Mediatek Corporation

Hfi Innovation Inc.

Man-Shu Chiang

Chih-Wei Hsu

Tzu-Der Chuang

Ching-Yeh Chen

Chun-Chia Chen

Yu-Wen Huang

Chia-Ming Tsai

Shih-Ta Hsiang

Zhi-Yi Lin

Cheng-Yen Chuang

Yu-Ling Hsiao

Mohammed Golam Sarwer

Chih-Hsuan Lo

Tzu Der Chuang

A method and apparatus for video coding. According to this method, a set of candidates associated with coding modes or coding parameters is determined. Boundary matching costs associated with the set of candidates are determined, where each of the boundary matching costs is determined, for one target candidate of the set of candidates, by using reconstructed or predicted samples of the current block and neighbouring reconstructed or predicted samples of the current block. The reconstructed or predicted samples of the current block are determined according to the one target candidate. The set of candidates are reordered according to the boundary matching costs. The current block is then encoded or decoded using a final candidate selected from the set of candidates based on reordered candidates of the set of candidates.

Method and apparatus for coding mode selection in video coding system

A video encoder receives raw pixel data to be encoded as a current block of a current picture of a video into a bitstream. The video encoder identifies multiple candidate bi-prediction positions for the current block, including a center position, a first set of offset positions, and a second set of offset positions. The first set of offset positions and the second set of offset positions interleave each other. The encoder computes distortion values for each of the candidate bi-prediction positions based on several possible weighting parameter values. The distortion values for the center position are based on each of the several possible weighting parameter values. The distortion values for the first set of offset positions are based on a first subset of the possible weighting parameter values. The distortion values for the second set of offset positions are based on a second subset of the possible weighting parameter values.

Shared architecture for multiple video coding modes

A method for video encoding and decoding using Low-Frequency Non-Separable Transform (LFNST) mode and apparatus thereof are disclosed. The input data correspond to primary transformed data at the encoder and the input data correspond to coded data of the current CU at the decoder. A CU is partitioned into one or more transform blocks (TBs). An LFNST syntax is determined at an encoder side or at a decoder side if one or more conditions are satisfied. The LFNST syntax indicates whether the LFNST mode is applied to the current CU and/or which LFNST kernel is applied when the LFNST mode is applied. The conditions comprise the CBF indications for the target TBs being false. The current CU is encoded or decoded according to the LFNST mode as indicated by the LFNST syntax.

Methods and apparatus for secondary transform signaling in video coding

A method and apparatus of prediction for video coding are disclosed. According to one method, a luma Intra prediction mode is determined for a corresponding luma block collocated with the current chroma block, where a predefined mode is assigned to the luma Intra prediction mode when the corresponding luma block collocated with the current chroma block satisfies one or more conditions. A chroma Intra prediction mode is determined for the current chroma block according to the luma Intra prediction mode. The current chroma block is then encoded or decoded according to the chroma Intra prediction mode. According to another method, a predefined mode is assigned to Intra prediction mode for the current block when the current block satisfies one or more conditions. The current block is then encoded or decoded according to the Intra prediction mode.

Method and apparatus of chroma direct mode generation for video coding

In a method and apparatus for video coding using Low-Frequency Non-Separable Transform (LFNST) mode, a coding unit (CU) is partitioned into one or more transform blocks (TBs). A syntax is determined at an encoder side or at a decoder side, where the determining step is performed by signaling the syntax at the encoder side or by parsing the syntax at the decoder side if one or more conditions are satisfied. The syntax indicates whether the LFNST mode is applied to the current CU and/or which LFNST kernel is applied when the LFNSF is applied, and the conditions comprise a target condition corresponding to that all target TBs in a target TB set have a TS mode indication as false, and the target TB set is selected from the TBs in the current CU. The current CU is encoded or decoded according to the LFNST mode.

Methods and apparatus for restricted secondary transform and signaling thereof in image coding

A method and apparatus of prediction for video coding are disclosed. According to one method, a block is partitioned into a first and second regions using a target partition selected from a partition set comprising triangle partition. A Merge candidate list is determined for a partitioned current block by including at least one HMVP (history-based motion vector prediction) candidate from an HMVP buffer, where the HMVP buffer stores motion information of previously coded blocks. The partitioned current block or current motion information associated with the partitioned current block are encoded or decoded using the Merge candidate list, where the Merge candidate list is used to derive a first candidate for the first region and a second candidate for the second region. In another method, whether to apply triangular CIIP (combined Inter/Intra prediction) to the current block is signaled at an encoder side or parsed at a decoder side.

Method and apparatus of combined inter and intra prediction for video coding

Video processing methods and apparatuses for coding a current block generate a final predictor by combining multiple predictors of the current block. One of the predictors for the current block is a motion compensated predictor, which is generated according to one candidate selected from a first candidate list. The construction of the first candidate list includes deriving an average candidate by averaging motion information of existing candidates in the first candidate list. A second predictor for the current block is another motion compensated predictor or an intra predictor.

Methods and apparatuses of combining multiple predictors for block prediction in video coding systems

Video processing methods and apparatuses in a video encoding or decoding system for transforming residuals of transform blocks into final transform coefficients or inverse transforming final transform coefficients into residuals. In order to solve the latency issue, exemplary embodiments check if a width or height of a coding block is larger than a predefined threshold, and disable secondary transform or inverse secondary transform for any transform block within the coding block if the width or height of the coding block is larger than the predefined threshold. Another embodiment checks if there are multiple transform blocks in a coding block, and disables secondary transform or inverse secondary transform if the coding block contains multiple transform blocks.

Methods and apparatuses for coding video data with secondary transform

Method and apparatus of video coding are disclosed. According to one method, in the decoder side, a predefined Intra mode is assigned to a neighboring block adjacent to the current luma block when the neighboring block satisfies one or more conditions. An MPM (Most Probable Mode) list is derived based on information comprising at least one of neighboring Intra modes. A current Intra mode is derived utilizing the MPM list. The current luma block is decoded according to the current Intra mode According to another method, a predefined Intra mode is assigned to a neighboring block adjacent to the current luma block if the neighboring block is coded in BDPCM (Block-based Delta Pulse Code Modulation) mode, where the predefined Intra mode is set to horizontal mode or vertical mode depending on prediction direction used by the BDPCM mode.

Method and apparatus of luma most probable mode list derivation for video coding

Video processing methods and apparatuses implemented in a video encoding or decoding system with conditional secondary transform signaling. The video encoding system determines and applies a transform operation to residuals of a transform block to generate final transform coefficients, and adaptively signals a secondary transform index according to a position of a last significant coefficient in the transform block. A value of the secondary transform index is determined according to the transform operation. The video decoding system parses last significant coefficient position syntax of each transform block in the current block from a video bitstream to determine a position of a last significant coefficient for each transform block, and infers inverse secondary transform is not applied to the current block according to the positions of the last significant coefficients; otherwise, the video decoding system determines an inverse transform operation by parsing a secondary transform index from the video bitstream.

Methods and apparatuses for coding video data with adaptive secondary transform signaling depending on TB level syntax

Video processing methods and apparatuses implemented in a video encoding or decoding system with conditional secondary transform signaling. The video encoding system determines and applies a transform operation to residuals of one or more transform blocks to generate final transform coefficients, and skip signaling a secondary transform index if a position of a last significant coefficient in each considered transform block is less than or equal to a predefined position; otherwise, the video encoding system signals a secondary transform index according to the transform operation. The video decoding system parses last significant coefficient position syntax of each considered transform block to determine a position of a last significant coefficient, and infers inverse secondary transform is not applied if the positions of the last significant coefficients are less than or equal to the predefined position; otherwise, the video decoding system determines an inverse transform operation by parsing a secondary transform index.

Methods and apparatuses for coding video data with adaptive secondary transform signaling

A video decoder that decodes a current block of pixels by using multi-hypothesis combined prediction mode is provided. The video decoder generates a first prediction of the current block based on an inter prediction mode. The video decoder enables the combined prediction mode for the current block based on a block size of the current block determined according to a width and a height of the current block. The combined prediction mode is disabled when the width of or the height of the current block is greater than a threshold length. When the combined prediction mode is enabled, the video decoder generates a second prediction based on an intra prediction mode that is inferred to be a planar mode, and subsequently a combined prediction for the current block based on the first prediction and the second prediction. The video decoder reconstructs the current block by using the combined prediction.

Intra prediction for multi-hypothesis

A method and apparatus of Inter prediction for video coding using Multi-hypothesis (MH) are disclosed. If an MH mode is used for the current block: at least one MH candidate is derived using reduced reference data by adjusting at least one coding-control setting; an Inter candidate list is generated, where the Inter candidate list comprises said at least one MH candidate; and current motion information associated with the current block is encoded using the Inter candidate list at the video encoder side or the current motion information associated with the current block is decoded at the video decoder side using the Merge candidate list. The coding control setting may correspond to prediction direction setting, filter tap setting, block size of reference block to be fetched, reference picture setting or motion limitation setting.

Method and apparatus of motion compensation bandwidth reduction for video coding system utilizing multi-hypothesis

A method and apparatus of Inter prediction for video coding using a target Merge mode comprising a triangle Merge mode are disclosed. According to this method, a current block is partitioned into a first region and a second region using the target partition. A candidate list is determined. Two candidates are determined for the two regions by deriving two target candidates from the candidate list. When a selected target candidate is a uni-prediction candidate, the selected target candidate is used as one candidate; and when the selected target candidate is a bi-prediction candidate, motion information associated of the selected target candidate with List 0 or List 1 is used as one candidate. The current block or current motion information associated with the current block is encoded or decoded according to the candidate list. The candidate list is used to derive the first candidate and the second candidate.

Method and apparatus of simplified triangle merge mode candidate list derivation

Video encoding methods and apparatuses in a video encoding system receive an input residual signal of a current block by a shared transform circuit, apply horizontal transform and vertical transform by a shared transform circuit to generate transform coefficients, apply quantization and inverse quantization to generate recovered transform coefficients, apply inverse vertical transform and inverse horizontal transform to the recovered transform coefficients by the shared transform circuit to generate a reconstructed residual signal for the current block, and encode the current block based on quantized levels of the current block. The shared transform circuit and a coefficient buffer in the folded 4-time transform architecture reuse computation resources in each transform stage. In some embodiments of the folded 4-time transform architecture, a hierarchical design for block size grouping is implemented with fixed throughput for uniform hardware scheduling.

Growing community of inventors

Hsinchu, Taiwan

Man-Shu Chiang