Abstract: A method of performing intra prediction for encoding or decoding uses multiple layers of reference samples. The layers are formed into reference arrays that are used by a function, such as a weighted combination, to form a final prediction. The weights can be variable, chosen from among a number of number of sets of weights. The prediction is used in encoding or decoding a block of video data. The weights can be determined in a number of ways, and for a given prediction mode, the same weights, or different weights can be used for all pixels in a target block. If the weights are varied, they can depend on the distance of the target pixel from reference arrays. An index can be sent indicating which set of weights is to be used.

Abstract: An improvement in coding efficiency is achieved through restrictions on successive divisions of asymmetric splitting in advanced video coding algorithms, which frequently rely on splitting of a block of video data prior to coding using several transform sizes. Successive divisions of asymmetric splitting are forbidden if an equivalent split can be attained using triple splitting. In an embodiment, a video block is split using successive splits, but the second type of split is dependent on the first type of split.

Abstract: A method and apparatus for performing intra prediction for encoding or decoding adds multiple prediction modes to those of prior intra prediction schemes. A horizontal mode, a vertical mode, and a diagonal mode are added. Reference pixels for each of the added modes can come from multiple pixel positions away from a block to be encoded or decoded. Reference pixels to the left and above a block are reconstructed from those already coded. Reference pixels from right of, and below, a block are estimated or extrapolated and can be based on other pixels around the block. An index can be sent in a bitstream indicating which prediction was used.

Abstract: A video encoder or decoder processes portions of video using intra coding and with variable block shapes. Under the general aspects, intra prediction directions are adapted to the block shape or aspect ratio. The general aspects described adaptively replace several conventional angular intra prediction modes with wide-angle intra prediction modes for non-square blocks. The total number of angular directions for any block can remain the same as in prior video coding standards or can be reduced or expanded. To keep the same number of prediction directions, directions along a shorter rectangular edge of a target block are removed but replaced with addition directions along the longer edge of the rectangular target block. For directions with wide angles, reference sample smoothing is performed. Signaling can be provided to inform a corresponding decoder regarding the prediction modes and directions.

Abstract: In general, encoding or decoding image information can involve processing a signal including image information based on determining a block of spatial-domain values for a prediction residual; replacing in a set of multiple transforms at least one first transform matrix with at least one second transform matrix and/or adding at least one second transform matrix to said set of multiple transforms; transforming the block of spatial-domain values using said second transform matrix; and encoding or decoding at least a portion of the image information based on the transforming of the block of spatial-domain values.

Abstract: An improvement in coding efficiency is achieved through restrictions on successive divisions of asymmetric splitting in advanced video coding algorithms, which frequently rely on splitting of a block of video data prior to coding using several transform sizes. Successive divisions of asymmetric splitting are forbidden if an equivalent split can be attained using triple splitting. In an embodiment, a video block is split using successive splits, but the second type of split is dependent on the first type of split.

Abstract: The present disclosure relates to methods, apparatus or systems for encoding and decoding sequence of images by applying a global rotation motion compensation to an input image. According to different embodiments, the input image is a reference image in a compression loop or the image to be encoded. The images to encode are omnidirectional images. As a result, applying a global rotation motion compensation to them corresponds to generate new images as if they have been captured according to a different front direction. When this new front direction is the one of a reference image, the compensation of apparent motion is facilitated.

Abstract: The present principles relates to a method for intra-predictive encoding a coding unit comprising picture data, said intra-predictive encoding depending on a prediction tree and a transform tree, characterized in that the method further comprises: —obtaining said prediction tree by spatially partitioning the coding unit according to a non-square partition type; —determining said transform tree from said coding unit in order that each of its leaves is embedded into a unique unit of said obtained prediction tree; and —signaling in a signal the size of the leaves of said transform tree and said a non-square partition type.

Abstract: At least a method and an apparatus are provided for efficiently encoding or decoding video. For example, a most probable mode (MPM) list comprising a number of intra prediction mode candidates for a current block is obtained depending on a shape of the current block. The current block is then encoded or decoded based on the obtained most probable mode list.

Abstract: A method of performing intra prediction for encoding or decoding uses multiple layers of reference samples. The layers are formed into reference arrays that are used by a function, such as a weighted combination, to form a final prediction. The prediction is used in encoding or decoding a block of video data. The weights can be determined in a number of ways, and for a given prediction mode, the same weights, or different weights can be used for all pixels in a target block. If the weights are varied, they can depend on the distance of the target pixel from reference arrays.

Abstract: A method for decoding a large field of view video is disclosed. At least one picture of said large field of view video is represented as a 3D surface projected onto at least one 2D picture using a projection function. The method comprises, for at least one current block of said 2D picture: —determining whether an absolute value of at least one component of a motion vector (d V) associated with another block of said 2D picture satisfies a condition; —transforming, based on said determining, said motion vector (d V) into a current motion vector (d P) associated with said current block responsive to said projection function; and —decoding said current block using said current motion vector (d P).

Abstract: Different implementations are described, particularly implementations for video encoding and decoding based on wherein the partitioning tree structure is partially shared between luma and chroma blocks are presented. According to an implementation, a single partitioning tree structure is shared between luma and chroma blocks from a root node of the partitioning tree down to a switching node and a dual partitioning tree structure is determined for luma and chroma blocks from the switching node down to a leaf node of the partitioning tree. Thus, this implementation optimizes the coding efficiency by allowing separated trees for smaller blocks, while limiting the complexity of decoding pipeline.

Abstract: In an encoding apparatus or a decoding apparatus, an encoding method or decoding method combines various coding tools with intra sub partitioning mode in which a coding unit is split in multiple sub partitions. At least one embodiment particularly aims at the selection of primary transforms among a set of multiple transforms for video encoding or decoding of intra sub block partitions. At least one embodiment particularly aims at intra coding using Ma-trix-Based Intra Prediction mode combined with Intra Sub Partition mode. At least one embodiment particularly aims at intra coding using Multi-Reference-Line intra prediction mode combined with Intra Sub Partition mode.

Abstract: Flexible methods to use a combination of coding modes while keeping good performance tradeoff are implemented with embodiments that determine coding mode information. In one embodiment, determination is made of activation of a first coding mode, and upon determination of whether a second coding mode is used, coding or decoding using the determined modes occurs. Other embodiments enable use of multiple reference lines, intra sub-block partitioning, matrix intra prediction, and low frequency non-separable transforms.

Abstract: A most probable mode flag is context encoded in an encoder using multiple reference lines. In a corresponding decoder, the most probable mode flag is always decoded regardless of the value of a multiple reference line index flag. When multiple reference line index is nonzero, a context is used in parsing of the most probable mode flag.

Abstract: The disclosure relates to a method for encoding image data, the method including intra-predicting, or predicting by combining inter-prediction and intra-prediction, a first block of the image data by using an intra-prediction mode using a first single transformation obtained by taking account of the first block size. The disclosure also relates to a method for encoding image data, a variable coding length being used for signaling a plurality of Prediction Modes by the encoding, the method comprising:—intra-predicting a first block of the image data by using an intra-prediction mode using a first transformation, the first transformation being obtained by taking account of the first block size, —encoding information signaling a use of the intra-prediction mode in a bitstream, the information being encoded as one of the plurality of Prediction Modes. The disclosure further relates to the corresponding decoding methods, devices and media.

Abstract: Different implementations are described, particularly implementations for video encoding and decoding based on wherein the partitioning tree structure is partially shared between luma and chroma blocks are presented. According to an implementation, a single partitioning tree structure is shared between luma and chroma blocks from a root node of the partitioning tree down to a switching node and a dual partitioning tree structure is determined for luma and chroma blocks from the switching node down to a leaf node of the partitioning tree. Thus, this implementation optimizes the coding efficiency by allowing separated trees for smaller blocks, while limiting the complexity of decoding pipeline.

Abstract: Decoding or encoding picture information can involve determining a value associated with a prediction of a pixel of a block of picture information, wherein, the prediction is based on an intra-prediction along a non-diagonal direction, determining, from among a plurality of decoded pixels neighboring the block on the top and the left, at least four reference samples for the block based on the non-diagonal direction, and wherein the determining of the value comprises an interpolation based on a quadratic model and the four reference samples; and decoding or encoding at least a portion of the picture information based on the value.

Abstract: A video coding system comprises a post-processing stage using position dependent intra prediction combination where a predicted sample is modified based on a weighting between a value of a left or top reference sample and the obtained predicted value for the sample, wherein the left or top reference sample is determined based on the intra prediction angle. This provides better computing efficiency while keeping identical compression performance. Encoding method, decoding method, encoding apparatus and decoding apparatus based on this post-processing stage are proposed.

Abstract: A block of video data is split using at least one splitting rule and coded using existing transform sizes through one of several embodiments. In one embodiment, the block is split using a triple tree splitting operation if said at least two rectangular sub-blocks can be achieved with two successions of split operations with at least one triple tree split. In another embodiment, the video block is split using an asymmetric binary tree splitting if said at least two rectangular sub-blocks can be achieved with two successions of split operations with at least one asymmetric binary split. In another embodiment, a video block is split using successive splits, using both of the rules of the other embodiments.