METHOD AND SYSTEM FOR DECODING VARIABLE LENGTH CODE DECODED IN TWO-WAY

摘要

PROBLEM TO BE SOLVED: To obtain a method and a system for decoding a variable length code that can be decoded in two-way where decoding is efficiently processed in both of forward and backward directions regardless of a simple configuration without increasing the processing time. SOLUTION: Among run information DRN, level information DLV, and last information DST obtained by decoding a variable length code, a delay circuit 32 of a forward direction processing section 30 delays the last information DST that is valid of its output at the forward decoding by one code, and a delay circuit 42 of a backward direction processing section 40 delays the run information DRN that is valid of its output at the backward decoding by one code respectively. The last information DST is detected at a head of each block in any of the decoding, and the run information DRN is processed as number of zero coefficients inserted between the sets of the level information DLV processed just before, and then detection of a block border and decoding of unit information into a coefficient string can be realized with similar control.