Variable-length encoding and decoding apparatus

摘要

The present invention provides a variable-length encoding and decoding apparatus which, when an overlap of a variable-length code and a synchronizing word is generated on a bit stream due to a transmission error or the like in the variable-length encoding and decoding apparatus of an image compression bit stream, can exactly detect the synchronizing word and a state where the overlap is generated. The variable-length encoding and decoding apparatus has a synchronizing word detecting unit 119 which detects the synchronizing word of the bit stream in a first shift register 104, a synchronizing word position management unit 122 which sets a head bit position of the synchronizing word at the timing that the head of the synchronizing word which exists in the first shift register 104 is moved to the second shift register 109 and thereafter updates the same, a variable-length encoding and decoding unit 113 which performs decoding processing of the variable-length code of the second shift register 109 and simultaneously obtains the code length of the variable-length code, and an overlap detecting unit 115 which detects the overlap of the synchronizing word and the variable-length code by the code length of the variable-length code and the head bit position of the synchronizing word.