Abstract: Methods and devices for encoding a point cloud. A bit sequence signaling an occupancy pattern for sub-volumes of a volume is coded. Predictive coding is used to find a set of predicted points, from which a corresponding predicted occupancy pattern may be determined. The search for and selection of a coding mode for generating the set of predicted points may include a geometric distortion metric for evaluating how closely the geometry of the predicted set of points aligns with the geometry of the set of points to be coded. The geometric distortion metric may include a sum of absolute value distance between each point and its nearest predicted point. The metric may sum a logarithm of the distances to match more closely with coding rate cost.

Abstract: Methods and devices for encoding a point cloud. A bit sequence signaling an occupancy pattern for sub-volumes of a volume is coded using binary entropy coding. Contexts may be based on neighbour configuration and a partial sequence of previously-coded bits of the bit sequence. A determination is made as to whether to apply a context reduction operation and, if so, the operation reduces the number of available contexts. Example context reduction operations include reducing neighbour configurations based on shielding by sub-volumes associated with previously-coded bits, special handling for empty neighbour configurations, and statistics-based context consolidation.

Abstract: Methods and devices for encoding a point cloud. More than one frame of reference is identified and a transform defines the relative motion of a second frame of reference to a first frame of reference. The space is segmented into regions and each region is associated with one of the frames of reference. Local motion vectors within a region are expressed relative to the frame of reference associated with that region. Occupancy of the bitstream is entropy encoded based on predictions determined using the location motion vectors and the transform associated with the attached frame of reference.

Abstract: A decoding method is disclosed that comprises:—decoding (S120) a stream to obtain a decoded standard dynamic range picture and colour metadata associated with the standard dynamic range picture, wherein the colour metadata are representative at least of characteristics of a high dynamic range picture associated with the standard dynamic range picture; and—reconstructing (S130) a high dynamic range access the input stream(s) picture from the decoded standard dynamic range picture and from the colour metadata.

Abstract: At least one embodiment provides a method comprising encoding or decoding a coding model information representative of an encoding of points of a point cloud, said encoding being defined from at least one point belonging to a bounding box encompassing said points of the point cloud.

Abstract: Methods and systems for encoding and decoding data, such as point cloud data. The methods may include using a coder map to map a range of discrete dependency states to a smaller set of binary coders each having an associated coding probability. The selection of one of the discrete dependency states may be based on a contextual or situational factors, which may include a prediction process, for a particular symbol, such as an occupancy bit. The coder map is updated after each symbol is coded to possibly alter to which binary coder the selected discrete dependency state maps.

Abstract: Method and device for encoding a point cloud that represents a three-dimensional (3D) object. One or more groups of temporally successive pictures are obtained. Each picture of the one or more groups comprises a first set of images, the images being spatially arranged in a same manner in each picture of the one or more groups. A second set of projections is associated with the one or more groups, a unique projection being associated with each image in such a way that a same projection is associated with only one single image and all projections are associated with the images. A first information representative of the projections is encoded. The point cloud may then be encoded according to the obtained pictures. A corresponding method and device for decoding a bitstream that comprises data representative of the encoded picture(s) are also described.

Abstract: Methods and devices for encoding a point cloud. A bit sequence signaling an occupancy pattern for sub-volumes of a volume is coded. Predictive coding is used to find a set of predicted points, from which a corresponding predicted occupancy pattern may be determined. The predicted occupancy pattern may be used to determine the contexts for entropy coding the occupancy pattern. The determination may include determining for each sub-volume, whether it contains a predicted point or not and, in some cases, the count of predicted points within the sub-volume. Various threshold numbers of predicted points may cause the selection of different context sets for coding the occupancy pattern. The predictive coding may be enabled by determining that the prediction of occupancy of a parent volume to the volume met a threshold level of accuracy.

Abstract: A method and device of encoding both a HDR picture (IHDR) and a first SDR picture (ISDR1) obtained from said HDR picture, in at least one bitstream (F1, F2, F3, F4). The method comprises: —obtaining (210) a second SDR picture (ISDR2) by tone-mapping the HDR picture (IHDR); —obtaining (230) a color mapping function (CMF) that allows the mapping of the colors of the second SDR picture (ISDR2) onto the colors of a third SDR picture (ISDR3) obtained (220) from the first SDR picture (ISDR1); —encoding (240), in a bitstream, an information (INF) representative of the color mapping function; and —encoding (260), in a bitstream, a fourth SDR picture (ISDR4) obtained (250) from the first SDR picture (ISDR1). The present disclosure further relates to a method and device of decoding.

Abstract: Method and devices for coding point cloud data using a planar coding mode. The planar coding mode may be signaled using in a planar mode flag to signal that a volume is planar. A planar volume has all of its occupied child nodes on one side of a plane bisecting the volume. A planar position flag may signal which side of the volume is occupied. Planarity may be determined and signaled with respect to a horizontal plane, vertical plane, or otherwise. Occupancy bits may be inferred as a result of planar coding mode signaling.

Abstract: A colored three-dimensional point cloud is encoded in at least two depth and texture images. The proposed method and device use inverse project pixels of the first image and inverse project pixels to the second image. When the inverse projecting of a first pixel of the first image and the inverse projecting of a second pixel of the second image refer to a common generated point, that is two 3D points closer to each other than the imprecision due to the encoding and compression of the images, the color value of the pixel of first and second pixels having the lowest local depth variance is attributed to the common generated point.

Abstract: Methods and devices for attribute coding for point clouds. In a top-down coding process a predicted geometry-weighted sum of attributes is determined for each occupied sub-volume of a volume based on a prediction operation that uses at least a geometry-weighted sum of attributes for the volume. The prediction operation involves up-sampling data from the preceding (parent) depth of the coding tree. The predicted geometry-weighted sums of attributes and corresponding original geometry-weighted sums of attributes are subtracted, in the attribute domain or in a transform domain to result in residual coefficients. The AC residual coefficients are coded in the bitstream. The transform used has a DC coefficient property, whereby the DC coefficient from transform of the geometry-weighted sums of attributes for the set of child sub-volumes is the geometry-weighted sum of attributes for the volume.

Abstract: A method for decoding a bitstream representative of a picture is disclosed. Information representative of at least one encoding precision is first determined. A transform is then decoded responsive to the determined information. Finally, the picture is decoded using the decoded transform. A method for encoding a bitstream representative of a picture, as well as encoding devices and decoding devices are also disclosed.

Abstract: A method and apparatus for improving the performance of video encoders and decoders involves selecting a set of transforms from among a plurality of sets of transforms that can be used for coding blocks in a region of a video image. Within a region, selection of a particular transform from among a plurality of transforms comprising the selected set of transforms is used to encoder or decode at least one block in the region. Associated indices representing the set of transforms to be used within a region and the selected transform for a block can be sent in a bitstream. In an alternate embodiment, a default set of transforms is complemented by selection of an additional set of transforms on a block or region basis.

Abstract: Methods and devices for encoding a point cloud. A current node associated with a sub-volume is split into further sub-volumes, each further sub-volume corresponding to a child node of the current node, and, at the encoder, an occupancy pattern is determined for the current node based on occupancy status of the child nodes. A probability distribution is selected from among a plurality of probability distributions based on occupancy data for a plurality of nodes neighbouring the current node. The encoder entropy encodes the occupancy pattern based on the selected probability distribution to produce encoded data for the bitstream and updates the selected probability distribution. The decoder makes the same selection based on occupancy data for neighbouring nodes and entropy decodes the bitstream to reconstruct the occupancy pattern.

Abstract: Method and devices for coding point cloud data using a planar coding mode. The planar coding mode may be signaled using in a planar mode flag to signal that a volume is planar. A planar volume has all of its occupied child nodes on one side of a plane bisecting the volume. A planar position flag may signal which side of the volume is occupied. Planarity may be determined and signaled with respect to a horizontal plane, vertical plane, or otherwise. Occupancy bits may be inferred as a result of planar coding mode signaling.

Abstract: A decoding method is disclosed. The decoding method comprises: determining an index from a bitstream, the index identifying a coding element in a set of a plurality of coding elements; decoding a picture block from the bitstream using the coding element of the set identified by the index. In a specific embodiment, determining the index comprises: determining, for each coding element in the set, a probability that the coding element was used for encoding the picture block; and determining the index responsive to the determined probabilities.

Abstract: Methods and devices for coding point clouds using direct coding mode to code coordinates of a point within a sub-volume associated with a current node instead of a pattern of occupancy for child nodes. Eligibility for use of direct coding is based on occupancy data from another node. If eligible, then a flag is represented in the bitstream to signal whether direct coding is applied to points in the sub-volume or not.

Abstract: The present principles relate to a method and a device for encoding an input colored point cloud representing the geometry and colors of a 3D object. The method comprises: a) determining an octree-based coding mode (OCM) associated with an encompassing cube (C) including points of a point cloud for encoding said points (Por) of the point cloud by a octree-based structure; b) determining a projection-based coding mode (PCM) associated with said encompassing cube (C) for encoding said points (Por) of the point cloud by a projection-based representation; c) encoding said points (Por) of the point cloud according to a coding mode associated with the lowest coding cost; and d) encoding a coding mode information data (CMID) representative of the coding mode associated with the lowest cost.

Abstract: Color mapping information can be used to transform one color to another color. The present embodiments provide a solution for representing the color mapping information using a successive application of multiple color mapping functions. Parameters for the multiple color mapping functions can be encoded into a bitstream. In one embodiment, color mapping functions are consecutively applied on their own domains of definition only. In another embodiment, the first color mapping (CRI1) is applied on its domain of definition only, but the second color mapping is applied only on samples that have been previously color mapped by CRI1 and which are also inside the domain of definition of the second color mapping function. At the decode side, the multiple color mapping functions can be reconstructed and successively applied to a decoded picture to generate another picture.