Patent ID: 8693546

Claim:
A video decoding method comprising the steps of: performing a variable length decoding process on a coded stream including: acquiring motion vectors of decoded blocks located near a block to be decoded, selecting one of multiple variable length code tables on the basis of a distribution of the motion vectors of the decoded blocks and added data included in the coded stream which indicates a result of selecting candidate values, and where the selection of the one of the multiple variable length code tables is changed on the basis of the added data, and decoding a differential motion vector using the selected variable length code table; calculating a predictive motion vector; calculating a motion vector by summing the predictive motion vector calculated in the predictive motion vector calculating step and a differential motion vector decoded from the coded stream; and performing an inter-prediction process using the motion vector calculated in the motion vector calculating step, wherein, in the predictive motion vector calculating step, a method for calculating the predictive motion vector is switched among methods for calculating the predictive motion vector based on a kind and a number of candidate values which are components of the motion vectors of the group of decoded blocks located near the block to be decoded.