Minimum allowed quantization for transform skip blocks 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:

• determine, for a conversion between a current video block of a video picture of a video and a bitstream of the video, whether a first coding mode is applied to the current video block according to a first rule, wherein in the first coding mode, reconstructed samples are represented by a set of representative color values, and the set of representative color values comprises at least one of 1) palette predictors, 2) escaped samples, or 3) palette information included in the bitstream;
• and
• perform the conversion at least based on the determination,
• wherein the first rule specifies that the first coding mode is conditionally allowed to the current video block when the current video block has a mode type of MODE_TYPE_ALL or a mode type of MODE_TYPE_INTRA, and that the first coding mode is disallowed to the current video block when the current video block has a mode type of MODE_TYPE_INTER,
• wherein a reconstructed picture sample array of the video picture is further obtained and a deblocking filter process is applied to at least one edge in the reconstructed picture sample array, wherein an array of boundary filtering strengths is derived for the deblocking filter process according to a second rule specifying that bS[xDi][yDj] is equal to 0 when a set of conditions are not satisfied, the reconstructed picture sample array is a reconstructed luma picture sample array, a variable related to an edge flag is not equal to 2, and two variables mapping to two samples have different values,
• wherein bS[xDi][yDj] denotes an element in the array of boundary filtering strengths for xDi with i=0 . . . xN and yDj with j=0 . . . yN,
• wherein the two samples are samples of the reconstructed picture sample array corresponding to bS[xDi][yDj], and
• wherein the two variables indicate prediction modes of two video blocks in the reconstructed picture sample array and containing the two samples, respectively, or the two variables indicate prediction modes of two video subblocks divided from one or more video blocks in the reconstructed picture sample array and containing the two samples, respectively.

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 picture of a video and a bitstream of the video, whether a first coding mode is applied to the current video block according to a first rule, wherein in the first coding mode, reconstructed samples are represented by a set of representative color values, and the set of representative color values comprises at least one of 1) palette predictors, 2) escaped samples, or 3) palette information included in the bitstream;
• and
• perform the conversion at least based on the determination,
• wherein the first rule specifies that the first coding mode is conditionally allowed to the current video block when the current video block has a mode type of MODE_TYPE_ALL or MODE_TYPE_INTRA, and that the first coding mode is disallowed to the current video block when the current video block has a mode type of MODE_TYPE_INTER,
• wherein a reconstructed picture sample array of the video picture is further obtained and a deblocking filter process is applied to at least one edge in the reconstructed picture sample array, wherein an array of boundary filtering strengths is derived for the deblocking filter process according to a second rule specifying that bS[xDi][yDj] is equal to 0 when a set of conditions are not satisfied, the reconstructed picture sample array is a reconstructed luma picture sample array, a variable related to an edge flag is not equal to 2, and two variables mapping to two samples have different values,
• wherein bS[xDi][yDj] denotes an element in the array of boundary filtering strengths for xDi with i=0 . . . xN and yDj with j=0 . . . yN,
• wherein the two samples are samples of the reconstructed picture sample array corresponding to bS[xDi][yDj], and
• wherein the two variables indicate prediction modes of two video blocks in the reconstructed picture sample array and containing the two samples, respectively, or the two variables indicate prediction modes of two video subblocks divided from one or more video blocks in the reconstructed picture sample array and containing the two samples, respectively.

A non-transitory computer-readable recording medium storing a bitstream 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 picture of a video, whether a first coding mode is applied to the current video block according to a first rule, wherein in the first coding mode, reconstructed samples are represented by a set of representative color values, and the set of representative color values comprises at least one of 1) palette predictors, 2) escaped samples, or 3) palette information included in the bitstream;
• and
• generating the bitstream at least based on the determining,
• wherein the first rule specifies that the first coding mode is conditionally allowed to the current video block when the current video block has a mode type of MODE_TYPE_ALL or MODE_TYPE_INTRA, and that the first coding mode is disallowed to the current video block when the current video block has a mode type of MODE_TYPE_INTER,
• wherein a reconstructed picture sample array of the video picture is further obtained and a deblocking filter process is applied to at least one edge in the reconstructed picture sample array, wherein an array of boundary filtering strengths is derived for the deblocking filter process according to a second rule specifying that bS[xDi][yDj] is equal to 0 when a set of conditions are not satisfied, the reconstructed picture sample array is a reconstructed luma picture sample array, a variable related to an edge flag is not equal to 2, and two variables mapping to two samples have different values,
• wherein bS[xDi][yDj] denotes an element in the array of boundary filtering strengths for xDi with i=0 . . . xN and yDj with j=0 . . . yN,
• wherein the two samples are samples of the reconstructed picture sample array corresponding to bS[xDi][yDj], and
• wherein the two variables indicate prediction modes of two video blocks in the reconstructed picture sample array and containing the two samples, respectively, or the two variables indicate prediction modes of two video subblocks divided from one or more video blocks in the reconstructed picture sample array and containing the two samples, respectively.