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

In Figure G.3, Ss is the start of spectral selection, Se is the end of spectral selection, K is the index into the list of

coefficients stored in the zig-zag sequence ZZ, R is the run length of zero coefficients, and EOBRUN is the run length of

EOBs. EOBRUN is set to zero at the start of each restart interval.

If the scan header parameter Al (successive approximation bit position low) is not zero, the DCT coefficient values ZZ(K)

in Figure G.3 and figures which follow in this annex, including those in the arithmetic coding section, shall be replaced

by the point transformed values ZZ'(K), where ZZ'(K) is defined by:

ZZ'(K) =

ZZ(K)x

2

*Al*

EOBSIZE is a procedure which returns the size of the EOB extension field given the EOB run length as input. CSIZE is a

procedure which maps an AC coefficient to the SSSS value defined in the subclauses on sequential encoding (see F.1.1

and F.1.3).

TISO1600-93/d098

Encode_EOBRUN

EOBRUN = 0

?

Yes

No

SSSS = EOBSIZE(EOBRUN)

I = SSSS × 16

Append EHUFSI(I)

bits of EHUFCO(I)

Append SSSS low order

bits of EOBRUN

EOBRUN = 0

Done

**Figure G.4 Progressive encoding of a non-zero AC coefficient**

Figure G.4 [98] = 11 cm = 430 %

TISO1610-93/d099

Encode_ZRL

Append EHUFSI(X'F0')

bits of EHUFCO(X'F0')

R = R 16

Done

**Figure G.5 Encoding of the run of zero coefficients**

**124**

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