A method of encoding a digital image signal comprising a plurality of samples. The method comprises the following steps, applied during the encoding of each sample with a view to its storage in a buffer. The level of occupancy of the buffer is determined, and the level of occupancy is compared with a predetermined threshold. An encoding mode is determined from among a plurality of encoding modes when the level of occupancy is above the predetermined threshold, and encoding the sample according to the determined encoding mode, and the sample is encoded according to a default encoding mode when the level of occupancy is below the predetermined threshold.