Binarization of dqp using separate absolute value and sign (savs) in cabac

Abstract

Video coding systems or apparatus utilizing context-based adaptive binary arithmetic coding (CABAC) during encoding and/or decoding, are configured according to the invention with an enhanced binarization of non-zero Delta-QP (dQP). During binarization the value of dQP and the sign are separately encoded using unary coding and then combined into a binary string which also contains the dQP non-zero flag. This invention capitalizes on the statistical symmetry of positive and negative values of dQP and results in saving bits and thus a higher coding efficiency.

1 . (canceled) 
     
     
         2 . An encoding apparatus, comprising:
 a quantization unit for setting a difference quantization parameter, wherein the difference quantization parameter is a difference between a quantization parameter of current CU (Coding Unit) and a predicted quantization parameter of current CU; and   an encoding unit for encoding positive and negative sign values of said difference quantization parameter and an absolute value of the difference quantization parameter set by said quantization unit, and generating a bit stream which uses said absolute value of the difference quantization parameter and said positive and negative sign values of the difference quantization parameter as a parameter.   
     
     
         3 . The encoding apparatus according to  claim 2 , wherein said encoding unit separates the difference quantization parameter set by said quantization unit to said absolute value of the difference quantization parameter and said positive and negative sign values of the difference quantization parameter. 
     
     
         4 . The encoding apparatus according to  claim 3 , wherein said encoding unit carries out binary arithmetic encoding for said absolute value of the difference quantization parameter and said positive and negative sign values of the difference quantization parameter. 
     
     
         5 . The encoding apparatus according to  claim 4 , wherein said quantization unit sets said difference quantization parameter for each CU which divides the maximum CU. 
     
     
         6 . The encoding apparatus according to  claim 1 , wherein said encoding unit sets a parameter of said bit stream in the order of said absolute value of the difference quantization parameter and said positive and negative sign values of the difference quantization parameter. 
     
     
         7 . The encoding apparatus according to  claim 3 , wherein said encoding unit, when said difference quantization parameter is nonzero, encodes said absolute value of the difference quantization parameter and said positive and negative sign values of the difference quantization parameter. 
     
     
         8 . The encoding apparatus according to  claim 7 , further comprising a determination unit for determining whether said difference quantization parameter is nonzero. 
     
     
         9 . The encoding apparatus according to  claim 8 , wherein said determination unit determines whether said difference quantization parameter is nonzero, using a value indicating whether said difference quantization parameter is nonzero. 
     
     
         10 . An method for encoding, comprising:
 a quantization step for setting a difference quantization parameter, wherein the difference quantization parameter is a difference between a quantization parameter of current CU (Coding Unit) and a predicted quantization parameter of current CU; and   an encoding step for encoding positive and negative sign values of said difference quantization parameter and an absolute value of the difference quantization parameter set by said quantization step, and generating a bit stream which uses said absolute value of the difference quantization parameter and said positive and negative sign values of the difference quantization parameter as a parameter.   
     
     
         11 . The method for encoding according to  claim 10 , wherein said encoding step separates said difference quantization parameter set by said quantization step to said absolute value of the difference quantization parameter and said positive and negative sign values of the difference quantization parameter. 
     
     
         12 . The method for encoding according to  claim 11 , wherein said encoding unit carries out binary arithmetic encoding for said absolute value of the difference quantization parameter and said positive and negative sign values of the difference quantization parameter. 
     
     
         13 . The method for encoding according to  claim 12 , wherein said quantization step sets said difference quantization parameter for each CU which divides the maximum CU. 
     
     
         14 . The method for encoding according to  claim 10 , wherein said encoding step sets a parameter of said bit stream in the order of said absolute value of the difference quantization parameter and said positive and negative sign values of the difference quantization parameter. 
     
     
         15 . The method for encoding according to  claim 11 , wherein said encoding step, when said difference quantization parameter is nonzero, encodes said absolute value of the difference quantization parameter and said positive and negative sign values of the difference quantization parameter. 
     
     
         16 . The method for encoding according to  claim 15 , further comprising a determination step for determining whether said difference quantization parameter is nonzero. 
     
     
         17 . The method for encoding according to  claim 16 , wherein said determination step determines whether said difference quantization parameter is nonzero, using a value indicating whether said difference quantization parameter is nonzero.