Methods for signaling virtual boundaries and wrap-around motion compensation

1. A video decoding method, comprising:

receiving a bitstream associated with a set of pictures;

determining, according to the received bitstream, whether a resolution of a first picture in the set of pictures is different from a resolution of a reference picture associated with the first picture;

in response to the resolution of the first picture being different from the resolution of the reference picture associated with the first picture, determining that wrap-around motion compensation is disabled for the first picture;

determining, according to the received bitstream, whether a virtual boundary is signaled at a sequence level for the set of pictures; and

controlling in-loop filtering operations based on whether the virtual boundary is signaled at the sequence level;

wherein the controlling of the in-loop filtering operations comprises:

in response to the virtual boundary being signaled at the sequence level, determining a position of the virtual boundary for the set of pictures, the position being bounded by a range signaled in the received bitstream; and

disabling in-loop filtering operations across the virtual boundary,

wherein the range by which the position is bounded comprises at least one of a vertical range or a horizontal range,

the vertical range is less than or equal to a first value associated with a maximum width of each picture of the set of pictures, the maximum width being signaled in the received bitstream, and

the horizontal range is less than or equal to a second value associated with a maximum height of each picture of the set of pictures, the maximum height being signaled in the received bitstream.

2. The method according to claim 1 , wherein the first value is equal to Ceil(pic_width_max_in_luma_samples÷8)−1 and the second value is equal to Ceil(pic_height_max_in_luma_samples÷8)−1, and

wherein pic_width_max_in_luma_samples represents the maximum width, in units of luma samples, of each picture of the set of pictures, and pic_height_max_in_luma_samples represents the maximum height, in units of luma samples, of each picture of the set of pictures.

3. The method according to claim 1 , wherein determining, according to the received bitstream, whether the virtual boundary is signaled at the sequence level comprises:

determining, according to the received bitstream, whether the resolution of the first picture is allowed to be changed; and

in response to the resolution of the first picture being allowed to be changed, determining that the virtual boundary is not signaled at the sequence level.

4. The method according to claim 3 , further comprising:

in response to the resolution of the first picture being allowed to be changed, determining that wrap-around motion compensation is disabled for the set of pictures.

5. A non-transitory computer readable medium that stores a bitstream of a set of pictures for processing according to a method comprising:

determining, according to the bitstream, whether a resolution of a first picture in the set of pictures is different from a resolution of a reference picture associated with the first picture;

in response to the resolution of the first picture being different from the resolution of the reference picture associated with the first picture, determining that wrap-around motion compensation is disabled for the first picture;

determining whether the bitstream signals a virtual boundary at a sequence level for the set of pictures;

in response to the bitstream signaling the virtual boundary at the sequence level, determining a position of the virtual boundary for the set of pictures, the position being bounded by a range signaled in the bitstream; and

disabling in-loop filtering operations across the virtual boundary,

wherein the range signaled in the bitstream comprises at least one of a vertical range or a horizontal range,

the vertical range is less than or equal to a first value associated with a maximum width of each picture of the set of pictures, the maximum width being signaled in the bitstream, and

the horizontal range is less than or equal to a second value associated with a maximum height of each picture of the set of pictures, the maximum height being signaled in the bitstream.

6. The non-transitory computer readable medium according to claim 5 , wherein the first value is equal to Ceil(pic_width_max_in_luma_samples÷8)−1 and the second value is equal to Ceil(pic_height_max_in_luma_samples÷8)−1, and

wherein pic_width_max_in_luma_samples represents the maximum width, in units of luma samples, of each picture of the set of pictures, and pic_height_max_in_luma_samples represents the maximum height, in units of luma samples, of each picture of the set of picture.

7. The non-transitory computer readable medium according to claim 5 , wherein the bitstream comprises:

a flag indicating whether the resolution of the first picture is allowed to be changed; and

wherein the method further comprises:

in response to the flag indicating the resolution of the first picture being allowed to be changed, determining that the virtual boundary is not signaled at the sequence level.

8. The non-transitory computer readable medium according to claim 7 , wherein the method further comprises:

in response to the flag indicating the resolution of the first picture being allowed to be changed, determining that wrap-around motion compensation is disabled for the set of pictures.

9. The non-transitory computer readable medium according to claim 5 , wherein the set of instructions that is executable by the computer to cause the computer to further perform:

in response to that the bitstream does not signal the virtual boundary at the sequence level,

determining whether the bitstream signals the virtual boundary at a picture level for one or more pictures in the set,

in response to that the bitstream signals the virtual boundary at the picture level for the one or more pictures in the set, determining a position of the virtual boundary for the one or more pictures.

10. A video encoding method, comprising:

setting a virtual boundary for a set of pictures;

disabling in-loop filtering operations across the virtual boundary;

determining whether a resolution of a first picture in the set of pictures is different from a resolution of a reference picture associated with the first picture;

in response to the resolution of the first picture being different from the resolution of the reference picture associated with the first picture, disabling wrap-around motion compensation for the first picture; and

signaling, in a bitstream, a maximum value indicative of a range by which a position of the virtual boundary is bounded,

wherein the range comprises at least one of a vertical range or a horizontal range, and the maximum value comprises at least one of a maximum width of each picture of the set of pictures or a maximum height of each picture of the set of pictures, wherein:

the vertical range is less than or equal to a first value associated with the maximum width, and

the horizontal range is less than or equal to a second value associated with the maximum height.

11. The method according to claim 10 , wherein the first value is equal to Ceil(pic_width_max_in_luma_samples÷8)−1 and the second value is equal to Ceil(pic_height_max_in_luma_samples÷8)−1, and

wherein pic_width_max_in_luma_samples represents the maximum width, in units of luma samples, of each picture of the set of pictures, and pic_height_max_in_luma_samples represents the maximum height, in units of luma samples, of each picture of the set of pictures.

12. The method according to claim 10 , further comprising:

determining whether the resolution of the first picture is allowed to be changed; and

in response to the resolution of the first picture being not allowed to be changed, signaling the virtual boundary at to sequence level, or

in response to the resolution of the first picture being allowed to be changed, skipping signaling of the virtual boundary at the sequence level.

13. The method according to claim 12 , further comprising:

in response to the resolution of the first picture being allowed to be changed, disabling the wrap-around motion compensation for the set of pictures.