Image encoding/decoding method and apparatus for performing in-loop filtering on basis of sub-picture structure, and method for transmitting bitstream

Patent metadata

Field	Value
Publication number	US-12096041-B2
Application number	US-202017766954-A
Country	US
Kind code	B2
Filing date	Oct 6, 2020
Priority date	Oct 7, 2019
Publication date	Sep 17, 2024
Grant date	Sep 17, 2024

Abstract

An image encoding/decoding method and apparatus are provided. An image decoding method performed by an image decoding apparatus comprises decoding a first flag specifying whether in-loop filtering is able to be performed across a boundary of a subpicture from a bitstream and performing the in-loop filtering on a boundary of a current block, based on the first flag. Based on the boundary of the current block being a boundary of a current subpicture including the current block, the in-loop filtering on the boundary of the current block is not performed, based on the first flag for the current subpicture specifying that the in-loop filtering is not able to be performed across the boundary of the current subpicture or the first flag for an adjacent subpicture adjacent to the boundary of the current block specifying that the in-loop filtering is not able to be performed across the boundary of the adjacent subpicture.

First claim

The invention claimed is:

1. An image decoding method performed by an image decoding apparatus, the image decoding method comprising:
decoding a first flag specifying whether in-loop filtering is able to be performed across a boundary of a subpicture from a bitstream; and
performing the in-loop filtering on a boundary of a current block, based on the first flag,
wherein, based on the boundary of the current block being a boundary of a current subpicture including the current block, the in-loop filtering on the boundary of the current block is not performed, based on the first flag for the current subpicture specifying that the in-loop filtering is not able to be performed across the boundary of the current subpicture or the first flag for an adjacent subpicture adjacent to the boundary of the current block specifying that the in-loop filtering is not able to be performed across the boundary of the adjacent subpicture.

2. The image decoding method of claim 1 , wherein, based on the boundary of the current block satisfying a predetermined filtering constraint, the in-loop filtering on the boundary of the current block is not performed.

3. The image decoding method of claim 2 , wherein the filtering constraint comprises a case where the boundary of the current block is a boundary of a current picture including the current block.

4. The image decoding method of claim 2 , wherein the filtering constraint comprises a case where the boundary of the current block is virtual boundaries of a current picture including the current block.

5. The image decoding method of claim 2 , wherein the filtering constraint comprises a case where the boundary of the current block is a boundary of a current tile including the current block and the in-loop filtering is not able to be performed across the boundary of the current tile.

6. The image decoding method of claim 2 , wherein the filtering constraint comprises a case where the boundary of the current block is a boundary of a current slice including the current block and the in-loop filtering is not able to be performed across the boundary of the current slice.

7. The image decoding method of claim 2 , wherein the filtering constraint comprises a case where the boundary of the current block is a left or top boundary of a current slice including the current block and the in-loop filtering is disabled for the current slice.

8. The image decoding method of claim 1 , wherein the in-loop filtering comprises deblocking filtering.

9. The image decoding method of claim 1 , wherein, based on a prediction mode of the current block being a palette mode, the in-loop filtering on the boundary of the current block is not performed.

10. The image decoding method of claim 1 , wherein the performing the in-loop filtering comprises:
determining a boundary strength with respect to the boundary of the current block, and
filtering the boundary of the current block based on the boundary strength.

11. The image decoding method of claim 10 , wherein, based on the boundary strength having a first value, the in-loop filtering on the boundary of the current block is not performed.

12. The image decoding method of claim 1 , wherein, based on the current subpicture being treated as a picture, the first flag for the current subpicture specifies that the in-loop filtering is not able to be performed across the boundary of the current subpicture.

13. An image encoding method performed by an image encoding apparatus, the image encoding method comprising:
determining whether in-loop filtering is able to be performed across a boundary of a subpicture; and
performing the in-loop filtering on a boundary of a current block based on a result of determination,
wherein, based on the boundary of the current block being a boundary of a current subpicture including the current block, the in-loop filtering on the boundary of the current block is not performed, based on a first flag for the current subpicture specifying that the in-loop filtering is not able to be performed across the boundary of the current subpicture or the first flag for an adjacent subpicture adjacent to the boundary of the current block specifying that the in-loop filtering is not able to be performed across the boundary of the adjacent subpicture.

14. A method of transmitting a bitstream generated by the image encoding method of claim 13 .

15. A non-transitory computer readable recording medium storing a bitstream generated by the image encoding method of claim 13 .

Assignees

• Lg Electronics Inc

Inventors

• Jang Hyeong Moon
• Paluri Seethal
• Hendry Hendry
• Nam Jung Hak

Classifications

• H04N19/86

  involving reduction of coding artifacts, e.g. of blockiness · CPC title

• H04N19/46

  Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence) · CPC title

• H04N19/176

  the region being a block, e.g. a macroblock · CPC title

• H04N19/174

  the region being a slice, e.g. a line of blocks or a group of blocks · CPC title

• H04N19/117

  Filters, e.g. for pre-processing or post-processing (sub-band filter banks H04N19/635) · CPC title