Tencent America LLC

Han Gao

Shan Liu

Xin Zhao

Liang Zhao

Jing Ye

Guichun Li

Lien-Fei Chen

Yushin Cho

Xiaozhong Xu

Madhu Peringassery Krishnan

Biao Wang

Tianqi Liu

Coded information of a current block and neighboring blocks of the current block is received, where the current block is predicted in an intra directional mode. The intra directional mode of the current block is determined to be associated with an angle that is one of smaller than 90 degrees and larger than 180 degrees. In response to the intra directional mode of the current block being associated with the angle, whether a delta angle associated with the current block is a pre-defined delta angle is determined. In response to the delta angle associated with the current block not being the pre-defined delta angle, a single direction intra prediction and not a bi-direction intra prediction is applied to the current block. A sample of the current block is reconstructed based on an adjacent reference sample on a reference line that is determined according to the single direction intra prediction.

Angular intra prediction

Various implementations described herein include methods and systems for coding video. In one aspect, a video bitstream includes a current image frame and a first syntax element. An electronic device determines that the first syntax element has a first predefined value indicating that the cross-component sample offset (CCSO) mode is enabled, and generates a set of adapted luma samples including an adapted first luma sample and its adapted neighboring luma samples based on a set of reconstructed luma samples. The reconstructed luma samples include a first luma sample that is collocated with a first color sample. The electronic device determines the first sample offset of the first color sample based on the adapted first luma sample and the one or more adapted neighboring luma samples. The current image frame is reconstructed at least by adjusting the first color sample based on the first sample offset.

CCSO with downsampling filters and sample position selection

Methods and systems for determining contexts for coding and decoding various syntax elements of a video stream in inter prediction modes are described. The methods and systems enable a limitation on numbers of possible coding contexts for syntax elements related to the inter prediction mode, and a selection of coding contexts for a current block based on coding information of spatially neighboring blocks and temporal motion prediction information.

Context design for coding and decoding syntax elements in inter prediction modes

This disclosure describes aspects of advanced video coding technologies and is particular related to cross-component sample offset (CCSO) filtering of reconstructed samples. For example, a quantizer for quantizing sample deltas in order to apply a CCSO filter may be constructed as an asymmetric quantizer with respect to zero sample delta. Either a symmetric or an asymmetric quantizer may be selected for processing sample deltas prior to applying a CCSO filter. An asymmetric quantizer may relate to a corresponding symmetric quantizer by a non-zero offset. Signaling of a selection of an asymmetric quantizer may be provided separately from or dependent on a signaling of a symmetric quantizer.

Cross component sample offset filtering with asymmetric quantizer

The implementations described herein include methods and systems for coding video. In one aspect, a method includes receiving a current frame including a current coding block. The current coding block has multiple subblocks. The subblocks are associated with different motion vectors, and include a first subblock located at a boundary of the current coding block. The method includes determining a motion vector of the current coding block, determining a first motion vector of the first subblock, and generating motion compensation data of the first subblock based on the motion vector and the first motion vector of the first subblock, e.g., by identifying a prediction block based on the motion vector of the current coding block, identifying a first prediction block based on the first motion vector of the first subblock, and combining the prediction block and the first prediction block to generate the motion compensation data of the first subblock.

Systems and methods for combining subblock motion compensation and overlapped block motion compensation

This disclosure relates generally to video coding and particularly to methods and systems for deriving context adaptive interpolation filter used for generating prediction samples in inter prediction involving a fractional motion vector or block vector. For example, an encoder and a decoder may derive interpolation filters adaptively using reconstructed samples. The reconstructed samples may belong to templates near a current block and a reference block related by the motion vector or block vector. The derivation of the adaptive interpolation filters may be based on minimizing distortions between interpolated templates associated with the reference block and the templates associated with the current block.

Context adaptive interpolation filter

This disclosure generally describes a set of advanced video coding technologies, and is specifically related to cross-component sample offset (CCSO) filtering. For example, a CCSO filter having fractional CCSO filtering tap positions may be used to generate sample offsets from one color component of a reconstructed video. The sample offsets may then be applied to a second color component of the reconstructed video. The reconstructed samples of the first color component may first be interpolated by an interpolation filter in order to generate interpolated samples of the first color component at the fractional CCSO tap positions. The interpolated samples may be used as input to the CCSO filter for the generation of the sample offsets.

Cross component sample offset filtering with interpolated filter taps

This disclosure relates generally to video coding/decoding and particularly for a transform dictionary. A method includes receiving the coded video bitstream; determining, based on the coded video bitstream, a transform pile for the current block, the transform pile being one transform pile in a transform dictionary, the transform dictionary comprising a plurality of transform piles, and the transform pile comprising a plurality of transform sets; determining a transform set in the transform pile; determining a transform kernel in the transform set; performing an inverse transform for the current block based on the transform kernel for obtaining a residual block for the current block; and reconstructing the current block based on the residual block.

Dictionary of transforms

This disclosure relates generally to video coding/decoding and particularly for providing extension to block adaptive weighted prediction (BAWP). One method includes receiving a coded video bitstream; determining, based on a syntax element signaled in the coded video bitstream, a prediction mode for predicting the current block based on a reference block, wherein the prediction mode comprises a linear equation; deriving a scaling factor for the current block, from at least one of the following: multiple scaling factors of neighboring blocks with respect to the current block, or a stored scaling factor bank; and reconstructing the current block based on the reference block and the identified scaling factor according to the linear equation.

Extension to block adaptive weighted prediction

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

This disclosure relates generally to video coding/decoding and particularly for implicitly indicating motion vector predictor precision. One method includes receiving a coded video bitstream; determining, based on the coded video bitstream, a current block of a current frame to be inter predicted by at least one reference block of at least one reference frame; determining, based on the coded video bitstream, a motion vector (MV) of the current block to be predicted by a motion vector predictor (MVP) and a corresponding motion vector difference (MVD); determining an MVP precision according to an implicit indication, a pre-defined rule, or a high-level syntax, wherein an MVD precision associated with the corresponding MVD is different from the MVP precision; and reconstructing, by the device, the current block based at least on the MVP at the determined MVP precision and the MVD at the MVD precision that is different from the MVP precision.

Method and apparatus for implicitly indicating motion vector predictor precision

Processing circuitry receives, from a coded video bitstream, coded information of a current coding block in a current picture. The coded information is indicative of a directional intra prediction of the current coding block. The processing circuitry determines an index to an entry in an angle-to-offset mapping lookup table according to the coded information of current coding block. The angle-to-offset mapping lookup table stores a set of derivative values that are associated with angles, the set of derivative values includes two or more integers that are powers of two. The processing circuitry accesses the entry to obtain a derivative value, determines, for a pixel in the current coding block, an offset indicative of a reference location in the current picture according to the derivative value and a location of the pixel, and reconstructs the pixel in the current coding block based on the reference location in the current picture.

Refined intra prediction angles

This disclosure relates generally to video coding and particularly to methods and systems for determining context for coding and decoding various syntax elements of a video stream in inter prediction modes. Various example implementations are disclosed for limiting numbers of possible coding contexts for syntax elements related to the inter prediction mode, and for selecting coding contexts for a current block based on coding information of spatially neighboring blocks and temporal motion prediction information.

The various implementations described herein include methods and systems for coding video. In one aspect, a method includes receiving a video bitstream including a current coding block in a current image frame, obtaining a syntax element value, and determining whether the current coding block is coded with a warped motion mode or a translational motion mode based on the syntax element value. The method further includes in accordance with a determination that the current coding block is coded with the warped motion mode, selecting a first motion vector difference (MVD) setting for the current coding block; in accordance with a determination that the current coding block is coded with the translational motion mode, selecting a second MVD setting distinct from the second MVD setting for the current coding block; and reconstructing the current coding block based at least in part on the selected MVD setting for the current coding block.

Adaptive motion vector for warped motion mode of video coding

The various implementations described herein include methods and systems for coding video. In one aspect, a method of video decoding includes receiving video data including a first block and a syntax element, from a video bitstream, where the syntax element is signaled at a first processing unit level. The method further includes selecting a transform coding mode based on the syntax element and performing a transform process for the first block using the selected transform coding mode, where the transform process is performed on a transform block at a second processing unit level, and where the second processing unit level is not signaled (e.g., is inferred from coded information).

Growing community of inventors

San Diego, CA, United States of America

Han Gao