A picture defined in video data is partitioned into blocks that include a luminance (luma) transform block and a chrominance (chroma) transform block. One or more constraints pertaining to the picture are determined from high-level syntax elements and transform skipping of one of both of the luma transform block and the chroma transform block is disallowed if the constraints are not met. The video data are encoded in a bitstream along with an indication that the transform of the luma transform block or the chroma transform block is skipped in response to the transform being skipped.