1. In a computer system, a computer-implemented method of processing blocks of pixels in a video frame of a video sequence, the method comprising: for a current block of plural pixels in the video frame of the video sequence, identifying plural context pixels in the video frame, wherein the plural context pixels form at least part of a causal neighborhood for the current block; computing a spatial extrapolation for pixel values of the plural pixels of the current block based at least in part upon pixel values of the plural context pixels, wherein the spatial extrapolation comprises one or more pixel value extrapolations from one or more of the plural context pixels into the current block to thereby spatially predict the pixel values of the plural pixels of the current block.