In one embodiment, a method of video encoding, the method comprising: encoding a position of a last non-zero coefficient within a video block, wherein the position of the last non-zero coefficient is provided in a significance map according to block width; and assigning at least one context model to the significance map; wherein the at least one context model includes at least three first contexts, and wherein each of the first three contexts is configured to be shared across two or more blocks of different widths.