A method for encoding a video signal comprises the steps of:
encoding a first complete frame by forming a bit-stream containing information for its subsequent full reconstruction (150) the information being prioritised (148) into high and low priority information;
defining (160) at least one virtual frame on the basis of a version of the first complete frame constructed using the high priority information of the first complete frame in the absence of at least some of the low priority information of the first complete frame; and
encoding (146) a second complete frame by forming a bit-stream containing information for its subsequent full reconstruction the information being prioritised into high and low priority information enabling the second complete frame to be fully reconstructed on the basis of the virtual frame rather than on the basis of the first complete frame. A corresponding decoding method is also described.