A method for video processing includes determining that a size of a residual block of a video is larger than a maximum block size allowed for a transform skip mode, in which, during a decoding operation, residual coefficients are decoded without performing an inverse transform operation; splitting, based on the size of a residual block, the residual block into multiple regions, wherein each region represents a portion of the residual block of a difference between a portion of a current video block and a prediction block corresponding to the portion of the current video block; and determining a reconstructed current video block from the residual block based on selectively performing the inverse transform operation according to an indicator that indicates the transform skip mode.