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ISO/IEC 10918-1 : 1993(E)
3.1.6
arithmetic decoder:
An embodiment of arithmetic decoding procedure.
3.1.7
arithmetic encoder:
An embodiment of arithmetic encoding procedure.
3.1.8
baseline (sequential):
A particular sequential DCT-based encoding and decoding process specified in this
Specification, and which is required for all DCT-based decoding processes.
3.1.9
binary decision:
Choice between two alternatives.
3.1.10
bit stream:
Partially encoded or decoded sequence of bits comprising an entropy-coded segment.
3.1.11
block:
An 8
8 array of samples or an 8
8 array of DCT coefficient values of one component.
3.1.12
block-row:
A sequence of eight contiguous component lines which are partitioned into 8
8 blocks.
3.1.13
byte:
A group of 8 bits.
3.1.14
byte stuffing:
A procedure in which either the Huffman coder or the arithmetic coder inserts a zero byte into
the entropy-coded segment following the generation of an encoded hexadecimal X'FF' byte.
3.1.15
carry bit:
A bit in the arithmetic encoder code register which is set if a carry-over in the code register overflows
the eight bits reserved for the output byte.
3.1.16
ceiling function:
The mathematical procedure in which the greatest integer value of a real number is obtained
by selecting the smallest integer value which is greater than or equal to the real number.
3.1.17
class (of coding process):
Lossy or lossless coding processes.
3.1.18
code register:
The arithmetic encoder register containing the least significant bits of the partially completed
entropy-coded segment. Alternatively, the arithmetic decoder register containing the most significant bits of a partially
decoded entropy-coded segment.
3.1.19
coder:
An embodiment of a coding process.
3.1.20
coding:
Encoding or decoding.
3.1.21
coding model:
A procedure used to convert input data into symbols to be coded.
3.1.22
(coding) process:
A general term for referring to an encoding process, a decoding process, or both.
3.1.23
colour image:
A continuous-tone image that has more than one component.
3.1.24
columns:
Samples per line in a component.
3.1.25
component:
One of the two-dimensional arrays which comprise an image.
3.1.26
compressed data:
Either compressed image data or table specification data or both.
3.1.27
compressed image data:
A coded representation of an image, as specified in this Specification.
3.1.28
compression:
Reduction in the number of bits used to represent source image data.
3.1.29
conditional exchange:
The interchange of MPS and LPS probability intervals whenever the size of the LPS
interval is greater than the size of the MPS interval (in arithmetic coding).
3.1.30
(conditional) probability estimate:
The probability value assigned to the LPS by the probability estimation
state machine (in arithmetic coding).
3.1.31
conditioning table:
The set of parameters which select one of the defined relationships between prior coding
decisions and the conditional probability estimates used in arithmetic coding.
3.1.32
context:
The set of previously coded binary decisions which is used to create the index to the probability
estimation state machine (in arithmetic coding).
3.1.33
continuous-tone image:
An image whose components have more than one bit per sample.
3.1.34
data unit:
An 8
8 block of samples of one component in DCT-based processes; a sample in lossless processes.
2
CCITT Rec. T.81 (1992 E)
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