Abstract: An intra prediction method comprises receiving input data of a current block in a current picture, deriving reference samples of the current block from boundary samples, selecting a matrix for the current block, generating intermediate predicted samples by multiplying the reference samples and the matrix, and clipping the intermediate predicted samples before up-sampling. The intra prediction method further comprises performing an up-sampling process on the clipped intermediate predicted samples to generate predicted samples for the current block, and encoding or decoding the current block according to the predicted samples of the current block.

Abstract: The techniques described herein relate to methods, apparatus, and computer readable media configured to encode or decode video data. A current block of video data is coded using affine prediction. A first set of candidates of a candidate list for the current block is generated, including determining one or more inherited candidates and deriving one or more constructed candidates. After generating the first set of candidates, it is determined whether the candidate list is full. Upon determining the candidate list is not full, the candidate list is filled by generating a second set of candidates of the candidate list, including one or more of generating one or more zero motion vector candidates, generating one or more additional derived candidates based on the plurality of associated neighboring blocks of the current block, and generating a temporal motion vector candidate based on a temporal collocated picture.

Abstract: Video encoding methods and apparatuses in a video encoding system receive an input residual signal of a current block by a shared transform circuit, apply horizontal transform and vertical transform by a shared transform circuit to generate transform coefficients, apply quantization and inverse quantization to generate recovered transform coefficients, apply inverse vertical transform and inverse horizontal transform to the recovered transform coefficients by the shared transform circuit to generate a reconstructed residual signal for the current block, and encode the current block based on quantized levels of the current block. The shared transform circuit and a coefficient buffer in the folded 4-time transform architecture reuse computation resources in each transform stage. In some embodiments of the folded 4-time transform architecture, a hierarchical design for block size grouping is implemented with fixed throughput for uniform hardware scheduling.

Abstract: A method and apparatus of Inter prediction for video coding using a target Merge mode comprising a triangle Merge mode are disclosed. According to this method, a current block is partitioned into a first region and a second region using the target partition. A candidate list is determined. Two candidates are determined for the two regions by deriving two target candidates from the candidate list. When a selected target candidate is a uni-prediction candidate, the selected target candidate is used as one candidate; and when the selected target candidate is a bi-prediction candidate, motion information associated of the selected target candidate with List 0 or List 1 is used as one candidate. The current block or current motion information associated with the current block is encoded or decoded according to the candidate list. The candidate list is used to derive the first candidate and the second candidate.

Abstract: Video encoding methods and apparatuses include receiving reconstructed video samples, determining an initial clipping setting for ALF coefficients, deriving clipping setting candidates from the initial clipping setting. ALF coefficients for the initial clipping setting and the clipping setting candidates are derived by solving inverse matrices, where partial intermediate results of solving ALF coefficients are shared by two or more clipping settings. A distortion value corresponds to the derived ALF coefficients for each clipping setting is computed, and final clipping indices for final ALF coefficients are determined according to the distortion values. ALF filtering is applied to the reconstructed video samples based on the final ALF coefficients and the final clipping indices.

Abstract: Video encoding methods and apparatuses in a video encoding system receive an input residual signal of a current block by a shared transform circuit, apply horizontal transform and vertical transform by a shared transform circuit to generate transform coefficients, apply quantization and inverse quantization to generate recovered transform coefficients, apply inverse vertical transform and inverse horizontal transform to the recovered transform coefficients by the shared transform circuit to generate a reconstructed residual signal for the current block, and encode the current block based on quantized levels of the current block. The shared transform circuit and a coefficient buffer in the folded 4-time transform architecture reuse computation resources in each transform stage. In some embodiments of the folded 4-time transform architecture, a hierarchical design for block size grouping is implemented with fixed throughput for uniform hardware scheduling.

Abstract: Video processing methods and apparatuses for coding a current block generate a final predictor by combining multiple predictors for the current block. A first predictor and a second predictor for the current block are generated by applying one or a combination of settings to the first, second, or both predictors. One or both the first and second predictors are generated from motion compensation. The final predictor is derived from the first and second predictors, and the current block is encoded or decoded according to the final predictor. The settings include supported-mode setting, combined-weight setting, applied-portion setting, motion information setting, precision setting, or a combination of the above settings.

Abstract: Video encoding or decoding methods and apparatuses include receiving input data associated with a current block in a current picture, determining a preload region in a reference picture shared by two or more coding configurations of affine prediction or motion compensation or by two or more affine refinement iterations, loading reference samples in the preload region, generating predictors for the current block, and encoding or decoding the current block according to the predictors. The predictors associated with the affine refinement iterations or coding configurations are generated based on some of the reference samples in the preload region.

Abstract: For each prediction candidate of a set of one or more prediction candidates of the current block, a video coder computes a matching cost between a set of reference pixels of the prediction candidate in a reference picture and a set of neighboring pixels of a current block in a current picture. The video coder identifies a subset of the reference pictures as major reference pictures based on a distribution of the prediction candidates among the reference pictures of the current picture. A bounding block is defined for each major reference picture, the bounding block encompassing at least portions of multiple sets of reference pixels for multiple prediction candidates. The video coder assigns an index to each prediction candidate based on the computed matching cost of the set of prediction candidates. A selection of a prediction candidate is signaled by using the assigned index of the selected prediction candidate.

Abstract: Method and apparatus for affine CPMV or ALF refinement are mentioned. According to this method, statistical data associated with the affine CPMV or ALF refinement are collected over a picture area. Updated parameters for the affine CPMV refinement or the ALF refinement are then derived based on the statistical data, where a process to derive the updated parameters includes performing multiplication using a reduced-precision multiplier for the statistical data. The reduced-precision multiplier truncates at least one bit of the mantissa part. In another embodiment, the process to derive the updated parameters includes performing reciprocal for the statistical data using a lookup table with (m?k)-bit input by truncating k bits from the m-bit mantissa part, and contents of the lookup table includes m-bit outputs. m and k are positive integers.

Abstract: Low-latency video coding methods and apparatuses include receiving input data associated with a current Intra slice composed of Coding Tree Units (CTU), where each CTU includes luma and chroma Coding Tree Blocks (CTBs), partitioning each CTB into non-overlapping pipeline units, and encoding or decoding the CTUs in the current Intra slices by performing processing of chroma pipeline units after beginning processing of luma pipeline units in at least one pipeline stage. Each of the pipeline units is processed by one pipeline stage after another pipeline stage, and different pipeline stages process different pipeline units simultaneously. The pipeline stage in the low-latency video coding methods and apparatuses simultaneously processes one luma pipeline unit and at least one previous chroma pipeline unit within one pipeline unit time interval.

Abstract: Method and apparatus of video coding are disclosed. According to one method, the left reference boundary samples and the top reference boundary samples are checked jointly. According to another method, selected original left reference boundary samples and selected original top reference boundary samples at specific positions are used for predictor up-sampling. According to yet another method, the horizontal interpolation and the vertical interpolation are in a fixed order regardless of a shape of the current block, size of the current block or both.

Abstract: According to a method for Adaptive Loop Filter (ALF) processing of reconstructed video, multiple indicators are signaled in slice at an encoder side or parsed at a decoder side, where the multiple indicators are Adaptive Parameter Set (APS) indices associated with temporal ALF filter sets for the ALF processing. A current indicator is determined from the multiple indicators, where the current indicator is used to select a current ALF filter set. Filtered-reconstructed pixels are derived for the current block by applying the current ALF filter to the current block. In another method, if the ALF processing applied at a target sample requires an outside sample on other side of a target virtual boundary from the target sample, the outside sample is replaced by a padded sample.

Abstract: A method and apparatus for Overlapped Boundary Motion Compensation (OBMC) are provided. According to the method, input data associated with a current block is received, wherein the input data includes pixel data for the current block to be encoded at an encoder side or coded data associated with the current block to be decoded at a decoder side. An inter prediction tool from a set of inter-prediction coding tools is determined for the current block. An OBMC subblock size for the current block is determined based on information related to the inter prediction tool selected for the current block or the inter prediction tool of a neighboring block. Subblock OBMC is applied to a subblock boundary between a neighboring subblock and a current subblock of the current block according to the OBMC subblock size.

Abstract: Methods and apparatus for video coding system utilizing Rate-Distortion Optimized Quantization (RDOQ) are provided. According to one method, a rate for a level belonging to a level set of a current quantized transform coefficient is estimated for a current coefficient group (CG) based on neighboring quantized coefficients of the current quantized transform coefficient and the current CG. A best level for the current quantized transform coefficient is selected from the level set for a best RD-cost. In another method, a TB is partitioned into M regions and M best regions are derived for the M regions according to RDOQ. At least two alternative region RD-costs are generated for each of the M best regions based on a relative position between each of the M best regions and a last significant region in the TB. TB RD-cost for the TB is selected according a last non-zero best region position.

Abstract: Video processing methods comprise receiving input data of a current block in a current picture, constructing a candidate list for the current block by including one or more History-based Motion Vector Predictor (HMVP) candidates, selecting one candidate from the candidate list, locating a reference block according to motion information of the selected candidate, and encoding or decoding the current block by predicting the current block using the reference block. The one or more HMVP candidates are fetched from a normal HMVP table if the current block is to be processed by a normal inter prediction mode, and the one or more HMVP candidates are fetched form a Current Picture Referencing (CPR) HMVP table if the current block is to be processed by a CPR mode. The two HMVP tables are separately maintained and updated.

Abstract: Various schemes for realizing JCCR mode decision in frequency domain are described. An apparatus receives first and second pixel data of a current block of a picture and transform the pixel data into first and second transformed data in frequency domain. The apparatus generates joint pixel data comprising a pixelwise linear combination of the first and second transformed data. The apparatus generates reconstructed joint pixel data based on the joint pixel data by quantization and inverse quantization operations. The apparatus derives first and second reconstructed pixel data based on the reconstructed joint pixel data. The apparatus accordingly calculates first and second distortion values in frequency domain, based on which a preferred mode may be determined to code the current block.

Abstract: A method for specifying layout of subpictures is provided. A video decoder receives data from a bitstream to be decoded as a current picture of a video. The video decoder parses the bitstream for positions and sizes of multiple subpictures of the current picture. A position of a first subpicture and a size of a last subpicture are skipped during the parsing. The video decoder reconstructs the current picture and the subpictures of the current picture according to the positions and the sizes of the subpictures.

Abstract: A method and apparatus of video coding for a video encoding system or video decoding system are disclosed. According to one method, the current block region is partitioned into one or more leaf blocks using quadtree (QT) partition and/or 1D (one-dimensional) partition by firstly signalling or parsing a first syntax element to indicate whether the current block region is split into multiple smaller blocks. According to a second method, a target syntax model from multiple syntax models is determined. The current block region is partitioned into one or more leaf blocks using QT partition and/or 1D partition and signalling block partition information according to the target syntax model at an encoder side, or the block partition information is parsed according to the target syntax model and the current block region is partitioned into one or more leaf blocks at a decoder side.

Abstract: Video processing methods and apparatuses for coding a current block include receiving input data of a current block, splitting the current block into sub-blocks, deriving motion information for the sub-blocks, performing motion compensation for the sub-blocks using the motion information to derive a final predictor, deriving and storing a representative motion vector for each grid in the current block, and encoding or decoding the current block using the final predictor. The representative motion vector for grids in a weighted area is determined by combining the motion vectors of the sub-blocks if the motion vectors of the sub-blocks are in different lists. The representative motion vector for grids in the weighted area is determined as one of the motion vectors of the sub-blocks if the motion vectors of the sub-blocks are in the same list.