US Patent 11936865 Low frequency non-separable transform signaling in video coding

Several techniques for video encoding and video decoding are described. A method for video processing includes performing a conversion between a video block of a video and a bitstream of the video, wherein the video block uses a low frequency non-separable transform for the conversion, wherein the bitstream conforms to a format rule that specifies that a syntax element is included at a syntax level for the bitstream, wherein the syntax element is indicative of whether use of a scaling matrix which is derived from a reference scaling list is enabled for the video block, and wherein the syntax level is a sequence level, a picture level, or a slice level.