Method of filter-unit based in-loop filtering
Implementations of the invention are provided in methods for filter-unit based in-loop filtering in a video decoder and encoder. In one implementation, filter parameters are selected from a filter parameter set for each filter based on a filter index. In another implementation, the picture is partitioned into filter units according to filter unit size, which can be selected between a default size and other size. When other size is selected, the filter unit size may be conveyed using direct size information or ratio information. In another implementation, a merge flag and a merge index are used to convey filter unit merge information. A method for filter-unit based in-loop filtering in a video encoder for color video is disclosed. In one embodiment, the method incorporates filter syntax in the video bitstream by interleaving the color-component filter syntax for the FUs.
1. A method for filter-unit based in-loop filtering in a video decoder, the method comprising:
receiving a video bitstream corresponding to compressed color video, wherein FU (Filter Unit) based in-loop filtering is used in a reconstruction loop associated with the compressed color video, wherein reconstructed color video is partitioned into FUs, and wherein each of the FUs comprises a first color component and a second color component;
receiving a first filter syntax associated with the first color component and a second filter syntax associated with the second color component for the FUs in the video bitstream, wherein the first filter syntax and the second filter syntax for the FUs are interleaved in the video bitstream, wherein the first filter syntax and the second filter syntax alternate in the bitstream, and both filter syntaxes for a given filter unit appear sequentially in the bitstream before filter syntaxes for another filter unit appear in the bitstream; and
applying the in-loop filtering to the first color component associated with each of FUs according to the first filter syntax; and
applying the in-loop filtering to the second color component associated with each of FUs according to the second filter syntax.
2. The method of claim 1 , wherein the first filter syntax and the second filter syntax for the FUs are interleaved based on a single FU.
3. The method of claim 1 , wherein the first filter syntax and the second filter syntax for the FUs are interleaved based on multiple FUs.
4. The method of claim 1 , wherein each of the FUs comprises a third color component, wherein picture-level in-loop filtering is applied to the third color component, and a third filter syntax for to the third color component is incorporated in the bitstream.
5. A method for filter-unit based in-loop filtering in a video encoder, the method comprising:
generating a video bitstream corresponding to compressed color video, wherein FU (Filter Unit) based in-loop filtering is used in a reconstruction loop associated with the compressed color video, wherein reconstructed color video is partitioned into FUs, and wherein each of the FUs comprises a first color component and a second color component;
incorporating a first filter syntax associated with the first color component and a second filter syntax associated with the second color component for the FUs in the video bitstream, wherein the first filter syntax and the second filter syntax for the FUs are interleaved in the video bitstream, wherein the first color component and the second color component alternate in the bitstream, and both color components for a given filter unit appear sequentially in the bitstream before color components for another filter unit appear in the bitstream; and
providing the video bitstream.
6. The method of claim 5 , wherein the first filter syntax and the second filter syntax for the FUs are interleaved based on a single FU.
7. The method of claim 5 , wherein the first filter syntax and the second filter syntax for the FUs are interleaved based on multiple FUs.
8. The method of claim 5 , wherein each of the FUs comprises a third color component, wherein picture-level in-loop filtering is applied to the third color component, and a third filter syntax for to the third color component is incorporated in the bitstream.
9. The method of claim 1 , wherein the first color component is a luma component (Y) and the second color component is a chroma component (Cb or Cr).
10. The method of claim 4 wherein the first color component is a luma component (Y), the second color component is a chroma component (Cb), and the third color component is a chroma component (Cr).