Methods, systems, and bitstream syntax are described for canvas size, single layer or multi-layer, scalable decoding, with support for regions of interest (ROI), using a decoder supporting reference picture resampling. Offset parameters for a region of interest in a current picture and offset parameters for an ROI in a reference picture are taken into consideration when computing scaling factors to apply reference picture resampling. Syntax elements for supporting ROI regions under reference picture resampling are also presented.