Patent ID: 11936841
Assignee: B1 INSTITUTE OF IMAGE TECHNOLOGY, INC.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H  G | IPC G  H

Claim 2:
3. A method of transmitting a bitstream performed by a transmitting apparatus, comprising:
transmitting the bitstream to an image decoding apparatus,
wherein the bitstream is generated by performing
obtaining a 2-dimensional image projected from an image with a 3-dimensional projection structure and including at least one face;
obtaining an expanded 2-dimensional image including the 2-dimensional image and a predetermined expansion region;
generating a predicted image by performing prediction, information on the prediction being encoded into the bitstream; and
encoding data of the expanded 2-dimensional image into the bitstream based on the predicted image and a residual image,
wherein a size of the expansion region is encoded based on first width information of the expansion region on a left side of the face and second width information of the expansion region on a right side of the face, both the first width information and the second width information being encoded into the bitstream,
wherein sample values of the expansion region are determined differently according to a padding method selected from a plurality of padding methods,
wherein the sample values of the expansion region are determined by horizontally copying the sample values of the face according to the padding method selected from the plurality of padding methods,
wherein size information on the size of the expansion region is encoded into the bitstream,
wherein the residual image is obtained based on the expanded 2-dimensional image and the predicted image, and
wherein the number of syntax elements for the size information is determined differently based on a projection format for the 3-dimensional projection structure, the projection format being one among a plurality of projection formats including an ERP format in which the 360-degree image is projected in a two-dimensional plane and a CMP format in which the 360-degree image is projected in a cube,
wherein residual information is included in the bitstream by encoding the residual image, and
wherein the 3-dimensional projection structure is selectively determined based on identification information, among a plurality of pre-defined projection formats including the ERP format in which the 360-degree image is projected in the two-dimensional plane and the CMP format in which the 360-degree image is projected in the cube.