Image encoding method and apparatus, and image decoding method and apparatus
Provided is a method of decoding motion information characterized in that information for determining motion-related information includes spatial information and time information, wherein the spatial information indicates a direction of spatial prediction candidates used for sub-units from among spatial prediction candidates located on a left side and an upper side of a current prediction unit, and the time information indicates a reference prediction unit of a previous picture used for prediction of the current prediction unit. Further, an encoding apparatus or a decoding apparatus capable of performing the above described encoding or decoding method may be provided.
1. A video encoding method comprising:
obtaining a residual block comprising a residual signal for a current coding unit, based on a prediction signal generated by intra prediction with respect to the current coding unit;
obtaining transform shape information about whether the current coding unit is split in a vertical direction or a horizontal direction or is not split;
determining a horizontal length and a vertical length of the residual block with respect to the current coding unit based on transform shape information,
obtaining transform kernel information about whether a transform is separable or non-separable in each of the vertical direction and the horizontal direction;
when transform kernel information indicate that the transform is non-separable, determining the transform kernel based on the horizontal length and the vertical length of the residual block and an intra mode used in the intra prediction; and
performing transformation on the residual signal by applying the determined transform kernel.
2. A video decoding method comprising:
obtaining data of a current coding unit from among coding units of an encoded current picture and transform shape information about whether the current coding unit is split in a vertical direction or a horizontal direction or is not split, from a parsed bitstream;
determining a horizontal length and a vertical length of a residual block with respect to the current coding unit based on transform shape information;
obtaining transform kernel information about whether a transform is separable or non-separable in each of the vertical direction and the horizontal direction;
when transform kernel information indicate that the transform is non-separable determining the transform kernel based on the horizontal length and the vertical length of the residual block and an intra mode used in intra prediction with respect to the current coding unit; and
generating residual signal of the residual block for the current coding unit by performing inverse transformation on the data by using the determined transform kernel; and
performing decoding based on the residual signal and a prediction signal generated by the intra prediction with respect to the current coding unit.