Interdigital Vc Holdings, Inc.

Interdigital Ce Patent Holdings, Sas

Interdigital Madison Patent Holdings, Sas

Interdigital Vc Holdings France, Sas

Ya Chen

Tangi Poirier

Fabrice Leleannec

Philippe Bordes

Franck Galpin

Philippe De Lagrange

Edouard Francois

Karam Naser

Fabrice Le Leannec

Fabien Racape

Antoine Robert

Fabrice LeLeannec

Fabrice Urban

Gagan Bihari Rath

Gaëlle Martin-Cocher

Pierre Andrivon

Fabrice Le Léannec

Methods and apparatus for implementing Discrete Trigonometric transforms are based on maximum transform size. In one embodiment, matrix-based intra prediction is enabled for coding unit sizes up to a specified size, regardless of the maximum transform size. In another embodiment, low-frequency non-separable transforms are used to improve coding gain. Syntax in a bitstream can be used to indicate a coding tool that is used.

Transform size interactions with coding tools

In one implementation, when coding a block in the intra prediction mode, the block can be split into two sub-partitions by a geometrically located straight line. Each geometric partition within the CU is intra predicted using its own intra mode with its available reference sample. One sub-partition copies and uses the intra prediction mode from the parent block, and another sub-partition uses another implicit or explicit signaled intra prediction mode. After predicting geometric partition, the sample values along the split boundary are adjusted using a blending process with adaptive weights. The geometric partition based intra prediction could be applied for one angular intra prediction mode, or only for one negative-directional intra prediction mode, or only for one specific intra prediction mode (e.g., mode 34). The transform selection or other intra coding tools (i.e., intra sub-partition) can be adapted for the geometric partition based intra prediction.

Intra prediction with geometric partition

A reconstruction method comprising: obtaining () a region predictor for a current region of a picture based on a spatial prediction; obtaining () an information representative of a partitioning of the current region into sub-regions; reconstructing () at least one residual sub-region based on an intra prediction residual and an intra prediction mode and obtaining a reconstructed residual region from the at least one reconstructed residual sub-region, wherein all reference samples external to the current region used for reconstructing the at least one sub-region are set to zero before reconstructing the at least one residual sub-region; and, reconstructing () the current region based on the reconstructed residual region and on the region predictor by adding a final predictor obtained from the region predictor and the reconstructed residual region.

Spatial illumination compensation on large areas

An encoding method is presented. Transform coefficients of a block are first obtained. They are then scanned according to a scan pattern for entropy coding. The scan pattern is determined responsive to a shape of the block.

Method and device for picture encoding and decoding

Various implementations for video encoding and decoding are presented involving determining, for a block being encoded or decoded in a picture, a coefficient group mode for coding at least one coefficient of a set of transform coefficients of the image block; encoding or decoding the set of transform coefficients of the image block responsive to the coefficient group mode. The coefficient group mode can be determined from at least one of image block size, number of non-zero transform coefficients inside the image block, position of a transform coefficient inside the image block, decoded syntax element, wherein the coefficient group mode can specify whether a coefficient group significance flag is coded/decoded, indicating that at least one coefficient is non-zero inside a coefficient group and/or specify at least one size of the coefficient group.

Method and apparatus for video encoding and decoding based on adaptive coefficient group

A decoding method is disclosed. First, context for a syntax element associated with a current transform coefficient of a block of a picture is determined. The context is determined based on the area of said block, on the position of the current transform coefficient within the block and on the number of non-zero neighboring transform coefficients in a local template. Second, the syntax element is decoded based at least on the determined context. Advantageously, the local template depends on the shape of said block.

Encoding and decoding methods and corresponding devices

An encoding method is disclosed. At least one context is first determined for encoding a syntax element associated with a block of a picture responsive to a current quantization parameter associated with the block. Second, the syntax element is context-based entropy encoded with the at least one determined context.

Context-based binary arithmetic encoding and decoding

Different implementations are described, particularly implementations for video encoding and decoding are presented. Accordingly, the encoding or decoding comprises obtaining a merging candidate index that enables deriving both a first merging candidate index and a second merging candidate index in a triangular shape based motion compensation candidates list in list in use in a triangular shape based motion compensation. According to a particular characteristic, a mapping function determines the derivation process of both indices among a subset of possible combinations of merge candidate indices.

Signaling of merge indices for triangle partitions

PROF (Prediction Refinement with Optical Flow) and BDOF (Bi-directional Optical Flow) use the optical flow model to provide sample-wise motion compensation refinement. In one implementation, to calculate the spatial gradients in BDOF, an extended region is generated around a block to be coded. To simplify the computation, BDOF may use the same padding operations as in PROF, namely, a padding sample is copied from the nearest integer neighbor in the reference picture. BDOF and PROF can also be used together when sub-block based affine motion-compensated prediction is used. BDOF can be applied after PROF generates new prediction blocks, or BDOF can use the spatial gradients in the original prediction blocks to re-use the computations with PROF. In addition, BDOF and PROF operations can be combined, and the prediction adjustment will be directly based on the spatial gradients in the original prediction blocks.

Bi-prediction refinement in affine with optical flow

Video content frequently seen in gaming content and having a higher probability of being coded in transform skip mode is coded separately from remaining portions of a video coding block before being combined with regular coded portions. This enables more efficient coding of video by reducing the switching between regular coding modes and transform skip modes. The regular coded portion and the transform skip coded portion are combined in an encoder. At a corresponding decoder, inverse operations occur, such that the transform skipped residual portions are decoded and the regularly coded portions are decoded before the portions are combined for a resultant decoded video block.

Hybrid texture particle coding mode improvements

Inferring an illumination compensation flag during encoding or decoding of a video image signal using frame rate up conversion can save one bit and eliminate complexity. The illumination compensation flag can be derived from the corresponding flags of at least one bi-predictive or bi-directional prediction candidates. The flag can also be derived from some function of the flags from those candidates. Alternatively, several flags can be used for respective coding or decoding of blocks if there are more than one prediction candidate using illumination compensation.

Illumination compensation flag in frame rate up-conversion with template matching

A method includes decoding a first portion of video data consisting of an information set consisting of information representative of a plurality of candidate sets of sample adaptive offset filter parameters. A set of sample adaptive offset parameters comprises information representative of an offset to be added to a sample value of a current block. A first syntax element representing an index that identifies a first candidate set of the plurality of candidate sets of sample adaptive offset filter parameters is decoded from the video data for the current block. The current block is decoded from a second portion of the video data different from the first portion. The decoded current block is filtered with the first candidate set identified by the index. The first portion is signaled with syntax elements at a level of a block of a group of blocks comprising the current block decoded first in decoding order.

Method and a device for picture encoding and decoding

A decoding method is disclosed. It comprises: —decoding parameters for a current block; —disabling a first coding tool for said current block in the case where one or more of the following conditions is verified: a second coding tool is used for said current block and a given condition on the decoded parameters is verified; —enabling for said current block said first coding tool otherwise; and —decoding said current block using said first coding tool if said first coding tool is enabled.

Different quantization matrices may be transmitted corresponding to different block sizes, color components and prediction modes. To more efficiently signal the coefficients of the quantization matrices, in one implementation, a unified matrix identifier matrixId is used, based on a size identifier (sizeId) that relates to CU size with larger sizes listed first, and a matrix type (matrixTypeId) with luma QMs listed first. For example, the unified identifier is derived as: matrixId=N*sizeId+matrixTypeId, where N is the number of possible type identifiers, e.g., N=6. This single identifier allows referring to any previously transmitted matrix when using prediction (copy), and transmitting larger matrices first avoids interpolation in the prediction process. When a block uses the Intra Block Copy prediction mode, QM identifier may be derived as if the block uses the INTER prediction mode.

Single-index quantization matrix design for video encoding and decoding

A method for decoding a current block of a picture is disclosed. First, at least one illumination compensation parameter for the current block is decoded responsive to a comparison of a parameter of the current block with a value. Then, an accessed motion compensation reference block is compensated in illumination responsive to the at least one illumination compensation parameter. Finally, the current block is reconstructed from the illumination and motion compensated reference block.

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Cesson-Sevigne, France

Ya Chen