Refined quantization steps in video coding

A non-transitory computer-readable recording medium storing a bitstream of a video which is generated by a method performed by a video processing apparatus, wherein the method comprises:

• determining, during a conversion between a current video block and a bitstream 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;
• 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;
• and
• generating the bitstream based on the determining and the performing.