Method and apparatus for selecting intra prediction mode

Abstract

A method for selecting intra prediction mode includes: calculating an error value for each of the prediction modes in a first group, wherein the first group includes two prediction modes where an included angle between their prediction directions is the largest; calculating an error value for each of the prediction modes in a second group, wherein the prediction modes in the second group refer to the prediction modes with prediction directions near the two sides of the prediction direction of the prediction mode with smaller error value in the first group; calculating an error value for the prediction mode in a third group, wherein the prediction mode in the third group is the prediction mode with prediction direction adjacent to the prediction direction of the prediction mode with smaller error value in the second group; calculating a DC prediction mode in the plurality of prediction modes; and among the prediction modes with calculated error values, selecting a prediction mode with a smallest error value to be the intra prediction mode for encoding the subblock.