1. A method of decoding, in a video decoder, a block of enhancement-layer transform domain data for an enhancement-layer encoded video and corresponding to a reconstructed block of reference-layer transform domain data, the method comprising: for an enhancement-layer element of the block of enhancement-layer transform domain data, determining a context for that enhancement-layer element based, at least in part, upon elements in the reconstructed block of reference-layer transform domain data, wherein the elements are identified by a template and wherein the position of the template in the reconstructed block of reference-layer transform domain data is based upon the position of that enhancement-layer element in the block of enhancement-layer transform domain data; and entropy decoding that enhancement-layer element using its determined context.