Method for wrap around motion compensation with reference picture resampling
A method of generating a coded video bitstream including setting a flag pps_ref_wraparound_enabled_flag, wherein the flag pps_ref_wraparound_enabled_flag being equal to 1 specifies that a horizontal wrap-around motion compensation is enabled for pictures referring to a picture parameter set (PPS) in a coded video stream; determining whether the reference picture is to be scaled based on whether reference picture resampling is enabled; in response to the reference picture being not scaled, setting a second flag refWraparoundEnabledFlag to be equal to a value of the flag pps_ref_wraparound_enabled_flag; and encoding the coded video bitstream comprising at least the current picture and the flag pps_ref_wraparound_enabled_flag.
1. A method for video decoding in a video decoder, the method comprising:
receiving a first flag pps_ref_wraparound_enabled_flag, wherein the first flag pps_ref_wraparound_enabled_flag being equal to 1 specifies that horizontal wrap-around motion compensation is enabled for pictures referring to a picture parameter set in a coded video bitstream; and
when a reference picture is not scaled and a second flag refWraparoundEnabledFlag is equal to a value of the first flag pps_ref_wraparound_enabled_flag,
decoding a current layer of a picture in the coded video bitstream without the wrap-around compensation at least based on the second flag refWraparoundEnabledFlag.
2. The method of claim 1 , wherein the wrap-around compensation is disabled when at least one of a first determination indicates that the current layer is not an independent layer, or a second determination indicates that reference picture resampling is enabled for the current layer.
3. The method of claim 2 , wherein
the first determination is made based on a flag signaled in a first syntax structure, and
the second determination is made based on a flag signaled in a second syntax structure lower than the first syntax structure.
4. The method of claim 1 , wherein the wrap-around compensation is disabled when the first flag pps_ref_wraparound_enabled_flag is absent from a sequence parameter set.
5. The method of claim 2 , the method further comprising:
when the current layer is not the independent layer and the reference picture resampling is enabled for the current layer, making a third determination regarding whether a width of a current picture is different from a width of a current reference picture,
the wrap-around compensation being disabled when the third determination indicates that the width of the current picture is different from the width of the current reference picture.
6. The method of claim 5 , wherein the third determination is made during an interpolation process for motion compensation.
7. A method for video encoding in a video encoder, the method comprising:
generating a first flag pps_ref_wraparound_enabled_flag, wherein the first flag pps_ref_wraparound_enabled_flag being equal to 1 specifies that horizontal wrap-around motion compensation is enabled for pictures referring to a picture parameter set in a video stream;
when a reference picture is being not scaled, generating a second flag refWraparoundEnabledFlag to be equal to a value of the first flag pps_ref_wraparound_enabled_flag; and
encoding a current layer of a picture in the video stream without the wrap-around compensation at least based on the second flag refWraparoundEnabledFlag is equal to the value of the first flag pps_ref_wraparound_enabled_flag.
8. The method of claim 7 , wherein the wrap-around compensation is disabled when at least one of a first determination indicates that the current layer is not an independent layer, or a second determination indicates that reference picture resampling is enabled for the current layer.
9. The method of claim 8 , wherein
the first determination is made based on a flag signaled in a first syntax structure, and
the second determination is made based on a flag signaled in a second syntax structure lower than the first syntax structure.
10. The method of claim 7 , wherein the wrap-around compensation is disabled when the first flag pps_ref_wraparound_enabled_flag is absent from a sequence parameter set.
11. The method of claim 8 , the method further comprising:
when the current layer is not the independent layer and the reference picture resampling is enabled for the current layer, making a third determination regarding whether a width of a current picture is different from a width of a current reference picture,
the wrap-around compensation being disabled when the third determination indicates that the width of the current picture is different from the width of the current reference picture.
12. The method of claim 11 , wherein the third determination is made during an interpolation process for motion compensation.
13. A method for processing visual media data, the method comprising:
processing a bitstream that includes the visual media data according to a format rule,
wherein
the bitstream includes a first flag pps_ref_wraparound_enabled_flag and a second flag refWraparoundEnabledFlag; and
the format rule specifies that:
the first flag pps_ref_wraparound_enabled_flag being equal to 1 specifies that horizontal wrap-around motion compensation is enabled for pictures referring to a picture parameter set in the bitstream,
when a reference picture is not scaled, the second flag refWraparoundEnabledFlag is equal to a value of the first flag pps_ref_wraparound_enabled_flag, and
a current layer of a picture in the bitstream is processed without the wrap-around compensation is at least based on the second flag refWraparoundEnabledFlag.
14. The method of claim 13 , wherein the wrap-around compensation is disabled when at least one of a first determination indicates that the current layer is not an independent layer, or a second determination indicates that reference picture resampling is enabled for the current layer.
15. The method of claim 14 , wherein
the first determination is made based on a flag signaled in a first syntax structure, and
the second determination is made based on a flag signaled in a second syntax structure lower than the first syntax structure.
16. The method of claim 13 , wherein the wrap-around compensation is disabled when the first flag pps_ref_wraparound_enabled_flag is absent from a sequence parameter set.
17. The method of claim 14 , wherein the format rule further specifies that:
when the current layer is not the independent layer and the reference picture resampling is enabled for the current layer, a third determination regarding whether a width of a current picture is different from a width of a current reference picture is made,
the wrap-around compensation is disabled based the third determination indicating that the width of the current picture is different from the width of the current reference picture.
18. The method of claim 11 , wherein the third determination is made during an interpolation process for motion compensation.