Abstract: The present principles relate to a method and device method for encoding depth values of orthogonally projected points of a point cloud onto a projection plane. The present principles also relate to a method and device for decoding a point cloud, a computer readable program and a video signal.

Abstract: A method and device for generating points of a 3D scene from a depth image. To reach that aim, depth information associated with a current pixel is compared with depth information associated with pixels spatially adjacent to the current pixel in the depth image. When the difference of depth between the current pixel and an adjacent pixel is greater than a first value and less than a second value, at least an additional point of said 3D scene is generated, in addition to a current point associated with the current pixel of the depth image, the number of additional points depending on the depth difference.

Abstract: Methods and apparatus are provided for signaling intra prediction for large blocks for video encoders and decoders. An apparatus includes a video encoder (400) for encoding picture data for at least one large block in a picture by signaling intra prediction for the at least one large block. The intra prediction is signaled by selecting a basic coding until size and assigning a single spatial intra partition type for the basic coding until size. The single spatial intra partition type is selectable from among a plurality of spatial intra partition types. The at least one large block has a large block size greater than a block size of the basic coding unit. The intra prediction is hierarchical layer intra prediction and is performed for the at least one large block by at least one of splitting from the large block size to the basic coding until size and merging from the basic coding unit size to the large block size.

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: Different implementations are described, particularly implementations for video encoding and decoding using motion compensation with bi-prediction are presented. The encoding method comprises for a picture, obtaining a first predictor for a block of the picture using a first reference picture; obtaining a second predictor for said block of the picture using a second reference picture; using the first predictor and the second predictor for forming a third predictor for the block in bi-prediction inter prediction, wherein the third predictor is obtained as a weighted average of the first predictor and the second predictor; and wherein a weight used in the weighed prediction depend on the position of the sample in the block. Ohers embodiments are presented for implementing block triangle partition prediction, for implementing block partition prediction using multiple patterns and for corresponding motion compensation in decoding method.

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.