Method and apparatus for generating and encoding projection-based frame with 360-degree content represented by triangular projection faces packed in octahedron projection layout

A video processing method comprising:

• receiving an omnidirectional image/video content corresponding to a viewing sphere;
• generating a projection-based frame according to the omnidirectional image/video content and an octahedron projection layout, wherein the projection-based frame has a 360-degree image/video content represented by triangular projection faces packed in the octahedron projection layout, the omnidirectional image/video content of the viewing sphere is mapped onto the triangular projection faces via an octahedron projection of the viewing sphere, and an equator of the viewing sphere is not mapped along any side of each of the triangular projection faces;
• and
• encoding, by a video encoder, the projection-based frame to generate a part of a bitstream;
• wherein the triangular projection faces packed in the octahedron projection layout comprise a first triangular projection face, a second triangular projection face and a third triangular projection face, one side of the first triangular projection face connects with one side of the second triangular projection face, one side of the third triangular projection face connects with another side of the second triangular projection face, there is an image content continuity boundary between said one side of the first triangular projection face and said one side of the second triangular projection face, and there is an image content continuity boundary between said one side of the third triangular projection face and said another side of the second triangular projection face;
• and
• wherein the triangular projection faces packed in the octahedron projection layout further comprise a fourth triangular projection face, a fifth triangular projection face, and a sixth triangular projection face, another side of the third triangular projection face connects with one side of the fourth triangular projection face, another side of the fourth triangular projection face connects with one side of the fifth triangular projection face, another side of the fifth triangular projection face connects with one side of the sixth triangular projection face, there is an image content continuity boundary between said another side of the third triangular projection face and said one side of the fourth triangular projection face, there is an image content continuity boundary between said another side of the fourth triangular projection face and said one side of the fifth triangular projection face, and there is an image content continuity boundary between said another side of the fifth triangular projection face and said one side of the sixth triangular projection face.

A video processing method comprising:

• receiving an omnidirectional image/video content corresponding to a viewing sphere;
• generating a projection-based frame according to the omnidirectional image/video content and an octahedron projection layout, wherein the projection-based frame has a 360-degree image/video content represented by triangular projection faces packed in the octahedron projection layout, the omnidirectional image/video content of the viewing sphere is mapped onto the triangular projection faces via an octahedron projection of the viewing sphere, and an equator of the viewing sphere is not mapped along any side of each of the triangular projection faces;
• and
• encoding, by a video encoder, the projection-based frame to generate a part of a bitstream;
• wherein there is an image content discontinuity boundary between sides of any two adjacent triangular projection faces in the octahedron projection layout;
• and
• wherein the triangular projection faces packed in the octahedron projection layout comprise a first triangular projection face, a second triangular projection face, a third triangular projection face, a fourth triangular projection face, a fifth triangular projection face, a sixth triangular projection face, a seventh triangular projection face, and an eighth triangular projection face, one side of the first triangular projection face connects with one side of the second triangular projection face, one side of the third triangular projection face connects with another side of the second triangular projection face, one side of the fourth triangular projection face connects with another side of the third triangular projection face, one side of the fifth triangular projection face connects with another side of the fourth triangular projection face, one side of the sixth triangular projection face connects with another side of the fifth triangular projection face, one side of the seventh triangular projection face connects with another side of the sixth triangular projection face, the eighth triangular projection face is split into a first right-triangle-shaped part and a second right-triangle-shaped part, the first right-triangle-shaped part has a first side being one side of the eighth triangular projection face and a second side being a first part of another side of the eighth triangular projection face, the second right-triangle-shaped part has a first side being yet another side of the eighth triangular projection face and a second side being a second part of said another side of the eighth triangular projection face, the first side of the first right-triangle-shaped part connects with another side of the seventh triangular projection face, and the first side of the second right-triangle-shaped part connects with another side of the first triangular projection face.

A video processing method comprising:

• receiving an omnidirectional image/video content corresponding to a viewing sphere;
• generating a projection-based frame according to the omnidirectional image/video content and an octahedron projection layout, wherein the projection-based frame has a 360-degree image/video content represented by triangular projection faces packed in the octahedron projection layout, the omnidirectional image/video content of the viewing sphere is mapped onto the triangular projection faces via an octahedron projection of the viewing sphere, and an equator of the viewing sphere is not mapped along any side of each of the triangular projection faces;
• and
• encoding, by a video encoder, the projection-based frame to generate a part of a bitstream;
• wherein the triangular projection faces comprise a first triangular projection face and a second triangular projection face, and generating the projection-based frame according to the omnidirectional image/video content and the octahedron projection layout comprises:
• before packing the first triangular projection face and the second triangular projection face, removing a plurality of boundary pixel samples at one side of the first triangular projection face;
• and
• after the plurality of boundary pixel samples at said one side of the first triangular projection face are removed, packing the first triangular projection face and the second triangular projection face in the octahedron projection layout, wherein said one side of the first triangular projection face connects with one side of the second triangular projection face, and there is an image content continuity boundary between said one side of the first triangular projection face and said one side of the second triangular projection face.

A video processing apparatus comprising:

• a conversion circuit, arranged to receive an omnidirectional image/video content corresponding to a viewing sphere, and generate a projection-based frame according to the omnidirectional image/video content and an octahedron projection layout, wherein the projection-based frame has a 360-degree image/video content represented by triangular projection faces packed in the octahedron projection layout, the omnidirectional image/video content of the viewing sphere is mapped onto the triangular projection faces via an octahedron projection of the viewing sphere, and an equator of the viewing sphere is not mapped along any side of each of the triangular projection faces;
• and
• a video encoder, arranged to encode the projection-based frame to generate a part of a bitstream;
• wherein the triangular projection faces packed in the octahedron projection layout comprise a first triangular projection face, a second triangular projection face and a third triangular projection face, one side of the first triangular projection face connects with one side of the second triangular projection face, one side of the third triangular projection face connects with another side of the second triangular projection face, there is an image content continuity boundary between said one side of the first triangular projection face and said one side of the second triangular projection face, and there is an image content continuity boundary between said one side of the third triangular projection face and said another side of the second triangular projection face;
• and
• wherein the triangular projection faces packed in the octahedron projection layout further comprise a fourth triangular projection face, one side of the fourth triangular projection face connects with yet another side of the second triangular projection face, and there is an image content continuity boundary between said one side of the fourth triangular projection face and said yet another side of the second triangular projection face.