# US 2021/0243471 A1 · Overlapped block motion compensation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0243471 A1 - Document ID: US20210243471A1 - Status: Published application - Kind: A1 - Application number: 17/238,639 - Filed: 2021-04-23 - Published: 2021-08-05 - Earliest claimed: 2018-10-31 - Assignees: Beijing Bytedance Network Technology Co., Ltd.; Bytedance Inc. - Applicants: Beijing Bytedance Network Technology Co., Ltd.; Bytedance Inc. - Inventors: Hongbin LIU; Li ZHANG; Kai ZHANG; Yue WANG - Web page: https://patentgrep.com/patent/US20210243471A1 ## CPC - H04N 19/583: Motion compensation with overlapping blocks - 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 19/139: Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability - 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 19/196: being specially adapted for the computation of encoding parameters, e.g. by averaging previously computed encoding parameters (processing of motion vectors H04N19/513) - H04N 19/513: Processing of motion vectors - H04N 19/521: {for estimating the reliability of the determined motion vectors or motion vector field, e.g. for smoothing the motion vector field or for correcting motion vectors} - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract The present disclosure relates to improvement on overlapped block motion compensation. A method for video processing comprises: determining, during a conversion between a current block and a bitstream representation of the current block, a motion vector for a first sub-block inside the current block; using overlapped block motion compensation (OBMC) mode to perform the conversion; wherein the OBMC mode uses intermediate prediction values of the first sub-block based on the motion vector of the first sub-block and prediction values of at least a second video unit that is neighboring the first sub-block to generate final prediction values for the first sub-block; wherein a sub-block size of the first sub-block is based on block size, block shape, motion information, or reference picture of the current block. ## Claims ### Claim 1 A method for processing video data, comprising: determining, during a conversion between a current block of a video and a bitstream of the video, a motion vector for a first sub-block inside the current block; and performing the conversion based on an overlapped block motion compensation (OBMC) mode; wherein the OBMC mode uses intermediate prediction values of the first sub-block based on the motion vector of the first sub-block and prediction values of at least a second video unit that is neighboring the first sub-block to generate final prediction values for the first sub-block; wherein a size of the first sub-block is based on block size, block shape, motion information, or reference picture of the current block. ### Claim 2 (depends on 1) The method of claim 1, wherein the conversion comprises decoding the bitstream to obtain the video data. ### Claim 3 (depends on 1) The method of claim 1, wherein the conversion comprises encoding the video data into the bitstream. ### Claim 4 (depends on 1) The method of claim 1, wherein the current block has a width w and a height h, and the size of the first sub-block is M1×M2 if w×h is greater than or equal to a first threshold T1, M1 representing a width of the first sub-block and M2 representing a height of the first sub-block; and the size of the first sub-block is N1×N2 if w×h is smaller than the first threshold T1, N1 representing the width of the first sub-block and N2 representing the height of the first sub-block, where M1, M2, w, h, N1, N2 and T1 are integers. ### Claim 5 (depends on 1) The method of claim 1, wherein the current block has a width w and a height h, and a ratio of width to height of the first sub-block of the current block w/h is M1 if w is greater than or equal to a second threshold T2, and the ratio of width to height of the first sub-block w/h is N1 if w is smaller than the second threshold T2, where M1, N1 and T2 are integers. ### Claim 6 (depends on 1) The method of claim 1, wherein the size of the first sub-block M1×M2 is used if the current block is a uni-predicted block, M1 representing a width of the first sub-block and M2 representing a height of the first sub-block, and otherwise, the size of the first sub-block N1×N2 is used, N1 representing the width of the first sub-block and N2 representing the height of the first sub-block. ### Claim 7 (depends on 4) The method of claim 4, wherein M1×M2 is equal to at least one of: 4×4; (w/4)×4 for an above region, and 4×(h/4) for a left region; (w/4)×2 for an above region, and 4×(h/2) for a left region. ### Claim 8 (depends on 4) The method of claim 4, wherein N1×N2 is equal to at least one of: 8×8, or 8×4, or 4×8; (w/2)×4 for an above region, and 4×(h/2) for a left region; (w/2)×2 for an above region, and 2×(h/2) for a left region. ### Claim 9 (depends on 1) The method of claim 1, wherein the method is disabled in affine mode. ### Claim 10 (depends on 1) The method of claim 1, wherein the method is applied to a translational motion mode. ### Claim 11 (depends on 1) The method of claim 1, wherein the method is applied to the current block if the current block has a product of width and height w×h greater than or equal to a third threshold T3, wherein T3 is 16 or 32. ### Claim 12 (depends on 1) The method of claim 1, wherein the method is applied to the current block if the current block has a width w greater than or equal to a fourth threshold T4 and a height h greater than or equal to the fourth threshold T4, where T4 is 8. ### Claim 13 (depends on 1) The method of claim 1, wherein the method is applied to the current block if the current block has a width w greater than or equal to a fifth threshold T5 and a height h greater than or equal to a sixth threshold T6, where T5 and T6 are integers, and T5 is different from T6. ### Claim 14 (depends on 13) The method of claim 13, wherein T5 and T6 are integer multiples of 8. ### Claim 15 (depends on 1) The method of claim 1, wherein the method is not applied to the current block if the current block has a width w greater than or equal to a seventh threshold T7 or a height h greater than or equal to an eighth threshold T8, where T7 and T8 are 128. ### Claim 16 (depends on 1) The method of claim 1, wherein the current block is coded with intra block copy (IBC) mode, wherein the IBC mode uses a picture of the current block as a reference picture; and the second video unit is coded using the IBC mode. ### Claim 17 (depends on 1) The method of claim 1, wherein the method is applied on one of: all color components; one or more color components; or only luma components. ### Claim 18 (depends on 1) The method of claim 1, wherein whether and how to apply the method is signaled from an encoder to a decoder in a video parameter set (VPS), a sequence parameter set (SPS), a picture parameter set (PPS), a picture header, a tile group, a slice header, a coding tree unit (CTU), a coding unit (CU), a group of CTUs, or a group of CUs. ### Claim 19 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, during a conversion between a current block of a video and a bitstream of the video, a motion vector for a first sub-block inside the current block; and perform the conversion base on an overlapped block motion compensation (OBMC) mode; wherein the OBMC mode uses intermediate prediction values of the first sub-block based on the motion vector of the first sub-block and prediction values of at least a second video unit that is neighboring the first sub-block to generate final prediction values for the first sub-block; wherein a size of the first sub-block is based on block size, block shape, motion information, or reference picture of the current block. ### Claim 20 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, during a conversion between a current block of the video and the bitstream of the video, a motion vector for a first sub-block inside the current block; and generating the bitstream of the video from the current block based on an overlapped block motion compensation (OBMC) mode; wherein the OBMC mode uses intermediate prediction values of the first sub-block based on the motion vector of the first sub-block and prediction values of at least a second video unit that is neighboring the first sub-block to generate final prediction values for the first sub-block; wherein a size of the first sub-block is based on block size, block shape, motion information, or reference picture of the current block.