A method for generating metadata for a three-dimensional, 3D, image, the method comprising: generating metadata related to a spherical 3D image; and transmitting the generated metadata, wherein the metadata includes: information specifying a first region of the spherical 3D image, wherein the first region is defined by four great circles, and the information specifying the first region includes information indicating yaw, pitch and roll values of a center of the first region, a horizontal angular range of the first region from a center of the spherical 3D image, and vertical angular range of the first region from the center of the spherical 3D image, and characterized in that the metadata further includes: information specifying a second region of the spherical 3D image, wherein the second region is defined by two yaw circles and two pitch circles, and the information specifying the second region includes information indicating yaw and pitch values of a center of the second region, a horizontal angular range of the second region from the center of the spherical 3D image, and vertical angular range of the second region from the center of the spherical 3D image, wherein the first region corresponds to a viewport, and wherein the second region includes the first region and a guard region other than the viewport. generating metadata related to a spherical 3D image; and transmitting the generated metadata, wherein the metadata includes: information specifying a first region of the spherical 3D image, wherein the first region is defined by four great circles, and the information specifying the first region includes information indicating yaw, pitch and roll values of a center of the first region, a horizontal angular range of the first region from a center of the spherical 3D image, and vertical angular range of the first region from the center of the spherical 3D image, and characterized in that the metadata further includes: information specifying a second region of the spherical 3D image, wherein the second region is defined by two yaw circles and two pitch circles, and the information specifying the second region includes information indicating yaw and pitch values of a center of the second region, a horizontal angular range of the second region from the center of the spherical 3D image, and vertical angular range of the second region from the center of the spherical 3D image, wherein the first region corresponds to a viewport, and wherein the second region includes the first region and a guard region other than the viewport. information specifying a first region of the spherical 3D image, wherein the first region is defined by four great circles, and the information specifying the first region includes information indicating yaw, pitch and roll values of a center of the first region, a horizontal angular range of the first region from a center of the spherical 3D image, and vertical angular range of the first region from the center of the spherical 3D image, and characterized in that the metadata further includes: information specifying a second region of the spherical 3D image, wherein the second region is defined by two yaw circles and two pitch circles, and the information specifying the second region includes information indicating yaw and pitch values of a center of the second region, a horizontal angular range of the second region from the center of the spherical 3D image, and vertical angular range of the second region from the center of the spherical 3D image, wherein the first region corresponds to a viewport, and wherein the second region includes the first region and a guard region other than the viewport. information specifying a second region of the spherical 3D image, wherein the second region is defined by two yaw circles and two pitch circles, and the information specifying the second region includes information indicating yaw and pitch values of a center of the second region, a horizontal angular range of the second region from the center of the spherical 3D image, and vertical angular range of the second region from the center of the spherical 3D image, wherein the first region corresponds to a viewport, and wherein the second region includes the first region and a guard region other than the viewport.