Samsung patents video decoding method for efficient reference picture sets

1. An apparatus of decoding a video, the apparatus comprising: at least one processor configured to: obtain, from a bitstream, information regarding a number of short term reference picture sets included in a part of the bitstream about a sequence parameter set, determine whether a current index of a short term reference picture set of a current picture is equal to the number of short term reference picture sets included in the part of the bitstream about the sequence parameter set, when the current index of the short term reference picture set of the current picture is equal to the number of short term reference picture sets, obtain, from the bitstream, delta index information about a difference between the current index of the short term reference picture set of the current picture and an index of a reference short term reference picture set, information about a sign of a delta RPS and information about an absolute value of the delta RPS, determine the index of the reference short term reference picture set which indicates the reference short term reference picture set based on the delta index information and the current index of the short term reference picture set, wherein the index of the reference short term reference picture set is smaller than the current index of the short term reference picture set, determine the delta RPS based on the information about the sign of the delta RPS and the information about the absolute value of the delta RPS, determine delta picture order count (POC) values between POC values of reference pictures included in the short term reference picture set of the current picture and a POC value of the current picture by adding each delta POC value between the POC value of reference picture in the reference short term reference picture set and the POC value of the current picture to the delta RPS, determine the POC values of the reference pictures included in the short term reference picture set of the current picture based on the POC value of the current picture and the delta POC values between the POC values of the reference pictures included in the short term reference picture set of the current picture and the POC value of the current picture, and predict the current picture by using a reference picture included in one of reference picture sets including the short term reference picture set of the current picture, wherein the current index of the short term reference picture set of the current picture being equal to the number of short term reference picture sets indicates the short term reference picture set regarding the current index is not defined in the sequence parameter set and is defined in a slice header.