Coding Unit Quantization Parameters in Video Coding

Abstract

A method is provided that includes receiving a coded largest coding unit in a video decoder, wherein the coded largest coding unit includes a coded coding unit structure and a plurality of coded quantization parameters, and decoding the coded largest coding unit based on the coded coding unit structure and the plurality of coded quantization parameters.

1 . A method comprising:
 receiving a coded largest coding unit in a video decoder, wherein the coded largest coding unit comprises a coded coding unit structure and a plurality of coded quantization parameters; and   decoding the coded largest coding unit based on the coded coding unit structure and the plurality of coded quantization parameters.   
     
     
         2 . The method of  claim 1 , wherein the coded largest coding unit comprises a plurality of coding units as indicated by the coded coding unit structure, wherein at least a first coding unit and a second coding unit are different sizes. 
     
     
         3 . The method of  claim 1 , wherein decoding the coded largest coding unit further comprises:
 receiving, at least one of a sequence level, a picture level, a slice level, and a largest coding unit level, a minimum quantization parameter coding unit size; and   decoding the coded largest coding unit based on the minimum quantization parameter coding unit size.   
     
     
         4 . The method of  claim 1 , wherein decoding the coded largest coding unit further comprises reconstructing a quantization parameter for a coding unit in the coded largest coding unit by adding a coded quantization parameter corresponding to the coding unit and a reconstructed quantization parameter for a coding unit preceding the coding unit in a coding order. 
     
     
         5 . The method of  claim 1 , wherein decoding the coded largest coding unit further comprises reconstructing a quantization parameter for a coding unit in the coded largest coding unit by adding a coded quantization parameter corresponding to the coding unit and a reconstructed quantization parameter for a left spatially neighboring coding unit of the coding unit. 
     
     
         6 . The method of  claim 1 , wherein decoding the coded largest coding unit further comprises reconstructing a quantization parameter for a coding unit in the coded largest coding unit by adding a coded quantization parameter corresponding to the coding unit and a function of one or more reconstructed quantization parameters of spatially neighboring coding units of the coding unit. 
     
     
         7 . The method of  claim 1 , further comprising:
 receiving a coded indicator of a first mode used to compute a first coded quantization parameter;   reconstructing the first coded quantization parameter according to the first mode;   receiving a coded indicator of a second mode used to compute a second coded quantization parameter; and   reconstructing the second coded quantization parameter according to the second mode.   
     
     
         8 . A method comprising:
 receiving a largest coding unit in a video encoder;   determining a coding unit structure comprising a plurality of coding units for the largest coding unit;   computing a plurality of quantization parameters for the largest coding unit, wherein there is a one-to-one correspondence between each quantization parameter and a coding unit in the coding unit structure;   coding coding units in the plurality of coding units based on the corresponding quantization parameters to generate a portion of a compressed bit stream; and   coding the coding unit structure and the plurality of quantization parameters in the compressed bit stream.   
     
     
         9 . The method of  claim 8 , wherein at least a first coding unit and a second coding unit are different sizes. 
     
     
         10 . The method of  claim 8 , wherein determining a coding unit structure further comprises:
 determining the coding unit structure based on a minimum quantization parameter coding unit size, wherein the minimum quantization parameter coding unit size is larger than a smallest coding unit size allowed in the coding unit structure.   
     
     
         11 . The method of  claim 10 , further comprising signaling the minimum quantization parameter coding unit size in the compressed bit stream at least one of a sequence level, a picture level, a slice level, and a largest coding unit level. 
     
     
         12 . The method of  claim 8 , wherein a quantization parameter is coded as a difference between a quantization parameter for a coding unit in the largest coding unit and a quantization parameter for a coding unit preceding the coding unit in a coding order. 
     
     
         13 . The method of  claim 8 , wherein a quantization parameter is coded as a difference between a quantization parameter for a coding unit in the largest coding unit and a quantization parameter for a left spatially neighboring coding unit of the coding unit. 
     
     
         14 . The method of  claim 8 , wherein a quantization parameter is coded as a difference between a quantization parameter for a coding unit in the largest coding unit and a function of one or more quantization parameters of spatially neighboring coding units of the coding unit. 
     
     
         15 . The method of  claim 8 , further comprising:
 selecting a mode for coding quantization parameters from a plurality of modes for coding quantization parameters; and   signaling the selected mode in the compressed bit stream at least one of a sequence level, a picture level, a slice level, and a largest coding unit level.   
     
     
         16 . A digital system comprising a video decoder configured to:
 receive a coded largest coding unit, wherein the coded largest coding unit comprises a coded coding unit structure and a plurality of coded quantization parameters; and   decode the coded largest coding unit based on the coded coding unit structure and the plurality of coded quantization parameters.   
     
     
         17 . The digital system of  claim 16 , wherein the coded largest coding unit comprises a plurality of coding units as indicated by the coded coding unit structure, wherein at least a first coding unit and a second coding unit are different sizes. 
     
     
         18 . The digital system of  claim 16 , wherein the video decoder is further configured to:
 receive, at least one of a sequence level, a picture level, a slice level, and a largest coding unit level, a minimum quantization parameter coding unit size; and   decode the largest coding unit based on the minimum quantization parameter coding unit size.   
     
     
         19 . The digital system of  claim 16 , wherein the video decoder is further configured to decode the coded largest coding unit by reconstructing a quantization parameter for a coding unit in the coded largest coding unit by adding a coded quantization parameter corresponding to the coding unit and one selected from a group consisting of a reconstructed quantization parameter for a coding unit preceding the coding unit in a coding order, a reconstructed quantization parameter for a left spatially neighboring coding unit of the coding unit, and a function of one or more reconstructed quantization parameters of spatially neighboring coding units of the coding unit. 
     
     
         20 . The digital system of  claim 16 , wherein the video decoder is further configured to:
 receive a coded indicator of a first mode used to code a first coded quantization parameter;   reconstruct the first coded quantization parameter according to the first mode;   receive a coded indicator of a second mode used to code a second coded quantization parameter; and   reconstruct the second coded quantization parameter according to the second mode.