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

Dzung T Hoang

Van Luong Pham

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.

Method and apparatus for signaling skip mode flag

Aspects of the disclosure provide methods and apparatuses for video encoding/decoding. An apparatus for video decoding includes processing circuitry that decodes prediction information for a current block in a current coded picture. The prediction information indicates a motion vector predictor index (MVP_idx) for selecting a motion vector predictor in a motion vector predictor list. The processing circuitry determines whether the MVP_idx is smaller than a threshold. When the MVP_idx is determined to be smaller than the threshold, the processing circuitry decodes a motion vector difference (MVD) corresponding to the motion vector predictor and reconstructs the current block based on the motion vector predictor and the MVD. When the MVP_idx is determined to be equal to or larger than the threshold, the processing circuitry reconstructs the current block based on the motion vector predictor without the MVD which is not signaled in the coded video sequence.

Methods and apparatuses for video coding

The various embodiments described herein include methods and systems for encoding and decoding video. In one aspect, a method includes receiving a video bitstream comprising a plurality of blocks, including a first block, where the first block includes a plurality of subblocks. The method also includes determining, based on a syntax element value in the video bitstream, that the first block is predicted in a subblock mode. The method further includes, in accordance with the first block being predicted in the subblock mode: deriving a set of motion vector predictors (MVPs) corresponding to a plurality of subblocks of the first block; deriving a set of motion vector differences (MVDs) for the plurality of subblocks; determining a set of motion vectors for the plurality of subblocks by applying the set of MVDs to the set of MVPs; and reconstructing the first block using the set of motion vectors.

Systems and methods for subblock motion vector coding

Video decoding and encoding methods and apparatuses are provided. The decoding method includes: obtaining a first parameter set corresponding to a to-be-decoded video frame; determining an effective quantization matrix (QM) according to syntax elements included in the first parameter set, the effective QM being a QM actually used for inversely quantizing quantized transform coefficients during decoding of the to-be-decoded video frame; and decoding the effective QM.

Video decoding method and apparatus, video encoding method and apparatus, device, and storage medium

Low complexity, hardware-friendly techniques are proposed for video coding systems to mitigate banding artifacts while maintaining the compression efficiency. In general, the proposed techniques consist of two stages including a banding detection stage and a de-banding stage. The banding detection stage may identify the image/video regions where the banding artifact may be present based on gradient information and other information. The de-banding stage may apply corrective techniques to regions identified as likely to possess banding artifacts. In one embodiment, the de-banding adapts the filtering logic proposed by prior video coding standards for other filtering applications to mitigate banding. When implemented over the AV1 video coding standard and the AOM Video Model (AVM) reference software, the proposed technique improves subjective quality significantly at a reasonable hardware implementation cost. The methods and embodiments presented in this document can be beneficial find application in a wide variety of image/video coding standards and systems.

Techniques for contouring/banding artifact removal in compressed image/video

A method and apparatus for inter prediction performed by at least one processor. The method for inter prediction comprising: receiving a coded video bitstream that includes a current picture, and first and second reference pictures associated with the current picture, the current picture including at least one block encoded in accordance with an inter bi-prediction mode, the at least one block including a first motion vector that points to the first reference picture and a second motion vector that points to the second reference picture; determining whether an out of boundary condition associated with the first motion vector and the second motion vector is satisfied; and adaptively disallowing bi-prediction to have MVs pointing to out of reference picture boundary, for inter bi-prediction mode.

Method and apparatus adaptive constraint on bi-prediction for out-of-boundary conditions

Coded information of a first color component and a second color component associated with a current block is determined. A first prediction mode is determined to be selected from an intra prediction mode, an inter prediction mode, or a combined intra-inter prediction mode for the first color component associated with the current block. A second prediction mode is determined to be selected from the intra prediction mode, the inter prediction mode, or the combined intra-inter prediction mode for the second color component associated with the current block. The second prediction mode is different from the first prediction mode. The current block is reconstructed based on predicting the first color component of the current block in the first prediction mode and predicting the second color component of the current block in the second prediction mode.

Component dependent intra and inter prediction signaling

Aspects of the disclosure provide a method and an apparatus for video decoding. The apparatus includes processing circuitry that receives a coded bitstream comprising a first block in a current picture. The processing circuitry obtains prediction information indicating whether the first block is coded in an intra template matching prediction (IntraTMP) mode. If the IntraTMP mode is applied to the first block, the first block is reconstructed based on a prediction block within a reconstructed search area in the current picture. A reference template of the prediction block is matched to a current template of the first block in the IntraTMP mode. An IntraTMP-based block vector BVof the first block is stored. The IntraTMP-based block vector indicates a position displacement between the current template of the first block and the reference template of the prediction block. A second block is reconstructed based on the stored IntraTMP-based block vector.

Intra block copy (IBC) candidate list construction with motion information of intra template-matching prediction

Aspects of the disclosure provide a method and an apparatus including processing circuitry that decodes a value of a syntax element that indicates whether a current block is coded with a geometric partition mode (GPM) along a partition edge intersecting the current block. If the value of the syntax element indicates that the current block is coded with the GPM and a condition for adaptive blending is satisfied, width candidates in a width candidate list are reordered using template matching (TM) that is based on a current template of the current block and reference templates that correspond to the respective width candidates. A width candidate is selected from the reordered width candidate list. A width of a blending area defined by boundaries on both sides of the partition edge is determined based on the selected width candidate. The blending area is determined based on the width of the blending area.

Adaptive blending for geometric partition mode (GPM)

Aspects of the disclose provide methods and an apparatus for video and/or image coding. The apparatus includes processing circuitry that receives a bitstream including a plurality of pictures. The processing circuitry determines an initial motion vector (MV) associated with a motion compensation padding (MCP) block according to motion information of a boundary block located at a picture boundary of a picture in the plurality of pictures. The boundary block is located in the picture. The MCP block is located in an MCP area outside of the picture and adjacent to the picture boundary. The initial MV has a fractional precision. The processing circuitry generates a final MV associated with the MCP block based on the initial MV. The final MV has an integer precision. The processing circuitry reconstructs, according to the generated final MV having the integer precision, at least a sample in the MCP block.

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Milpitas, CA, United States of America

Guichun Li