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

摘要

An apparatus for decoding an image, the apparatus comprising: an extractor configured to extract, from a bit stream, division information of a current coding unit indicating whether the current coding unit is divided into lower depth coding units, in that the current coding unit is divided hierarchically 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, of the bit stream, information about a prediction mode of the current coding unit indicating an intra-mode or an inter-mode and information about a partition type indicating a size of a prediction unit obtained from the current coding unit and obtain, from the bit stream, a coded block warning indicating whether a residual transformation block ob 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 coefficient warnings effective for a plurality of frequency band units, in which the effective coefficient notices for the plurality of frequency band units are obtained from frequency band units except a first frequency band unit corresponding to the band of lower frequency among the plurality of frequency band units, the plurality of frequency band units being included in the residual transformation block, when an effective coefficient warning of a second frequency band unit indicates that the second unit of frequency band includes at least one effective transformation coefficient that n or is zero, obtain transformation coefficients of the second frequency band unit based on a map of significance indicating locations of effective non-zero transformation coefficients in the second frequency band unit and level information of the effective non-zero transformation coefficients in the second frequency band unit obtained from the bit stream, and when the effective coefficient notice of the second frequency band unit indicates that the second frequency band does not include the minus an effective transformation coefficient that is not zero, 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 does not is zero, obtain transformation coefficients of the first frequency band unit based on a map of significance indicating locations of effective non-zero transformation coefficients existing in the first frequency band unit and level information of the effective non-zero transformation coefficients existing in the first band unit of frequency obtained from the bit stream; and a decoder configured to perform an inverse transformation in the residual transformation block, said decoder being configured to perform an intra-prediction or an inter-prediction in the prediction unit based on the information on the prediction mode and the information on the type of partition; wherein the second frequency band unit is one of the plurality of frequency band units obtained from the residual transformation block and different from the first frequency band unit, in which one form of the maximum coding unit is a square having a width and length in powers of 2, in which a form of the current coding unit is a square, and in which a form of the residual transformation block is a square.