Method and apparatus for performing deblocking filtering with interlace capability
View Patent ↗A method and apparatus are disclosed for adaptively selecting a deblocking filter used in video de-blocking. Determinations are made as to whether each of a set of spatially adjacent video blocks is inter-coded or intra-coded and whether each of said adjacent video blocks is field-coded or frame-coded. A deblocking filter is selected (an interlace deblocking filter or a frame deblocking filter) based on the determinations. The selected deblocking filter is used to filter across a boundary between adjacent video blocks.
1. A method of selecting a deblocking filter used in video processing, said method comprising:
determining whether a first video block and a second video block are frame-coded or field-coded, wherein the first video block and the second video block are spatially adjacent;
selecting the deblocking filter based on said determining wherein if the first video block is frame-coded and the second video block is field-coded and the video blocks share a border that is horizontal, the deblocking filter uses samples from the first video block that are adjacent and samples from the second video block that are in one of a top field and a bottom field; and
filtering, with the deblocking filter.
2. The method of claim 1 wherein said determining comprises reading video header data associated with each of said adjacent video blocks, wherein said video header data indicates field-coded or frame-coded.
3. The method of claim 1 , wherein if the border is vertical, the deblocking filter uses samples from the first video block that are adjacent and samples from the second video block that are adjacent.
4. The method of claim 1 , wherein if the video blocks are both frame-coded and the border is horizontal, the deblocking filter uses samples from the first video block that are adjacent and samples from the second video block that are adjacent.
5. The method of claim 1 , wherein if the video blocks are both field-coded and the border is horizontal, the deblocking filter uses samples in the top field of the first video block with samples in the top field of the second video block.
6. The method of claim 1 , wherein if the video blocks are both field-coded and the border is horizontal, the deblocking filter uses samples in the bottom field of the first video block with samples in the bottom field of the second video block.
7. The method of claim 1 wherein said frame deblocking filtering comprises generating at least one filtered video sample on at least one side of said boundary between said adjacent video blocks by performing digital filtering on a predetermined number of contiguous video samples across said boundary.
8. An apparatus for selecting a deblocking filter used in video processing, said apparatus comprising:
a deblocking filter selection module for selecting a deblocking filter associated with a border between a first video block and a second video block, wherein the deblocking filter selection is based on the size of the first video block and the second video block; and
a deblocking filter module responsive to said selecting to perform filtering,
wherein if the first video block is frame-coded and the second video block is field-coded and the border is horizontal, the deblocking filter uses adjacent video samples in the first video block and video samples from one of a top field and a bottom field in the second video block.
9. The apparatus of claim 8 , wherein if the border is vertical, the deblocking filter uses samples from the first video block that are adjacent and samples from the second video block that are adjacent.
10. The apparatus of claim 8 , wherein if the video blocks are both frame-coded and the border is horizontal, the deblocking filter uses samples from the first video block that are adjacent and samples from the second video block that are adjacent.
11. The apparatus of claim 8 , wherein if the video blocks are both field-coded and the border is horizontal, the deblocking filter uses samples in the top field of the first video block with samples in the top field of the second video block.
12. The apparatus of claim 8 , wherein if the video blocks are both field-coded and the border is horizontal, the deblocking filter uses samples in the bottom field of the first video block with samples in the bottom field of the second video block.
13. The apparatus of claim 9 wherein said frame deblocking filter generates at least one filtered video sample on at least one side of said at least one boundary between said at least two adjacent video blocks by performing digital filtering on a predetermined number of contiguous video samples across said at least one boundary.
14. The apparatus of claim 8 wherein said apparatus is integrated and embedded into an ASIC chip used in video processing.
15. A system for deblock filtering in a video processor, said system comprising:
an integrated circuit comprising:
a first circuit for identifying the size of a first video block and a second video block; and
a second circuit for deblock filtering a common border of the pair of adjacent blocks using a first set of filter coefficients based on the size of the first video block and the second video block,
wherein if the first video block is frame-coded and the second video block is field-coded and the common border is horizontal, the deblocking filter uses adjacent video samples in the first video block and video samples from one of a top field and a bottom field in the second video block.
16. The system of claim 15 , wherein the second circuit generates at least one filtered video sample on at least one side of the common border of the pair of adjacent blocks.
17. The system of claim 15 , wherein if the common border is horizontal and the video blocks are both field-coded, the second circuit uses a second set of filter coefficients.
18. The system of claim 17 , wherein the second set of filter coefficients is applied to a set of video samples that are separated by at least one row.