Method of determining binary codewords for transform coefficients

Abstract

A system is provided for creating level parameter updating codewords for transform coefficients used for relating transform units (TUs) that divide up coding units (CUs) in a High Efficiency Video Coding (HEVC) system. The system provides binarization of the codewords and removes unnecessary operations to reduce system complexity and increase compression performance. The system generates transform coefficients that relate the TUs and begins by providing a parameter variable (cRiceParam) set to an initial value of zero. The parameter variable is then converted into a binary codeword based on the current value of the parameter variable and the value of a symbol and then updated with a new current value after each symbol has been converted. Updating can be provided with reference to table values or the values can be provided from combination logic.

What is claimed: 
     
       1. A method of determining binary codewords for transform coefficients, comprising:
 providing a transform unit comprising one or more subsets of the transform coefficients, each of the transform coefficients having a quantized value; 
 determining a symbol for each of the transform coefficients that have a quantized value equal to or greater than a threshold value, by subtracting said threshold value from the quantized value of said transform coefficient; 
 providing a parameter variable set to an initial value of zero; 
 converting the symbols into a binary codeword based on a current value of said parameter variable and a value of said symbol; and 
 updating the value of said parameter variable with a new current value for each of the symbols after each symbols has been converted by mathematically incrementing the last value of said parameter variable when the last value of said parameter variable and the value of the last converted symbol together satisfy one or more conditions including a conditional symbol threshold and a conditional parameter threshold and wherein one of said one or more conditions is satisfied when the value of the last converted symbol is greater than or equal to said conditional symbol threshold for that condition and the last value of said parameter variable is less than or equal to said conditional parameter threshold for that condition. 
 
     
     
       2. The method of  claim 1 , wherein said converting comprises looking up said binary codeword from a table based on the value of the said symbol and said updated value of said parameter variable. 
     
     
       3. The method of  claim 1 , wherein said threshold value is three. 
     
     
       4. The method of  claim 1 , wherein updating said parameter variable comprises:
 looking up said new value from a table based on: (1) the last value of said parameter variable, and (2) the value of the last converted symbol. 
 
     
     
       5. The method of  claim 1 , wherein said conditional symbol threshold is different for each of said one or more conditions. 
     
     
       6. The method of  claim 1 , wherein the value of said parameter variable is configured to be zero, one, two, or three. 
     
     
       7. The method of  claim 1 , wherein the value of said parameter variable is configured to be zero, one, two, or any integer between two and a designated upper limit value. 
     
     
       8. The method of  claim 1 , wherein the transform coefficients are provided within a transform unit (TU) that provides a subdivision of a coding unit (CU) in a High Efficiency Video Coding (HEVC) signal. 
     
     
       9. The method of  claim 1 , wherein the transform coefficients are provided within a subset of a transform unit (TU) that provides a subdivision of a coding unit (CU) in a High Efficiency Video Coding (HEVC) signal. 
     
     
       10. The method of  claim 1 , wherein mathematically incrementing the last value comprises mathematically adding an integer of one to the last value of said parameter variable for each of said one or more conditions that are satisfied. 
     
     
       11. A method of determining binary codewords for transform coefficients, comprising:
 providing a transform unit comprising one or more subsets of the transform coefficients, of the each transform coefficients having a quantized value; 
 determining a symbol for each of the transform coefficients that have a quantized value equal to or greater than a threshold value, by subtracting said threshold value from the quantized value of said transform coefficient; 
 providing a parameter variable set to an initial value of zero; 
 converting the symbols into a binary codeword based on a current value of said parameter variable and a value of said symbol; 
 looking up a new current value from a table based on the last value of said parameter variable and the value of the last converted symbol; and 
 replacing the value of said parameter variable with said new current value, said new current value being a value resulting from incrementing the last value of said parameter variable when the last value of said parameter variable and the value of the last converted symbol together satisfy one or more conditions including a conditional symbol threshold and a conditional parameter threshold and wherein one of said one or more conditions is satisfied when the value of the last converted symbol is greater than or equal to said conditional symbol threshold for that condition and the last value of said parameter variable is less than or equal to said conditional parameter threshold for that condition. 
 
     
     
       12. The method of  claim 11 , wherein incrementing the last value comprises adding an integer of one to the last value of said parameter variable for each of said one or more conditions that are satisfied. 
     
     
       13. A method of determining binary codewords for transform coefficients, comprising:
 providing a transform unit comprising one or more subsets of transform coefficients, each transform coefficient having a quantized value; 
 determining a symbol for each transform coefficient having a quantized value equal to or greater than a threshold value, by subtracting said threshold value from the quantized value of said transform coefficient; 
 providing a parameter variable set to an initial value of zero; 
 converting each symbol into a binary codeword based on the current value of said parameter variable and the value of said symbol; and 
 determining whether the last value of said parameter variable and the value of the last converted symbol together satisfy one or more conditions, wherein each of said one or more conditions comprises a conditional symbol threshold and a conditional parameter threshold; and 
 mathematically adding an integer of one to the last value of said parameter variable for each of said one or more conditions that are satisfied; 
 wherein one of said one or more conditions is satisfied when the value of the last converted symbol is greater than or equal to a conditional symbol threshold for that condition and the last value of said parameter variable is less than or equal to a conditional parameter threshold for that condition. 
 
     
     
       14. The method of  claim 13 , wherein said conditional symbol threshold is different for each of said one or more conditions. 
     
     
       15. The method of  claim 13 , wherein the value of said parameter variable is configured to be zero, one, two, or three. 
     
     
       16. The method of  claim 13 , wherein the value of said parameter variable is configured to be zero, one, two, or any integer between two and a designated upper limit value.