Techniques for modifying quantization parameter in transform skip mode

An apparatus for processing video data comprising a processor and a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to:

• determine, for a conversion between a current video block of a video and a bitstream of the video, to clip a quantization parameter indicated by a syntax field for the current video block coded with a transform skip mode in which transform and inverse transform processes are skipped;
• clip a value of the quantization parameter based on a variable indicating a minimum allowed quantization parameter for the transform skip mode;
• and
• perform the conversion based on the clipping,
• wherein the value of the variable is greater than 4,
• wherein the value of the variable is equal to (4+X), wherein X is a pre-defined value being greater than or equal to 0,
• wherein X=6*Y, wherein Y is determined based on at least one syntax element included in the bitstream.

A non-transitory computer-readable storage medium storing instructions that cause a processor to:

• determine, for a conversion between a current video block of a video and a bitstream of the video, to clip a quantization parameter indicated by a syntax field for the current video block coded with a transform skip mode in which transform and inverse transform processes are skipped;
• clip a value of the quantization parameter based on a variable indicating a minimum allowed quantization parameter for the transform skip mode;
• and
• perform the conversion based on the clipping,
• wherein the value of the variable is greater than or equal to 4,
• wherein the value of the variable is equal to (4+X), X is a pre-defined value being greater than or equal to 0, and
• wherein X=6*Y, wherein Y is determined based on at least one syntax element included in the bitstream.

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, for a current video block of a video, to clip a quantization parameter indicated by a syntax field for the current video block coded with a transform skip mode in which transform and inverse transform processes are skipped;
• clipping a value of the quantization parameter based on a variable indicating a minimum allowed quantization parameter for the transform skip mode;
• and
• generating the bitstream based on the clipping,
• wherein the value of the variable is greater than 4,
• wherein the value of the variable is equal to (4+X), wherein X is a pre-defined value being greater than or equal to 0,
• wherein X=6*Y, wherein Y is determined based on at least one syntax element included in the bitstream.