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, including: a video decoding method including: obtaining a quantization parameter (QP) initial value to be applied to a current picture from a picture parameter set; obtaining a QP difference value mark indicating whether a QP difference value exists in a picture header of the current picture or not from the picture parameter set; when the QP difference flag indicates that no QP difference exists in the picture header, obtaining a first QP difference of a current slice included in the current picture from a slice header of the current slice, determining a first QP for being included in the current slice in the current picture using a QP initial value and the first QP difference obtained for the current slice, and performing inverse quantization on transform coefficients in a codec unit included in the current slice using the first QP of the current slice.

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