| CPC H04N 19/625 (2014.11) [H04N 19/105 (2014.11); H04N 19/136 (2014.11); H04N 19/176 (2014.11); H04N 19/186 (2014.11); H04N 19/503 (2014.11); H04N 19/593 (2014.11); H04N 19/70 (2014.11)] | 4 Claims |

|
1. An image decoding method comprising:
obtaining a sub-block transform flag, from a bitstream, indicating whether or not a sub-block transform is used for a current coding unit;
obtaining, from a coding unit syntax structure in the bitstream, a syntax element regarding multiple transform selection (MTS) based on the sub-block transform flag indicating that the sub-block transform is not used for the current coding unit, with respect to the current coding unit, wherein the current coding unit includes a plurality of transform units and the syntax element regarding the MTS is index information indicating a type of a horizontal transform kernel and a type of a vertical transform kernel with respect to the plurality of transform units included in the current coding unit;
determining the horizontal transform kernel and the vertical transform kernel with respect to the plurality of transform units included in the current coding unit based on the obtained syntax element regarding the MTS;
obtaining a residual block with respect to a current transform unit among the plurality of transform units by applying the determined horizontal transform kernel and vertical transform kernel to the current transform unit; and
generating a reconstruction block for the current coding unit based on the residual block with respect to the current transform unit,
wherein the same horizontal transform kernel is applied to the plurality of transform units included in the current coding unit and the same vertical transform kernel is applied to the plurality of transform units included in the current coding unit.
|