1. A method for deriving a set of enabled coding modes relative to the encoding of an image or image portion which forms part of an image sequence, the method comprising: obtaining statistics related to enabled coding modes of one or more previously encoded images of the sequence; analyzing the statistics and deducing from the analyzed statistics one or more coding modes to be enabled for the current image or image portion; and enabling, for the current image or image portion, the one or more coding modes to be enabled.