Method and device for processing video signal for intra prediction

Patent metadata

Field	Value
Publication number	US-12563188-B2
Application number	US-202418432905-A
Country	US
Kind code	B2
Filing date	Feb 5, 2024
Priority date	Feb 21, 2019
Publication date	Feb 24, 2026
Grant date	Feb 24, 2026

Abstract

Embodiments of the present specification provide a method and a device for processing a video signal for intra prediction. A method for decoding a video signal according an embodiment of the present disclosure includes: obtaining intra prediction information of a current block to which the intra prediction is applied, in which the intra prediction information includes a first flag indicating a predetermined first mode; determining an intra prediction mode of the current block based on the intra prediction information, wherein when the first flag corresponds to a first value, the first mode is determined as the intra prediction mode and when the first flag corresponds to a second value, one of a plurality of candidate modes is determined as the intra prediction mode; and generating a prediction sample of the current block based on the intra prediction mode and a reference sample in a current picture. A separate flag indicating whether to use a primarily used specific mode is used to reduce a data amount for transmission of the intra prediction mode and a processing time of information of the intra prediction.

First claim

The invention claimed is:

1 . A method for decoding a video signal for intra prediction, the method comprising:
determining whether a top boundary of a current block is a boundary of a current coding tree unit (CTU); obtaining reference sample line information of the current block from the video signal based on whether the top boundary of the current block is the boundary of the current CTU, wherein the reference sample line information includes an index indicating reference sample line being used for the intra prediction; obtaining an intra sub-partition (ISP) flag representing whether the current block is partitioned into sub-partitions based on the reference sample line information; obtaining intra prediction information of the current block to which the intra prediction is applied based on the reference sample line information, wherein the intra prediction information includes a first flag representing an intra prediction mode being a predetermined first mode; determining the intra prediction mode of the current block based on the intra prediction information, wherein based on the first flag corresponding to a first value, the predetermined first mode is determined as the intra prediction mode and based on the first flag corresponding to a second value, one of a plurality of candidate modes is determined as the intra prediction mode; generating a prediction sample of the current block based on the intra prediction mode and reference samples, wherein the predetermined first mode is a planar mode, and wherein, based on the first flag corresponding to the second value, a most probable mode (MPM) index specifying one among the plurality of candidate modes is obtained.

2 . The method of claim 1 , further comprising
obtaining an ISP type flag representing whether an ISP type is horizontal or vertical based on the current block being partitioned into sub-partitions.

3 . The method of claim 1 ,
wherein the first flag is obtained based on the reference sample line information corresponding to the reference samples positioned on a line adjacent to the current block.

4 . The method of claim 1 ,
wherein the predetermined first mode is the planar mode based on the first value being 0.

5 . The method of claim 1 , further comprising
determining whether to use MPM candidate modes based on a MPM flag; obtaining the MPM index based on the MPM candidate modes being used; and obtaining a remaining index based on the MPM candidate modes being not used.

6 . The method of claim 5 ,
wherein the MPM index or the remaining index is obtained based on the reference samples positioned spaced apart from the current block by a 2-sample distance or more being used.

7 . The method of claim 1 ,
wherein the determining of the intra prediction mode comprises: configuring an MPM candidate list including MPM candidate modes based on the first flag corresponding to the second value, and wherein the MPM candidate list is configured based on intra prediction modes other than the first mode among all modes.

8 . The method of claim 1 ,
wherein the obtaining the intra prediction information comprises: obtaining a reference index representing a position of the reference samples for predicting the current block, and obtaining the first flag based on the reference samples positioned spaced apart from the current block by a 2-sample distance or more being used, wherein the intra prediction mode of the current block is determined as DC mode based on the first flag corresponding to the first value.

9 . A method for encoding a video signal for intra prediction, the method comprising:
determining whether a top boundary of a current block is a boundary of a current coding tree unit (CTU); determining reference samples being used for the intra prediction based on whether the top boundary of the current block is the boundary of the current CTU; generating reference sample line information of the current block, wherein the reference sample line information includes an index indicating reference sample line being used for the intra prediction; determining an intra prediction mode of the current block; generating intra prediction information based on the intra prediction mode; generating an intra sub-partition (ISP) flag representing whether the current block is partitioned into sub-partitions based on the reference sample line information; and generating prediction samples of the current block based on the intra prediction mode and the reference samples, wherein the intra prediction information includes a first flag, and wherein the first flag is coded with a first value based on the intra prediction mode corresponding to a predetermined first mode and coded with a second value based on the intra prediction mode corresponding to one of modes other than the first mode, wherein the predetermined first mode is a planar mode, and wherein, based on the intra prediction mode corresponding to one of modes other than the first mode, a most probable mode (MPM) index specifying one among a plurality of candidate modes is encoded.

10 . A method of transmitting a bitstream comprising:
determining whether a top boundary of a current block is a boundary of a current coding tree unit (CTU); determining reference samples being used for the intra prediction based on whether the top boundary of the current block is the boundary of the current CTU; generating reference sample line information of the current block, wherein the reference sample line information includes an index indicating reference sample line being used for the intra prediction; determining an intra prediction mode of the current block; generating intra prediction information based on the intra prediction mode; generating an intra sub-partition (ISP) flag representing whether the current block is partitioned into sub-partitions based on the reference sample line information; generating prediction samples of the current block based on the intra prediction mode and the reference samples; encoding the bitstream including the reference sample line information, the intra prediction information and the ISP flag; and transmitting the bitstream, encoding the bitstream including the reference sample line information, the intra prediction information and the ISP flag; and transmitting the bitstream, wherein the intra prediction information includes a first flag, and wherein the first flag is coded with a first value based on the intra prediction mode corresponding to a predetermined first mode and coded with a second value based on the intra prediction mode corresponding to one of modes other than the first mode, wherein the predetermined first mode is a planar mode, and wherein, based on the intra prediction mode corresponding to one of modes other than the first mode, a most probable mode (MPM) index specifying one among a plurality of candidate modes is encoded and transmitted and transmitted.

Assignees

• Lg Electronics Inc

Inventors

• Heo Jin
• Yoo Sunmi
• Li Ling
• Choi Jangwon
• Choi Jungah

Classifications

• H04N19/593

  involving spatial prediction techniques · 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

• H04N19/119

  Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks · CPC title

• H04N19/105 Primary

  Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction · CPC title