Predictor-copy coding mode for coding of point clouds

A method of decoding a bitstream of compressed point cloud data to produce a reconstructed point cloud, the point cloud being located within a volumetric space recursively split into sub-volumes and containing the points of the point cloud, and wherein occupancy of sub-volumes of the volume is indicated using a bit sequence with each bit of the bit sequence indicating whether a respective sub-volume in a scan order within the volume contains at least one of the points in the set of points, the method comprising:

• determining a prediction for a current sub-volume, the prediction being based on a reference sub-volume containing one or more previously-coded points, the prediction including at least one predicted point within the current sub-volume;
• decoding a predictor-copy coding mode flag from the bitstream;
• and
• determining that the decoded predictor-copy coding mode flag indicates that predictor-copy coding mode is to be used and, in response, foregoing decoding of any further occupancy data for the current sub-volume and copying the at least one predicted point as at least one reconstructed point of the current sub-volume.

An encoder for encoding a point cloud to generate a bitstream of compressed point cloud data, the point cloud being located within a volumetric space recursively split into sub-volumes and containing the points of the point cloud, and wherein occupancy of sub-volumes of the volume is indicated using a bit sequence with each bit of the bit sequence indicating whether a respective sub-volume in a scan order within the volume contains at least one of the points in the set of points, the encoder comprising:

• a processor;
• memory;
• and
• an encoding application containing instructions executable by the processor that, when executed, cause the processor to:
• determine a prediction for a current sub-volume, the prediction being based on a reference sub-volume containing one or more previously-coded points and wherein the prediction includes at least one predicted point within the current sub-volume;
• determine that the current sub-volume is to use a predictor-copy coding mode and, in response, set a predictor-copy coding mode flag to 1, wherein the predictor-copy coding mode flag set to 1 signals that occupancy data for the current sub-volume will not be encoded and the at least one predicted point is to be copied and designated as at least one reconstructed point within the current sub-volume;
• and
• encode the predictor-copy coding mode flag in the bitstream.

A decoder for decoding a bitstream of compressed point cloud data to produce a reconstructed point cloud, the point cloud being located within a volumetric space recursively split into sub-volumes and containing the points of the point cloud, and wherein occupancy of sub-volumes of the volume is indicated using a bit sequence with each bit of the bit sequence indicating whether a respective sub-volume in a scan order within the volume contains at least one of the points in the set of points, the decoder comprising:

• a processor;
• memory;
• and
• a decoding application containing instructions executable by the processor that, when executed, cause the processor to:
• determine a prediction for a current sub-volume, the prediction being based on a reference sub-volume containing one or more previously-coded points, the prediction including at least one predicted point within the current sub-volume;
• decode a predictor-copy coding mode flag from the bitstream;
• and
• determine that the decoded predictor-copy coding mode flag indicates that predictor-copy coding mode is to be used and, in response, forego decoding of any further occupancy data for the current sub-volume and copy the at least one predicted point as at least one reconstructed point of the current sub-volume.