# US 11,451,780 B2 · Techniques for modifying quantization parameter in transform skip mode > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,451,780 B2 - Document ID: US11451780B2 - Status: Granted - Kind: B2 - Application number: 17/528,312 - Filed: 2021-11-17 - Published: 2022-03-10 - Granted: 2022-09-20 - Earliest claimed: 2019-06-28 - Assignees: Bytedance Inc. - Applicants: Bytedance Inc. - Inventors: Weijia Zhu; Li Zhang; Jizheng Xu - Web page: https://patentgrep.com/patent/US11451780B2 ## CPC - H04N 19/124: Quantisation - H04N 19/157: Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter - H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction - H04N 19/176: the region being a block, e.g. a macroblock - H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards - H04N 19/61: in combination with predictive coding - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A method of video processing is described. The method includes performing a conversion between a current video block of a video and a coded representation of the current video block according to a rule, wherein the rule specifies that, due to use of an identity transform coding tool for representing the current video block into the coded representation, a syntax field indicative of a quantization parameter used for decoding the current video block is included such that a value of the quantization parameter is modified according to a rule, wherein the identity transform coding tool allows coefficient values at a transform domain of the current block to be same as values of a residual block of the current video block. ## Claims ### Claim 1 A method of processing video data, comprising: determining, 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; clipping a value of the quantization parameter based on a variable indicating a minimum allowed quantization parameter for the transform skip mode; and performing 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), 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. ### Claim 2 (depends on 1) The method of claim 1, wherein in the clipping, the value of the quantization parameter is set to the value of the variable if the value of the quantization parameter is smaller than the value of the variable. ### Claim 3 (depends on 1) The method of claim 1, wherein Y=bd−bdi, wherein bd is an internal bitdepth of coding the video, bdi is an input bitdepth of the video. ### Claim 4 (depends on 1) The method of claim 1, wherein the current video block is coded based on a differential coding mode, wherein in the differential coding mode, differences between quantized residuals derived with an intra prediction mode of the current video block and predictions of the quantized residuals are included in the bitstream. ### Claim 5 (depends on 1) The method of claim 1, wherein the conversion comprises encoding the current video block into the bitstream. ### Claim 6 (depends on 1) The method of claim 1, wherein the conversion comprises decoding the current video block from the bitstream. ### Claim 7 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. ### Claim 8 (depends on 7) The apparatus of claim 7, wherein in the clipping, the value of the quantization parameter is set to the value of the variable if the value of the quantization parameter is smaller than the value of the variable. ### Claim 9 (depends on 7) The apparatus of claim 7, wherein the current video block is coded based on a differential coding mode, wherein in the differential coding mode, differences between quantized residuals derived with an intra prediction mode of the current video block and predictions of the quantized residuals are included in the bitstream. ### Claim 10 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. ### Claim 11 (depends on 10) The non-transitory computer-readable storage medium of claim 10, wherein in the clipping, the value of the quantization parameter is set to the value of the variable if the value of the quantization parameter is smaller than the value of the variable. ### Claim 12 (depends on 10) The non-transitory computer-readable storage medium of claim 10, wherein Y=bd−bdi, wherein bd is an internal bitdepth of coding the video, bdi is an input bitdepth of the video. ### Claim 13 (depends on 10) The non-transitory computer-readable storage medium of claim 10, wherein the current video block is coded based on a differential coding mode, wherein in the differential coding mode, differences between quantized residuals derived with an intra prediction mode of the current video block and predictions of the quantized residuals are included in the bitstream. ### Claim 14 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. ### Claim 15 (depends on 14) The non-transitory computer-readable recording medium of claim 14, wherein in the clipping, the value of the quantization parameter is set to the value of the variable if the value of the quantization parameter is smaller than the value of the variable. ### Claim 16 (depends on 14) The non-transitory computer-readable recording medium of claim 14, wherein Y=bd−bdi, wherein bd is an internal bitdepth of coding the video, bdi is an input bitdepth of the video. ### Claim 17 (depends on 14) The non-transitory computer-readable recording medium of claim 14, wherein the current video block is coded based on a differential coding mode, wherein in the differential coding mode, differences between quantized residuals derived with an intra prediction mode of the current video block and predictions of the quantized residuals are included in the bitstream.