Abstract: Methods, apparatus and data stream are described to encode, transmit and decode an atlas-based representation of a 3D scene based on a multiplane image (MPI) representation in which a depth component is encoded in each layer. Layers of the MPI are clustered on a transparency basis to generate texture, transparency and depth patch pictures. Patch pictures are packed in at least one atlas image. Metadata associating each patch to a layer and each layer to a depth and a depth quantization law are encoded in the data stream with the at least one atlas. At the decoding side, the MPI with a depth component is retrieved from the data stream and is used to render a viewport image from a viewpoint in the neighborhood of the center of the MPI.

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. 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: 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 projection maps according to at least two centers of projection, to determine a patch data item lists. One of the centers of projection is selected and corresponding 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: Methods and apparatus for encoding and decoding a volumetric scene are disclosed. A set of attribute and geometry patches is obtained by projecting samples of the volumetric scene onto the patches according to projection parameters. If the geometry patch is comparable to a planar layer located at a constant depth according to the projection parameters, only the attribute patch is packed in an attribute atlas image and the depth value is encoded in metadata. Otherwise, both attribute and geometry patches are packed in an atlas. At the decoding, if metadata for an attribute patch indicates that its geometry may be determined from the projection parameters and a constant depth, the attributes are inverse projected on a planar layer. Otherwise, attributes are inverse projected according to the associated geometry patch.

Abstract: Methods, devices and stream are disclosed to encode and decode a scene (such as a point cloud) in the context of a patch-based transmission of a volumetric video content. Attributes of points of the scene are projected onto patches. Every point has a geometry attribute. For other attributes, like transparency of displacement attribute, some points may have no value. According to the present principles, each attribute is encoded in a different atlas with its own layout. This allow to save pixel rate in memory of the renderer.

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: Methods and device for encoding/decoding data representative of a 3D scene.

Abstract: Methods and devices for encoding and decoding data representative of a 3D scene are disclosed. A set of first patches is generated from a first MVD content acquired from a first region of the 3D scene. A patch is a part of one of the views of the MVD content. A set of second patches is generated from a second MVD content acquired from a second region of the 3D scene. An atlas packing first and second patches is generated and associated with metadata indicating, for a patch of the atlas, whether the patch is a first or a second patch At the decoding side, first patches are used for rendering the viewport image and second patches are used for pre-processing or post-processing the viewport image.

Abstract: Methods and devices are provided for encoding, transmitting and decoding 3DoF+ volumetric video. At the encoding stage one input view (among all the input ones) is selected to convey the viewport dependent light effect and its id is transmitted to the decoder as an extra metadata. On the decoder side, when patches coming from this selected view are available for the rendering of the viewport, they are preferentially used regarding the other candidates whatever the view to synthesize position.

Abstract: Methods, devices and stream for encoding, decoding and transmitting a multi-views frame are disclosed. A non-pruned MVD frame is obtained and an acyclic graph representing pruning precedence relations between views is determined. The MVD is pruned by using these precedence relations. The pruned MVD and data representative of the graph are encoded in the data stream. At the decoding, the contribution of each view for a pixel of a viewport frame to generate is determined as a function of the decoded pruning graph.

Abstract: Methods, devices and streams are disclosed for encoding a depth atlas representative of the geometry of a volumetric video. Views to be encoded are analyzed to detect regions of the views with simple depth or color, that is regions for which the depth or color has a local variance lower than a given threshold. Resolution of such regions is reduced and the atlas comprises first regions in full resolution and downscaled second regions. Metadata indicating whether a patch is a downscaled region and, if so the downscaling factor, are associated with the atlas in the data stream. The decoder uses these metadata to compose the view from different patches.

Abstract: At least one embodiment relates to a method and apparatus for encoding a volumetric video representing a scene, said encoding being based on patches representing the color and depth of a 2D projection of subparts of the scene, wherein a first patch is packed in a second patch for a given time interval lower than or equal to a time period along which the second patch is defined when said first patch can be packed in said second patch over said time interval. Decoding method and apparatus are also provided.

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: 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, devices and stream are disclosed for encoding, transporting and decoding a 3D scene prepared to be viewed from the inside of a viewing zone. A central view comprising texture and depth information is encoded by projected points of the 3D scene visible from a central point of view onto an image plane. Patches are generated to encode small parts of the 3D scene not visible from the central point of view. At the rendering, a viewport image is generated for the current point of view. Holes, that is dis-occluded areas, of the viewport are filled using a patch based inpainting algorithm adapted to take the patches, warped according to the rotation and translation between virtual camera used for capturing the patch and the current virtual camera.

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 device for encoding/decoding data representative of a 3D scene.

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.