# US 2019/0246128 A1 · Method and apparatus for video coding > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0246128 A1 - Document ID: US20190246128A1 - Status: Published application - Kind: A1 - Application number: 16/203,224 - Filed: 2018-11-28 - Published: 2019-08-08 - Earliest claimed: 2018-02-05 - Assignees: Tencent America LLC - Applicants: Tencent America LLC - Inventors: Xiaozhong XU; Xiang Li; Shan Liu - Web page: https://patentgrep.com/patent/US20190246128A1 ## CPC - H04N 19/11: among a plurality of spatial predictive coding modes - H04N 19/44: Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder - H04N 19/14: Coding unit complexity, e.g. amount of activity or edge presence estimation (H04N19/146 takes precedence) - 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 19/186: the unit being a colour or a chrominance component - H04N 19/593: involving spatial prediction techniques - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Aspects of the disclosure provide method and apparatus for video coding. In some examples, an apparatus includes processing circuitry for video decoding. The processing circuitry locates luma units of a luma coding unit that are co-located with chroma units of a chroma coding unit, and then determines a popularity of an intra block copy mode in the luma units. Further, the processing circuitry determines a block vector for a chroma unit in the chroma coding unit when the popularity meets a requirement, and reconstructs at least one sample of the chroma unit according to the block vector. ## Claims ### Claim 1 A method for video decoding, comprising: locating luma units of a luma coding unit that are co-located with chroma units of a chroma coding unit; determining a popularity of an intra block copy mode in the luma units by determining a percentage of the luma units of the luma coding unit that is coded in the intra block copy mode; determining whether the determined percentage of the luma units coded in the intra block copy mode is greater than a first threshold; in response to the determination that the determined percentage of the luma units coded in the intra block copy mode is greater than the first threshold, determining a block vector for a chroma unit of the chroma units in the chroma coding unit; and reconstructing at least one sample of the chroma unit according to the block vector. ### Claim 2 (depends on 1) The method of claim 1, further comprising: determining the block vector for the chroma unit of the chroma coding unit based on the luma units when all the luma units are coded in the intra block copy mode. ### Claim 3 (depends on 2) The method of claim 2, further comprising: locating a specific luma unit that is co-located with the chroma unit in the chroma coding unit; and determining the block vector that is associated with the specific luma unit for the chroma unit. ### Claim 4 (depends on 1) The method of claim 1, further comprising: determining the block vector for the chroma unit of the chroma coding unit based on the co-located luma units in response to the determination that the determined percentage of the luma units coded in the intra block copy mode is greater than the first threshold. ### Claim 5 (depends on 4) The method of claim 4, further comprising: when a specific luma unit that is co-located with the chroma unit is coded in the intra block code mode, associating the block vector of the specific luma unit with the chroma unit. ### Claim 6 (depends on 5) The method of claim 5, further comprising: when the specific luma unit that is co-located with the chroma unit is coded in a mode other than the intra block code mode, determining the block vector according to a neighboring chroma unit for the chroma unit. ### Claim 7 (depends on 4) The method of claim 4, further comprising: decoding the first threshold from at least one of sequence parameter set (SPS), picture parameter set (PPS) and slice header. ### Claim 8 (depends on 4) The method of claim 4, further comprising: determining whether the predetermined percentage of the luma units coded in the intra block copy mode is below a second threshold that is lower than the first threshold; and disabling the intra block copy mode for the chroma coding unit in response to the determination that the determined percentage of the luma units coded in the intra block copy mode is below the second threshold. ### Claim 9 (depends on 4) The method of claim 4, further comprising: determining whether at least one of the luma units of the luma coding unit is not coded in the intra block copy mode; and disabling the intra block copy mode for the chroma coding unit in response to the determination that at least one of the luma units of the luma coding unit is not coded in the intra block copy mode. ### Claim 10 (depends on 1) The method of claim 1, further comprising: splitting the chroma coding unit into chroma coding sub-units when a non-intra block copy mode exists in the luma units; and determining whether the respective chroma coding sub-units are decodable using the intra block copy mode. ### Claim 11 (depends on 10) The method of claim 10, further comprising: detecting a splitting flag associated with the chroma coding unit; and splitting the chroma coding unit into the chroma coding sub-units in response to the splitting flag. ### Claim 12 An apparatus for video decoding, comprising: processing circuitry configured to: locate luma units of a luma coding unit that are co-located with chroma units of a chroma coding unit; determine a popularity of an intra block copy mode in the luma units by a determination of a percentage of the luma units of the luma coding unit that is coded in the intra block copy mode; determine whether the determined percentage of the luma units coded in the intra block copy mode is greater than a first threshold; in response to the determination that the determined percentage of the luma units coded in the intra block copy mode is greater than the first threshold, determine a block vector for a chroma unit of the chroma units in the chroma coding unit; and reconstruct at least one sample of the chroma unit according to the block vector. ### Claim 13 (depends on 12) The apparatus of claim 12, wherein the processing circuitry is configured to: determine the block vector for the chroma unit of the chroma coding unit based on the luma units when all the luma units are coded in the intra block copy mode. ### Claim 14 (depends on 13) The apparatus of claim 13, wherein the processing circuitry is configured to: locate a specific luma unit that is co-located with the chroma unit in the chroma coding unit; and determine the block vector that is associated with the specific luma unit for the chroma unit. ### Claim 15 (depends on 12) The apparatus of claim 12, wherein the processing circuitry is configured to: determine the block vector for the chroma unit of the chroma units in the chroma coding unit based on the co-located luma units in response to the determination that the determined percentage of the luma units coded in the intra block copy mode is greater than the first threshold. ### Claim 16 (depends on 15) The apparatus of claim 15, wherein the processing circuitry is configured to: when a specific luma unit that is co-located with the chroma unit is coded in the intra block code mode, associate the block vector of the specific luma unit with the chroma unit; and when the specific luma unit that is co-located with the chroma unit is coded in a mode other than the intra block code mode, determine the block vector according to a neighboring chroma unit for the chroma unit. ### Claim 17 (depends on 15) The apparatus of claim 15, wherein the processing circuitry is configured to: decode the first threshold from at least one of sequence parameter set (SPS), picture parameter set (PPS) and slice header. ### Claim 18 (depends on 15) The apparatus of claim 15, further wherein the processing circuitry is configured to: determine whether the predetermined percentage of the luma units coded in the intra block copy mode is below a second threshold that is lower than the first threshold and disable the intra block copy mode for the chroma coding unit in response to the determination that the determined percentage of the luma units coded in the intra block copy mode is below the second threshold; or determine whether at least one of the luma units of the luma coding unit is not coded in the intra block copy mode and disable the intra block copy mode for the chroma coding unit in response to the determination that at least one of the luma units of the luma coding unit is not coded in the intra block copy mode. ### Claim 19 (depends on 12) The apparatus of claim 12, wherein the processing circuitry is configured to: split the chroma coding unit into chroma coding sub-units when a non-intra block copy mode exists in the luma units; and determine whether the respective chroma coding sub-units are decodable using the intra block copy mode. ### Claim 20 A non-transitory computer-readable medium storing instructions which when executed by a computer for video decoding cause the computer to perform: locating luma units of a luma coding unit that are co-located with chroma units of a chroma coding unit; determining a popularity of an intra block copy mode in the luma units by determining a percentage of the luma units of the luma coding unit that is coded in the intra block copy mode; determining whether the determined percentage of the luma units coded in the intra block copy mode is greater than a first threshold; in response to the determination that the determined percentage of the luma units coded in the intra block copy mode is greater than the first threshold, determining a block vector for a chroma unit of the chroma units in the chroma coding unit; and reconstructing at least one sample of the chroma unit according to the block vector.