Method and apparatus for encoding video by compensating for pixel value according to pixel groups, and method and apparatus for decoding video by the same
Provided are a method and apparatus of encoding a video by compensating for a pixel value and a method and apparatus of decoding a video by compensating for a pixel value. The method of encoding the video includes: encoding image data; decoding the encoded image data and generating a restored image by performing loop filtering on the decoded image data; determining a compensation value corresponding to errors between a predetermined group restored pixels in the restored image and corresponding original pixels, and a pixel group including a restored pixel to be compensated for by using the compensation value; and encoding the compensation value and transmitting the encoded compensation value and a bitstream of the encoded image data.
1. A video decoding method comprising:
obtaining information about pixel value compensation, from a bitstream;
when the information about pixel value compensation indicates a band type, obtaining information about an offset of a compensation value of a pixel band from the bitstream;
applying the information about an offset of compensation value of a predetermined band to one or more pixel included in the predetermined band among pixels of a current block; and
when the information about pixel value compensation indicates an edge type, obtaining information about an offset of a compensation value of a predetermined direction of an edge;
applying the information about an offset of a compensation value of the predetermined direction of an edge to a pixel among pixels in the predetermined direction of an edge among pixels of a current block,
wherein the band is one of bands generated by splitting total range of pixel values.
2. The method of claim 1 , wherein the applying information about an offset of a compensation value of a band comprises obtaining compensation values respectively assigned to a plurality of bands, determining a current band in which a current pixel of the current block is included, among the plurality of bands, and applying a compensation value of the current band among the obtained compensation values to a pixel value of the current pixel.
3. The method of claim 2 , wherein the applying information about an offset of a compensation value of a predetermined direction of an edge comprises obtaining compensation values respectively assigned to a plurality of directions of edges, determining a current edge direction which a current pixel of the current block forms, among the plurality of directions of edges, and applying a compensation value of the current direction of an edge among the obtained compensation values to a pixel value of the current direction of an edge.