Video decoding method and apparatus for obtaining quantization parameter, and video encoding method and apparatus for transmitting quantization parameter

Abstract

Provided is a video decoding method according to an embodiment provided in the present disclosure, the video decoding method comprising: obtaining, from a picture parameter set, a QP initial value and picture header QP difference value information to be applied to a current picture; when the picture header QP difference value information indicates that QP difference value information is present in a picture header of the current picture, obtaining, from the picture header, a first QP difference value for the current picture; determining a QP for a coding unit included in the current picture by using the QP initial value and the first QP difference value; obtaining transformation coefficients of the coding unit by performing inverse quantization on the coding unit by using the QP; and reconstructing the coding unit by using the transformation coefficients.