Procedure and apparatus for coding residual block and procedure and apparatus for decoding residual block

摘要

A method of decoding an image, comprising the procedure: extracting, from a bit stream, division information of a current coding unit indicating whether the current coding unit is divided into shallower coding units, in which the Current coding unit is hierarchically divided from a maximum coding unit, when the division information of the current coding unit indicates that the current coding unit is no longer divided into coding units of the lowest depth, extract, from the flow of bits, information on a prediction mode of the current coding unit indicating an intra-mode or an inter-mode and information on a type of partition indicating a size of a prediction unit obtained from the current coding unit and obtaining, from bit stream, a coded block warning that indicates whether a residual transformation block obtained from the current coding unit includes at least one effective transformation coefficient that is not zero; when the coded block warning indicates that the residual transformation block includes at least one effective transformation coefficient that is not zero, obtain effective coefficient notices for each of a plurality of frequency band units, wherein said plurality of frequency band units are obtained from the residual transformation block except for a first frequency band unit corresponding to the lowest frequency band among the plurality of frequency band units; When an effective coefficient warning of a second frequency band unit indicates that the second frequency band unit includes at least one effective non-zero transformation coefficient, obtain transformation coefficients of the second base frequency band unit to a map of significance indicating locations of effective non-zero transformation coefficients existing in the second frequency band unit and level information of effective non-zero transformation coefficients in the second obtained frequency band unit from the bit stream; When the effective coefficient warning of the second frequency band unit indicates that the second frequency band unit does not include at least one effective non-zero transformation coefficient, determine the transformation coefficients of the second frequency band unit as zero; When the coded block warning indicates that the residual transformation block includes at least one effective transformation coefficient that is not zero, obtain transformation coefficients of the first frequency band unit based on a significance map indicating coefficient locations of effective non-zero transformation in the first frequency band unit and level information of the effective non-zero transformation coefficients in the first frequency band unit obtained from the bit stream; perform an inverse transformation in the residual transformation block; perform an intra-prediction or an inter-prediction in the prediction unit based on information on the prediction mode and information on the type of partition, in which the second frequency band unit is one of the plurality of units of frequency band and different from the first frequency band unit, in which a form of the maximum coding unit is a square having a width and a length in squares of 2, in which a form of the coding unit current is a square, and in which one form of the residual transformation block is a square, and in which the frequency band units have the same size.