Sampling grid information for spatial layers in multi-layer video coding
Sampling grid information may be determined for multi-layer video coding systems. The sampling grid information may be used to align the video layers of a coding system. Sampling grid correction may be performed based on the sampling grid information. The sampling grids may also be detected. In some embodiments, a sampling grid precision may also be detected and/or signaled.
1. A method for multi-layer video coding, comprising:
receiving, by a wireless transmit/receive unit (WTRU), a signal comprising sampling grid information, the sampling grid information comprising luma plane shift data and chroma plane phase shift data, the luma plane phase shift data specifying a luma phase shift between a luma sampling grid of a first picture in a first video layer and a luma sampling grid of a second picture in a second video layer, the chroma plane phase shift data specifying a chroma phase shift between a chroma sampling grid of the first picture and a chroma sampling grid of the second picture;
determining, by the WTRU, one or more poly-phase filters based on the luma plane phase shift data and the chroma plane phase shift data; and
performing, by the WTRU, sampling grid correction based on the received sampling grid information and using the determined one or more poly-phase filters to align the luma sampling grid of the first picture with the luma sampling grid of the second picture, and to align the chroma sampling grid of the first picture with the chroma sampling grid of the second picture.
2. The method of claim 1 , wherein determining one or more poly-phase filters comprises selecting one or more High Efficiency Video Coding (HEVC) poly-phase filters.
3. The method of claim 1 , wherein the chroma plane phase shift data includes at least one of: a horizontal chroma phase shift or a vertical chroma phase shift.
4. The method of claim 1 , wherein the luma plane phase includes at least one of: a horizontal luma phase shift or a vertical luma phase shift.
5. The method of claim 1 , wherein the signal includes a flag, the flag indicating that the sampling grid information is included in the signal.
6. The method of claim 1 , wherein the first video layer is a base layer and the second video layer is an enhancement layer.
7. The method of claim 1 ,
wherein the luma plane phase shift data indicates a non-zero relative phase shift between the first picture in the first video layer and the second picture in the second video layer, and
wherein the chroma plane phase shift data indicates a non-zero relative phase shift between the first picture in the first video layer and the second picture in the second video layer.
8. A device for performing multi-layer video coding, comprising:
a processor configured at least to:
receive a signal comprising sampling grid information, the sampling grid information comprising luma plane shift data and chroma plane phase shift data, the luma plane phase shift data specifying a luma phase shift between a luma sampling grid of a first picture in a first video layer and a luma sampling grid of a second picture in a second video layer, the chroma plane phase shift data specifying a chroma phase shift between a chroma sampling grid of the first picture and a chroma sampling grid of the second picture;
determine one or more poly-phase filters based on the luma plane phase shift data and the chroma plane phase shift data; and
perform sampling grid correction based on the received sampling grid information and using the determined one or more poly-phase filters to align the luma sampling grid of the first picture with the luma sampling grid of the second picture, and to align the chroma sampling grid of the first picture with the chroma sampling grid of the second picture.
9. The device of claim 8 , wherein selecting one or more poly-phase filters based on the luma plane shift data and the chroma plane shift data comprises selecting one or more High Efficiency Video Coding (HEVC) poly-phase filters.
10. The device of claim 8 , wherein the chroma plane phase shift data includes at least one of: a horizontal chroma phase shift or a vertical chroma phase shift.
11. The device of claim 8 , wherein the luma plane phase includes at least one of: a horizontal luma phase shift or a vertical luma phase shift.
12. The device of claim 8 , wherein the signal includes a flag, the flag indicating that the sampling grid information is included in the signal.
13. The device of claim 8 , wherein the first video layer is a base layer and the second video layer is an enhancement layer.
14. The device of claim 8 ,
wherein the luma plane phase shift data indicates a non-zero relative phase shift in luma between the first picture in the first video layer and the second picture in the second video layer, and
wherein the chroma plane phase shift data indicates a non-zero relative phase shift in chroma between the first picture in the first video layer and the second picture in the second video layer.
15. A method for multi-layer video coding, comprising:
receiving a signal comprising sampling grid information, the sampling grid information comprising luma plane shift data and chroma plane phase shift data, the luma plane phase shift data specifying a luma phase shift between a luma sampling grid of a first picture in a first video layer and a luma sampling grid of a second picture in a second video layer, the chroma plane phase shift data specifying a chroma phase shift between a chroma sampling grid of the first picture and a chroma sampling grid of the second picture; and
selecting one or more poly-phase filters based on at least one of the luma plane phase shift data and the chroma plane phase shift data; and
applying the one or more poly-phase filters to align the luma sampling grid of the first picture with the luma sampling grid of the second picture, and to align the chroma sampling grid of the first picture with the chroma sampling grid of the second picture.
16. The method of claim 15 , wherein selecting one or more poly-phase filters based on the luma plane shift data and the chroma plane shift data comprises selecting one or more High Efficiency Video Coding (HEVC) poly-phase filters.
17. The method of claim 16 , wherein the chroma plane phase shift data includes at least one of: a horizontal chroma phase shift or a vertical chroma phase shift.
18. The method of claim 16 , wherein the luma plane phase includes at least one of: a horizontal luma phase shift or a vertical luma phase shift.
19. The method of claim 15 , wherein the signal includes a flag, the flag indicating that the sampling grid information is included in the signal.
20. The method of claim 15 , wherein the first video layer is a base layer and the second video layer is an enhancement layer.