US Patent 12015774 Slice level signaling in video bitstreams that include subpictures

An example method of video processing includes partitioning, for a conversion between a current video block of a picture of a video and a bitstream of the video, the picture into one or more slices according to a requirement of bitstream conformance. The requirement of bitstream conformance specifies that a union of the one or more slices covers the whole picture, and a first syntax element is included in the bitstream to indicate whether the one or more slices have a rectangular shape. The method also includes performing the conversion at least based on the partitioning.