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: A decoding method is disclosed that comprises: —decoding (S120) a block of a picture, said block being intra predicted from a plurality of reference blocks; —determining (S130) a frontier inside the decoded block based on a frontier existing between said plurality of reference blocks; and —filtering (S140) with a de-artifacting filter along the frontier determined inside the decoded block.

Abstract: Methods and devices are provided to encode and decode a data stream carrying data representative of a three-dimensional scene, the data stream comprising color pictures packed in a color image; depth pictures packed in a depth image; and a set of patch data items comprising de-projection data; data for retrieving a color picture in the color image and geometry data. Two types of geometry data are possible. The first type of data describes how to retrieve a depth picture in the depth image. The second type of data comprises an identifier of a parametric function and a list of parameter values for the identified parametric function.

Abstract: The invention relates to layered depth data. In multi-view images, there is a large amount of redundancy between images. Layered Depth Video format is a well-known formatting solution for formatting multi-view images which reduces the amount of redundant information between images. In LDV, a reference central image is selected and information brought by other images of the multi-view images that are mainly regions occluded in the central image are provided. However, LDV format contains a single horizontal occlusion layer, and thus fails rendering viewpoints that uncover multiple layers dis-occlusions. The invention uses light filed content which offers disparities in every directions and enables a change in viewpoint in a plurality of directions distinct from the viewing direction of the considered image enabling to render viewpoints that may uncover multiple layer dis-occlusions which may occurs with complex scenes viewed with wide inter-axial distance.

Abstract: A method of predicting or inferring a piece of information for encoding or decoding uses a predictor from a spatial neighbor, or from a reference picture, instead of predicting or inferring the information, such as a flag for a current block, from a motion predictor block. This procedure can be used in several ways, or used in various motion vector prediction modes, such as Frame Rate Up Conversion or various variations of Advanced Motion Prediction. Other embodiments provide other methods and combinations to derive or infer motion information to increase coding efficiency.

Abstract: Implementations for video encoding and decoding based on a linear model responsive to neighboring samples are described. 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 decoding method is presented. At least one high level syntax element is decoded that indicates whether generalized bi-prediction applies for predicting blocks of a slice. A block is then decoded from said slice using generalized bi-prediction in the case where said at least one high level syntax element indicates to apply generalized bi-prediction.

Abstract: Conventional intra-prediction uses pixels from left and upper neighbour blocks to predict a macroblock (MB). Thus, the MBs must be sequentially processed, since reconstructed left and upper MBs must be available for prediction. In an improved method for encoding Intra predicted MBs, a MB is encoded in two steps: first, a first portion of the MB is encoded independently, without references outside the MB. Pixels of the first portion can be Intra predicted using DC mode. Then, the first portion is reconstructed. The remaining pixels of the MB, being a second portion, are intra predicted from the reconstructed pixels of the first portion and then reconstructed. The first portion comprises at least one column or one row of pixels of the MB. The encoding is applied to at least two Intra predicted MBs per slice, or per picture if no slices are used.

Abstract: Methods and devices are provided to encode and decode a data stream carrying data representative of a three-dimensional scene, the data stream comprising color pictures packed in a color image; depth pictures packed in a depth image; and a set of patch data items comprising de-projection data; data for retrieving a color picture in the color image and geometry data. Two types of geometry data are possible. The first type of data describes how to retrieve a depth picture in the depth image. The second type of data comprises an identifier of a parametric function and a list of parameter values for the identified parametric function.

Abstract: There are provided methods and apparatus for video usability information (VUI) for scalable video coding (SVC). An apparatus includes an encoder (100) for encoding video signal data into a bitstream. The encoder specifies video user information, excluding hypothetical reference decoder parameters, in the bitstream using a high level syntax element. The video user information corresponds to a set of interoperability points in the bitstream relating to scalable video coding (340, 355).

Abstract: Different implementations are described, particularly implementations for selecting a predictor candidate from a set of multiple predictor candidates for motion compensation of a picture block based on a motion model. The motion model, may be, e.g., an affine model in a merge mode for a video content encoder or decoder. In an embodiment, a predictor candidate is selected from the set based on a motion model for each of the multiple predictor candidates, and may be based on a criterion such as, e.g., a rate distortion cost. The corresponding motion field is determined based on, e.g., one or more corresponding control point motion vectors for the block being encoded or decoded. The corresponding motion field of an embodiment identifies motion vectors used for prediction of sub-blocks of the block being encoded or decoded.

Abstract: At least one embodiment obtain a method for reconstructing an image from metadata representing a given color space, comprising mapping said given color space to a candidate color space which encompasses in its convex hull all the primaries of the given color space; and reconstructing the image using said candidate color space.

Abstract: When dependent scalar quantization is used, the choice of the quantizer depends on the decoding of the preceding transform coefficient, and the entropy decoding of a transform coefficient depends on quantizer choice. To maintain high throughput in hardware implementations for transform coefficient entropy coding, several decision schemes of the scaler quantizer are proposed. In one implementation, the state transition and the context model selection are based on only regular coded bins. For example, the state transition can be based on the sum of the SIG, gt1 and gt2 flags, the exclusive-or function of the SIG, gt1 and gt2 flags, or based on only the gt1 or gt2 flag. When a block of transform coefficients is coded, the regular mode bins can be coded first in one or more scan passes, and the remaining bypass coded bins are grouped together in another one or more scan passes.

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: This method for inter-predictive encoding of a time-varying 3D point cloud including a series of successive frames divided in 3D blocks into at least one bitstream comprises encoding (20) 3D motion information including a geometric transformation comprising rotation information representative of a rotation transformation and translation information representative of a translation transformation, wherein the translation information comprises a vector ?T representing an estimation error of the translation transformation.

Abstract: The present principles a method and a device for encoding the colors of a point cloud (IPC) representing a 3D object. The method is characterized in that the method comprises: —obtaining (210) a set of points (SP) approximating the geometry of said point cloud (IPC); —encoding (220) a color information data indicating that the color of at least one of the point of said set of points is encoded in a bitstream and that the colors of the other points of said set of points are not encoded in the bitstream. The present principles also relates to a method and a device for decoding the colors of a point cloud.

Abstract: A decoding method is disclosed. First, context for a syntax clement 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: Methods and apparatus for performing in-loop filtering in an encoder or a decoder provide regions which use a common set of filter parameters An index can be sent from an encoder to a decoder indicating which set of filter parameters is to be used for a particular region. The in-loop filter can be Sample Adaptive Offset, Adaptive Loop Filter, or any other such filter. An encoder classifies regions of a picture according to blocks using a common set of filter parameter. The classification can be in the form of a map. Filtering blocks use the common set of filter parameters for a region. A decoder parses a bitstream for a set of filter parameters and an index indicative of the filter parameter set for a region being decoded.

Abstract: At least one embodiment relates to a method comprising encoding a projection mode associated with an image region of a first depth image, said projection mode indicating if said image region stores either the minimum or the maximum depth value of at least one orthogonally projected 3D point of the point cloud along a same projection direction; and encoding said depth minimum and maximum depth values as a function of said projection mode.

Abstract: A Local illumination compensation system for video encoding and decoding uses memory for storing illumination compensation parameters and does not require access to reconstructed pixels of neighboring blocks. A set of illumination compensation parameters is stored in a dedicated buffer, which is of limited size, and which is decoupled from the coding unit level storage of information. The buffer contains a set of illumination compensation parameters, which may be, for example, computed (or determined in some other manner) on the fly or determined beforehand (for example for example obtained from the video signal or from a device).