1. A system comprising: an analyzer that analyzes a current image area in an input video to select a transform; a selectable residue transformer, controlled by the analyzer, to perform the selectable transform on a residue image generated from the current image area and a predicted current image area, to generate a transformed residue image; and an encoder that encodes the transformed residue image to generate output data, wherein the analyzer controls the encoder to encode information to identify the selectable transform and to indicate that the selectable transform for the current image area overrides a transform predicted from a previous image area of the input video.