Method for transmitting data about three-dimensional image
Provided is a method for transmitting data about an omnidirectional image by a server. The method comprises the steps of: receiving, from a terminal, information about a viewport of the terminal; selecting, on the basis of information about the viewport and the respective qualities of a plurality of tracks associated with the omnidirectional image, at least one track among the plurality of tracks; and transmitting data about the selected at least one track to the terminal.
1. A method for transmitting, by a transmission device, data related to an omnidirectional image, the method comprising:
identifying data of a 2 dimensional (2D) image which is generated based on projecting an omnidirectional image to a planar space;
identifying metadata related to the omnidirectional image; and
transmitting the data of the 2D image and the metadata,
wherein the metadata comprises information on quality ranking of each of one or more regions of the omnidirectional image or information on quality ranking of one or more regions of the 2D image.
2. The method of claim 1 , wherein the information on quality ranking of each of the one or more regions of the omnidirectional image comprises:
information indicating whether each of the one or more regions of the omnidirectional image is defined by four great circles or by two yaw circles and two pitch circles;
information indicating a number of the one or more regions of the omnidirectional image for which quality ranking information is given;
information indicating the quality ranking of each of the one or more regions of the omnidirectional image;
information indicating whether a region of the one or more of regions of the omnidirectional image is monoscopic, or is on a left view of stereoscopic content, or on a right view of the stereoscopic content, or is on both the left view and the right view; and
information indicating location and size of each of the one or more of regions of the omnidirectional image.
3. The method of claim 1 , wherein the information on quality ranking of one or more regions of the 2D image comprises:
information indicating a number of the one or more regions of the 2D image for which quality ranking information is given;
information indicating the quality ranking of each of the one or more regions of the 2D image;
information indicating whether a region of the one or more of regions of the 2D image is monoscopic, or is on a left view of stereoscopic content, or on a right view of the stereoscopic content, or is on both the left view and the right view; and
information indicating location and size of each of the one or more of regions of the 2D image.
4. The method of claim 1 , wherein, if the 2D image is generated by region-wise packing a plurality of regions of a projected 2D image which is projected from the omnidirectional image, the metadata comprises information indicating each of the plurality of regions on the projected 2D image and information indicating a packed region on the 2D image corresponding to each of the plurality of regions on the projected 2D image.
5. The method of claim 4 , wherein the information indicating each of the plurality of regions on the projected 2D image comprise width, height top offset, and left offset of each of the plurality of regions on the projected 2D image.
6. The method of claim 4 , wherein information indicating the packed region on the 2D image corresponding to each of the plurality of regions on the projected 2D image comprises height top offset, and left offset of the packed region.
7. The method of claim 4 , wherein, if the 2D image is generated by region-wise packing the plurality of regions of the projected 2D image, the metadata further comprises information indicating transform type for a first region among the plurality of regions on the projected 2D image, and the transform type is applied when transforming the first region to a first packed region on the 2D image.
8. The method of claim 7 , wherein the transform type indicates one of no transform, mirroring horizontally, rotation by 180 degree (counter-clockwise), rotation by 180 degrees (counter-clockwise) and mirroring horizontally, rotation by 90 degrees (counter-clockwise) and mirroring horizontally, rotation by 90 degrees (counter-clockwise), rotation by 270 degrees (counter-clockwise) or mirroring horizontally, and rotation by 270 degrees (counter-clockwise).
9. The method of claim 1 , wherein the metadata further comprises information on content coverage of a track, and the information on the content coverage of the track comprises information indicating a region of the omnidirectional image.
10. The method of claim 1 , wherein information indicating the region of the omnidirectional image comprises:
information indicating center of the region of the omnidirectional image;
information indicating horizontal range of the region of the omnidirectional image; and
information indicating vertical range of the region of the omnidirectional image.
11. A transmission device for transmitting data related to an omnidirectional image, the transmission device comprising:
at least one processor configured to:
identify data of a 2 dimensional (2D) image which is generated based on projecting an omnidirectional image to a planar space, and
identify metadata related to the omnidirectional image; and
a transceiver configured to transmit the data of the 2D image and the metadata,
wherein the metadata comprises information on quality ranking of each of one or more regions of the omnidirectional image.
12. The transmission device of claim 11 , wherein the information on quality ranking of each of the one or more regions of the omnidirectional image comprises:
information indicating whether each of the one or more regions of the omnidirectional image is defined by four great circles or by two yaw circles and two pitch circles;
information indicating a number of the one or more regions for which quality ranking information is given;
information indicating the quality ranking of each of the one or more regions of the omnidirectional image;
information indicating whether a region of the one or more regions of the omnidirectional image is monoscopic, or is on a left view of stereoscopic content, or on a right view of the stereoscopic content, or is on both the left view and the right view; and
information indicating location and size of each of the one or more regions of the omnidirectional image.
13. The transmission device of claim 11 , wherein the information on quality ranking of one or more regions of the 2D image comprises:
information indicating a number of the one or more regions of the 2D image for which quality ranking information is given;
information indicating the quality ranking of each of the one or more regions of the 2D image;
information indicating whether a region of the one or more of regions of the 2D image is monoscopic, or is on a left view of stereoscopic content, or on a right view of the stereoscopic content, or is on both the left view and the right view; and
information indicating location and size of each of the one or more of regions of the 2D image.
14. The transmission device of claim 11 , wherein, if the 2D image is generated by region-wise packing a plurality of regions of a projected 2D image which is projected from the omnidirectional image, the metadata comprises information indicating each of the plurality of regions on the projected 2D image and information indicating a packed region on the 2D image corresponding to each of the plurality of regions on the projected 2D image.
15. The transmission device of claim 14 , wherein the information indicating each of the plurality of regions on the projected 2D image comprise width, height top offset, and left offset of each of the plurality of regions on the projected 2D image.
16. The transmission device of claim 14 , wherein information indicating the packed region on the 2D image corresponding to each of the plurality of regions on the projected 2D image comprises height top offset, and left offset of the packed region.
17. The transmission device of claim 14 , wherein, if the 2D image is generated by region-wise packing the plurality of regions of the projected 2D image, the metadata further comprises information indicating transform type for a first region among the plurality of regions on the projected 2D image, and the transform type is applied when transforming the first region to a first packed region on the 2D image.
18. The transmission device of claim 17 , wherein the transform type indicates one of no transform, mirroring horizontally, rotation by 180 degree (counter-clockwise), rotation by 180 degrees (counter-clockwise) and mirroring horizontally, rotation by 90 degrees (counter-clockwise) and mirroring horizontally, rotation by 90 degrees (counter-clockwise), rotation by 270 degrees (counter-clockwise) or mirroring horizontally, and rotation by 270 degrees (counter-clockwise).
19. The transmission device of claim 11 , wherein the metadata further comprises information on content coverage of a track, and the information on the content coverage of the track comprises information indicating a region of the omnidirectional image.
20. The transmission device of claim 11 , wherein information indicating the region of the omnidirectional image comprises:
information indicating center of the region of the omnidirectional image;
information indicating horizontal range of the region of the omnidirectional image; and
information indicating vertical range of the region of the omnidirectional image.