Encoding device, decoding device, and data structure

Abstract

A video encoding device includes a side information determination section and a side information encoding section. The side information determination section sets a quantization parameter for each macroblock in such a manner that a difference between quantization parameters for each pair of macroblocks with successive encoding orders is equal to one of n difference values, and transforms the difference into one of n indices with respect to each pair. The side information encoding section generates a binary sequence having a length corresponding to the size of the absolute value of the index. The total of absolute values of the n indices is smaller than the total of absolute values of the n difference values.

1 . An encoding device for quantizing, in accordance with a value of a quantization parameter, an image in each of a plurality of unit regions constituting an input image to be encoded,
 the encoding device comprising:   setting means for setting a quantization parameter used in encoding each unit region, the setting means setting an quantization parameter for each unit region in such a manner that a difference between a quantization parameter for a unit region and a predetermined reference value is equal to one of n predetermined difference values;   transform means for transforming, with respect to each unit region, the difference between the quantization parameter for the unit region and the predetermined reference value into an integer in accordance with a transform rule by which the n difference values are transformed into n number of integers, respectively; and   binary sequence generation means for generating a binary sequence having a length corresponding to a size of an absolute value of the integer into which the difference is transformed by the transform means,   a total of absolute values of the n integers being smaller than a total of absolute values of the n difference values.   
     
     
         2 . The encoding device as set forth in  claim 1 , further comprising information generation means for generating information indicative of correspondences between the n difference values and the n integers, respectively,
 the information generated by the information generation means being outputted to outside as encoded data together with the binary sequence.   
     
     
         3 . The encoding device as set forth in  claim 2 , wherein the n difference values are obtained by multiplying the n integers with a predetermined value, and the information is the predetermined value. 
     
     
         4 . The encoding device as set forth in  claim 1 , wherein the transform means transforms one of the n difference values which one has i-th smallest absolute value into one of the n integers which one has i-th smallest absolute value, and the absolute value of the integer is smaller than the absolute value of the difference value. 
     
     
         5 . The encoding device as set forth in Claim  1 , further comprising calculation means for calculating a ratio of said each of the n difference values to a group consisting of the difference between the quantization parameter and the predetermined reference value in each unit region,
 the transform means transforming the difference value into the integer in such a manner that as the difference value has the larger ratio calculated by the calculation means, the integer has a smaller absolute value.   
     
     
         6 . The encoding device as set forth in  claim 1 , wherein
 the input image consists of a plurality of second unit regions, and each of the plurality of second unit regions consists of the plurality of unit regions,   the setting means sets a quantization parameter of a specific unit region predetermined for each of the plurality of second unit regions in such a manner that a difference in quantization parameter between a pair of the specific unit region and a unit region earlier in an order of encoding is capable of being a value other than the n difference values, and   the binary sequence generation means generates a binary sequence having a length corresponding to an absolute value of the difference in quantization parameter between the pair.   
     
     
         7 . A decoding device for decoding encoded data to set quantization parameters regarding unit regions constituting a decoded image,
 the decoding device comprising:   extraction means for extracting data of binary sequences regarding the unit regions from the encoded data;   integer generation means for generating integers corresponding to lengths of the binary sequences regarding the unit regions from the data of binary sequences extracted by the extraction means; and specifying means for specifying, according to information in which n integers are related to n difference values regarding quantization parameters, respectively, difference values for the unit regions based on integers for the unit regions that are generated by the integer generation means,   the quantization parameters for the unit regions being generated based on the difference values specified by the specifying means.   
     
     
         8 . The decoding device as set forth in  claim 7 , wherein
 the encoded data includes the information in which n integers are related to n difference values regarding quantization parameters, respectively, and   the extraction means extracts the information from the encoded data.   
     
     
         9 . The decoding device as set forth in  claim 8 , wherein
 The information extracted by the extraction means from the encoded data is a predetermined value, and   the specifying means specifies the difference values by multiplying the integers generated by the integer generation means with the predetermined value extracted by the extraction means.   
     
     
         10 . The decoding device as set forth in  claim 7 , wherein
 the decoded image consists of a plurality of second unit regions, and each of the second unit regions consists of the unit regions,   with respect to each of unit regions which are included in a plurality of unit regions constituting the decoded image as a whole and which are other than specific regions predetermined respectively for the second unit regions, the specifying means specifying a difference value for said each of unit regions from an integer for said each of unit regions according to the information, and   with respect to the specific unit regions, the specifying means specifies the integers generated by the integer generation means themselves as difference values.   
     
     
         11 . Encoded data outputted by an encoding device as set forth in  claim 2 , including the information in which n integers are related to n difference values regarding quantization parameters, respectively. 
     
     
         12 - 17 . (canceled) 
     
     
         18 . A decoding device for decoding encoded data to set quantization parameters regarding unit regions constituting a decoded image,
 the decoding device comprising:   selection means for selecting, in a predetermined order, a plurality of third unit regions constituting each of the unit regions constituting the decoded image;   reading means for reading, from the encoded data, a difference value of a quantization parameter for one of third unit regions to be inverse-quantized in each of the unit regions constituting the decoded image, said one of third unit regions being firstly selected by the selection means; and   specifying means for specifying a value of the quantization parameter to be referred to when a quantization image in each third unit region to be inverse-quantized in each of the unit regions constituting the decoded image, the specifying being made based on the difference value of the quantization parameter read out in said each of the unit regions by the reading means.   
     
     
         19 . The decoding device as set forth in  claim 18 , wherein the third unit region is a coding unit (CU) or a transform unit (TU). 
     
     
         20 . The decoding device as set forth in  claim 19 , wherein
 the third unit region is a CU,   the unit regions are LCUs, and   the decoding device further comprises determination means for determining, in accordance with a predetermined standard, whether a quantization image in each of the LCUs is to be inverse-quantized according to the value of the quantization parameter specified by the specifying means, or a quantization image in each of CUs constituting each of the LCUs is to be inverse-quantized according to the value of the quantization parameter of said each of CUs.   
     
     
         21 . The decoding device as set forth in  claim 18 , wherein
 the third unit region is a CU,   the encoding device further comprises judgment means for judging whether a prediction mode for a CU firstly selected by the selection means in each of a plurality of fourth unit regions constituting the unit region is an intra-prediction mode or not, and   the specifying means specifies a value of the quantization parameter to be referred to when a quantization image in each CU to be inverse-quantized in a fourth unit region for which the prediction mode is judged as an intra-prediction mode is quantized, the specifying being made based on a difference value of a quantization parameter of the CU firstly selected in the fourth unit region instead of the difference value of the quantization parameter read out by the reading means with respect to a unit region to which the fourth unit region belongs.   
     
     
         22 . The decoding device as set forth in  claim 18 , further comprising:
 judgment means for judging a slice type of each of a plurality of slices constituting the input image; and   unit region setting means for setting sizes of unit regions constituting each of the plurality of slices to sizes according to the slice type judged by the judgment means.   
     
     
         23 . The decoding device as set forth in  claim 18 , wherein
 the reading means reads out, instead of the difference value of the quantization parameter, an integer corresponding to the difference value from the encoded data,   the decoding device further comprises:   transform means for transforming the integer read out by the reading means with respect to each unit region into a corresponding difference value in accordance with a transform rule by which the difference value of the quantization parameter is related to the integer one by one so as to provide n sets of the difference value of the quantization parameter and the integer; and   the specifying means specifies a value of the quantization parameter to be referred to when inverse-quantizing a quantization image in each of the third unit regions to be inverse-quantized in each of the unit regions, the specifying being made based on the difference value of the quantization parameter obtained by the transform means transforming the integer read out by the reading means in the unit region, and   a total of absolute values of n number of the integer is smaller than a total of absolute values of n number of the difference value.