Point cloud data transmission apparatus, point cloud data transmission method, point cloud data reception apparatus, and point cloud data reception method
A point cloud data transmission method according to embodiments comprises the steps of: encoding geometry data of point cloud data; encoding attribute data of the point cloud data on the basis of the geometry data; and transmitting the encoded geometry data, the encoded attribute data, and signaling data. The step of encoding the geometry data may comprise the steps of: dividing the geometry data into a plurality of compression units; generating, for each compression unit, a prediction tree on the basis of the geometry data within each compression unit; and compressing the geometry data within the compression unit by performing prediction on the basis of the prediction tree.
1. A point cloud data transmission method by a device, comprising:
encoding geometry data of point cloud data;
encoding attribute data of the point cloud data based on the geometry data; and
transmitting the encoded geometry data, the encoded attribute data, and signaling data,
wherein the encoding the geometry data includes:
dividing the geometry data into a plurality of compression units,
generating, for each compression unit, a predictive tree based on the geometry data within each compression unit, and
compressing the geometry data within the compression unit by performing prediction based on the prediction tree,
wherein the compressing the geometry data includes:
detecting one or more reference compression units referenced by a root node within a current compression unit from other compression units,
detecting a reference node referenced by the root node within the current compression unit from the detected one or more reference compression units, and
compressing the root node by performing prediction on the root node within the current compression unit based on the detected reference node.
2. The point cloud data transmission method of claim 1 , wherein the signaling data includes information related to the one or more reference compression units and to the reference node.
3. The point cloud data transmission method of claim 1 , wherein the compressing the geometry data includes:
constructing a new compression unit by gathering root nodes of the compression units;
generating a geometry tree based on root nodes within the constructed compression unit; and
compressing the root nodes by performing prediction based on the generated geometry tree.
4. The point cloud data transmission method of claim 3 , wherein the signaling data includes information related to the new compression unit and information related to an original compression unit of each root node.
5. A point cloud data transmission device, comprising:
a geometry encoder configured to encode geometry data of point cloud data;
an attribute encoder configured to encode attribute data of the point cloud data based on the geometry data; and
a transmitter configured to transmit the encoded geometry data, the encoded attribute data, and signaling data,
wherein the geometry encoder:
divides the geometry data into a plurality of compression units,
generates, for each compression unit, a predictive tree based on the geometry data within each compression unit, and
compresses the geometry data within the compression unit by performing prediction based on the prediction tree,
wherein the geometry encoder further:
detects one or more reference compression units referenced by a root node within a current compression unit from other compression units, detects a reference node referenced by the root node within the current compression unit from the detected one or more reference compression units, and compresses the root node by performing prediction on the root node within the current compression unit based on the detected reference node.
6. The point cloud data transmission device of claim 5 ,
wherein the signaling data includes information related to the one or more reference compression units and to the reference node.
7. The point cloud data transmission device of claim 5 ,
wherein the geometry encoder constructs a new compression unit by gathering root nodes of the compression units, generates a geometry tree based on root nodes within the constructed compression unit, and compresses the root nodes by performing prediction based on the generated geometry tree.
8. The point cloud data transmission device of claim 7 ,
wherein the signaling data includes information related to the new compression unit and information related to an original compression unit of each root node.
9. A point cloud data reception method, comprising:
receiving geometry data, attribute data, and signaling data;
decoding the geometry data based on the signaling data;
decoding the attribute data based on the signaling data and the decoded geometry data; and
rendering point cloud data that is restored based on the signaling data, the decoded geometry data, and the decoded attribute data,
wherein the decoding the geometry data includes:
generating a predictive tree within a compression unit based on the signaling data, and
reconstructing the geometry data within the compression unit by performing prediction based on the predictive tree,
wherein the reconstructing the geometry data includes:
identifying a reference compression unit for a root node of a current compression unit and identifying a reference node, based on the signaling data,
acquiring prediction information of the root node by performing prediction for the root node of the current compression unit, based on the signaling data and the reference node, and
reconstructing a position of the root node, based on prediction information of the root node and residual information of the root node.
10. The point cloud data reception method of claim 9 , wherein the signaling data includes information related to one or more reference compression units referenced by the root node of the current compression unit and to a reference node referenced by the root node of the current compression unit from the one or more reference compression units.
11. The point cloud data reception method of claim 9 , wherein the reconstructing the geometry data includes:
acquiring prediction information of root nodes of compression units by performing prediction on the root nodes based on the signaling data; and
reconstructing a position of the root nodes based on prediction information of the root nodes and residual information of received root nodes.
12. The point cloud data reception method of claim 11 , wherein the signaling data includes information related to a new compression unit and information related to an original compression unit of each root node.