Methods and apparatuses for encoding/decoding a volumetric video, methods and apparatus for reconstructing a computer generated hologram

1 . A method, comprising:

decoding, from a bitstream, data content representative of a volumetric video; and

decoding, from the bitstream, an indicator specifying whether the data content has information representative of at least two sets of depth layers, each depth layer in the at least two sets of depth layers associated with a group of pixels at an associated depth, the information representative of the at least two sets of depth layers specifying an indication of a number of sets of depth layers in the at least two sets of depth layers, and for each of the at least two sets of depth layers, a number of depth layers in a respective set of the at least two sets of depth layers and a depth value for each depth layer in the respective set of the at least two sets of depth layers for a layer-based representation of the volumetric video.

2 . The method of claim 1 , wherein responsive to the indicator specifying that the data content has information representative of the at least two sets of depth layers, the method further comprises:

decoding, from the bitstream, the information representative of the at least two sets of depth layers;

selecting a set of depth layers among the at least two sets of depth layers; and

reconstructing the layer-based representation of the volumetric video, the layer-based representation of the volumetric video comprising a number of depth layers and a depth value for each depth layer corresponding to a number of depth layers and a depth value for each depth layer of the selected set of depth layers.

3 . The method of claim 2 , wherein the data content representative of a volumetric video is a sequence of multiple plane images, and wherein the sequence of multiple plane images comprises at least one multiple plane image, the at least one multiple plane image comprising a plurality of layers.

4 . The method of claim 3 , wherein reconstructing the layer-based representation of the volumetric video further comprises:

decoding a subset of patches from an atlas of patches of the sequence of multiple plane images;

assigning each patch of the decoded subset of patches to a nearest depth layer in the selected set of depth layers; and

reconstructing each layer of the selected set of depth layers using an assigned patch.

5 . The method of claim 3 , wherein the indicator specifying whether data content has information representative of the at least two sets of depth layers and the information representative of the at least two sets of depth layers are signaled as a common atlas sequence parameter set.

6 . The method of claim 2 , wherein the data content representative of a volumetric video is a point cloud.

7 . The method of claim 6 , wherein reconstructing the layer-based representation of the volumetric video further comprises:

decoding a subset of samples of the point cloud;

assigning each sample of the decoded subset of samples to a nearest depth layer in the selected set of depth layers; and

reconstructing each layer of the selected set of depth layers using an assigned sample.

8 . The method of claim 7 , wherein the indicator specifying whether data content has information representative of the at least two sets of depth layers and information representative of the at least two sets of depth layers are signaled as general atlas frame parameter set of a raw byte sequence payload syntax.

9 . The method of claim 2 , further comprising reconstructing at least one computer generated hologram from the reconstructed layer-based representation of the volumetric video.

10 . A method, comprising:

encoding in a bitstream, data content representative of a volumetric video; and

encoding in the bitstream, an indicator specifying whether the data content has information representative of at least two sets of depth layers, each depth layer in the at least two sets of depth layers associated with a group of pixels at an associated depth, the information representative of the at least two sets of depth layers specifying an indication of a number of sets of depth layers in the at least two sets of depth layers, and for each of the at least two sets of depth layers, a number of depth layers in a respective set of the at least two sets of depth layers and a depth value for each depth layer in the respective set of the at least two sets of depth layers for a layer-based representation of the volumetric video.

11 . The method of claim 10 , wherein responsive to the indicator specifying that the data content has information representative of the at least two sets of depth layers, the method further comprising encoding the information representative of the at least two sets of depth layers.

12 . The method of claim 11 , wherein the data content representative of the volumetric video is a sequence of multiple plane images, and wherein the sequence of multiple plane images comprises at least one multiple plane image, the at least one multiple plane image comprising a plurality of layers.

13 . The method of claim 12 , wherein the indicator specifying whether the data content has information representative of the at least two sets of depth layers and the information representative of the at least two sets of depth layers are encoded in a common atlas sequence parameter set.

14 . The method of claim 11 , wherein the data content representative of the volumetric video is a point cloud.

15 . The method of claim 14 , wherein the indicator specifying whether the data content has information representative of the at least two sets of depth layers and information representative of the at least two sets of depth layers are signaled as general atlas frame parameter set of a raw byte sequence payload syntax.

16 . An apparatus comprising one or more processors configured for:

decoding, from a bitstream, a data content representative of a volumetric video;

decoding, from the bitstream, an indicator specifying whether the data content has information representative of at least two sets of depth layers, each depth layer in the at least two sets of depth layers associated with a group of pixels at an associated depth, the information representative of the at least two sets of depth layers specifying an indication of a number of sets of depth layers in the at least two sets of depth layers, and for each of the at least two sets of depth layers, a number of depth layers in a respective set of the at least two sets of depth layers and a depth value for each depth layer in the respective set of the at least two sets of depth layers for a layer-based representation of the volumetric video;

responsive to the indicator specifying that the data content has information representative of the at least two sets of depth layers, decoding, from the bitstream, the information representative of the at least two sets of depth layers;

selecting a set of depth layers among the at least two sets of depth layers;

reconstructing the layer-based representation of the volumetric video, the layer-based representation of the volumetric video comprising a number of depth layers and a depth value for each depth layer corresponding to a number of depth layers and a depth value for each depth layer of the selected set of depth layers; and

reconstructing at least one computer generated hologram from the reconstructed layer-based representation of the volumetric video.

17 . The apparatus of claim 16 , wherein selecting the set of depth layers comprises:

determining resources required to reconstruct the layer-based representation of the volumetric video and to reconstruct the at least one computer generated hologram using each of at least one set of depth layers; and

selecting a depth layer set with a largest number of depth layers for which the determined resources required to reconstruct the layer-based representation of the volumetric video and to generate the at least one computer generated hologram fits within a resources budget.

18 . The apparatus of claim 17 , wherein the determined resources comprise at least one of a number of processing cycles, an amount of decoding time, or an amount of memory.

19 . The apparatus of claim 18 , wherein the resources budget comprises at least one of a number of processing cycles available in the apparatus, an amount of decoding time available in the apparatus, or an amount of memory available in the apparatus.