Apparatus, a method and a computer program for volumetric video

1. An apparatus comprising:

at least one processor; and

at least one non-transitory memory including computer program code; wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least:

obtain one or more patches comprising information of an object in a three-dimensional scene;

form an attribute parameter set on the basis of visual properties of a surface of the object in the three-dimensional scene;

wherein the attribute parameter set is formed to describe a smoothness or roughness of the surface of the object;

wherein the description of the smoothness or roughness of the surface of the object comprises a value that at least partially indicates whether a difference between a first surface normal of a first region of the object and a second surface normal of a second region of the object is within a threshold;

form an indication that the attribute parameter set relates to visual properties of the surface of the object;

signal the indication that the attribute parameter set relates to visual properties of the surface of the object at least partially within at least one syntax element that indicates that the attribute parameter set is formed to describe the smoothness or roughness of the surface of the object; and

form an indication on a range for which the attribute parameter set is valid.

2. The apparatus of claim 1 , wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least perform one of the following:

calculate an average of values of an attribute within the range;

select a median of the values of the attribute within the range;

select a maximum of the values of the attribute within the range; or

select a minimum of the values of the attribute within the range.

3. The apparatus of claim 1 , wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least:

signal attribute values per block of pixels in each patch.

4. The apparatus of claim 1 , wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least:

segment content of the one or more patches to different regions; and

calculate and signal for each segment a respective attribute value.

5. The apparatus of claim 1 , wherein the range for which the attribute parameter set is valid is one of a block of pixels, a patch, or a group of frames.

6. The apparatus of claim 1 , wherein the attribute parameter set comprises one or more attributes indicating one or more of the following visual properties of the surface of the object:

the smoothness or roughness;

specular amount;

surface albedo;

bidirectional reflectance distribution function;

bidirectional scattering distribution function;

bidirectional scattering-surface reflectance distribution function;

bidirectional transmittance distribution function;

opacity; or

translucency.

7. The apparatus of claim 1 , wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least:

combine a set of different attribute types to an attribute superset, the attribute superset describing the visual properties of the surface of the object in the three-dimensional scene.

8. The apparatus of claim 7 , wherein the attribute superset comprises smoothness, albedo and a bidirectional scattering-surface reflectance distribution function to describe a surface attribute for patches of the object, the surface attribute describing anatomical skin.

9. The apparatus of claim 1 , wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least:

signal the attribute values as a residual between a previous attribute value and a current attribute value;

signal the attribute values as a residual between at least one previous attribute index value and at least one current attribute index value; or

signal the attribute values as indexes to a look-up table.

10. The apparatus of claim 1 , wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least:

encode and signal the attribute parameter set into or along a bitstream.

11. The apparatus of claim 1 , wherein the attribute parameter set is formed to describe albedo of the surface of the object, and the indication that the attribute parameter set relates to visual properties of the surface of the object comprises, at least partially, a syntax element that indicates that the attribute parameter set is formed to describe the albedo of the surface of the object.

12. The apparatus of claim 1 , wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least:

signal an information element to indicate the presence of the indication that the attribute parameter set relates to visual properties of the surface of the object;

wherein the indication that the attribute parameter set relates to visual properties of the surface of the object is configured to be decoded in response to the flag indicating the presence of the indication that the attribute parameter set relates to visual properties of the surface of the object.

13. The apparatus of claim 1 , wherein the attribute parameter set is formed to describe an effect the surface of the object causes to radiation arriving on the surface of the object.

14. A method comprising:

obtaining one or more patches comprising information of a three-dimensional scene;

forming an attribute parameter set on the basis of visual properties of a surface of an object in the three-dimensional scene;

wherein the attribute parameter set is formed to describe a smoothness or roughness of the surface of the object;

wherein the description of the smoothness or roughness of the surface of the object comprises a value that at least partially indicates whether a difference between a first surface normal of a first region of the object and a second surface normal of a second region of the object is within a threshold;

forming an indication that the attribute parameter set relates to visual properties of the surface of the object;

signaling the indication that the attribute parameter set relates to visual properties of the surface of the object at least partially within at least one syntax element that indicates that the attribute parameter set is formed to describe the smoothness or roughness of the surface of the object; and

forming an indication on a range for which the attribute parameter set is valid.

15. The method of claim 14 , further comprising:

calculating an average of values of an attribute within the range;

selecting a median of the values of the attribute within the range;

selecting a maximum of the values of the attribute within the range; and

selecting a minimum of values of an attribute within the range.

16. The method of claim 14 , further comprising:

signaling attribute values of the attribute parameter set per block of pixels in each patch;

signaling the attribute values as a residual between a previous attribute value and a current attribute value;

signaling the attribute values as a residual between at least one previous attribute index value and at least one current attribute index value;

signaling the attribute values per a region of interest; or

signaling the attribute values as indexes to a look-up table.

17. The method of claim 14 , further comprising:

segmenting content of the one or more patches to different regions; and

calculating and signaling for each segment a respective attribute value.

18. An apparatus comprising:

at least one processor; and

at least one non-transitory memory including computer program code;

wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least:

receive an information element carrying an attribute parameter set, which relates to one or more patches comprising information of a three-dimensional scene;

wherein the attribute parameter set has been formed to describe a smoothness or roughness of the surface of an object in the three-dimensional scene;

wherein the description of the smoothness or roughness of the surface of the object comprises a value that at least partially indicates whether a difference between a first surface normal of a first region of the object and a second surface normal of a second region of the object is within a threshold;

examine an indication to determine whether the attribute parameter set has been formed on the basis of visual properties of the surface of the object in the three-dimensional scene;

decode the indication of whether the attribute parameter set has been formed on the basis of visual properties of the surface of the object at least partially from at least one syntax element that indicates that the attribute parameter set has been formed to describe the smoothness or roughness of the surface of the object; and

use the attribute parameter set to reconstruct the three-dimensional scene, in response to the examination revealing that the attribute parameter set has been formed on the basis of visual properties of the surface of the object.

19. The apparatus of claim 18 , wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least:

examine a range for which the attribute parameter set is valid.

20. The apparatus of claim 18 , wherein the at least one memory and the computer program code are configured to, with the at least one processor, cause the apparatus to at least:

receive attribute values per block of pixels in each patch;

receive the attribute values as a residual between a previous attribute value and a current attribute value;

receiving the attribute values as a residual between at least one previous attribute index value and at least one current attribute index value;

receive the attribute values per a region of interest; or

receive the attribute values as indexes to a look-up table.

21. The apparatus of claim 18 , wherein the attribute parameter set comprises one or more attributes indicating one or more of the following visual properties of the surface of the object:

the smoothness or roughness;

specular amount;

surface albedo;

bidirectional reflectance distribution function;

bidirectional scattering distribution function;

bidirectional scattering-surface reflectance distribution function;

bidirectional transmittance distribution function;

opacity; or

translucency.

22. A method comprising:

receiving an information element carrying an attribute parameter set, which relates to one or more patches comprising information of a three-dimensional scene;

wherein the attribute parameter set has been formed to describe a smoothness or roughness of the surface of an object in the three-dimensional scene;

wherein the description of the smoothness or roughness of the surface of the object comprises a value that at least partially indicates whether a difference between a first surface normal of a first region of the object and a second surface normal of a second region of the object is within a threshold;

examining an indication to determine whether the attribute parameter set has been formed on the basis of visual properties of a surface of an object in the three-dimensional scene;

decoding the indication of whether the attribute parameter set has been formed on the basis of visual properties of the surface of the object at least partially from at least one syntax element that indicates that the attribute parameter set has been formed to describe the smoothness or roughness of the surface of the object; and

in response to the examination revealing that the attribute parameter set has been formed on the basis of visual properties of the surface of the object, using the attribute parameter set to reconstruct the three-dimensional scene.

23. The method of claim 22 , further comprising:

examining a range for which the attribute parameter set is valid.

24. The method of claim 22 further comprising:

receiving attribute values per block of pixels in each patch;

receiving the attribute values as a residual between a previous attribute value and a current attribute value;

receiving the attribute values as a residual between at least one previous attribute index value and at least one current attribute index value;

receiving the attribute values per a region of interest; or

receiving the attribute values as indexes to a look-up table.