Method and apparatus for determining reference picture set of image

An apparatus of encoding a video, the apparatus comprising:

• at least one processor configured to determine reference picture sets available to predict a current picture, to generate information of the number of reference picture sets, wherein the reference picture sets are included in a sequence parameter set, to generate delta index information about a difference between an index of a current reference picture set of the current picture and an index of a reference reference picture set(reference RPS) and a delta RPS which is a difference value between a picture order count (POC) value of a reference picture in the current reference picture set of the current picture and a picture order count (POC) value of a reference picture in the reference reference picture set, wherein the index of the current reference picture set of the current picture indicates the current reference picture set of the current picture among reference picture sets, wherein the delta index information and the delta RPS are generated to be used to determine the current reference picture set of the current picture set when the index of the current reference picture set of the current picture is equal to the number of the reference picture sets included in a sequence parameter set, and to generate the bistream including the information of the number of reference picture sets included in the sequence parameter set, the delta index information and the delta RPS.

A non-transitory computer-readable storage medium storing a bitstream comprising:

• information of the number of reference picture sets, wherein the reference picture sets are included in a sequence parameter set and available to predict a current picture;
• and
• delta index information about a difference between an index of a current reference picture set of the current picture and an index of a reference reference picture set (reference RPS), wherein the index of the current reference picture set of the current picture indicates the current reference picture set of the current picture among reference picture sets;
• and
• a delta RPS which is a difference value between a picture order count (POC) value of a reference picture in the current reference picture set of the current picture and a picture order count (POC) value of a reference picture in the reference RPS of the current picture, wherein the delta index information and the delta RPS are generated to be used to determine the current reference picture set of the current picture when the index of the current reference picture set of the current picture is equal to the number of reference picture sets included in the sequence parameter set,
• wherein a value about the index of the reference reference picture set s smaller than a value about the index of the current reference picture set.