Glossary - A Practical Guide to Video and Audio Compression - page 724

Topic Description

Cascade Several processing steps connected together in a series, one after

the other. Not recommended for compression logarithms.

CCD Charge-coupled devices are used in digital video cameras as

imaging sensors.

CCITT Consultative Committee for International Telephony and

Telegraphy. See ITU.

CD Compact Disk is a format developed by Phillips for delivering

digital audio.

CD-ROM Compact Disk-Read Only Memory is a derivative of CD audio

that allows data to be stored on the disk for use by computer
systems.

Chunk A fragment of data in an object-structured video file that is

larger than an atom but smaller than a track. The process of
breaking down the video into pieces is sometimes informally
called chunking. A chunk most likely corresponds to a GOP
(Group Of Pictures).

CIF Common Intermediate Format, Common Interchange Format, or

Common Image Format, depending on the source you consult.
It describes an image size that is 352 240 pixels

depending on whether the source is 625 or 525 lines. The ITU
H.261 standard originally specified this image size.

× 288 or 352 ×

Cinepak This is a very old legacy codec from the early days of QuickTime.

Cinepak mobile This is a mobile variant of the Cinepak codec.

CMYK Cyan, magenta, yellow, black. The primary colors used to print

images on paper.

Codec A software or hardware device to encode and decode video,

audio or other media. The encoder and decoder for a particular
compression format. The word is contracted from Coder-
Decoder. The codec refers to both ends of the process of
squeezing video down and expanding it on playback.
Compatible coders and decoders must be used and so they tend
to be paired up when they are delivered.

Coefficients The output of the DCT algorithm yields one DC coefficient,

which is the average value for the 8 8 macroblock, plus 63 AC

coefficients, which describe the frequency distribution of image-
intensity changes across the macroblock.

×

Complexity Complexity in video compression describes how the

compression process is carried out. This translates to how
easy it is to decode. If the decoding process is too complex,
the hardware needs to be more powerful. Complexity can be