SECTION 3.3
83
Filters
The JBIG2 bit stream for this example is as follows:
97 4A
00 00
A5 38
FF AC
00 00
00 00
FF AC
42
03
B4
00
00
00
00
32 0D 0A 1A 0A 01 00 00 00 01 00 00 00 00 00 01 00 00 00 00 32
FF FD FF 02 FE FE FE 00 00 00 01 00 00 00 01 2A E2 25 AE A9 A5
D9 99 9C 5C 8E 56 EF 0F 87 27 F2 B5 3D 4E 37 EF 79 5C C5 50 6D
00 00 01 30 00 01 00 00 00 13 00 00 00 34 00 00 00 42 00 00 00
00 00 40 00 00 00 00 00 02 06 20 00 01 00 00 00 1E 00 00 00 34
42 00 00 00 00 00 00 00 00 02 00 10 00 00 00 02 31 DB 51 CE 51
00 00 03 31 00 01 00 00 00 00 00 00 00 04 33 01 00 00 00 00
This bit stream is made up of the following parts (in the order listed):
1. The JBIG2 file header
97 4A 42 32 0D 0A 1A 0A 01 00 00 00 01
Since the JBIG2 file header is not used in PDF, this header is not placed in the
JBIG2 stream object and is discarded.
2. The first JBIG2 segment (segment 0)—in this case, the symbol dictionary seg-
ment
00 00 00 00 00 01 00 00 00 00 32 00 00 03 FF FD FF 02 FE FE FE 00 00 00
01 00 00 00 01 2A E2 25 AE A9 A5 A5 38 B4 D9 99 9C 5C 8E 56 EF 0F 87
27 F2 B5 3D 4E 37 EF 79 5C C5 50 6D FF AC
This is a global segment (segment page association = 0) and so is placed in the
JBIG2Globals
stream.
3. The page information segment
00 00 00 01 30 00 01 00 00 00 13 00 00 00 34 00 00 00 42 00 00 00 00
00 00 00 00 40 00 00
and the immediate text region segment
00 00 00 02 06 20 00 01 00 00 00 1E 00 00 00 34 00 00 00 42 00 00 00
00 00 00 00 00 02 00 10 00 00 00 02 31 DB 51 CE 51 FF AC
These two segments constitute the contents of the JBIG2 page and are placed
in the PDF XObject representing this image.
4. The end-of-page segment
00 00 00 03 31 00 01 00 00 00 00
and the end-of-file segment
00 00 00 04 33 01 00 00 00 00
Since these segments are not used in PDF, they are discarded.