US-12621451-B2 - Method and apparatus for acquiring information about sub-units split from picture

US12621451B2US 12621451 B2US12621451 B2US 12621451B2US-12621451-B2

Abstract

Disclosed is a method for obtaining information on sub-units partitioned from a picture. The method comprises: decoding, from a bitstream, CTU size information indicating the size of coding tree units (CTUs) within the picture; decoding, from the bitstream, sub-picture partition information expressing sub-pictures within the picture in units of the CTU sizes; decoding, from the bitstream, partition information related to partition of the picture into one or more tiles; and decoding, from the bitstream, partition information related to partition of the picture into one or more slices.

Inventors

Jae Il Kim
Sun Young Lee
Se Hoon SON

Assignees

SK TELECOM CO., LTD.

Dates

Publication Date: 20260505
Application Date: 20240730
Priority Date: 20190927

Claims (5)

1 . A video decoding method comprising: decoding, from a bitstream, information on sub-units partitioned from a picture; and reconstructing the picture based on the information on the sub-units, wherein the decoding of the information on the sub-units comprises: decoding CTU size information indicating the size of coding tree units (CTUs) within the picture from the bitstream, decoding sub-picture partition information for partitioning the picture to one or more sub-pictures each of which is comprised of at least one slice from the bitstream, wherein the sub-picture partition information is defined by the unit of the CTU size, decoding tile partition information related to partition of the picture into one or more tiles from the bitstream, wherein the tile partition information includes at least one of information on the number of the tiles and information on a size of the tiles, decoding slice partition information related to partition of the picture into one or more slices from the bitstream, and decoding, from the bitstream, an enable flag indicating whether filtering is performed at a boundary of the one or more slices, based on a slice mode of the one or more slices among a plurality of slice modes including a rectangular slice mode and a raster-scan slice mode.
2 . The method of claim 1 , wherein the slice partition information is defined on a basis of tiles determined by the tile partition information.
3 . The method of claim 2 , wherein the enable flag is decoded when the number of the one or more slices is plural and the slice mode is the rectangular slice mode, or when the slice mode is the raster-scan slice mode.
4 . A video encoding method comprising: partitioning a picture into sub-units to encode the picture; and encoding information on the sub-units, wherein the encoding of the information on the sub-units comprises: encoding CTU size information indicating the size of coding tree units (CTUs) within the picture, encoding sub-picture partition information for partitioning the picture to one or more sub-pictures each of which is comprised of at least one slice, wherein the sub-picture partition information is defined by the unit of the CTU size, encoding tile partition information related to partition of the picture into one or more tiles, wherein the tile partition information includes at least one of information on the number of the tiles and information on a size of the tiles, encoding slice partition information related to partition of the picture into one or more slices, and encoding an enable flag indicating whether filtering is performed at a boundary of the one or more slices, based on a slice mode of the one or more slices among a plurality of slice modes including a rectangular slice mode and a raster-scan slice mode.
5 . A method for transmitting a bitstream containing encoded video data, the method comprising: generating the bitstream, by partitioning a picture into sub-units to encode the picture and encoding information on the sub-units; and transmitting the bitstream to a video decoding apparatus, wherein the encoding of the information on the sub-units comprises: encoding CTU size information indicating the size of coding tree units (CTUs) within the picture, encoding sub-picture partition information for partitioning the picture to one or more sub-pictures each of which is comprised of at least one slice, wherein the sub-picture partition information is defined by the unit of the CTU size, encoding tile partition information related to partition of the picture into one or more tiles, wherein the tile partition information includes at least one of information on the number of the tiles and information on a size of the tiles, encoding slice partition information related to partition of the picture into one or more slices, and encoding an enable flag indicating whether filtering is performed at a boundary of the one or more slices, based on a slice mode of the one or more slices among a plurality of slice modes including a rectangular slice mode and a raster-scan slice mode.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application is a Continuation of U.S. patent application Ser. No. 17/763,751, filed on Mar. 25, 2022, which is a national phase of PCT/KR2020/012769 filed on Sep. 22, 2020, which is based on and claims priority to Korean Patent Application No. 10-2019-0119353 filed on Sep. 27, 2019 and Korean Patent Application No. 10-2020-0113632 filed on Sep. 7, 2020, the disclosures of which are incorporated herein by reference in their entireties. TECHNICAL FIELD The present disclosure relates to video encoding and decoding and, more particularly, to a method and apparatus for improving encoding and decoding efficiency by efficiently obtaining information on various sub-units. BACKGROUND Since the volume of video data is larger than that of voice data or still image data, storing or transmitting video data without processing for compression requires a lot of hardware resources including memory. Accordingly, in storing or transmitting video data, the video data is generally compressed using an encoder so as to be stored or transmitted. Then, a decoder receives the compressed video data, and decompresses and reproduces the video data. Compression techniques for such video include H.264/AVC and High Efficiency Video Coding (HEVC), which improves coding efficiency over H.264/AVC by about 40%. However, the video size, resolution, and frame rate are gradually increasing, and accordingly the amount of data to be encoded is also increasing. Accordingly, a new compression technique having better encoding efficiency and higher image quality than the existing compression technique is required. SUMMARY An object of the present disclosure is to provide an improved video encoding and decoding technology to meet the needs. In particular, one aspect of the present disclosure relates to the technology for improving encoding and decoding efficiency through various methods that partition a picture into sub-units. According to one aspect, the present disclosure provides a method for obtaining information on sub-units partitioned from a picture. The method includes: decoding, from a bitstream, CTU size information indicating the size of coding tree units (CTUs) within the picture; decoding, from the bitstream, sub-picture partition information expressing sub-pictures within the picture in units of the CTU sizes; decoding, from the bitstream, partition information related to partition of the picture into one or more tiles; and decoding, from the bitstream, partition information related to partition of the picture into one or more slices. According to another aspect, the present disclosure provides a video decoding apparatus. The apparatus comprises to decode, from a bitstream, information on sub-units partitioned from a picture, and a picture reconstructor configured to reconstruct the picture based on the information on the sub-units. The decoder is configured to decode CTU size information indicating the size of coding tree units (CTUs) within the picture from the bitstream, decode sub-picture partition information expressing sub-pictures within the picture in units of the CTU sizes from the bitstream, decode partition information related to partition of the picture into one or more tiles from the bitstream, and decode partition information related to partition of the picture into one or more slices from the bitstream. As described above, according to one embodiment of the present disclosure, since overlapping of syntax elements used to partition a picture into sub-units is prevented, bit efficiency may be improved. Also, according to another embodiment of the present disclosure, whether to apply in-loop filtering between sub-unit boundaries may be reasonably designed based on a partition relationship between sub-units. Furthermore, according to yet another embodiment of the present disclosure, since the partition information of a sub-picture is expressed in CTU units, it is possible to ensure unity with other sub-units, through which the partition information of a sub-picture may be more efficiently expressed. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exemplary block diagram of a video encoding apparatus capable of implementing the techniques of the present disclosure. FIG. 2 exemplarily shows block partitioning structure using a QTBTTT structure. FIG. 3 exemplarily shows a plurality of intra-prediction modes. FIG. 4 is an exemplary block diagram of a video decoding apparatus capable of implementing the techniques of the present disclosure. FIGS. 5 to 8 illustrate a slice, a tile, and a sub-picture. FIG. 9 is a flow diagram illustrating one example of a method capable of implementing techniques of the present disclosure. FIG. 10 is a flow diagram illustrating one example of a method for partitioning a picture into tiles. FIG. 11 is a flow diagram illustrating one example of a method for partitioning a picture into bricks. FIG. 12 illustrates a partition relationship between a tile/brick and