A method to decode a coded bitstream with region of interest (ROI) support, the method performed by a processor and comprising: receiving a coded bitstream comprising coded pictures and syntax parameters for one or more regions of interest (ROI) within the coded pictures, wherein the syntax parameters comprise a picture header with ROI picture header parameters and a slice header with ROI slice header parameters, wherein the ROI picture header parameters comprise an ROI enabling flag and ROI offset parameters for a scaling window, and the ROI slice header parameters comprise an ROI switch parameter denoting whether ROI scaling is enabled at a slice level and whether the ROI offset parameters in the picture header are applied to a reference picture or a current picture; and decoding a coded region in a current picture in the coded bitstream, wherein decoding the coded region comprises: for the current picture and an active reference picture in an Inter slice: initializing a default scaling window in the Inter slice using values defined in a picture parameter set; if detecting that the ROI enabling flag is set to 1: overriding the parameters of the default scaling window based on the ROI offset parameters and the ROI switch parameter to generate an ROI scaling window; and applying reference picture resampling using the ROI scaling window. receiving a coded bitstream comprising coded pictures and syntax parameters for one or more regions of interest (ROI) within the coded pictures, wherein the syntax parameters comprise a picture header with ROI picture header parameters and a slice header with ROI slice header parameters, wherein the ROI picture header parameters comprise an ROI enabling flag and ROI offset parameters for a scaling window, and the ROI slice header parameters comprise an ROI switch parameter denoting whether ROI scaling is enabled at a slice level and whether the ROI offset parameters in the picture header are applied to a reference picture or a current picture; and decoding a coded region in a current picture in the coded bitstream, wherein decoding the coded region comprises: for the current picture and an active reference picture in an Inter slice: initializing a default scaling window in the Inter slice using values defined in a picture parameter set; if detecting that the ROI enabling flag is set to 1: overriding the parameters of the default scaling window based on the ROI offset parameters and the ROI switch parameter to generate an ROI scaling window; and applying reference picture resampling using the ROI scaling window. initializing a default scaling window in the Inter slice using values defined in a picture parameter set; if detecting that the ROI enabling flag is set to 1: overriding the parameters of the default scaling window based on the ROI offset parameters and the ROI switch parameter to generate an ROI scaling window; and applying reference picture resampling using the ROI scaling window. overriding the parameters of the default scaling window based on the ROI offset parameters and the ROI switch parameter to generate an ROI scaling window; and applying reference picture resampling using the ROI scaling window. <EOS>