VIDEO SIGNAL PROCESSING METHOD AND DEVICE USING REFERENCE SAMPLE

1 . A video signal decoding device comprising a processor,

wherein the processor is configured to:

obtain reference samples corresponding to a first side of a current block and reference samples corresponding to a second side of the current block,

wherein a length of the first side corresponds to a height of the current block and a length of the second side corresponds to a width of the current block,

obtain a direct current (DC) value for prediction of the current block based on a reference sample set comprising at least some of the reference samples corresponding to the first side and the reference samples corresponding to the second side,

wherein the DC value is obtained based on a result of comparing the length of the first side and the length of the second side,

wherein the reference samples corresponding to the first side of the current block are determined based on a line spaced apart by a specific sample in parallel to the first side,

wherein the reference samples corresponding to the second side of the current block are determined based on a line spaced apart by the specific sample in parallel to the second side, and

reconstruct the current block based on the DC value.

2 . The video signal decoding device of claim 1 ,

wherein the reference sample set comprises 2{circumflex over ( )}n reference samples.

3 . The video signal decoding device of claim 2 ,

wherein the reference sample set includes reference samples corresponding to any one of the first side and the second side of the current block.

4 . The video signal decoding device of claim 3 ,

wherein the reference sample set includes reference samples corresponding to a greater side of the first side and the second side.

5 . The video signal decoding device of claim 3 ,

wherein the reference sample set includes remaining reference samples, excluding reference samples corresponding to a shorter side of the first side and the second side from the reference samples corresponding to the first side and the reference samples corresponding to the second side.

6 . The video signal decoding device of claim 1 ,

wherein when the length of the first side is equal to the length of the second side, the DC value is obtained based on the reference samples corresponding to the first side of the current block and the reference samples corresponding to the second side of the current block,

wherein when the length of the first side is greater than the length of the second side, the DC value is obtained based on the reference samples corresponding to the first side of the current block,

wherein when the length of the first side is less than the length of the second side, the DC value is obtained based on the reference samples corresponding to the second side of the current block.

7 . The video signal decoding device of claim 6 ,

wherein when the length of the first side is equal to the length of the second side, the DC value is obtained based on an average of the reference samples corresponding to the first side and the reference samples corresponding to the second side,

wherein when the length of the first side is greater than the length of the second side, the DC value is obtained based on an average of the reference samples corresponding to the first side,

wherein when the length of the first side is less than the length of the second side, the DC value is obtained based on an average of the reference samples corresponding to the second side.

8 . The video signal decoding device of claim 7 ,

wherein the line spaced apart by the specific sample in parallel to the first side and the line spaced apart by the specific sample in parallel to the second side are indicated by a reference line index.

9 . The video signal decoding device of claim 8 ,

wherein a coordinate for a top-left sample of the current block is (0, 0),

wherein coordinates of the reference samples corresponding to the first side are (−1−the reference line index, y), where y=0, . . . , the length of the first side−1,

wherein coordinates of the reference samples corresponding to the second side are (x, −1−the reference line index), where x=0, . . . , the length of the second side−1.

10 . A video signal encoding device comprising a processor,

wherein the processor is configured to:

obtain a bitstream to be decoded by a decoder using a decoding method,

wherein the decoding method comprising:

obtaining reference samples corresponding to a first side of a current block and reference samples corresponding to a second side of the current block,

wherein a length of the first side corresponds to a height of the current block and a length of the second side corresponds to a width of the current block;

obtaining a direct current (DC) value for prediction of the current block based on a reference sample set comprising at least some of the reference samples corresponding to the first side and the reference samples corresponding to the second side,

wherein the DC value is obtained based on a result of comparing the length of the first side and the length of the second side,

wherein the reference samples corresponding to the first side of the current block are determined based on a line spaced apart by a specific sample in parallel to the first side,

wherein the reference samples corresponding to the second side of the current block are determined based on a line spaced apart by the specific sample in parallel to the second side; and

reconstructing the current block based on the DC value.

11 . The video signal encoding device of claim 10 ,

wherein the reference sample set comprises 2{circumflex over ( )}n reference samples.

12 . The video signal encoding device of claim 11 ,

wherein the reference sample set includes reference samples corresponding to any one of the first side and the second side of the current block.

13 . The video signal decoding device of claim 12 ,

wherein the reference sample set includes reference samples corresponding to a greater side of the first side and the second side.

14 . The video signal decoding device of claim 12 ,

wherein the reference sample set includes remaining reference samples, excluding reference samples corresponding to a shorter side of the first side and the second side from the reference samples corresponding to the first side and the reference samples corresponding to the second side.

15 . The video signal decoding device of claim 10 ,

wherein when the length of the first side is equal to the length of the second side, the DC value is obtained based on the reference samples corresponding to the first side of the current block and the reference samples corresponding to the second side of the current block,

wherein when the length of the first side is greater than the length of the second side, the DC value is obtained based on the reference samples corresponding to the first side of the current block,

wherein when the length of the first side is less than the length of the second side, the DC value is obtained based on the reference samples corresponding to the second side of the current block.

16 . The video signal decoding device of claim 15 ,

wherein when the length of the first side is equal to the length of the second side, the DC value is obtained based on an average of the reference samples corresponding to the first side and the reference samples corresponding to the second side,

wherein when the length of the first side is greater than the length of the second side, the DC value is obtained based on an average of the reference samples corresponding to the first side,

wherein when the length of the first side is less than the length of the second side, the DC value is obtained based on an average of the reference samples corresponding to the second side.

17 . The video signal decoding device of claim 16 ,

wherein the line spaced apart by the specific sample in parallel to the first side and the line spaced apart by the specific sample in parallel to the second side are indicated by a reference line index.

18 . The video signal decoding device of claim 17 ,

wherein a coordinate for a top-left sample of the current block is (0, 0),

wherein coordinates of the reference samples corresponding to the first side are (−1−the reference line index, y), where y=0, . . . , the length of the first side−1,

wherein coordinates of the reference samples corresponding to the second side are (x, −1−the reference line index), where x=0, . . . , the length of the second side−1.

19 . A non-transitory computer-readable medium storing a bitstream, the bitstream being decoded by a decoding method,

wherein the decoding method, comprising:

obtaining reference samples corresponding to a first side of a current block and reference samples corresponding to a second side of the current block,

wherein a length of the first side corresponds to a height of the current block and a length of the second side corresponds to a width of the current block;

obtaining a direct current (DC) value for prediction of the current block based on a reference sample set comprising at least some of the reference samples corresponding to the first side and the reference samples corresponding to the second side,

wherein the DC value is obtained based on a result of comparing the length of the first side and the length of the second side,

wherein the reference samples corresponding to the first side of the current block are determined based on a line spaced apart by a specific sample in parallel to the first side,

wherein the reference samples corresponding to the second side of the current block are determined based on a line spaced apart by the specific sample in parallel to the second side; and

reconstructing the current block based on the DC value.

20 . The non-transitory computer-readable medium storing a bitstream of claim 19 ,

wherein the reference sample set comprises 2{circumflex over ( )}n reference samples.