Video signal processing method and device
A method of video decoding according to the present invention may comprise determining an intra prediction mode of a current block, determining a DC value using reference samples adjacent to the current block when the intra prediction mode of the current block is a DC mode, and deriving a prediction sample of the current block based on the DC value.
1. A method of decoding an image, comprising:
receiving a bitstream including the image;
dividing, based on a triple division, a first coding block into three second coding blocks;
dividing, based on a binary division one of the three second coding blocks into two third coding blocks; and
decoding each of the two third coding blocks,
wherein a largest second coding block among the three second coding blocks has a size greater than a size of the other two of the three second coding blocks,
wherein the other two of the three second coding blocks have a same size,
wherein the largest second coding block is located between the other two of the three second coding blocks,
wherein whether the one of the three second coding blocks is divided based on the binary division is determined based on first information signaled via the bitstream,
wherein in response to the first information indicates that the one of the three second coding blocks is divided based on the binary division, the one of the three second coding blocks is divided into the two third coding blocks by dividing it in a horizontal direction or a vertical direction, and
wherein, in response to the one of the three second coding blocks is the largest second coding block, the binary division with a same division direction as a division direction of the triple division for the first coding block is not allowed for the largest second coding block.
2. The method of claim 1 , wherein the restriction is applied only to the one of the three second coding blocks which is located between the other two of the three second coding blocks.
3. The method of claim 2 , wherein one of the horizontal direction or the vertical direction is selected based on second information selectively signaled via the bitstreams, and
wherein in response to the one of the three second coding blocks is the largest second coding block, signaling of the second information for the largest second coding block is omitted.
4. The method of claim 1 , wherein, in response to a product of a width and a height of the first coding block being equal to 64, the triple division is not allowed for the first coding block.
5. The method of claim 4 , wherein, in response to a product of a width and a height of a second coding block being equal to 32, the binary division is not allowed for the second coding block.
6. The method of claim 1 , wherein decoding a third coding block comprises:
determining an intra prediction mode of the third coding block from a first candidate list or a second candidate list, a number of candidates included in the first candidate list being less than a number of candidates included in the second candidate list; and
performing intra prediction of the third coding block based on the intra prediction mode.
7. The method of claim 6 , wherein the number of candidates included in the second candidate list is 5.
8. The method of claim 7 , wherein one of the first candidate list or the second candidate list is adaptively used according to third information signaled from the bitstream.
9. A method of encoding an image, comprising:
dividing, based on a triple division, a first coding block into three second coding blocks;
dividing, based on a binary division, one of the three second coding blocks into two third coding blocks; and
encoding each of the two third coding blocks,
wherein a largest second coding block among the three second coding blocks has a size greater than a size of the other two of the three second coding blocks,
wherein the other two of the three second coding blocks have a same size,
wherein the largest second coding block is located between the other two of the three second coding blocks,
wherein first information, indicating whether the one of the three second coding blocks is divided by the binary division is encoded into the bitstream, and
wherein, in response to the one of the three second coding blocks is the largest second coding block, the binary division with a same division direction as a division direction of the triple division for the first coding block is not allowed for the largest second coding block.
10. A non-transitory computer-readable medium for storing a compressed image signal, comprising:
a data stream including the compressed image signal,
wherein a first coding block is divided, based on a triple division, into three second coding blocks,
wherein one of the three second coding blocks is divided, based on a binary division, into two third coding blocks,
wherein a largest second coding block among the three second coding blocks has a size greater than a size of the other two of the three second coding blocks,
wherein the other two of the three second coding blocks have a same size,
wherein the largest second coding block is located between the other two of the three second coding blocks,
wherein first information, indicating whether the one of the three second coding blocks is divided by the binary division, is included in the compressed video data, and
wherein, in response to the one of the three second coding blocks is the largest second coding block, the binary division with a same division direction as a division direction of the triple division for the first coding block is not allowed for the largest second coding block.