Adaptive color transform in video coding

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:
• apply, during a conversion between a video unit of a video and a bitstream of the video, a deblocking filter to at least some samples on boundaries of the video unit, wherein deblocking quantization parameter (QP) values used in the deblocking filter are determined according to a rule;
• and
• perform the conversion based on the deblocking QP values,
• wherein the rule specifies that a relationship between the deblocking QP values and dequantization QP values used in a quantization or dequantization process for the video unit is based on whether an adaptive color transform mode is applied to the video unit,
• wherein in the adaptive color transform mode, for an encoding operation, visual signals are converted from a first color domain to a second color domain, or for a decoding operation, the visual signals are converted from the second color domain to the first color domain,
• wherein the video unit is a chroma coding block, and the rule specifies that a differential coding tool is not applied to the chroma coding block when the adaptive color transform mode is applied to the chroma coding block, and
• wherein in a differential coding mode, residuals of samples of the chroma coding block are represented in the bitstream using differences between quantized residuals and predictors of the quantized residuals.

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

• apply, during a conversion between a video unit of a video and a bitstream of the video, a deblocking filter to at least some samples on boundaries of the video unit, wherein deblocking quantization parameter (QP) values used in the deblocking filter are determined according to a rule;
• and
• perform the conversion based on the deblocking QP values,
• wherein the rule specifies that a relationship between the deblocking QP values and dequantization QP values used in a quantization or dequantization process for the video unit is based on whether an adaptive color transform mode is applied to the video unit,
• wherein in the adaptive color transform mode, for an encoding operation, visual signals are converted from a first color domain to a second color domain, or for a decoding operation, the visual signals are converted from the second color domain to the first color domain,
• wherein the video unit is a chroma coding block, and the rule specifies that a differential coding tool is not applied to the chroma coding block when the adaptive color transform mode is applied to the chroma coding block, and
• wherein in a differential coding mode, residuals of samples of the chroma coding block are represented in the bitstream using differences between quantized residuals and predictors of the quantized residuals.

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:

• applying a deblocking filter to at least some samples on boundaries of a video unit of the video, wherein deblocking quantization parameter (QP) values used in the deblocking filter are determined according to a rule;
• and
• generating the bitstream based on the deblocking QP values,
• wherein the rule specifies that a relationship between the deblocking QP values and dequantization QP values used in a quantization or dequantization process for the video unit is based on whether an adaptive color transform mode is applied to the video unit,
• wherein in the adaptive color transform mode, for an encoding operation, visual signals are converted from a first color domain to a second color domain, or for a decoding operation, the visual signals are converted from the second color domain to the first color domain,
• wherein the video unit is a chroma coding block, and the rule specifies that a differential coding tool is not applied to the chroma coding block when the adaptive color transform mode is applied to the chroma coding block, and
• wherein in a differential coding mode, residuals of samples of the chroma coding block are represented in the bitstream using differences between quantized residuals and predictors of the quantized residuals.