Methods, devices and stream for encoding and decoding volumetric video

A device for encoding a point cloud into a stream, the device comprising a memory associated with at least one processor configured to:

• obtain a group of centers of projection determined according to a viewing point;
• determine, for said point cloud, a list of patch data items by projecting on a projection map, points of said point cloud visible from one center of projection of said group of centers of projection and clustering adjacent pixels as image patches, a patch data item being associated with an image patch and comprising:
• information identifying said one center of projection;
• a description of a region of the space, said region being defined according to said one center of projection, an angular range and a depth range;
• and,
• information identifying an area for the associated image patch within a picture;
• generate said picture comprising a set of image patches;
• and
• encode, in said stream, the picture and the list of patch data items.

A method of decoding a point cloud from a stream, the method comprising:

• obtaining a group of centers of projection determined according to a viewing point relative to the point cloud;
• decoding a picture packing image patches and a list of patch data items from the stream, a patch data item comprising:
• information identifying one center of projection within the group of centers of projection;
• a description of a region of the space, said region being defined according to the one center of projection, an angular range and a depth range;
• and,
• information identifying an area of an image patch within the picture;
• decoding points of said point cloud by un-projecting pixels of each image patch according to the associated patch data item.

A device for decoding a point cloud from a stream, the device comprising a memory associated with at least a processor configured to:

• obtain a group of centers of projection determined according to a viewing point relative to the point cloud;
• decode a picture packing image patches and a list of patch data items from the stream, a patch data item comprising:
• information identifying one center of projection within the group of centers of projection;
• a description of a region of the space, said region being defined according to the one center of projection, an angular range and a depth range;
• and,
• information identifying an area of an image patch within the picture;
• decode points of said point cloud by un-projecting pixels of each image patch according to the associated patch data item.