System and method for decoding signal and method of generating lookup table for using in signal decoding

Abstract

A signal decoding system performs variable length decoding and inverse quantization at high speed. From a bit stream temporarily held in a bit string buffer, the bit string is parsed as a table address for a lookup table in a table looking-up unit and a table selecting unit. By looking up the table address in the lookup table, variable length decoding is performed simultaneously for a maximum of two codewords. Furthermore, the decoded data is inversely quantized in parallel by using inverse quantizers. The results of inverse quantization are stored at appropriate positions in the block by the block storage unit.

What is claimed is:  
     
         1 . A signal decoding system comprising: 
 a decoder which performs a variable length decoding process simultaneously for multiple codewords of a variable length code; and    inverse quantization means for inversely quantizing in parallel the multiple decoded codewords received from said decoder.    
     
     
         2 . A signal decoding system as set forth in  claim 1 , wherein said decoder comprises a plurality of lookup tables showing correspondence between codeword data and decoded data, and table lookup means for selectively looking-up data in said lookup tables.  
     
     
         3 . A signal decoding system as set forth in  claim 2 , wherein said data looked-up in said lookup tables includes run and level data for each codeword, and said inverse quantization means inversely quantizes only said level data in parallel.  
     
     
         4 . A signal decoding system as set forth in  claim 1 , wherein said inverse quantization means includes multiple inverse quantizers for performing in parallel inverse quantization for decoded data.  
     
     
         5 . A signal decoding system as set forth in  claim 1 , wherein said variable length code represents a moving picture.  
     
     
         6 . A signal decoding system as set forth in  claim 1 , wherein the maximum number of codewords in said multiple codewords is two.  
     
     
         7 . A signal decoding system as set forth in  claim 1 , wherein said decoder performs said variable length decoding process to yield a set of run and level data for each codeword, and said inverse quantization means inversely quantizes said level data in parallel.  
     
     
         8 . A signal decoding method comprising the steps of: 
 simultaneously decoding multiple codewords of a variable length code; and    inversely quantizing in parallel the decoded multiple codewords.    
     
     
         9 . A signal decoding method as set forth in  claim 8 , wherein said variable length code represents a moving picture.  
     
     
         10 . A signal decoding method as set forth in  claim 8 , wherein the maximum number of codewords in said multiple codewords is two.  
     
     
         11 . A signal decoding method as set forth in  claim 8 , wherein the decoding step is performed using a plurality of lookup tables showing correspondence between codeword data and decoded data.  
     
     
         12 . A signal decoding method as set forth in  claim 8 , wherein said step of simultaneously decoding multiple codewords yields a set of run and level data for each codeword, and said step of inversely quantizing in parallel is performed only on said level data.