An example method of video processing includes determining, for a conversion between a current video unit of a video and a bitstream representation of the video, availability of one or more samples in a first neighboring region of the current block for a coding process of the conversion independently from information of a second neighboring region of the current block. The second neighboring region is adjacent to the first neighboring region, and the one or more samples are padded in case determined to be unavailable. The method includes performing the conversion based on the determining.