Variable length code decoding apparatus

Claim 1

A variable length code decoding apparatus having an interface means for parallelly extracting an objective bit stream from input bit streams which includes variable length codewords and a table-lookup memory means, which is connected to the interface means, for decoding the objective bit stream and outputting a decoded symbol and word length information which indicates the length of decoded codeword corresponding to the decoded symbol, wherein said interface means comprises: a first latch means for receiving and holding a first 2 n -bit input bit stream; a second latch means for receiving and holding the first 2 n -bit input bit stream held in the first latch means when a second 2 n -bit input bit stream is fed to the first latch means; a plurality of window registers, hardwiredly coupled to the first and the second latch means and the table-lookup memory means, for receiving and holding the first and the second 2 n -bit input bit streams outputted from the first and the second latch means, each of the window registers having 2 n -bit storage locations for storing a 2 n -bit bit stream shifted by 1 bit from that stored in adjacent window register; and a control means responsive to word length information outputted from the table-lookup memory means for producing a window selection signal to directly select a window register holding a 2 n -bit stream correctly shifted according to the word length information so as to extract the objective bit stream.