A video decoding method performed by a video decoding apparatus, according to the present document, comprises the steps of: obtaining image information from a bitstream, wherein the image information includes a picture header associated with a current picture, and the current picture includes a plurality of slices; parsing at least one of a first flag and a second flag from the picture header; generating prediction samples by performing at least one of intra prediction and inter prediction on a current block in the current picture on the basis of at least one of the first flag and the second flag; generating reconstructed samples on the basis of the prediction samples; and generating a reconstructed picture on the basis of the reconstructed samples.