US Patent 11997277 Refined quantization steps in video coding

The application relates to refined quantization steps in video coding. A method for video processing includes: determining, during a conversion between a current video block and a bitstream representation of a video including the current video block, two-level quantization parameters comprising a first level quantization parameter QP1 and a second level quantization parameter QP2 for the current video block; and performing, at least based on the two-level quantization parameters, a first level quantization and/or a second level quantization during the conversion, wherein the two-level quantization parameters correspond to different quantization precisions respectively.