A method of decoding a coding unit from a video bitstream determines reconstructed samples for a first coding unit, from the video bitstream, and decodes a dictionary store flag from the video bitstream for the first coding unit. Where the dictionary store flag indicates that reconstructed samples for the first coding unit be stored, the method (i) stores the reconstructed samples for the first coding unit into a memory buffer; (ii) determines reconstructed samples for a second coding unit, the reconstructed samples for the second coding unit being copied from reconstructed samples for the first coding unit from the memory buffer, and (iii) outputs the reconstructed samples for the second coding unit. Also disclosed is a complementary method for encoding, a decoder and an encoder.