A video decoding method performed by a video decoding apparatus, the method comprising: receiving a bitstream comprising image information, the image information including a picture header related to a current picture, the current picture including slices; parsing, from the picture header, a first flag related to whether information for an inter slice is present in the picture header, wherein a value of the first flag being equal to 1 is related that the information for the inter slice is present in the picture header; parsing, from the picture header, a second flag related to whether information for an intra slice is present in the picture header, wherein a value of the second flag being equal to 1 is related that the information for the intra slice is present in the picture header; and generating prediction samples by performing at least one of an intra prediction or an inter prediction on blocks in the slices in the current picture based on the first flag and the second flag, wherein based on the value of the first flag being equal to 1, the information for the inter slice is comprised in the picture header, wherein the information for the inter slice includes a syntax element representing difference between base 2 logarithm of a minimum size resulting from quad-tree splitting and base 2 logarithm of a minimum coding block size in the inter slice in the current picture, and wherein based on the value of the second flag being equal to 1, the information for the intra slice is comprised in the picture header, wherein the information for the intra slice includes a syntax element representing a difference between base 2 logarithm of a minimum size resulting from quad-tree splitting and base 2 logarithm of a minimum coding block size in the intra slice in the current picture. receiving a bitstream comprising image information, the image information including a picture header related to a current picture, the current picture including slices; parsing, from the picture header, a first flag related to whether information for an inter slice is present in the picture header, wherein a value of the first flag being equal to 1 is related that the information for the inter slice is present in the picture header; parsing, from the picture header, a second flag related to whether information for an intra slice is present in the picture header, wherein a value of the second flag being equal to 1 is related that the information for the intra slice is present in the picture header; and generating prediction samples by performing at least one of an intra prediction or an inter prediction on blocks in the slices in the current picture based on the first flag and the second flag, wherein based on the value of the first flag being equal to 1, the information for the inter slice is comprised in the picture header, wherein the information for the inter slice includes a syntax element representing difference between base 2 logarithm of a minimum size resulting from quad-tree splitting and base 2 logarithm of a minimum coding block size in the inter slice in the current picture, and wherein based on the value of the second flag being equal to 1, the information for the intra slice is comprised in the picture header, wherein the information for the intra slice includes a syntax element representing a difference between base 2 logarithm of a minimum size resulting from quad-tree splitting and base 2 logarithm of a minimum coding block size in the intra slice in the current picture.