**ISO/IEC 10918-1 : 1993(E)**

**Table G.1 EOBn code run length extensions**

EOBn code

Run length

EOB0

1

EOB1

2,3

EOB2

4..7

EOB3

8..15

EOB4

16..31

EOB5

32..63

EOB6

64..127

EOB7

128..255

EOB8

256..511

EOB9

512..1 023

EOB10

1 024..2 047

EOB11

2 048..4 095

EOB12

4 096..8 191

EOB13

8 192..16 383

EOB14

16 384..32 767

The end-of-band run structure allows efficient coding of blocks which have only zero coefficients. An EOB run of length

5 means that the current block and the next four blocks have an end-of-band with no intervening non-zero coefficients.

The EOB run length is limited only by the restart interval.

The extension of the code table is illustrated in Figure G.2.

0

1

2

. . .

RRRR

SSSS

13

14

EOB0

EOB1

.

.

.

EOB14

ZRL

0

1

.

.

.

14

15

TISO1580-93/d096

COMPOSITE VALUES

**Figure G.2 Two-dimensional value array for Huffman coding**

Figure G.2 [D96] = 4.5 cm = 176 %

The EOBn code sequence is defined as follows. Each EOBn code is followed by an extension field similar to the

extension field for the coefficient amplitudes (but with positive numbers only). The number of bits appended to the EOBn

code is the minimum number required to specify the run length.

If an EOB run is greater than 32 767, it is coded as a sequence of EOB runs of length 32 767 followed by a final EOB run

sufficient to complete the run.

At the beginning of each restart interval the EOB run count, EOBRUN, is set to zero. At the end of each restart interval

any remaining EOB run is coded.

The Huffman encoding procedure for AC coefficients in spectral selection and in the first scan of successive

approximation is illustrated in Figures G.3, G.4, G.5, and G.6.

**122**

**CCITT Rec. T.81 (1992 E)**