Image coding method and apparatus using spatial predictive coding of chrominance and image decoding method apparatus
A coding method including dividing pixels of a chrominance component of an input image into blocks having a predetermined size; selecting one among a direct current prediction method, a vertical prediction method, a horizontal prediction method, and a hybrid prediction method according to a user's input; generating a prediction value of each pixel in a current block to be predictively coded, using at least one pixel value among pixel values in an upper reference block adjacent to the current block and in a side reference block adjacent to the current block, according to the selected prediction method; generating a differential value between the prediction value and a corresponding real pixel value in the current block; and coding the differential value and information on the selected prediction method using a predetermined coding method.
1. A method of processing a color component in a video, the method comprising:
obtaining a residual value of the color component by performing entropy decoding on a bitstream to generate quantized values from the bitstream, performing dequantization on the quantized values to generate transform coefficients and performing inverse transformation on the transform coefficients;
checking information related to intra prediction from the decoded bitstream, for a current prediction block of the color component;
generating, performed by using at least one processor, a prediction value for the current prediction block of the color component, by performing the intra prediction on the current prediction block in response to checking of the information related to the intra prediction from the decoded bitstream; and
reconstructing the current prediction block of the color component by using the prediction value and the residual value,
wherein the generating the prediction value for the current prediction block of the color component comprises performing the intra prediction,
based on an intra prediction mode determined from a neighboring block of the current prediction block of the color component, the neighboring block being located on at least one of a left side of the current prediction block of the color component or an upper side of the current prediction block of the color component, or
based on an intra prediction mode from among a plurality of intra prediction modes as indicated by the information related to the intra prediction from the decoded bitstream,
the plurality of intra prediction modes include a direct current (DC) prediction mode, a vertical prediction mode and a horizontal prediction mode.