Systems and methods for generating scaling ratios and full resolution pictures

1. A method of coding video data, the method comprising:

obtaining a current picture of video data;

determining one or more scaling windows identifying at least one of a top offset, a bottom offset, a left offset, or a right offset for determining at least one scaling ratio for at least one of the current picture and a reference picture selected for use in coding the current picture;

determining at least one of a first size of the current picture or a second size of the reference picture, the first size comprising a first height and a first width of the current picture and the second size comprising a second height and a second width of the reference picture;

based on the one or more scaling windows and at least one of the first size or the second size, determining one or more scaling ratios associated with adjusting one or more motion compensation parameters corresponding to at least one of the current picture or the reference picture; and

determining one or more conformance windows associated with resizing at least one of the current picture or the reference picture for output, wherein the one or more conformance windows are different from the one or more scaling windows.

2. The method of claim 1 , wherein the one or more scaling ratios are derived for horizontal and vertical directions.

3. The method of claim 1 , wherein the one or more scaling windows comprise a scaling window of the current picture, wherein the scaling window of the current picture is determined from a picture parameter set (PPS) referred by the current picture.

4. The method of claim 1 , wherein the one or more scaling windows comprise a scaling window of the reference picture, wherein the scaling window of the reference picture is determined from a picture parameter set (PPS) referred by the reference picture.

5. The method of claim 1 , wherein the one or more scaling windows comprise scaling window offsets, wherein the scaling window offsets comprise at least one of a left scaling window offset, a right scaling window offset, a top scaling window offset, or a bottom scaling window offset.

6. The method of claim 5 , wherein at least one scaling window offset of the scaling window offsets comprises a negative value.

7. The method of claim 5 , wherein determining the one or more scaling ratios comprises adding the scaling window offsets to at least one of the first size of the current picture or the second size of the reference picture.

8. The method of claim 1 , wherein the one or more scaling windows comprise a first scaling window associated with the current picture and a second scaling window associated with the reference picture, and wherein the one or more scaling ratios are determined based on the first scaling window and the second scaling window.

9. The method of claim 1 , further comprising:

including the one or more scaling windows in a picture parameter set (PPS); and

at least one of storing or transmitting the PPS including the one or more scaling windows.

10. The method of claim 1 , further comprising:

based on the one or more scaling ratios, adjusting one or more motion compensation parameters associated with at least one of the current picture or the reference picture.

11. The method of claim 1 , further comprising:

resizing at least one of the current picture or the reference picture based on the one or more conformance windows.

12. The method of claim 11 , wherein the one or more conformance windows are determined from a sequence parameter set (SPS).

13. The method of claim 11 , further comprising:

including the one or more conformance windows in a sequence parameter set (SPS); and

at least one of storing or transmitting the SPS including the one or more conformance windows.

14. The method of claim 1 , further comprising:

obtaining a maximum picture size indicating a maximum picture width and a maximum picture height; and

generating an output picture based on the maximum picture size and a conformance window comprising one or more window offsets, wherein a size of the current picture equals the maximum picture size, and wherein the output picture comprises the current picture with the size equal to the maximum picture size cropped based on the conformance window.

15. The method of claim 14 , wherein the current picture is cropped by applying the one or more window offsets to the current picture.

16. The method of claim 14 , wherein the maximum picture size and the conformance window are determined from a sequence parameter set (SPS).

17. The method of claim 14 , further comprising:

including the maximum picture size and the conformance window in a sequence parameter set (SPS); and

at least one of storing or transmitting the SPS including the maximum picture size and the conformance window.

18. The method of claim 1 , wherein the one or more scaling windows are further associated with one or more additional reference pictures selected for use in coding the current picture, wherein the one or more scaling ratios are further associated with the one or more additional reference pictures.

19. The method of claim 1 , further comprising:

generating an encoded video bitstream including the one or more scaling windows and a set of conformance windows, the set of conformance windows including one or more first window offsets for resizing the current picture and one or more second window offsets for resizing the reference picture; and

at least one of storing or transmitting the encoded video bitstream.

20. An apparatus comprising:

memory; and

one or more processors coupled to the memory, the one or more processors being configured to:

obtain a current picture of video data;

determine one or more scaling windows identifying at least one of a top offset, a bottom offset, a left offset, or a right offset for determining at least one scaling ratio for at least one of the current picture or a reference picture selected for use in coding the current picture;

determine at least one of a first size of the current picture or a second size of the reference picture, the first size comprising a first height and a first width of the current picture and the second size comprising a second height and a second width of the reference picture;

based on the one or more scaling windows and at least one of the first size or the second size, determine one or more scaling ratios associated with adjusting one or more motion compensation parameters corresponding to at least one of the current picture or the reference picture; and

determine one or more conformance windows associated with resizing at least one of the current picture or the reference picture for output, wherein the one or more conformance windows are different from the one or more scaling windows.

21. The apparatus of claim 20 , wherein the one or more scaling ratios are derived for horizontal and vertical directions.

22. The apparatus of claim 20 , wherein the one or more scaling windows comprise a scaling window of the current picture, wherein the scaling window of the current picture is determined from a picture parameter set (PPS) referred by the current picture.

23. The apparatus of claim 20 , wherein the one or more scaling windows comprise a scaling window of the reference picture, wherein the scaling window of the reference picture is determined from a picture parameter set (PPS) referred by the reference picture.

24. The apparatus of claim 20 , wherein the one or more scaling windows comprise scaling window offsets, wherein the scaling window offsets comprise at least one of a left scaling window offset, a right scaling window offset, a top scaling window offset, or a bottom scaling window offset.

25. The apparatus of claim 24 , wherein at least one scaling window offset of the scaling window offsets comprises a negative value.

26. The apparatus of claim 24 , wherein determining the one or more scaling ratios comprises adding the scaling window offsets to at least one of the first size of the current picture or the second size of the reference picture.

27. The apparatus of claim 20 , wherein the one or more scaling windows comprise a first scaling window associated with the current picture and a second scaling window associated with the reference picture, and wherein the one or more scaling ratios are determined based on the first scaling window and the second scaling window.

28. The apparatus of claim 20 , the one or more processors being configured to:

include the one or more scaling windows in a picture parameter set (PPS); and

at least one of store or transmit the PPS including the one or more scaling windows.

29. The apparatus of claim 20 , the one or more processors being configured to:

adjust, based on the one or more scaling ratios, one or more motion compensation parameters associated with at least one of the current picture or the reference picture.

30. The apparatus of claim 20 , the one or more processors being configured to:

resize at least one of the current picture or the reference picture based on the one or more conformance windows.

31. The apparatus of claim 30 , wherein the one or more conformance windows are determined from a sequence parameter set (SPS).

32. The apparatus of claim 30 , the one or more processors being configured to:

include the one or more conformance windows in a sequence parameter set (SPS); and

at least one of store or transmit the SPS including the one or more conformance windows.

33. The apparatus of claim 20 , the one or more processors being configured to:

obtain a maximum picture size indicating a maximum picture width and a maximum picture height; and

generate an output picture based on the maximum picture size and a conformance window comprising one or more window offsets, wherein a size of the current picture equals the maximum picture size, and wherein the output picture comprises the current picture with the size equal to the maximum picture size cropped based on the conformance window.

34. The apparatus of claim 33 , wherein the current picture is cropped by applying the one or more window offsets to the current picture.

35. The apparatus of claim 33 , wherein the maximum picture size and the conformance window are determined from a sequence parameter set (SPS).

36. The apparatus of claim 33 , the one or more processors being configured to:

include the maximum picture size and the conformance window in a sequence parameter set (SPS); and

at least one of store or transmit the SPS including the maximum picture size and the conformance window.

37. The apparatus of claim 20 , wherein the one or more scaling windows are further associated with one or more additional reference pictures selected for use in coding the current picture, wherein the one or more scaling ratios are further associated with the one or more additional reference pictures.

38. The apparatus of claim 20 , the one or more processors being configured to:

generate an encoded video bitstream including the one or more scaling windows and a set of conformance windows, the set of conformance windows including one or more first window offsets for resizing the current picture and one or more second window offsets for resizing the reference picture; and

at least one of store or transmit the encoded video bitstream.

39. The apparatus of claim 20 , wherein the apparatus is a mobile device.

40. A non-transitory computer-readable storage medium comprising instructions stored thereon which, when executed by one or more processors, cause the one or more processors to:

obtain a current picture of video data;

determine one or more scaling windows identifying at least one of a top offset, a bottom offset, a left offset, or a right offset for determining at least one scaling ratio for at least one of the current picture and a reference picture selected for use in coding the current picture;

determine at least one of a first size of the current picture or a second size of the reference picture, the first size comprising a first height and a first width of the current picture and the second size comprising a second height and a second width of the reference picture;

based on the one or more scaling windows and at least one of the first size or the second size, determine one or more scaling ratios associated with adjusting one or more motion compensation parameters corresponding to at least one of the current picture or the reference picture; and

determine one or more conformance windows associated with resizing at least one of the current picture or the reference picture for output, wherein the one or more conformance windows are different from the one or more scaling windows.