# US 11,909,966 B2 · Syntax constraints in parameter set signaling of subpictures > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,909,966 B2 - Document ID: US11909966B2 - Status: Granted - Kind: B2 - Application number: 17/723,089 - Filed: 2022-04-18 - Published: 2022-08-11 - Granted: 2024-02-20 - Earliest claimed: 2019-10-18 - Assignees: Beijing Bytedance Network Technology Co., Ltd.; Bytedance Inc. - Applicants: Beijing Bytedance Network Technology Co., Ltd.; Bytedance Inc. - Inventors: Kai Zhang; Zhipin Deng; Hongbin Liu; Li Zhang; Jizheng Xu - Web page: https://patentgrep.com/patent/US11909966B2 ## CPC - H04N 19/119: Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks - H04N 19/117: Filters, e.g. for pre-processing or post-processing (sub-band filter banks H04N19/635) - H04N 19/132: Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking - H04N 19/176: the region being a block, e.g. a macroblock - H04N 19/186: the unit being a colour or a chrominance component - H04N 19/46: Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence) - H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards - H04N 19/82: involving filtering within a prediction loop - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract An example method of video processing includes performing a conversion between a picture of a video and a bitstream representation of the video. The picture includes one or more sub-pictures, and the bitstream representation conforms to a format rule that specifies that a length of a syntax element is equal to Ceil(Log 2(SS)) bits. SS is greater than 0, and the syntax element indicating a horizontal or a vertical position of a top-left corner of a coding tree unit of a sub-picture of the picture. ## Claims ### Claim 1 A method of processing video data, comprising: determining, for a conversion between a video comprising a picture which is divided into one or more subpictures and a bitstream of the video, a position of a subpicture of the one or more subpictures based on a first syntax element and a second syntax element included in the bitstream; and performing the conversion based on the determining, wherein the first syntax element indicates a horizontal position of a top-left coding tree unit of the subpicture in unit of CtbSizeY and a length of the first syntax element is derived to be Ceil(Log 2(S1)) bits, wherein the second syntax element indicates a vertical position of the top-left coding tree unit of the subpicture in unit of CtbSizeY and a length of the second syntax element is derived to be Ceil(Log 2(S2)) bits, wherein S1 and S2 are greater than 0, and CtbSizeY denotes a size of a coding tree block, and wherein S1 is equal to (S3+CtbSizeY−1)/CtbSizeY, and S2 is equal to (S4+CtbSizeY−1)/CtbSizeY, wherein S3 is a value of a syntax element included in a sequence parameter set and specifying a maximum width of a decoded picture referring to the sequence parameter set in units of luma samples, and wherein S4 is a value of a syntax element included in the sequence parameter set and specifying a maximum height of a decoded picture referring to the sequence parameter set in units of luma samples. ### Claim 2 (depends on 1) The method of claim 1, wherein a third syntax element is included in the bitstream to specify a width of the subpicture in unit of CtbSizeY and a length of the third syntax element is derived to be Ceil(Log 2(S1)) bits, and wherein a fourth syntax element is included in the bitstream to specify a height of the subpicture in unit of CtbSizeY and a length of the fourth syntax element is derived to be Ceil(Log 2(S2)) bits. ### Claim 3 (depends on 1) The method of claim 1, wherein S3 and S4 are an integer multiple of Max(8, MinCbSizeY), respectively. ### Claim 4 (depends on 1) The method of claim 1, wherein the bitstream conforms to a format rule which specifies that different subpictures have different subpicture ID values. ### Claim 5 (depends on 4) The method of claim 4, wherein when a value of one or more syntax elements is equal to 0, a default value is assigned to the subpicture ID value of the subpicture, wherein, when the value of the one or more syntax elements is equal to 0, a subpicture ID mapping is not explicitly signaled, neither in the sequence parameter set nor in the picture parameter set. ### Claim 6 (depends on 5) The method of claim 5, wherein when the value of the one or more syntax elements is equal to 0, a fifth syntax element specifying ID of the subpicture is not included in a picture parameter set and a sixth syntax element specifying ID of the subpicture is not included in a sequence parameter set. ### Claim 7 (depends on 5) The method of claim 5, wherein the subpicture is an i-th subpicture in the picture and the default value is equal to i, and wherein i is an integer smaller than a number of subpictures in the picture. ### Claim 8 (depends on 1) The method of claim 1, wherein the conversion includes encoding the picture into the bitstream. ### Claim 9 (depends on 1) The method of claim 1, wherein the conversion includes decoding the picture from the bitstream. ### Claim 10 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 video comprising a picture which is divided into one or more subpictures and a bitstream of the video, a position of a subpicture of the one or more subpictures based on a first syntax element and a second syntax element included in the bitstream; and perform the conversion based on the determining, wherein the first syntax element indicates a horizontal position of a top-left coding tree unit of the subpicture in unit of CtbSizeY and a length of the first syntax element is derived to be Ceil(Log 2(S1)) bits, wherein the second syntax element indicates a vertical position of the top-left coding tree unit of the subpicture in unit of CtbSizeY and a length of the second syntax element is derived to be Ceil(Log 2(S2)) bits, wherein S1 and S2 are greater than 0, and CtbSizeY denotes a size of a coding tree block, and wherein S1 is equal to (S3+CtbSizeY−1)/CtbSizeY, and S2 is equal to (S4+CtbSizeY−1)/CtbSizeY, wherein S3 is a value of a syntax element included in a sequence parameter set and specifying a maximum width of a decoded picture referring to the sequence parameter set in units of luma samples, and wherein S4 is a value of a syntax element included in the sequence parameter set and specifying a maximum height of a decoded picture referring to the sequence parameter set in units of luma samples. ### Claim 11 (depends on 10) The apparatus of claim 10, wherein a third syntax element is included in the bitstream to specify a width of the subpicture in unit of CtbSizeY and a length of the third syntax element is derived to be Ceil(Log 2(S1)) bits, and wherein a fourth syntax element is included in the bitstream to specify a height of the subpicture in unit of CtbSizeY and a length of the fourth syntax element is derived to be Ceil(Log 2(S2)) bits. ### Claim 12 (depends on 10) The apparatus of claim 10, wherein S3 and S4 are an integer multiple of Max(8, MinCbSizeY), respectively. ### Claim 13 (depends on 10) The apparatus of claim 10, wherein the bitstream conforms to a format rule which specifies that different subpictures have different subpicture ID values. ### Claim 14 (depends on 13) The apparatus of claim 13, wherein when a value of one or more syntax elements is equal to 0, a default value is assigned to the subpicture ID value of the subpicture, wherein when the value of the one or more syntax elements is equal to 0, a subpicture ID mapping is not explicitly signalled, neither in the sequence parameter set nor in the picture parameter set. ### Claim 15 A non-transitory computer-readable storage medium storing instructions that cause a processor to: determine, for a conversion between a video comprising a picture which is divided into one or more subpictures and a bitstream of the video, a position of a subpicture of the one or more subpictures based on a first syntax element and a second syntax element included in the bitstream; and perform the conversion based on the determining, wherein the first syntax element indicates a horizontal position of a top-left coding tree unit of the subpicture in unit of CtbSizeY and a length of the first syntax element is derived to be Ceil(Log 2(S1)) bits, wherein the second syntax element indicates a vertical position of the top-left coding tree unit of the subpicture in unit of CtbSizeY and a length of the second syntax element is derived to be Ceil(Log 2(S2)) bits, wherein S1 and S2 are greater than 0, and CtbSizeY denotes a size of a coding tree block, and wherein S1 is equal to (S3+CtbSizeY−1)/CtbSizeY, and S2 is equal to (S4+CtbSizeY−1)/CtbSizeY, wherein S3 is a value of a syntax element included in a sequence parameter set and specifying a maximum width of a decoded picture referring to the sequence parameter set in units of luma samples, and wherein S4 is a value of a syntax element included in the sequence parameter set and specifying a maximum height of a decoded picture referring to the sequence parameter set in units of luma samples. ### Claim 16 (depends on 15) The non-transitory computer-readable storage medium of claim 15, wherein a third syntax element is included in the bitstream to specify a width of the subpicture in unit of CtbSizeY and a length of the third syntax element is derived to be Ceil(Log 2(S1)) bits, and wherein a fourth syntax element is included in the bitstream to specify a height of the subpicture in unit of CtbSizeY and a length of the fourth syntax element is derived to be Ceil(Log 2(S2)) bits. ### Claim 17 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 video comprising a picture which is divided into one or more subpictures, a position of a subpicture of the one or more subpictures based on a first syntax element and a second syntax element included in the bitstream; and generating the bitstream based on the determining, wherein the first syntax element indicates a horizontal position of a top-left coding tree unit of the subpicture in unit of CtbSizeY and a length of the first syntax element is derived to be Ceil(Log 2(S1)) bits, wherein the second syntax element indicates a vertical position of the top-left coding tree unit of the subpicture in unit of CtbSizeY and a length of the second syntax element is derived to be Ceil(Log 2(S2)) bits, wherein S1 and S2 are greater than 0, and CtbSizeY denotes a size of a coding tree block, and wherein S1 is equal to (S3+CtbSizeY−1)/CtbSizeY, and S2 is equal to (S4+CtbSizeY−1)/CtbSizeY, wherein S3 is a value of a syntax element included in a sequence parameter set and specifying a maximum width of a decoded picture referring to the sequence parameter set in units of luma samples, and wherein S4 is the value of a syntax element included in the sequence parameter set and specifying a maximum height of a decoded picture referring to the sequence parameter set in units of luma samples. ### Claim 18 (depends on 17) The non-transitory computer-readable recording medium of claim 17, wherein a third syntax element is included in the bitstream to specify a width of the subpicture in unit of CtbSizeY and a length of the third syntax element is derived to be Ceil(Log 2(S1)) bits, and wherein a fourth syntax element is included in the bitstream to specify a height of the subpicture in unit of CtbSizeY and a length of the fourth syntax element is derived to be Ceil(Log 2(S2)) bits.