Method and apparatus for encoding video, and method and apparatus for decoding video

Abstract

Disclosed are a video encoding method and apparatus and a video decoding method and apparatus. The method of encoding video includes: producing a first predicted coding unit of a current coding unit, which is to be encoded; determining whether the current coding unit comprises a portion located outside a boundary of a current picture; and producing a second predicted coding unit is produced by changing a value of pixels of the first predicted coding unit by using the pixels of the first predicted coding unit and neighboring pixels of the pixels when the current coding unit does not include a portion located outside a boundary of the current picture. Accordingly, a residual block that is the difference between the current encoding unit and the second predicted encoding unit, can be encoded, thereby improving video prediction efficiency.

What is claimed is: 
     
       1. A method of decoding video, the method comprising:
 extracting information regarding a prediction mode for a current decoding unit, which is to be decoded, from a received bitstream;   producing a first predicted decoding unit of the current decoding unit, based on the extracted information;   determining whether the current decoding unit includes a portion located outside a boundary of a current picture; and   producing a second predicted decoding unit by changing values of pixels of the first predicted decoding unit by using pixels of the first predicted decoding unit and neighboring pixels of the pixels when the current decoding unit does not include the portion located outside the boundary of the current picture, and skipping the producing the second predicted decoding unit when the current decoding unit includes the portion located outside the boundary of the current picture.   
     
     
       2. The method of  claim 1 , wherein the determining whether the current decoding unit includes the portion located outside the boundary of the current picture comprises obtaining index information indicating whether the producing the second predicted decoding unit is to be performed. 
     
     
       3. The method of  claim 2 , wherein:
 if the index information has a first predetermined value, the index information indicates that the producing the second predicted decoding unit is not to be performed; and   if the index information has a second predetermined value, the index information indicates that the producing the second predicted decoding unit is to be performed.   
     
     
       4. An apparatus for decoding video, the apparatus comprising:
 an entropy decoder which extracts information regarding a prediction mode for a current decoding unit, which is to be decoded, from a received bitstream;   a predictor which produces a first predicted decoding unit of the current decoding unit, based on the extracted information;   a determiner which determines whether the current decoding unit includes a portion located outside a boundary of a current picture; and   a post-processor which produces a second predicted decoding unit by changing values of pixels of the first predicted decoding unit by using the pixels of the first predicted decoding unit and neighboring pixels of the pixels when the current decoding unit does not include the portion located outside the boundary of the current picture, and which skips the producing the second predicted decoding unit when the current decoding unit includes the portion located outside the boundary of the current picture.   
     
     
       5. The apparatus of  claim 4 , wherein the determiner obtains index information indicating whether a process of producing the second predicted decoding unit is to be performed. 
     
     
       6. The apparatus of  claim 5 , wherein:
 if the index information has a first predetermined value, the index information indicates that the process of producing the second predicted decoding unit is not to be performed; and   if the index information has a second predetermined value, the index information indicates that the process of producing the second predicted decoding unit is to be performed.   
     
     
       7. A non-transitory computer readable recording medium having recorded thereon a program code for executing the method of  claim 1 . 
     
     
       8. A method of restoring an encoded block, the method executed by one or more processors, comprising:
 extracting, by the one or more processors, information regarding a prediction mode of a current block from a received bitstream;   determining, by the one or more processors, neighboring pixels of the current block used for intra prediction by using available neighboring pixels of the current block when the extracted information indicates the prediction mode of the current block is intra prediction;   producing, by the one or more processors, a first prediction value of the current block by calculating an average value of at least one of the neighboring pixels adjacent to the current block;   producing, by the one or more processors, a second prediction value of a first pixel located on a top border in the current block by using a weighted value of the first prediction value and a pixel value of one neighboring pixel adjacent to the first pixel and located on a same column with the first pixel;   producing, by the one or more processors, a second prediction value of a second pixel located on a left border in the current block by using a weighted value of the first prediction value and a pixel value of one neighboring pixel adjacent to the second pixel and located on a same row with the second pixel;   producing, by the one or more processors, a second prediction value of a third pixel located on a upper left corner in the current block by using a weighted value of the first prediction value, a pixel value of one neighboring pixel adjacent to the third pixel and located on a same column with the third pixel, and a pixel value of one neighboring pixel adjacent to the third pixel and located on a same row with the third pixel;   obtaining, by the one or more processors, residual of the first pixel, residual of the second pixel and residual of the third pixel included in the current block from the received bitstream;   restoring, by the one or more processors, the current block including a restored pixel value of the first pixel, a restored pixel value of the second pixel and a restored pixel value of the third pixel,   wherein the restored pixel value of the first pixel is obtained by adding the residual of the first pixel and the second prediction value of the first pixel, the restored pixel value of the second pixel is obtained by adding the residual of the second pixel and the second prediction value of the second pixel, and the restored pixel value of the third pixel is obtained by adding the residual of the third pixel and the second prediction value of the third pixel; and   outputting a restored current block including the restored pixel value of the first pixel, the restored pixel value of the second pixel, and the restored pixel value of the third pixel,   wherein,
 the image is split into a plurality of maximum coding units, according to information about a maximum size of a coding unit, 
 the maximum coding unit is hierarchically split into one or more coding units of depths according to a split information, 
 a coding unit of a current depth is one of rectangular data units split from a coding unit of an upper depth, 
 when the split information indicates a split for the current depth, the coding unit of the current depth is split into coding units of a lower depth, independently from neighboring coding units, 
 when the split information indicates a non-split of the current depth, at least one prediction unit is obtained from the coding unit of the current depth, and 
 the current block is a data unit obtained from the coding unit of the current depth.