JEITA CP-3451
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D. Restart Interoperability definition (DRI: Define Restart Interoperability)
DRI is a marker defining the Interoperability at which restart markers are inserted (see Figure 21). The recording of
DRI and insertion of restart markers are optional. If restart markers are inserted, DRI shall be recorded and its
values shall be 4 MCU (Minimum Coding Unit), i.e., 64 pixel units, regardless of whether 4:2:2 or 4:2:0 is used for
color sampling (see Annex F). Only one DRI shall be recorded.
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
+00
DD
DRI
+02
00
Length of field
2+2 = 4 (Bytes)
+04
XX
00
YY
04
Figure 21 DRI Structure