount of data processed for some time period. Usually
measured in bits per second (bps). Also called Data Rate. The higher the rate
the better the picture/sound.
Bitstream
A stream of data meant to be processed sequentially. Dolby Digital sound on a
DVD is encoded onto a bitstream for processing.
Bonded
Disc
In order to make a DVD more resilient, and less likely to warp, two 0.6mm layers
are permanently bonded together. This also allows DVDs to be two-sided.
Book A
DVD Read only specification.
Book B
DVD Video specification. Organized into Physical, Logical, and Application
sections.
Book C
DVD Audio specification.
Book D
DVD Write once specification.
Book E
DVD Rewritable specification.
Brightness
The value of a pixel along the black-white axis.
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