Image decoding method which obtains a predicted value of a coding unit by weighted average of predicted values
A video encoding method and apparatus and a video decoding method and apparatus. In the video encoding method, a first predicted coding unit of a current coding unit that is to be encoded is produced, a second predicted coding unit is produced by changing a value of each pixel of the first predicted coding unit by using each pixel of the first predicted coding unit and at least one neighboring pixel of each pixel, and the difference between the current coding unit and the second predicted coding unit is encoded, thereby improving video prediction efficiency.
1. A method of decoding a video image, the method comprising:
determining coding units of a hierarchical structure by using information about whether to divide a coding unit parsed from a received bitstream;
obtaining a first predicted value of a current coding unit, among the determined coding units, by using neighboring pixels of the current coding unit;
obtaining a second predicted value of each of pixels of the current coding unit located on a top border and a left border of the current coding unit by using at least one neighboring pixel adjacent to each of the pixels located on the top border and the left border of the current coding unit; and
obtaining a final predicted value of the current coding unit by using the obtained first predicted value and the obtained second predicted value,
wherein the final predicted value of the current coding unit is obtained by using a weighted average of the obtained first predicted value and the obtained second predicted value with weights depending on size of the coding unit to be predicted.
2. The method of claim 1 , wherein the second predicted value of a pixel located on a top-left of the current coding unit is obtained by using both a first pixel, which is located at a same column as the pixel located on the top-left of the current coding unit and included in a border of a coding unit adjacent to the top border of the current coding unit, and a second pixel, which is located at a same row as the pixel located on the top-left of the current coding unit and included in a border of a coding unit adjacent to the left border of the current coding unit.
3. The method of claim 1 , wherein the second predicted value of a pixel located on the top border of the current coding unit is obtained by using a third pixel, which is located at a same column as the pixel located on the top border of the current coding unit and included in a border of a coding unit adjacent to the top border of the current coding unit.
4. The method of claim 1 , wherein a value of the second predicted value of a pixel located on the left border of the current coding unit is obtained by using a fourth pixel, which is located at a same row as the pixel located on the left border of the current coding unit and included in a border of a coding unit adjacent to the left border of the current coding unit.