WE CLAIM:
1. An image decoding method performed by a decoding apparatus, the method
comprising:
deriving prediction mode for a current block;
deriving reference samples adjacent to the left and the top of the current block based on
an intra prediction being applied to the current block according to the prediction mode;
deriving prediction samples for the current block based on the reference samples; and
deriving a reconstructed picture based on the prediction samples,
wherein a position of a top-left corner sample of the current block is (0, 0), a width of
the current block is w and a height of the current block is h, and,
wherein the deriving of the reference samples includes performing padding on at least
one reference sample with x-coordinate value in the range from w to (w+h-1).
2. The image decoding method of claim 1, wherein the deriving of the reference
samples includes performing padding on at least one reference sample with y-coordinate value
in the range from h to (w+h-1).
3. The image decoding method of claim 1, wherein the deriving of the reference
samples performs padding on at least one reference sample without determining availability of
reference sample.
4. The image decoding method of claim 1, wherein at least one reference sample
is padded with adjacent reference sample to its left.
5. The image decoding method of claim 4, wherein the height h of the current
block is greater than the width w of the current block.
6. The image decoding method of claim 2, wherein at least one reference sample
is padded with adjacent reference sample to its above.
7. The image decoding method of claim 6, wherein the width w of the current
block is greater than the height h of the current block.
8. An image encoding method performed by an image encoding apparatus, the
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method comprising:
deriving prediction mode for a current block;
deriving reference samples adjacent to the left and the top of the current block based on
an intra prediction being applied to the current block;
deriving prediction samples for the current block based on the reference samples;
deriving residual samples based on the prediction samples, and
encoding image information comprising prediction mode information for the current
block,
wherein a position of a top-left corner sample of the current block is (0, 0), a width of
the current block is w and a height of the current block is h, and,
wherein the deriving of the reference samples includes performing padding on at least
one reference sample with x-coordinate value in the range from w to (w+h-1).
9. A transmission method for image data, the method comprising:
obtaining a bitstream for the image data, wherein the bitstream is generated based on
deriving prediction mode for a current block; deriving reference samples adjacent to the left
and the top of the current block based on an intra prediction being applied to the current block;
deriving prediction samples for the current block based on the reference samples; deriving
residual samples based on the prediction samples and encoding image information comprising
prediction mode information; and
transmitting the image data comprising the bitstream,
wherein a position of a top-left corner sample of the current block is (0, 0), a width of
the current block is w and a height of the current block is h, and,
wherein the deriving of the reference samples includes performing padding on at least
one reference sample with x-coordinate value in the range from w to (w+h-1).