# US 10,771,799 B2 · 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 10,771,799 B2 - Document ID: US10771799B2 - Status: Granted - Kind: B2 - Application number: 16/533,719 - Filed: 2019-08-06 - Published: 2020-07-16 - Granted: 2020-09-08 - Earliest claimed: 2019-01-15 - Assignees: Tencent America LLC - Applicants: Tencent America LLC - Inventors: Xiaozhong Xu; Shan Liu; Xiang Li - Web page: https://patentgrep.com/patent/US10771799B2 ## CPC - H04N 19/44: Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder - H04N 19/593: involving spatial prediction techniques - H04N 19/105: Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction - 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 19/159: 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 19/433: characterised by techniques for memory access - H04N 19/517: by encoding - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Aspects of the disclosure provide methods and apparatuses for video encoding/decoding. In some examples, an apparatus for video decoding includes receiving circuitry and processing circuitry. For example, the processing circuitry decodes prediction information of a current block in a current coding tree unit (CTU) from a coded video bitstream. The prediction information is indicative of an intra block copy mode. A size of the current CTU is smaller than a maximum size of a reference sample memory for storing reconstructed samples. The processing circuitry determines a block vector that points to a reference block in a same picture as the current block. The reference block has reconstructed samples buffered in the reference sample memory. Then, the processing circuitry reconstructs at least a sample of the current block based on the reconstructed samples of the reference block that are retrieved from the reference sample memory. ## Claims ### Claim 1 A method for video decoding in a decoder, comprising: decoding prediction information of a current block in a current coding tree unit (CTU) from a coded video bitstream, the prediction information being indicative of an intra block copy mode, a size of the current CTU being smaller than a maximum size of a reference sample memory for storing reconstructed samples; determining a block vector that points to a reference block in a same picture as the current block, the reference block having reconstructed samples buffered in the reference sample memory; and reconstructing at least a sample of the current block based on the reconstructed samples of the reference block that are retrieved from the reference sample memory. ### Claim 2 (depends on 1) The method of claim 1, further comprising: determining the block vector that points to the reference block that is in a same CTU row as the current CTU and located in a region from an (N−1)th left CTU to an adjacent left CTU of the current CTU, wherein the maximum size of the reference sample memory is N times of the size of the current CTU, and N is a positive number that is larger than one. ### Claim 3 (depends on 2) The method of claim 2, further comprising: checking whether a top boundary of the reference block is in the same CTU row; checking whether a bottom boundary of the reference block is in the same CTU row; checking whether a left boundary of the reference block is to the right of the Nth left CTU; and checking whether a right boundary of the reference block is to the left of the current CTU. ### Claim 4 (depends on 1) The method of claim 1, further comprising: checking whether the reference block is at least partially in an Nth left CTU that is in a same CTU row as the current CTU, wherein the maximum size is the N times of the size of the current CTU, and N is a positive number that is larger than one. ### Claim 5 (depends on 4) The method of claim 4, further comprising: checking whether a left boundary of the reference block is in the Nth left CTU. ### Claim 6 (depends on 4) The method of claim 4, further comprising: determining, when the reference block is at least partially in the Nth left CTU, whether, in the current CTU, a collocated block of the reference block is at least partially reconstructed. ### Claim 7 (depends on 6) The method of claim 6, further comprising: determining whether a top-left corner of the collocated block has been reconstructed. ### Claim 8 (depends on 6) The method of claim 6, further comprising: invalidating the block vector that points to the reference block when the collocated block in the current CTU is at least partially reconstructed. ### Claim 9 (depends on 4) The method of claim 4, further comprising: determining a reference block region in the Nth left CTU that includes the reference block; determining, in the current CTU, whether a collocated block region of the reference block region is at least partially reconstructed; and invalidating the block vector that points to the reference block when the collocated block region in the current CTU is at least partially reconstructed. ### Claim 10 An apparatus for video decoding, comprising: processing circuitry configured to: decode prediction information of a current block in a current coding tree unit (CTU) from a coded video bitstream, the prediction information being indicative of an intra block copy mode, a size of the current CTU being smaller than a maximum size of a reference sample memory for storing reconstructed samples; determine a block vector that points to a reference block in a same picture as the current block, the reference block having reconstructed samples buffered in the reference sample memory; and reconstruct at least a sample of the current block based on the reconstructed samples of the reference block that are retrieved from the reference sample memory. ### Claim 11 (depends on 10) The apparatus of claim 10, wherein the processing circuitry is further configured to: determine the block vector that points to the reference block in a same CTU row as the current CTU and located in a region from an (N−1)th left CTU to an adjacent left CTU of the current CTU, wherein the maximum size of the reference sample memory is N times of the size of the current CTU, and N is a positive number that is larger than one. ### Claim 12 (depends on 11) The apparatus of claim 11, wherein the processing circuitry is further configured to: check whether a top boundary of the reference block is in the same CTU row; check whether a bottom boundary of the reference block is in the same CTU row; check whether a left boundary of the reference block is to the right of the Nth left CTU; and check whether a right boundary of the reference block is to the left of the current CTU. ### Claim 13 (depends on 10) The apparatus of claim 10, wherein the processing circuitry is further configured to: check whether the reference block is at least partially in an Nth left CTU that is in a same CTU row as the current CTU, wherein the maximum size of the reference sample memory is N times of the size of the current CTU, and N is a positive number that is larger than one. ### Claim 14 (depends on 13) The apparatus of claim 13, wherein the processing circuitry is further configured to: check whether a left boundary of the reference block is in the Nth left CTU. ### Claim 15 (depends on 13) The apparatus of claim 13, wherein the processing circuitry is further configured to: determine, when the reference block is at least partially in the Nth left CTU, whether, in the current CTU, a collocated block of the reference block is at least partially reconstructed. ### Claim 16 (depends on 15) The apparatus of claim 15, wherein the processing circuitry is further configured to: determine whether a top-left corner of the collocated block has been reconstructed. ### Claim 17 (depends on 15) The apparatus of claim 15, wherein the processing circuitry is further configured to: invalidate the block vector that points to the reference block when the collocated block in the current CTU is at least partially reconstructed. ### Claim 18 (depends on 13) The apparatus of claim 13, wherein the processing circuitry is further configured to: determine a reference block region in the Nth left CTU that includes the reference block; determine, in the current CTU, whether a collocated block region of the reference block region is at least partially reconstructed; and invalidate the block vector that points to the reference block when the collocated block region in the current CTU is at least partially reconstructed. ### Claim 19 A non-transitory computer-readable medium storing instructions which when executed by a computer for video decoding cause the computer to perform: decoding prediction information of a current block in a current coding tree unit (CTU) from a coded video bitstream, a size of the current CTU being smaller than a maximum size of a reference sample memory for storing reconstructed samples, the prediction information being indicative of an intra block copy mode; determining a block vector that points to a reference block in a same picture as the current block, the reference block having reconstructed samples buffered in the reference sample memory; and reconstructing at least a sample of the current block based on the reconstructed samples of the reference block that are retrieved from the reference sample memory. ### Claim 20 (depends on 19) The non-transitory computer-readable medium of claim 19, wherein the instructions further cause the computer to perform: determining the block vector that points to the reference block that is in a same CTU row as the current CTU and located in a region from an (N−1)th left CTU to an adjacent left CTU of the current CTU, wherein the maximum size of the reference sample memory is N times of the size of the current CTU, and N is a positive number that is larger than one.