Tencent America LLC

Other

Tencent Technology (shenzhen) Company Limited

Apple Inc.

Guichun Li

Shan Liu

Xiaozhong Xu

Xiang Yang Li

Xiang Li

Lien-Fei Chen

Xin Zhao

Meng Xu

Liang Zhao

Jing Ye

Byeongdoo Choi

Ling Li

Han Gao

Hong Zhang

Yixin Du

Alexandros Michael Tourapis

Anish Tamse

Arash Vosoughi

Bin Zhu

Hilmi Enes Egilmez

Alican Nalci

Thuong Nguyen Canh

Linfeng Guo

Lien-fei Chen

Dzung T Hoang

Van Luong Pham

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. The processing circuitry receives a bitstream carrying a plurality of pictures, and determines at least a motion compensation padding (MCP) block that is located in an MCP area outside of a picture and next to a picture boundary of the picture. The processing circuitry derives, according to a plurality of candidates with positions located at the picture boundary within the picture, a motion vector of the MCP block for motion compensated boundary padding, and reconstructs at least a sample in the MCP block according to the derived motion vector for the motion compensated boundary padding.

On motion compensated picture boundary padding

Processing circuitry for video decoding receives coded information of a current block in a current picture from a coded video bitstream, the coded information is indicative of applying local illumination compensation (LIC) on the current block in the current picture. The processing circuitry derives, parameters of an LIC model, according to a first template of a current block and a second template of a reference block in a reference picture. The reference block is pointed based on a motion vector for the current block. The first template includes a subset of reconstructed neighboring samples that are above and left to the current block, and the second template includes collocated samples to the subset of the reconstructed neighboring samples. The processing circuitry applies the LIC model on the current block according to the reference block to generate compensated samples of the current block.

Local illumination compensation

Processing circuitry receives coded information of a current block indicative of applying LIC on the current block according to at least a first reference block in a first reference picture. The processing circuitry determines, for a sample in the current block, at least a first reference sample in the first reference block, the first reference sample is co-located to the sample in the current block. The processing circuitry calculates a weighted sum of a plurality of terms and an offset for the LIC according to a plurality of parameter values for a plurality of parameters used in the LIC, and reconstructs the sample accordingly. The plurality of parameter values includes at least a first weighting value for a first weighting that is applied to a non-linear term of the first reference sample of a kth power, k is a power index value and is not equal to 1.

Local illumination compensation for bi-prediction

Aspects of the disclosure provide methods and apparatuses for video encoding/decoding. In some examples, an apparatus for video decoding includes processing circuitry. The processing circuitry extracts, from a bitstream, merge with motion vector difference (MMVD) candidate information for a current block in a current picture. The processing circuitry generates a first MV refinement offset associated with a first motion vector for the MMVD candidate based on a refined step size and a plurality of refinement positions. The processing circuitry derives a first refined motion vector (MV) value associated with a MMVD candidate according to the MMVD candidate information and the generated first MV refinement offset. The processing circuitry reconstructing the current block according to a first reference block in a first reference picture, the first reference block is indicated by the derived first refined MV value.

MMVD candidate refinement methods

A method and an apparatus are provided. The apparatus includes processing circuitry that receives a coded video bitstream comprising a current picture that includes a current block. The processing circuitry determines, based on a syntax element in the coded video bitstream, that the current block including a plurality of subblocks is coded in a subblock-based temporal motion vector prediction (SbTMVP) mode. The processing circuitry determines a plurality of displacement vector (DV) predictor (DVP) candidates and receives a base index indicating a DVP in the plurality of DVP candidates and a DV offset of the current block. The processing circuitry determines a DV based on the DVP and the DV offset. The DV indicates a block collocated with the current block in a collocated reference picture. The processing circuitry reconstructs a subblock in the plurality of subblocks based on motion information of a corresponding subblock in the collocated block.

Subblock level temporal motion vector prediction with multiple displacement vector predictors and an offset

Aspects of the disclosure provide a method and an apparatus including processing circuitry that adds merge candidates into a merge candidate list of a current block in a current picture. The merge candidates include available merge candidates including one or more of spatial motion vector predictors (MVP(s)), temporal MVP(s), non-adjacent MVP(s), history-based MVP(s), and pairwise average MVP(s). Whether the merge candidate list includes all available SMVP, TMVP, NA-MVP, HMVP, and PAMVP, and no merge candidate in the merge candidate list has a zero motion vector (zero MV) are determined. If the merge candidate list includes all available SMVP, TMVP, NA-MVP, HMVP, and PAMVP, and no merge candidate in the merge candidate list has the zero MV, the merge candidate having the zero MV is added to the merge candidate list. Merge candidates in the merge candidate list including the merge candidate having the zero MV are reordered using template matching.

Zero motion vector in adaptive reordering of merge candidates (ARMC)

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. The processing circuitry determines, a use of an inherited context initialization in a context-based adaptive binary arithmetic coding (CABAC) for decoding a current portion of a video sequence carried by a bitstream. The processing circuitry decodes, from the bitstream, a syntax value that indicates a decoded portion in the video sequence for a context inheriting, and initializes context models for the CABAC based on stored context states associated with the decoded portion. Further, the processing circuitry decodes, the current portion from the bitstream according to the context models that are initialized based on the stored context states associated with the decoded portion.

CABAC inherited context initialization

Method, apparatus, and non-transitory storage medium for fusing sub-block motion vector predictors into one sub-block motion vector predictor during video coding and decoding is provided. The method may include deriving a first displacement vector for a sub-block of a current block identifying a co-located sub-block of a co-located picture, and based on the identified co-located sub-block, determine whether the co-located sub-block overlaps with one or more sub-blocks associated with a motion field grid in the co-located picture. Based on determining that the co-located sub-block overlaps with the one or more sub-blocks, the method may include, retrieving two or more sub-block motion vectors respectively associated with the one or more sub-blocks. A final motion vector predictor for the sub-block of the current block may be derived based on the two or more sub-block motion vectors retrieved.

Motion vector prediction fusion for subblock-based temporal motion vector prediction (SbTMVP) and temporal motion vector prediction (TMVP)

A current block is partitioned into a first partition and a second partition. Template samples of the current block are split into a first template region adjacent to the first partition and a second template region adjacent to the second partition. A plurality of first candidate reference blocks is determined for the first partition. A plurality of second candidate reference blocks is determined for the second partition. At least one of the plurality of first candidate reference blocks and the plurality of second candidate reference blocks is reordered based on a size of the first template region of the template samples and a size of the second template region of the template samples. The current block is reconstructed based on a received index value and based on the reordered at least one of the plurality of first candidate reference blocks and the plurality of second candidate reference blocks.

Template-matching based merge index reordering for geometric partition mode (GPM)

In some examples, an apparatus for video decoding includes receiving circuitry and processing circuitry. The processing circuitry receives coded information of a current block in a current picture from a coded video bitstream. The coded information includes a syntax element with a value indicative of a merge with motion vector difference (MMVD) mode being applied on the current block. The processing circuitry determines, in response to a motion vector predictor of a merge candidate being a bi-predictor, whether the merge candidate for the current block satisfies a requirement for applying a bi-prediction motion refinement. The processing circuitry can constrain the merge candidate for use in the MMVD mode when the merge candidate for the current block satisfies the requirement. Then, the processing circuitry reconstructs the current block in the MMVD mode with the merge candidate being constrained for use in the MMVD mode.

Merge with motion vector difference

A reference block is determined from a plurality of candidate reference blocks for a current block in a current picture based on template matching (TM) costs of the plurality of candidate reference blocks. The TM costs indicate differences between a template of the current block and respective reference templates of the plurality of candidate reference blocks. Samples of the determined reference block are classified into a plurality of classes of samples. A partitioning pattern of the current block is derived based on the determined reference block from a predetermined plurality of partitioning patterns. The derived partitioning pattern indicates a plurality of partitions of the current block. Each of the plurality of classes of the samples of the determined reference block corresponds to a respective partition of the plurality of partitions of the current block. The current block is reconstructed based on the derived partitioning pattern of the current block.

Template matching based partitioning pattern derivation

Aspects of the disclosure provide a method and an apparatus including processing circuitry that obtaining prediction information indicating whether a current block is coded in a subblock-based temporal motion vector prediction (SbTMVP) mode. If the current block is coded in the SbTMVP mode, whether a subblock in a plurality of subblocks of the current block is bi-predicted is determined. If the subblock is bi-predicted, motion information of the subblock is determined based on the SbTMVP mode. At least one of (i) a bilateral matching (BM)-based motion vector (MV) refinement and (ii) a bi-directional optical flow (BDOF) mode is applied to the subblock to refine the motion information of the subblock. The current block is reconstructed based on refined motion information corresponding to one or more subblocks in the plurality of subblocks. The refined motion information corresponding to the one or more subblocks includes the refined motion information of the subblock.

Decoder-side motion vector refinement and bi-directional optical flow in subblock-based temporal motion vector prediction (SBTMVP)

Processing circuitry determines an initial affine model with bi-prediction for a current block in an affine motion inter prediction mode, the initial affine model predicts the current block based on a first reference picture and a second reference picture. The processing circuitry performs a multi-stage bilateral matching motion refinement with at least a first stage and a second stage on the initial affine model to derive a refined affine model, one of the first stage and the second stage applies a first bilateral matching motion refinement on a translational component of the initial affine model, and the other of the first stage and the second stage applies a second bilateral matching motion refinement on a non-translational component of the initial affine model. The processing circuitry reconstructs the current block using the refined affine model based on the first reference picture and the second reference picture.

Method and apparatus for affine motion refinement

First affine parameters and second affine parameters for each of one or more affine models associated with a current block are determined. The first affine parameters of the respective affine model are associated with a first motion vector for a first reference picture of the current block. The second affine parameters of the respective affine model are associated with a second motion vector for a second reference picture of the current block. The first affine parameters and the second affine parameters of the respective affine model have opposite signs. Control point motion vectors (CPMVs) of the affine motion of the current block are determined by performing the affine bilateral matching based on the determined first affine parameters and the determined second affine parameters of the one or more affine models. The current block is reconstructed based on the CPMVs of the affine motion of the current block.

Affine models use in affine bilateral matching

Aspects of the disclosure provide methods for video encoding/decoding and processing circuitry. In some embodiments, the processing circuitry receives a block in an I slice from a video. In response to a slice type parameter indicating the I slice and at least a width or height of the block being greater than 64, the processing circuitry sets a current mode type parameter to MODE_TYPE_INTRA. The processing circuitry then determines whether a skip mode is possible for the block in the I slice based on at least one of the width or the height of the block being greater than 64 and the current mode type parameter. When neither the width nor the height of the block is greater than 64 and the current mode type parameter is not MODE_TYPE_INTRA, the processing circuitry determines to output the skip mode flag into a coded video bitstream for the block.

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Milpitas, CA, United States of America

Guichun Li