ISO/IEC 10918-1 : 1993(E)
E.1.2
Control procedure for encoding a frame
In all cases where markers are appended to the compressed data, optional X'FF' fill bytes may precede the marker.
The control procedure for encoding a frame is oriented around the scans in the frame. The frame header is first appended,
and then the scans are coded. Table specifications and other marker segments may precede the SOF
n
marker, as indicated
by [tables/miscellaneous] in Figure E.2.
Figure E.2 shows the encoding process frame control procedure.
TISO1240-93/d062
Encode_frame
Encode_scan
Yes
No
Done
[Append DNL
segment]
Yes
No
[Append tables/miscellaneous]
Append SOF marker and rest
of frame header
First scan
?
More scans
?
Figure E.2 Control procedure for encoding a frame
n
Figure E.2 [D62], = 14 cm = 547.%
E.1.3
Control procedure for encoding a scan
A scan consists of a single pass through the data of each component in the scan. Table specifications and other marker
segments may precede the SOS marker. If more than one component is coded in the scan, the data are interleaved. If
restart is enabled, the data are segmented into restart intervals. If restart is enabled, a RST
m
marker is placed in the coded
data between restart intervals. If restart is disabled, the control procedure is the same, except that the entire scan contains a
single restart interval. The compressed image data generated by a scan is always followed by a marker, either the EOI
marker or the marker of the next marker segment.
78
CCITT Rec. T.81 (1992 E)