| CPC H04N 19/44 (2014.11) [H04N 19/132 (2014.11); H04N 19/159 (2014.11); H04N 19/176 (2014.11); H04N 19/625 (2014.11); H04N 19/70 (2014.11)] | 8 Claims |
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1. A method of decoding a video signal based on a Multiple Transform Selection (MTS), comprising:
obtaining a sequence parameter set from the video signal, wherein the sequence parameter set includes an MTS intra enabling flag representing whether an MTS index could be present in a syntax for an intra coding unit and an MTS inter enabling flag representing whether the MTS index could be present in a syntax for an inter coding unit;
obtaining, from the video signal, the MTS index based on the MTS intra enabling flag, wherein the MTS index corresponds to one of a plurality of transform combinations within a transform configuration group, and wherein the MTS represents a transform method performed based on a transform combination selected from the plurality of transform combinations;
deriving an inverse quantized transform coefficient array with a width and a height of a current block by performing inverse quantization on the current block;
determining a vertical transform type applied to a vertical direction and horizontal transform type applied to a horizontal direction of a current block based on the MTS index; and
deriving a residual sample array with the width and height of the current block by performing inverse transform on the inverse quantized transform coefficient array based on the vertical transform type and the horizontal transform type,
wherein deriving the residual sample array includes:
performing, based on the vertical transform type, a one-dimensional transform process in the vertical direction on each of columns of the inverse quantized transform coefficient array; and
performing, based on the horizontal transform type, a one-dimensional transform process in the horizontal direction on each of rows of an intermediate sample array output by the one-dimensional transform process for each of the columns,
wherein performing the one-dimensional transform process in the horizontal direction includes:
clipping an intermediate sample value output by the one-dimensional transform process for each of the columns based on a minimum value and maximum value of a predefined coefficient,
wherein the plurality of transform combinations includes at least one of a first transform type, a second transform type, or a third transform type, and
wherein the first transform type, the second transform type, and the third transform type are different from each other.
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