Point Cloud Encoding Method, and Decoding Method Using Rotation Matrices, Encoder, and Decoder

A method comprising:

• obtaining a bitstream comprising a syntax element that determines a transformation matrix for a patch of a point cloud or determines an inverse of the transformation matrix of a point cloud;
• and
• reconstructing the point cloud by transforming, based on the transformation matrix or the inverse of the transformation matrix, second coordinates (x2, y2) of a point of the patch to first coordinates (x1, y1) of the point,
• wherein the first coordinates (x1, y1) are in a first coordinate system, and wherein the second coordinates (x2, y2) are in a second coordinate system.

A non-transitory storage medium comprising instructions that, when executed by one or more processors, cause a source apparatus to:

• project a patch from a three-dimensional space to a two-dimensional space;
• transform, based on a transformation matrix or an inverse of the transformation matrix, first coordinates (x1, y1) of a point of the patch in the two-dimensional space to second coordinates (x2, y2) of the point in the two-dimensional space, wherein the first coordinates (x1, y1) are in a first coordinate system, and wherein the second coordinates (x2, y2) are in a second coordinate system;
• and
• encode a syntax element into a bitstream,
• wherein the syntax element indicates the transformation matrix for the patch or indicates the inverse of the transformation matrix.