DECODING METHOD AND DECODING APPARATUS

摘要

According to the present invention, an image coding apparatus provides a run-length encoding unit (RLE1) that subjects quantized coefficients which are obtained by quantizing frequency components of an image signal to a variable length coding process by using a run value (Run) that indicates the number of successive zero coefficients and a level value (Lev) that indicates a value of a non-zero coefficient following the zero coefficients. The run- length encoding unit (RLE1) includes a reordering unit (Lreodr) for reordering level values (Lev); a variable length coder (LVLC) for coding reordered level values (ROLev) by using a code table that is selected according to the value of a quantization parameter (QP); a reordering unit (Rreodr) for reordering run values (Run) from high frequency component of the quantized coefficients to low frequency component; and a variable length coder (RVLC) for coding reordered run values (RORun) by using a code table that is selected according to the number of already- processed run values. Accordingly, a variable length coding process for quantized coefficients is carried out at a higher coding efficiency, with redundant information included in the coefficients being effectively reduced.