1. A method of encoding or decoding a current video frame by successively encoding or decoding different blocks of pixels of the current video frame, the method comprising, for a current block: generating a predicted block as a prediction of the current block, from pixels of either: a partially reconstructed current frame comprising an assembly of one or more previous blocks that have been reconstructed as if, or as actually, decoded; or a reconstructed previous frame; creating a local structure of reconstructed pixels in a region of the partially reconstructed current frame where the current block, as reconstructed, is to be assembled, the reconstructed pixels of the local structure differing from the corresponding pixels of the predicted block; aligning the predicted block with the local structure to produce an aligned predicted block; and encoding or decoding the current block based on the aligned predicted block.