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 decoding method comprising:
obtaining transform shape information about whether a current coding unit is split in a vertical direction or a horizontal direction or is not split, from a bitstream;
determining a horizontal length and a vertical length of a transform block with respect to the current coding unit based on the transform shape information;
obtaining an encoded data from the bitstream;
obtaining transform kernel information indicating whether a non-separable transform is used or which transform kernel is used from among transform kernel candidates;
when the transform kernel information indicates that the non-separable transform is used, determining a transform kernel among the transform kernel candidates based on the horizontal length and the vertical length of the transform block, an intra prediction mode used in intra prediction, and the transform kernel information;
performing inverse transformation on the encoded data by using the determined transform kernel in order to obtain a residual sample; and
reconstructing the current coding unit based on the residual sample and a prediction sample obtained by performing intra prediction.
2. A video encoding method comprising:
generating transform shape information about whether a 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 a residual block with respect to the current coding unit based on the transform shape information;
generating transform kernel information indicating whether a non-separable transform is used or which transform kernel is used from among transform kernel candidates;
when the transform kernel information indicates that the non-separable transform is used, determining a transform kernel among the transform kernel candidates based on the horizontal length and the vertical length of the residual block, an intra prediction mode used in intra prediction, and the transform kernel information; and
performing transformation on a residual sample by applying the determined transform kernel to obtain an encoded data.
3. A non-transitory computer-readable storage medium having stored thereon computer executable instructions that when executed by at least one processor perform operations for video encoding to generate a bitstream, the bitstream comprising:
transform shape information about whether a current coding unit is split in a vertical direction or a horizontal direction or is not split; and
transform kernel information indicating whether a non-separable transform is used or which transform kernel is used from among transform kernel candidates, wherein the operations for video encoding comprises:
generating the transform shape information about whether the current coding unit is split in the vertical direction or the horizontal direction or is not split;
determining a horizontal length and a vertical length of a residual block with respect to the current coding unit based on the transform shape information;
generating the transform kernel information indicating whether the non-separable transform is used or which transform kernel is used from among transform kernel candidates;
when the transform kernel information indicates that the non-separable transform is used, determining a transform kernel among the transform kernel candidates based on the horizontal length and the vertical length of the residual block, an intra prediction mode used in intra prediction, and the transform kernel information; and
performing transformation on a residual sample by applying the determined transform kernel to obtain an encoded data.