Tencent America LLC

Beijing Dajia Internet Information Technology Co., Ltd.

Han Gao

Shan Liu

Xin Zhao

Liang Zhao

Jing Ye

Guichun Li

Lien-Fei Chen

Yushin Cho

Xiaozhong Xu

Madhu Peringassery Krishnan

Tianqi Liu

Xianglin Wang

Xiaoyu Xiu

Yi-Wen Chen

Bing Yu

Wei Chen

Hong-Jheng Jhu

Che-Wei Kuo

Ning Yan

Biao Wang

Lien-fei Chen

A computing system receives a video bitstream comprising a current picture and a current block within the current picture. The current block is encoded using information from a first reference block and a second reference block. When a portion of the current block corresponds to a first area that is within reference boundaries in both of the first and second reference blocks, the system reconstructs the portion using an average of reference values from the first and second reference blocks. When the portion of the current block corresponds to (i) a second area that is not within the reference boundaries in both of the first and second reference blocks or (ii) a third area that is within the reference boundaries in only one of the first and second reference blocks, the system reconstructs the portion using a weighted average of respective values of the first and second reference blocks.

Implicit masked blending mode improvement

The various implementations described herein include methods and systems for encoding and decoding video. In one aspect, a method of video decoding includes receiving video data that includes a first block from a video bitstream, where the first block is predicted in an angular prediction mode. The method also includes identifying a set of reference samples for a portion of the first block using a prediction angle for the angular prediction mode and deriving a first angular prediction value for the portion using at least a first subset of the set of reference samples. The method further includes deriving a second angular prediction value for the portion using a weighted sum of at least a second subset of the set of reference samples and the first angular prediction value and decoding the portion using the second angular prediction value.

Systems and methods for angular intra mode coding

The various implementations described herein include methods and systems for coding video. In one aspect, a video bitstream includes distinct coding blocks of a current image frame and signals a cross-component intra prediction mode. A method includes for each distinct coding block, identifying a chroma component, a luma sample co-located with the chroma component, and neighboring luma samples of the luma sample. The method includes deriving a respective bias value based on a set of luma samples within a reference area of the respective coding block, which includes one or more coding blocks that are adjacent to, and decoded prior to, the respective coding block in the current image frame. The method further includes combining the luma sample, the neighboring luma samples, and the respective bias value to generate the chroma component and reconstructing the distinct coding blocks including the chroma component of each distinct coding block.

Bias value determination for chroma-for-luma (CfL) mode

The various implementations described herein include methods and systems for coding video. In one aspect, a video bitstream includes a current coding block of an image frame and a syntax element for a cross-component intra prediction (CCIP) mode. The CCIP mode indicates whether each chroma sample of the current coding block is determined based on one or more luma samples. An electronic device generates a plurality of hypothesis values to be used in predicting a first chroma sample by combining a plurality of neighboring luma samples of a first luma sample that is co-located with the first chroma sample using a plurality of coefficients. The first chroma sample is predicted by combining the first luma sample and the plurality of hypothesis values based on a plurality of weighing factors. The electronic device reconstructs the current coding block including the first chroma sample.

Multi-hypothesis cross component prediction

This disclosure relates generally to video coding/decoding and particularly to motion vector prediction based on subblock motion vectors. One method is disclosed for processing a current block of a current frame in a coded video bitstream. The method includes receiving, by a device, a coded video bitstream; determining, by the device based on the coded video bitstream, the current block of the current frame to be inter predicted by at least one reference block of at least one reference frame; determining, by the device based on the coded video bitstream, a current-block motion vector (MV) corresponding to each of the at least one reference block, the current-block MV to be predicted by a reference MV; and identifying, by the device, a subblock MV of a MV reference block as the reference MV for predicting the current-block MV.

Method and apparatus for motion vector prediction based on subblock motion vector

This disclosure relates generally to video coding and particularly to smooth-sub-block motion compensation, disclosing methods and systems for determining subblock motion vectors of a video block based on motion information of its spatial neighboring block, temporal blocs spatially co-located with the neighboring blocks, or co-located temporal block of the video block.

Smooth sub-block motion vector prediction

A decoding device is provided for decoding of a bitstream, and more specifically for predicting a picture area of an input image for decoding. The picture area has been divided into at least first and second parts by a partitioning boundary, and the pixels of each part are predicted according to suitable measures. Blending masks are then applied to generate blended regions for the predicted pixels, modifying the pixels to generate a complete prediction of the picture area based on both parts. The blending mask is based on first and second thresholds, which are defined relative to the partitioning boundary, and which may have different values to produce an asymmetrical blending relative to the boundary. Based on suitable threshold values, the prediction, combination, and decoding of the picture area is more adaptive to differing contents of the parts therein.

Method and apparatus for asymmetric blending of predictions of partitioned pictures

The various implementations described herein include methods and systems for coding video. In one aspect, a method includes receiving video data including a picture, wherein the picture is coded using at least a first color component and a second color component, and the picture includes a first block that is coded in a geometric partition mode, the first block including a first geometric partition and a second geometric partition; reconstructing samples in a first geometric partition of the first color component of the first block; deriving samples in the first geometric partition of the second color component of the first block based on the reconstructed samples of the first color component of the first block; and decoding the first block in the picture based at least on the reconstructed samples in the first geometric partition of the first color component and the second color component of the first block.

Systems and methods for cross-component geometric/wedgelet partition derivation

An example method of video coding includes receiving a video bitstream including a plurality of coding blocks; identifying, based on a first indicator in the video bitstream, a coding region that comprises two or more blocks of the plurality of coding blocks, where at least one block in the coding region is encoded in an intra prediction mode and at least one block in the coding region is encoded in a non-intra prediction mode. For a last block in the coding region, when all preceding blocks in the coding region are encoded in the intra prediction mode, the method includes inferring a prediction mode of the last block as being an inter prediction mode without receiving an inter prediction mode indicator for the last block; and reconstructing the last block using the inferred prediction mode.

Systems and methods for implicit derivation in a recursive intra region

Implementations of the disclosure provide video processing apparatuses and methods for inter-prediction. A video processing method for the inter-prediction performed by a video decoder includes determining a reference index for a video block in a video frame of a video from a bitstream. The video processing method also includes generating a joint list including a plurality pairs of reference pictures based on a first reference list and a second reference list for the video block. The video processing method further includes reordering the plurality pairs of reference pictures in the joint list based on bilateral matching using one or more motion vectors of the video block to generate a reordered joint list. The video processing method further includes performing the inter-prediction on the video block based on the reordered joint list and the reference index.

Bilateral matching based reference picture reordering

Various implementations described herein include methods and systems for coding video. In one aspect, a video bitstream includes a high level syntax element for a frame level cross-component sample offset (CCSO) flag indicating whether to apply CCSO filtering on a current image frame. When the frame level CCSO flag indicates that CCSO filtering is applied the current image frame, an electronic device identifies, in the video bitstream, a first syntax element for a first component CCSO flag indicating whether to apply CCSO filtering on a first color component of the current image frame, and determines whether to apply CCSO filtering on a first color sample of the first color component based on the first syntax element. The current image frame including the first color sample of the first color component is reconstructed.

CCSO with high level flags

The various implementations described herein include methods and systems for coding video. In one aspect, a method of video decoding includes receiving video data that includes a first block and a plurality of residual coefficients, from a video bitstream. The first block is encoded in an intra prediction mode, and the plurality of residual coefficients are generated by applying a short distance intra prediction to a residue block for the first block. The residue block generated from applying the intra prediction mode to the first block. The method includes generating, from the plurality of residual coefficients, a refined residue block for the first block, and generating a reconstructed residue block for the first block, where the reconstructed residue block is generated using an intra prediction block and the refined residue block. The method also includes reconstructing the first block using the refined residue block.

Short distance predictions for residual blocks

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.

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San Diego, CA, United States of America

Han Gao