Abstract: A method and an apparatus for encoding a video are disclosed. For at least one block from a picture of said video, a first rate-distortion optimization is performed (602) for determining for a first splitting mode of said block into at least one first subblock, coding parameters of said at least one first subblock. At least one second rate-distortion optimization is performed (609) for determining for at least one second splitting mode of said block into at least one second subblock, coding parameters of said at least one second subblock. A best splitting mode for coding said block is determined (613) according to at least said first rate-distortion optimization and said second rate-distortion optimization, and said block is encoded (616) according to said best splitting mode.

Abstract: A decoding method is disclosed that comprises: —decoding a block of transform coefficients from a bitstream; —de-quantizing the decoded block of transform coefficients by a quantization step size; —scaling said dequantized block by a scaling factor; and —transforming said scaled block into an image block, wherein the scaling factor's value depends on whether at least one of the width and the height of the block is a power of 2.

Abstract: Different implementations are described, particularly implementations for video encoding and decoding based on a linear model responsive to neighboring samples are presented. Accordingly, for a block being encoded or decoded in a picture, at least one spatial neighboring template is determined and at least one linear model parameter is determined based on reconstructed samples of the at least one spatial neighboring template. In a first embodiment, the number N of reconstructed samples corresponds to N=2k with k chosen so that n is the maxim integer smaller than sum of the block width and block height. In a second embodiment, an offset for the relative position of a first sample in the template among samples of a left, respectively top, neighboring line of the block is determined. In a third embodiment, the number of reconstructed samples is set to a higher number in the larger dimension of the block.

Abstract: A video coding system uses a value of a chroma quantization parameter table to quantize or de-quantize chroma values of a block of the video, the chroma quantization parameter table being directly coded in a set of parameters at the picture level or at the sequence level of the coded video stream. A corresponding encoding method, encoding device, decoding method, decoding device, and non-transitory readable medium are proposed.

Abstract: A Frame Rate Up-Conversion (FRUC) derivation process, based on frame rate up-conversion techniques, is developed in the reference software JEM (Joint Exploration Model) by the Joint Video Exploration Team (JVET). In one embodiment, a modified FRUC derivation process improves the performance of the current FRUC tool is provided. For example, an initial list of motion vector candidates defined in the FRUC derivation process may be reordered, and/or one or more of the ordered motion vector candidates in the defined list may be removed to improve the efficiency of the process. The reordering and/or the removal may be based on, e.g., one or more of previously determined motion vector candidates of one or more previously decoded blocks. In addition, the adaptive reordering mode may be signaled by the encoder to the decoder as part of the modified FRUC derivation process.

Abstract: A significance-coefficient flag indicates whether a given quantized transform coefficient is equal to zero or not. To encode the significant-coefficient flags, context-based entropy coding can be used. To adapt to the characteristics of a video sequence, the context model is selected based on the statistics of the transform coefficients. In one embodiment, the non-zero probabilities of transform coefficients are compared to different thresholds to divide a transform block into several context regions, where all coefficients in a context region use the same set of context models. In another embodiment, the transform block is first divided into several context regions based on the positions of the transform coefficients, and the non-zero probabilities of transform coefficients are compared with a threshold to divide each context region into two sub-regions, where all coefficients in a sub-region share the same set of context models.

Abstract: Decoders can use prediction based on weighted distortion to determine information used to make decisions regarding motion vectors, reference pixels, and coding modes, similar to a corresponding encoder operation. Samples in and around a current block and samples of reference pictures are weighted and a distortion metric generated to determine the decisions. Embodiments are described for prediction modes such as Cross-component linear model (CCLM), Local Illumination Compensation (LIC), and Frame Rate Up-Conversion (FRUC). Various embodiments describe derivation of weighting factors used in the decision making, comprising inference by a decoder, basing weighting factors on a quantization parameter, local activity of a block, and samples of temporally close reference pictures.

Abstract: The present principles relates to a method for encoding an image unit comprising image data represented by a luminance channel and at least one chrominance channel, the method comprising obtaining a luma coding-tree by splitting a luminance unit representative of the luminance channel of said image unit and obtaining a chroma coding-tree by splitting a chrominance unit representative of at least one chrominance channel of said image unit. The method is characterized in that obtaining said chroma coding-tree comprises: —determining whether said chroma coding-tree and said luma coding-tree are identical; and—signaling an information data indicating whether said chroma coding-tree and said luma coding-tree are identical.

Abstract: A block of video data that is split into sub-blocks forms a prediction for that sub-block using predictions from neighboring sub-blocks such that a current prediction for the sub-block is combined with weighted versions of the neighboring predictions. The neighboring sub-blocks motion vectors are checked to determine whether they are different than the motion vector of the sub-block being predicted. If so, than that corresponding neighboring sub-block is used to generate the prediction of the current sub-block. In an embodiment, two lines or two columns of pixels within a sub-block are used in forming the prediction for the current sub-block when the size of the block containing the sub-block is under a particular size.

Abstract: The method for intra frame prediction allows for the recovery of some intra directional modes that are otherwise rendered useless due to the classical padding process. Directional modes are recovered by filling pixel locations in the prediction unit with samples from the portion of the unit that is determined to have samples available for use using a counterpart directional mode to the one that is useless. When it is determined that reference samples are missing for a particular prediction unit or portion thereof given a particular directional mode, a determination is made about whether reference samples along another portion of the prediction unit are available. The other portion is the side of the prediction unit at an opposite end of the particular directional mode.

Abstract: 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.

Abstract: A method and an apparatus for encoding a picture are disclosed. Such method comprises: —determining a rate-distortion cost (41) for a current block of said picture when said current block is not split into subblocks, taking into account quantization parameters assigned to the subblocks of said current block, —determining (42) whether said current block is split or not according at least to the determined rate-distortion cost, —encoding (43) the current block according to the result of determining whether a current block is split or not into subblocks.

Abstract: Different implementations arc described, particularly implementations for selecting a scan order of the sub-blocks of a current block being encoded or decoded when the current block is composed of multiple sub-blocks. In one example, a corresponding dependency number indicative of a number of the other of the plurality of sub-blocks that each of the sub-blocks uses for spatial prediction is determined, based on the corresponding intra prediction mode for the each of the plurality of sub-blocks. A scan order of the plurality of sub-blocks is determined based on the determined corresponding dependency number for the each of the plurality of the sub-blocks. The current block is encoded or decoded using the determined scan order of the plurality of sub-blocks.

Abstract: Edges of the plurality of reference blocks are adjacent to a current block of a picture. A single transform is applied to samples of each reference block. A single transform is applied to samples of the current block. A decoding method includes decoding a plurality of reference blocks, obtaining a plurality of filtered reference blocks by filtering with a deblocking filter along the edges of the plurality of decoded reference blocks, and decoding the current block by intra prediction from the plurality of filtered reference blocks. An encoding method includes encoding and reconstructing a plurality of reference blocks, obtaining a plurality of filtered reference blocks by filtering with a deblocking filter along the edges of the plurality of reconstructed reference blocks, and encoding the current block by intra prediction from the plurality of filtered reference blocks.

Abstract: The method for intra frame prediction allows for the recovery of some intra directional modes that are otherwise rendered useless due to the classical padding process. Directional modes are recovered by filling pixel locations in the prediction unit with samples from the portion of the unit that is determined to have samples available for use using a counterpart directional mode to the one that is useless. When it is determined that reference samples are missing for a particular prediction unit or portion thereof given a particular directional mode, a determination is made about whether reference samples along another portion of the prediction unit are available. The other portion is the side of the prediction unit at an opposite end of the particular directional mode.

Abstract: Methods and apparatuses for video coding and decoding are provided. The method of video encoding includes accessing (1410) a bin of a syntax element associated with a block in a picture of a video, determining (1420) a context for the bin of the syntax element from a set of contexts associated with a block type of the block, the set of contexts including at least a first context and a second context, the second context being associated with a larger number of block types than the first context and entropy encoding (1430) the bin of the syntax element based on the determined context. A bitstream formatted to include encoded data, a computer-readable storage medium and a computer-readable program product are also described.

Abstract: A method and an apparatus for encoding a picture are disclosed. A first rate-distortion cost is determined (42) for a current block of said picture when said current block is not split into subblocks, from a distortion computed for each subblock of said current block, said distortion being scaled by an inverse of a lagrangian parameter determined (40) according to a quantization parameter assigned to said subblock. It is then determined (44) whether said current block is split or not according at least to the determined first rate-distortion cost, and the current block is encoded (45) according to the result of determining whether a current block is split or not into subblocks.

Abstract: Different implementations are described for determining a set of predictor candidates for affine merge coding mode from neighboring blocks for motion compensation of a picture block based on a motion model for a video content encoder or decoder.

Abstract: Implementations are described for determining, for a block being encoded in a picture, at least one predictor candidate, determining for the at least one predictor candidate, one or more corresponding control point generator motion vectors, based on motion information associated to the at least one predictor candidate, determining for the block being encoded, one or more corresponding control point motion vectors, based on the one or more corresponding control point generator motion vectors determined for the at least one predictor candidate, determining, based on the one or more corresponding control point motion vectors determined for the block, a corresponding motion field, and encoding the block based on the corresponding motion field.

Abstract: A method and apparatus adapts motion vector prediction for suitability to omnidirectional video. One embodiment improves handling of temporal motion vector predictors or rescaled motion vector predictors. Another embodiment is suited to spatial motion vector predictors, and another to a combination of either temporal or spatial motion vector predictors. The method analyzes a scale factor derived from, at least one of, the time index of the predictor, the time index of the reference image's predictor, the time index of a reference image's current block, and the time index of the current block. If, for example, the scale factor is greater than one, motion vector transformation is performed before motion vector rescaling. If, however, the scale factor is less than or equal to one, the motion vector rescaling is performed before motion vector transformation.