# US 2021/0084331 A1 · Method for intra prediction and device therefor

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- Number: US 2021/0084331 A1
- Document ID: US20210084331A1
- Status: Published application
- Kind: A1
- Application number: 17/103,333
- Filed: 2020-11-24
- Published: 2021-03-18
- Earliest claimed: 2011-10-18
- Assignees: LG Electronics Inc.
- Applicants: LG Electronics Inc.
- Inventors: Jaehyun LIM; Seungwook PARK; Yongjoon JEON; Jungsun KIM; Hendry HENDRY; Byeongmoon JEON; Joonyoung PARK; Chulkeun KIM; Naeri PARK
- Web page: https://patentgrep.com/patent/US20210084331A1

## CPC

- H04N 19/593: involving spatial prediction techniques
- H04N 19/11: among a plurality of spatial predictive coding modes
- H04N 19/117: Filters, e.g. for pre-processing or post-processing (sub-band filter banks H04N19/635)
- H04N 19/122: Selection of transform size, e.g. 8x8 or 2x4x8 DCT; Selection of sub-band transforms of varying structure or type
- H04N 19/124: Quantisation
- H04N 19/129: Scanning of coding units, e.g. zig-zag scan of transform coefficients or flexible macroblock ordering [FMO]
- H04N 19/13: Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
- H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
- H04N 19/174: the region being a slice, e.g. a line of blocks or a group of blocks
- H04N 19/176: the region being a block, e.g. a macroblock
- H04N 19/426: using memory downsizing methods
- H04N 19/44: Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
- H04N 19/463: by compressing encoding parameters before transmission
- H04N 19/61: in combination with predictive coding
- H04N 19/625: using discrete cosine transform [DCT]
- H04N 19/82: involving filtering within a prediction loop
- H04N 19/96: Tree coding, e.g. quad-tree coding
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

A method for intra prediction comprises determining a first MPM candidate corresponding to a left-side candidate block on the basis of a position of the left-side candidate block adjacent to a left side of a current block; determining a second MPM candidate corresponding to an upper-end candidate block on the basis of a position of the upper-end candidate block adjacent to an upper end of the current block; generating an MPM candidate list including a plurality of MPM candidates, on the basis of the first MPM candidate and the second MPM candidate; and determining one MPM candidate of the plurality of the MPM candidates that constitute the MPM candidate list as an intra prediction mode of the current block, and performing intra prediction for the current block on the basis of the determined intra prediction mode to generate a prediction block corresponding to the current block.

## Claims

### Claim 1

An intra prediction method by a decoding apparatus, the method comprising:
determining an availability of a left neighboring block;
deriving a first candidate intra prediction mode based on the availability of the left neighboring block;
determining an availability of an upper neighboring block;
deriving a second candidate intra prediction mode based on the availability of the upper neighboring block;
deriving an intra prediction mode of the current block based on the first candidate intra prediction mode and the second candidate intra prediction mode; and
deriving a prediction sample in the current block based on the derived intra prediction mode;
wherein when the left neighboring block is not available and the upper neighboring block is available, the first candidate intra prediction mode is set to an intra planar mode and an intra prediction mode of the upper neighboring block is used as the second candidate intra prediction mode;
wherein when the upper neighboring block is located outside of a current largest coding unit (LCU) to which the current block belongs or the upper neighboring block is not an intra coded block, the second candidate intra prediction mode is set to the intra planar mode.

### Claim 2 (depends on 1)

The method of claim 1, wherein the left neighboring block is an upper-most block among one or more blocks which are adjacent to a left side of the current block.

### Claim 3 (depends on 2)

The method of claim 2, wherein the upper neighboring block is a left-most block among one or more blocks which are adjacent to an upper side of the current block.

### Claim 4 (depends on 1)

The method of claim 1, further comprising obtaining information on the intra prediction mode including indication information indicating one of candidate intra prediction modes is used for the current block, wherein the candidate intra prediction modes includes the first candidate intra prediction mode and the second candidate intra prediction mode.

### Claim 5

An image encoding method by an encoding apparatus, the method comprising:
determining an availability of a left neighboring block;
deriving a first candidate intra prediction mode based on the availability of the left neighboring block;
determining an availability of an upper neighboring block;
deriving a second candidate intra prediction mode based on the availability of the upper neighboring block;
wherein when the left neighboring block is not available and the upper neighboring block is available, the first candidate intra prediction mode is set to an intra planar mode and an intra prediction mode of the upper neighboring block is used as the second candidate intra prediction mode;
wherein when the upper neighboring block is located outside of a current largest coding unit (LCU) to which the current block belongs or the upper neighboring block is not an intra coded block, the second candidate intra prediction mode is set to the intra planar mode,
deriving information on an intra prediction mode for the current block based on the first candidate intra prediction mode and the second candidate intra prediction mode; and
encoding image information including the information on the intra prediction mode.

### Claim 6 (depends on 5)

The method of claim 5, wherein the left neighboring block is an upper-most block among one or more blocks which are adjacent to a left side of the current block.

### Claim 7 (depends on 6)

The method of claim 6, wherein the upper neighboring block is a left-most block among one or more blocks which are adjacent to an upper side of the current block.

### Claim 8 (depends on 5)

The method of claim 5, wherein the information on the intra prediction mode include indication information indicating one of candidate intra prediction modes is used for the current block, wherein the candidate intra prediction modes includes the first candidate intra prediction mode and the second candidate intra prediction mode.

### Claim 9

A non-transitory decoder-readable storage medium storing encoded image information comprising encoded information on an intra prediction mode generated by performing the steps of: determining an availability of a left neighboring block; deriving a first candidate intra prediction mode based on the availability of the left neighboring block; determining an availability of an upper neighboring block; deriving a second candidate intra prediction mode based on the availability of the upper neighboring block; wherein when the left neighboring block is not available and the upper neighboring block is available, the first candidate intra prediction mode is set to an intra planar mode and an intra prediction mode of the upper neighboring block is used as the second candidate intra prediction mode; wherein when the upper neighboring block is located outside of a current largest coding unit (LCU) to which the current block belongs or the upper neighboring block is not an intra coded block, the second candidate intra prediction mode is set to the intra planar mode, deriving information on an intra prediction mode for the current block based on the first candidate intra prediction mode and the second candidate intra prediction mode; and encoding image information including the information on the intra prediction mode.