1. A method of selecting, for each of a series of blocks of pixels in a first image accessible from at least one computer device, a respective similar block of pixels in a second image, the method comprising: for a block of pixels of said series of blocks in the first image, determining a respective value of a cost function for each of a plurality of candidate locations in the second image, the determining the respective value comprising: determining a similarity measure between the current block of pixels in the first image and a candidate block of pixels at a candidate locations of the plurality of candidate locations in the second image; and determining a function of a candidate motion vector corresponding to the candidate location, a predicted motion vector associated with the current block, and a future predicted motion vector of at least one block of the first image which is later in the series of blocks in the first image than the current block; and selecting a block of pixels at the candidate location as the respective similar block of pixels in the second image including comparing the plurality of candidate locations in the second image based on the respective value of the cost function for each of the plurality of candidate locations in the second image.