Adaptive deblocking filter
Systems and methods are provided for selecting and applying an appropriate deblocking filter for improved coding efficiency and compression performance by partitioning a frame into a plurality of rectangular coding units (CUs) according to the QTBT frame partitioning scheme, selecting a first and a second CUs of the plurality of rectangular CUs, where the second CU is adjacent to the first CU, identifying a CU boundary shared by the first and second CUs, determining that at least one of the first or the second CU is non-square in shape, determining a first shape of the first CU and a second shape of the second CU, adaptively selecting a deblocking filter based on the first shape and the second shape, and applying the selected deblocking filter to pixels across the CU boundary.
1. A method comprising:
partitioning a frame into a plurality of rectangular coding units;
selecting a first coding unit and a second coding unit of the plurality of rectangular coding units, the second coding unit being adjacent to the first coding unit;
identifying a coding unit boundary shared by the first coding unit and second coding unit;
determining a first shape of the first coding unit and a second shape of the second coding unit;
upon determining that at least one of the first coding unit or the second coding unit is non-square in shape,
adaptively selecting a deblocking filter based on the first shape and the second shape by:
determining whether the first shape and the second shape are both non-square in shape or only one of the first shape or the second shape is non-square in shape,
upon determining that the first shape and the second shape are both non-square in shape, selecting a first deblocking filter as the deblocking filter, or
upon determining that only one of the first shape or the second shape is non-square in shape, selecting a second deblocking filter as the deblocking filter; and
applying the selected deblocking filter to pixels across the coding unit boundary.
2. The method of claim 1 , wherein the second coding unit is vertically adjacent to the first coding unit.
3. The method of claim 1 , wherein the second coding unit is horizontally adjacent to the first coding unit.
4. The method of claim 1 , wherein adaptively selecting the deblocking filter based on the first shape and the second shape includes selecting the deblocking filter from a plurality of deblocking filters based on the first shape and second shape.
5. The method of claim 1 , wherein the first deblocking filter is a strong filter and the second deblocking filter is a weak filter.
6. The method of claim 5 , wherein the strong filter is a long tap filter and the weak filter is a short tap filter.
7. The method of claim 1 , wherein the first deblocking filter is a weak filter and the second deblocking filter is a strong filter.
8. The method of claim 7 , wherein the strong filter is a long tap filter and the weak filter is a short tap filter.
9. A non-transitory computer-readable storage medium storing computer-readable instructions executable by one or more processors, that when executed by the one or more processors, cause the one or more processors to perform operations comprising:
partitioning a frame into a plurality of rectangular coding units;
selecting a first coding unit and a second coding unit of the plurality of rectangular coding units, the second coding unit being adjacent to the first coding unit;
identifying a coding unit boundary shared by the first coding unit and second coding unit;
determining whether at least one of the first coding unit or the second coding unit is non-square in shape;
upon determining that at least one of the first coding unit or the second coding unit is non-square in shape,
determining a first shape of the first coding unit and a second shape of the second coding unit;
adaptively selecting a deblocking filter based on the first shape and the second shape by:
determining whether the first shape and the second shape are both non-square in shape or only one of the first shape or the second shape is non-square in shape,
upon determining that the first shape and the second shape are both non-square in shape, selecting a first deblocking filter as the deblocking filter, or
upon determining that only one of the first shape or the second shape is non-square, selecting a second deblocking filter as the deblocking filter; and
applying the selected deblocking filter to pixels across the coding unit boundary.
10. The non-transitory computer-readable storage medium of claim 9 , wherein the second coding unit is vertically adjacent to the first coding unit.
11. The non-transitory computer-readable storage medium of claim 9 , wherein the second coding unit is horizontally adjacent to the first coding unit.
12. The non-transitory computer-readable storage medium of claim 9 , wherein adaptively selecting the deblocking filter based on the first shape and the second shape includes selecting the deblocking filter from a plurality of deblocking filters based on the first shape and second shape.
13. The non-transitory computer-readable storage medium of claim 9 , wherein the first deblocking filter is a strong filter and the second deblocking filter is a weak filter.
14. The non-transitory computer-readable storage medium of claim 13 , wherein the strong filter is a long tap filter and the weak filter is a short tap filter.
15. The non-transitory computer-readable storage medium of claim 9 , wherein the first deblocking filter is a weak filter as the deblocking filter and the second deblocking filter is a strong filter.
16. The non-transitory computer-readable storage medium of claim 15 , wherein the strong filter is a long tap filter and the weak filter is a short tap filter.
17. A computing device comprising:
one or more processors; and
memory communicatively coupled to the one or more processors, the memory storing computer-executable modules executable by the one or more processors, that when executed by the one or more processors, perform associated operations, the computer-executable modules including:
a partition module configured to partition a frame into a plurality of rectangular coding units;
a selection module configured to select a first coding unit and a second coding unit of the plurality of rectangular coding units, the second coding unit being adjacent to the first coding unit;
a determination module configured to:
determine whether at least one of the first coding unit or the second coding unit is non-square in shape,
upon determining that at least one of the first coding unit or the second coding unit is non-square in shape, identify a coding unit boundary shared by the first and second coding units,
determine a first shape of the first coding unit and a second shape of the second coding unit, and
determine whether the first shape and the second shape are both non-square in shape or only one on of the first shape or the second shape is non-square in shape; and
a decoder module configured to:
adaptively select a deblocking filter based on the first shape and the second shape by
selecting a first deblocking filter as the deblocking filter upon the determination module determining that the first shape and the second shape are both non-square in shape, or
selecting a second deblocking filter as the deblocking filter upon the determination module determining that only one of the first shape or the second shape is non-square, and
apply the selected deblocking filter to pixels across the coding unit boundary.
18. The computing device of claim 17 , wherein the second coding unit is one of:
vertically adjacent to the first coding unit, or
horizontally adjacent to the first coding unit.
19. The computing device of claim 17 , wherein the decoder module is further configured to adaptively select the deblocking filter based on the first shape and the second shape by selecting the deblocking filter from a plurality of deblocking filters based on the first shape and second shape.
20. The computing device of claim 17 , wherein:
the first deblocking filter is a strong filter and the second deblocking filter is a weak filter, or
the first deblocking filter is a weak filter and the second deblocking filter is a strong filter.