Global scaling for geometry-based point cloud coding

A device for decoding point cloud data, the device comprising:

• a memory configured to store point cloud data;
• and
• a processing system comprising one or more processors implemented in circuitry, the processing system being configured to:
• decode a frame of the point cloud data including a plurality of points, each of the points being associated with position values defining a respective position of the point;
• decode a sequence parameter set (SPS) for the frame of point cloud data, wherein to decode the SPS, the processing system is configured to:
• decode an initial global scale value from the SPS;
• decode data from the SPS representing a number of bits for a scale factor refinement value;
• and
• decode the scale factor refinement value from the SPS, the scale factor refinement value having the number of bits;
• determine a global scaling factor for the frame using the initial scale value, the value representing the number of bits for the scale factor refinement value, and the scale factor refinement value, the global scaling factor including an integer component and a non-integer component;
• and
• scale the position values of each of the points by the global scaling factor.

A non-transitory computer-readable storage medium having stored thereon instructions that, when executed, cause a processor to:

• decode a frame of point cloud data including a plurality of points, each of the points being associated with position values defining a respective position of the point;
• decode a sequence parameter set (SPS) for the frame of point cloud data, wherein the instructions that cause the processor to decode the SPS comprise instructions that cause the processor to:
• decode an initial global scale value from the SPS;
• decode data from the SPS representing a number of bits for a scale factor refinement value;
• and
• decode the scale factor refinement value from the SPS, the scale factor refinement value having the number of bits;
• determine a global scaling factor for the frame using the initial scale value, the value representing the number of bits for the scale factor refinement value, and the scale factor refinement value, the global scaling factor including an integer component and a non-integer component;
• and
• scale the position values of each of the points by the global scaling factor.

A device for decoding point cloud data, the device comprising:

• means for decoding a frame of point cloud data including a plurality of points, each of the points being associated with position values defining a respective position of the point;
• means for decoding a sequence parameter set (SPS) for the frame of point cloud data, including:
• means for decoding an initial global scale value from the SPS;
• means for decoding data from the SPS representing a number of bits for a scale factor refinement value;
• and
• means for decoding the scale factor refinement value from the SPS, the scale factor refinement value having the number of bits;
• means for determining a global scaling factor for the frame using the initial scale value, the value representing the number of bits for the scale factor refinement value, and the scale factor refinement value, the global scaling factor including an integer component and a non-integer component;
• and
• means for scaling the position values of each of the points by the global scaling factor.

A method of encoding point cloud data, the method comprising:

• downscaling a frame of point cloud data including a plurality of points using a global scaling factor, the global scaling factor including an integer component and a non-integer component, to form a downscaled frame of point cloud data, each of the points being associated with position values defining a respective position of the point;
• determining an initial global scaling factor for the frame for the global scaling factor;
• determining a number of bits for a scale factor refinement value;
• determining the scale factor refinement value for the global scaling factor, the scale factor refinement value having the number of bits;
• encoding a sequence parameter set (SPS) for the frame of point cloud data, the SPS including the initial global scaling factor, the data representing the number of bits, and the scale factor refinement value;
• encoding the downscaled frame;
• and
• generating a bitstream including data representing the encoded downscaled frame and the SPS including the initial global scaling factor, the number of bits for the scale refinement value, and the scale factor refinement value.