Abstract: Methods, devices and data stream are provided for signaling and decoding information representative of restrictions of navigation in a volumetric video. The data stream comprises metadata associated to video data representative of the volumetric video. The metadata comprise data representative of a viewing bounding box, data representative of a curvilinear path in the 3D space of said volumetric video; and data representative of at least one viewing direction range associated with a point on the curvilinear path.

Abstract: Generating an image from a source image can involve encoding a projection of a part of a three-dimensional scene. Pixels of a source image comprise a depth and a color attribute. Pixels of a source image are de-projected as colored point cloud. A de-projected point in a 3D space has the color attribute of the pixel that it has been de-projected from. Also, a score is attributed to the generated point according to a local depth gradient and/or a local color gradient of the pixel it comes from, the lower the gradient, the higher the score. The generated point cloud is captured by a virtual camera for rendering on a display device. The point cloud is projected onto the viewport image by blending color of points projected on a same pixel, the blending being weighted by the scores of these points.

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 3D mesh. Vertex coordinates and faces of this mesh are used to retrieve the location of points in the de-projected scene.

Abstract: Encoding/decoding data representative of a 3D representation of a scene according to a range of points of view can involve generating a depth map associated with a part of the 3D representation according to a parameter representative of a two-dimensional parameterization associated with the part and data associated with a point included in the part, wherein the two-dimensional parameterization can be responsive to geometric information associated with the point and to pose information associated with the range of points of view. A texture map associated with the part can be generated according to the parameter and data associated with the point. First information representative of point density of points in a part of the part can be obtained. The depth map, texture map, parameter, and first information can be included in respective syntax elements of a bitstream.

Abstract: The present disclosure relates to methods, apparatus or systems for determining an aiming direction (22) of a remote motorized camera (10). The immersive video content captured by the camera (10) is associated with reference directions (13). Parameters of a discrepancy function (32, 42, 53) are calculated. This function is used to control the aiming direction (22) of the camera. It introduces a discrepancy between the rotation wanted by the user (21) and the rotation of the camera (22). An example purpose of the present disclosure is to encourage a user to rotate the camera toward reference directions, preventing him/her to rotate the camera toward the opposite direction. The present principles have the advantage to create pseudo-haptic effects, inciting the user to look toward a reference direction without making him/her sick.

Abstract: A method and a device are disclosed to encode volumetric video in a patch-based atlas format in intra-periods of varying length. A first atlas layout is built for a first sequence of 3D scenes. The number of 3D scenes in the sequence is chosen to fit the size of a GoP of the codec. A second sequence is iteratively set up by appending the next 3D scene of the sequence to encode while the number of patches of the layout built for this iterative second sequence is lower than or equal to the number of patches of the first layout. When iterations end, one of the layouts is selected to generate every atlas of the group. In such a way, size of metadata is decreased and compression is enhanced.

Abstract: Methods, device and data stream format are disclosed in the present document for the encoding, the formatting and the decoding of depth information representative of a 3D scene. Compression and decompression of quantized values by a video codec leads to a value error. This error on values is particularly sensitive for depth encoding. The present invention proposes to encode and decode depth with a quantization function that minimize an angle error when a value error on quantized depth creates a location delta between the projected point and the de-projected point. The inverse of such a quantization function has to be encoded in metadata associated with the 3D scene, for example as a LUT, to be retrieved at the decoding, as such functions are not tractable.

Abstract: A sequence of three-dimension scenes is encoded as a video by an encoder and transmitted to a decoder which retrieves the sequence of 3D scenes. Points of a 3D scene visible from a determined point of view are encoded as a color image in a first track of the stream in order to be decodable independently from other tracks of the stream. The color image is compatible with a three degrees of freedom rendering. Depth information and depth and color of residual points of the scene are encoded in separate tracks of the stream and are decoded only in case the decoder is configured to decode the scene for a volumetric rendering.

Abstract: Methods and devices are provided to encode points of a sphere onto an image by projecting them as a function of an isotropic region guided mapping operator and/or to decode pixels of an image onto a sphere by de-projected them according to the same parametrized mapping operator. A region of interest is determined on the sphere and the angular resolution of pixels of the image is modulated as a function of their distance to the reference pixel corresponding to the center of the region of interest. Chosen angular resolutions and size of the region of interest are associated with the image and encoded in a stream.

Abstract: Methods and devices are provided to play back a video content item comprising loop sequences. The player manages two or three playing modes and switch between first-in first-out video buffer and circular video buffer with a size adapted to the loop sequences for which the player is in loop mode. A start point and an end point are obtained for each loop sequence of the video. In an embodiment, a code is associated with frames of the video to indicate to which loop(s) a frame belongs to.

Abstract: Methods and device for encoding/decoding data representative of depth of a 3D scene. The depth data are quantized in a range of quantized depth values larger than a range of encoding values allowed by a determined encoding bit depth. For blocks of pixels comprising the depth data, a first set of candidate quantization parameters is determined. A second set of quantization parameters is determined as a subset of the union of the first sets. The second set comprising candidate quantization parameters common to a plurality of blocks. One or more quantization parameters of the second set being associated with each block of pixels of the picture. The second set of quantization parameters is encoded, and the quantized depth values are encoded according to the quantization parameters.

Abstract: The present disclosure relates to a method for embedding key information in an image, the method comprising reserving a range of DMZ values, in a predetermined range of 2N values used for storing useful data in the image, the reserved range being used for storing a key information associated with at least one coordinates in the image, with N>0 and DMZ<<2N.

Abstract: The present disclosure relates to methods, devices or streams for encoding, transmitting and decoding two-dimension point clouds. When encoding point clouds as frames, a large number of pixels are not used. A dense mapping operator optimizes the use of pixels but requires a lot of data to be encoded in the stream and its inverse operator is difficult to compute. A simplified mapping operator is generated according to a dense mapping operator and is stored as matrices of two-dimension coordinates representative of an unfolded grid which requires low space in the stream. The inverse operator is easy to generate according to the unfolded grid.

Abstract: A method and a device provide for transmitting information representing a viewpoint in a 3D scene represented with a set of volumetric video contents; receiving a first volumetric video content of the set, the first volumetric video content being according to a range of points of view comprising the viewpoint, the first volumetric video content being represented with a set of first patches, each of which corresponds to a 2D parametrization of a first group of points in a 3D part of the 3D scene associated with the first volumetric video content, and at least one first patch refers to an area of a second patch corresponding to a 2D parametrization of a second group of points in another 3D part of the 3D scene associated with a second volumetric video content of the set of volumetric video contents.

Abstract: The present disclosure relates to method for embedding key information in an image, the method comprising reserving a range of DMZ values, in a predetermined range of 2N values used for storing useful data in the image, the reserved range being used for storing a key information associated with at least one coordinates in the image, with N>0 and DMZ<<2N.

Abstract: A sequence of point clouds is encoded as a video by an encoder and transmitted to a decoder which retrieves the sequence of point clouds. Visible points of a point cloud are iteratively projected on a projection map to determine a patch data item list. Image patches are generated and packed into a picture. Pictures and associated patch data item list are encoded in a stream. The decoding method decodes pictures and associated patch data item lists. Pixels of image patches comprised in pictures are un-projected according to data stored in associated patches. The methods have the advantage of encoding every point of point clouds in a manner avoiding artifacts and allowing decoding at video frame rate.

Abstract: The present disclosure relates to methods, apparatus or systems for formatting of backward compatible immersive video streams. At least one legacy rectangular video is captured from an immersive video obtained from a source (82). A set of camera control data are used to determine which parts of the immersive video will constitute legacy videos (84). These part are removed from the immersive video (83) and every prepared videos are packaged in a stream (85). The structure from the stream is a container. Information data about the location and size of removed parts may be added in the stream.

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: 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. These data are inserted in the video track of the stream with associated temporal information. The color and depth pictures that are repeated at least two times in a sequence of patches are not packed in the images but inserted in the image track of the stream and are pointed by color or geometry data.

Abstract: Method and device for generating a stream of data representative of a 3D point cloud. The 3D point cloud is partitioned into a plurality of 3D elementary parts. A set of two-dimensional 2D parametrizations is determined, each 2D parametrization representing one 3D part of the point cloud with a set of parameters. Each 3D part is represented as a 2D pixel image. A depth map and a color map are determined as a first patch atlas and a second patch atlas. A data stream is generated by combining and/or coding the parameters of the 2D parametrization, the first patch atlas, the second patch atlas and mapping information that links each 2D parametrization with its associated depth map and color map in respectively the first and second patch atlas.