background image
ISO/IEC 10918-1 : 1993(E)
The marker and parameters shown in Figure B.10 are defined below. The size and allowed values of each parameter are
given in Table B.8.
COM:
Comment marker Marks the beginning of a comment.
Lc:
Comment segment length Specifies the length of the comment segment shown in Figure B.10
(see B.1.1.4).
Cm
i
:
Comment byte The interpretation is left to the application.
Table B.8 Comment segment parameter sizes and values
Values
Parameter
Size (bits)
Sequential DCT
Progressive DCT
Lossless
Baseline
Extended
Lc
16
2-65 535
Cm
i
1
8
0-255
22
B.2.4.6
Application data syntax
Figure B.11 specifies the marker segment structure for an application data segment.
1
. . .
APP
n
Lp
Ap
Ap
Lp-2
TISO0930-93/d029
Application data segment
Figure B.11 Application data syntax
Figure B.11 [D29], = 2.8 cm = 98.%
The marker and parameters shown in Figure B.11 are defined below. The size and allowed values of each parameter are
given in Table B.9.
APP
n
:
Application data marker Marks the beginning of an application data segment.
Lp:
Application data segment length Specifies the length of the application data segment shown in
Figure B.11 (see B.1.1.4).
Ap
i
:
Application data byte The interpretation is left to the application.
The APP
n
(Application) segments are reserved for application use. Since these segments may be defined differently for
different applications, they should be removed when the data are exchanged between application environments.
Table B.9 Application data segment parameter sizes and values
Values
Parameter
Size (bits)
Sequential DCT
Progressive DCT
Lossless
Baseline
Extended
Lp
16
2-65 535
Ap
i
1
8
0-255
22
44
CCITT Rec. T.81 (1992 E)
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