JEITA CP-3451
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C. Huffman table definition (DHT: Define Huffman Table)
DHT is a marker code defining a Huffman table.
In this standard a single component shall have a Huffman table consisting of a set of DC and AC, and each
component shall be mapped to one or another of the Huffman tables defined by DHT. All Huffman tables shall be
recorded in one DHT marker segment; recording of multiple DHT markers is not allowed. A Huffman table may
have any values, or the JPEG reference values may be used as the base table (see Figure 20).
DQT, DHT, DRI and SOF may line up in any order, but shall be recorded after APP1 (or APP2 if any) and before
SOS.
Address Offset
Code
Meaning
(Hex)
(Hex)
+00
FF
Marker Prefix
+01
C4
DHT
+02
01
Length of field
A2
2+(1+16+12+1+16+162)*2
= 418 Bytes
+04
00
Table number Y-DC : 00
+05
:
:
:
DHT parameter
+21
10
Table number Y-AC : 10
+22
:
:
:
DHT parameter
+D4
01
Table number C-DC : 01
+D5
:
:
:
DHT parameter
+F1
11
Table number C-AC : 11
+F2
:
:
:
DHT parameter
Figure 20 DHT Structure