公开(公告)号：JP2002271208A

公开(公告)日：2002-09-20

申请号：JP2001375518

申请日：2001-12-10

Applicant: IBM

Inventor： MITCHELL JOAN L ,  CAZES ALBERT N ,  LEEDER NEIL M

IPC: H04N7/30 ,  G06T9/00 ,  H03M7/40 ,  H03M7/42 ,  H04N1/419

Abstract: PROBLEM TO BE SOLVED: To provide a Huffman encoding and decoding method which can be realized in a short time, using reduced processing resources and hardware. SOLUTION: Huffman encoding performed from an especially packed data format can be simplified by using two different table formats depending on the code length. In this way, a Huffman table can be also reduced in size. In performing the Huffman decoding method, the performing time can be reduced, by testing for the length of valid Huffman codes in a compressed data stream and using an offset corresponding to testing criteria. Thus, a particular test result for forming direct index into Huffman table symbol values can be obtained, while reducing the size of a reference table used for such a purpose.