Hfi Innovation Inc.

Mediatek Corporation

Mediatek Singapore Pte. Ltd.

Chen-Yen Lai

Ching-Yeh Chen

Tzu-Der Chuang

Chih-Wei Hsu

Yu-Wen Huang

Olena Chubach

Chun-Chia Chen

Yu-Ling Hsiao

Lulin Chen

Shih-Ta Hsiang

Yu-Chi Su

Chia-Ming Tsai

Han Huang

Zhi-Yi Lin

Yu-Cheng Lin

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.

Method and apparatus for hardware-friendly rate-distortion optimized quantization in video coding

Methods and apparatus for video coding using Adaptive Loop Filter (ALF) processing are disclosed. According to one method, the ALF virtual boundary processing is always applied to the bottom CTU row regardless whether the bottom CTU row is for a picture or a sub-picture. In another method, the ALF padding process is unified for different boundary types belonging to the target boundary belongs to a boundary-type group comprising two or more of slice boundary, tile boundary, VR360 face boundary, and sub-picture boundary. In yet another method, the ALF VB processing has a fixed priority for a corner region that both horizontal and vertical virtual boundaries can be applied.

Method and apparatus for adaptive loop filtering at picture and sub-picture boundary in video coding

A method for specifying layout of subpictures in video pictures is provided. A video decoder receives data from a bitstream to be decoded as a current picture of a video. For a current subpicture of a set of subpictures of the current picture, the video decoder determines a position of the current subpicture based on a width and a height of the current picture and a previously determined width and height of a particular subpicture in the set of subpictures. The video decoder reconstructs the current picture and the current subpicture based on the determined position.

Specifying layout in video pictures

A method and apparatus for video coding using a coding mode belonging to a mode group comprising an Intra Block Copy (IBC) mode and an Intra mode are disclosed. According to the present invention, for both IBC and Intra mode, a same default scaling matrix is used to derive the scaling matrix for a current block. In another embodiment, for the current block with block size of M×N or N×M, and M greater than N, a target scaling matrix is derived from an M×M scaling matrix by down-sampling the M×M scaling matrix to an M×N or N×M scaling matrix.

Method and apparatus of the quantization matrix computation and representation for video coding

Methods and apparatus of for video coding using sub-block based affine mode are disclosed. In one method, if affine fallback is used or the control-point motion vectors are the same, the sub-block based affine mode is disabled in order to reduce computational complexity. According to another method for video coding using a coding tool belonging to a coding tool group comprising Prediction Refinement with Optical Flow (PROF) and Bi-Directional Optical Flow (BDOF), predictor refinement is derived for pixels of a target subblock of the current block, where a step to derive the predictor refinement comprises to derive gradients for the pixels of the target subblock of the current block and to right-shift the first gradients by a common shift.

Method and apparatus of simplified affine subblock process for video coding system

Encoding methods and apparatuses include receiving input video data of a current block in a current picture and applying a Cross-Component Adaptive Loop Filter (CCALF) processing on the current block based on cross-component filter coefficients to refine chroma components of the current block according to luma sample values. The method further includes signaling two Adaptive Loop Filter (ALF) signal flags and two CCALF signal flags in an Adaptation Parameter Set (APS) with an APS parameter type equal to ALF or parsing two ALF signal flags and two CCALF signal flags from an APS with an APS parameter type equal to ALF, signaling or parsing one or more Picture Header (PH) CCALF syntax elements or Slice Header (SH) CCALF syntax elements, wherein both ALF and CCALF signaling are present either in a PH or SH, and encoding or decoding the current block in the current picture.

Methods and apparatuses of syntax signaling constraint for cross-component adaptive loop filter in video coding system

Video processing methods and apparatuses for coding a current block comprise receiving input data of a current block, partitioning the current block into multiple sub-blocks, deriving sub-block MVs for the current block according to a sub-block motion compensation coding tool, constraining the sub-block MVs to form constrained sub-block MVs, and encoding or decoding the current block using the constrained sub-block MVs, and applying motion compensation to the current block using the constrained sub-block MVs to encode or decode the current block. The sub-block MVs may be constrained according to a size, width, or height of the current block or a sub-block, an inter prediction direction of one of control point MVs of the current block, the current block, or current sub-block, the control point MVs, or a combination of the above.

Video processing methods and apparatuses for sub-block motion compensation in video coding systems

Methods and apparatus for video coding are disclosed. According to one method, First ALF (Adaptive Loop Filter) processing is applied to the reconstructed chroma samples for a target reconstructed chroma sample to generate a first filtered chroma sample. Second ALF processing is applied to the related reconstructed luma samples to generate a second filtered chroma sample for the target reconstructed chroma sample, where positions of the related reconstructed luma samples selected for the second ALF processing are determined according to the target chroma format. According to another method, the luma ALF and the cross-component ALF have the same filter coefficient precision.

Method and apparatus of cross-component adaptive loop filtering for video coding

A video system that applies constraints on block partitioning is provided. The system receives a partitioning control parameter from a bitstream specifying a maximum block size for enabling ternary-tree split that is constrained to be 64 or smaller. The system receives data from a bitstream for a block of pixels to be decoded as a current block of a current picture of a video. The system splits the current block into one or more partitions recursively, wherein ternary split is disallowed for a partition of the current block unless the partition is less than or equal to the maximum block size. The system reconstructs the one or more partitions of the current block.

Signaling block partitioning of image and video

Methods and apparatus for Adaptive Loop Filter (ALF) processing of reconstructed video are disclosed. According to one implementation, a method receives reconstructed pixels of a current block and determines one or more clipping values for the ALF processing, wherein a target clipping value is always signaled at an encoder side or parsed at a decoder side even if the target clipping value is zero. The method then derives a current ALF output for the current block, wherein the current ALF output has a weighted sum of clipped differences and each of the original differences is calculated between a first reconstructed pixel at a non-center filter location and a center reconstructed pixel at a center filter location, and each of the original differences is clipped according to a corresponding clipping value to form one clipped difference. The method then provides filtered-reconstructed pixels.

Method and apparatus for non-linear adaptive loop filtering in video coding

Video processing methods comprise receiving input data of a current block in a current picture having a plurality of Virtual Pipeline Data Units (VPDUs), wherein each VDPU is a fixed size, performing a decoding process to decode Coding Units (CUs) in the current VPDU and generate decoded samples of the current VPDU, wherein each CU coded in a Current Picture Referencing (CPR) mode is decoded by fetching decoded samples in a reference block stored in a CPR referring buffer, and updating the CPR referring buffer by storing the decoded samples of the current VPDU when finishing the decoding process of the current VPDU, wherein the CPR referring buffer is updated one VPDU by one VPDU.

Method of encoding or decoding video blocks by current picture referencing coding

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.

Apparatus of encoding or decoding video blocks by current picture referencing coding

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.

Frequency domain mode decision for joint chroma coding

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.

Specifying video picture information

Aspects of the disclosure provide a method and an apparatus for video coding. A processing circuitry determines a process unit size for a decoder-side motion vector refinement (DMVR). Then, the processing circuitry enables an application of the DMVR on a current block when a size of the current block is smaller than or equal to the process unit size; and disables the application of the DMVR on the current block when the size of the current block is larger than the process unit size. In an example, the application of the DMVR refines the motion vectors with or without a template block.

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Hsinchu, Taiwan

Chen-Yen Lai