Abstract
A method of selecting a number of candidate prediction modes for a block in a video sequence, the method comprising calculating a cost value of each of prediction modes for each of a predetermined number of blocks, identifying one of the prediction modes having the smallest cost value for the each block, calculating a function value of each of the prediction modes for the each block using a cost function, ranking the prediction modes for the each block by the function value of each of the prediction modes and identifying an ordinal value of the one prediction mode having the smallest cost value, the ordinal value being related to the ordinal number of the one prediction mode after the ranking, calculating a feature value of the each block based on the function value of each of the prediction modes related to the each block, identifying a plurality of sets of blocks, each set of blocks having substantially the same feature value, identifying the number of each set of blocks and calculating a sum of the ordinal value of the one prediction mode for the each block in the each set of blocks, calculating an average value of the sum over the number of the each set of blocks for each set of the plurality sets of blocks, and determining a relation between the average values and the feature values for the predetermined number of blocks.