Method and apparatuses for delivering a volumetric video content
Methods, apparatuses and streams are disclosed for transmitting tiled volumetric video and, at the receiver, for generating an atlas image compatible with a legacy decoder. At the server side, viewport information is obtained and a first list of central tiles and a second list of border tiles are selected. A central tile is a part of an image obtained by projecting the 3D scene onto an image plane according to a central point of view. A border tile is an image comprising dis-occluding patches. Sizes and shapes of border tiles are function of size and shape of central tiles. At the client side, tiles are arranged according to a layout selected in a set of layouts according to the number, sizes and shapes of border tiles.
1 . A method comprising:
obtaining an image by projecting a 3D scene according to a central point of view onto an image plane, the image being divided into first tiles having a same size;
obtaining second tiles, wherein a second tile is an image comprising patch pictures representative of a projection of a part of the 3D scene onto a picture plane according to a point of view different from the central point of view, a second tile having a same width and/or a same height as a first tile, wherein each first tile is associated with a collection of second tiles and wherein an association between a first tile and a second tile has a score;
identifying a viewport for displaying of a part of the 3D scene;
selecting a subset of first tiles according to the viewport;
selecting a set of second tiles comprising second tiles associated with first tiles of the subset of first tiles, the set of second tiles being selected as a function of a size of second tiles associated with first tiles of the subset and of the score of the associations; and
encoding an atlas image comprising the subset of first tiles and the set of second tiles arranged according to a layout selected in a set of layouts, the layout being selected according to a number of first tiles in the subset of first tiles and a number of second tiles in the set of second tiles and to a size of the second tiles in the set of second tiles.
2 . The method of claim 1 , wherein the second tiles are horizontal tiles having a width of the first tiles, vertical tiles having a height of the first tiles, or corner tiles having a same width and a same height as the first tiles.
3 . The method of claim 1 , wherein the number and the size of the second tiles in the set of second tiles are predetermined.
4 . The method of claim 1 , wherein the second tiles are associated with metadata, the metadata being used to select the layout of the atlas image.
5 . The method of claim 1 , wherein the viewport is obtained from a remote device and wherein the subset of first tiles and the set of second tiles are transmitted to the remote device.
6 . The method of claim 1 , wherein the viewport is obtained from a remote device and wherein the atlas image is transmitted to the remote device.
7 . A non-transitory computer readable medium storing instructions which, when executed by one or more processors, cause the one or more processors to perform the method of claim 1 .
8 . An apparatus comprising a memory associated with a processor configured to:
obtain an image by projecting a 3D scene according to a central point of view onto an image plane, the image being divided into first tiles having a same size;
obtain second tiles, wherein a second tile is an image comprising patch pictures representative of a projection of a part of the 3D scene onto a picture plane according to a point of view different from the central point of view, a second tile having a same width and/or a same height as a first tile, wherein each first tile is associated with a collection of second tiles and wherein an association between a first tile and a second tile has a score;
identify a viewport for displaying of a part of the 3D scene;
select a subset of first tiles according to the viewport;
select a set of second tiles comprising second tiles associated with first tiles of the subset of first tiles, the set of second tiles being selected as a function of a size of second tiles associated with first tiles of the subset and of the score of the associations; and
encode an atlas image comprising the subset of first tiles and the set of second tiles arranged according to a layout selected in a set of layouts, the layout being selected according to a number of first tiles in the subset of first tiles and a number of second tiles in the set of second tiles and to a size of the second tiles in the set of second tiles.
9 . The apparatus of claim 8 , wherein the second tiles are horizontal tiles having a width of the first tiles, vertical tiles having a height of the first tiles, or corner tiles having a same width and a same height as the first tiles.
10 . The apparatus of claim 8 , wherein the number and the size of the second tiles in the set of second tiles are predetermined.
11 . The apparatus of claim 8 , wherein the second tiles are associated with metadata, the metadata being used to select the layout of the atlas image.
12 . The apparatus of claim 8 , wherein the viewport is obtained from a remote device and wherein the subset of first tiles and the set of second tiles are transmitted to the remote device.
13 . The apparatus of claim 8 , wherein the viewport is obtained from a remote device and wherein the atlas image is transmitted to the remote device.