US-20260129211-A1 - VIDEO SIGNAL PROCESSING METHOD USING LUMINANCE SAMPLE-BASED CHROMINANCE SAMPLE PREDICTION AND APPARATUS THEREFOR

US20260129211A1US 20260129211 A1US20260129211 A1US 20260129211A1US-20260129211-A1

Abstract

A video signal decoding apparatus is disclosed. The decoding apparatus comprises a processor. The processor: acquires a model that models the relationship between a value of a luma sample of the current block and a value of a chroma sample of the current block, on the basis of a value of at least one sample from among a neighboring luma sample of the current block, a chroma sample corresponding to the neighboring luma sample of the current block, a neighboring luma sample of a reference block, and a chroma sample corresponding to the neighboring luma sample of the reference block; and predicts a chroma block of the current block by using the acquired model and a luma block of the current block.

Inventors

Kyungyong Kim
Dongcheol Kim
Juhyung Son
Jinsam Kwak

Assignees

WILUS INSTITUTE OF STANDARDS AND TECHNOLOGY INC.

Dates

Publication Date: 20260507
Application Date: 20231023
Priority Date: 20221026

Claims (17)

1 . A decoding apparatus for decoding a video signal, the decoding apparatus comprising a processor, wherein the processor is configured to: acquire a model that models a relationship between a value of a luma sample of a current block and a value of a chroma sample of the current block, based on a value of at least one sample from among a neighboring luma sample of the current block, a chroma sample corresponding to the neighboring luma sample of the current block, a neighboring luma sample of a reference block, and a chroma sample corresponding to the neighboring luma sample of the reference block; and predict a chroma block of the current block by using the acquired model and a luma block of the current block.
2 . The decoding apparatus of claim 1 , wherein the processor is configured to: generate a chroma prediction block by using the acquired model and the luma block of the current block; and reconstruct the chroma block of the current block by adding an error block to the chroma prediction block.
3 . The decoding apparatus of claim 1 , wherein the processor is configured to: when the decoding apparatus acquires the model, acquire a first model and a second model; generate a first chroma prediction sample by using the luma sample of the current block and the first model; generate a second chroma prediction sample by using the luma sample of the current block and the second model; generate a third chroma prediction sample by performing weighted averaging of the first chroma prediction sample and the second chroma prediction sample; generate a chroma prediction block by using the third chroma prediction sample; and reconstruct the chroma block of the current block by adding the error block to the chroma prediction block.
4 . The decoding apparatus of claim 3 , wherein the processor is configured to, in case that the current block is coded in an inter-coding mode and is applied with bi-directional prediction, derive the first model by using a first prediction block predicted using L0 motion information and derive the second model by using a second prediction block predicted using L1 motion information.
5 . The decoding apparatus of claim 2 , wherein an input value input to the model comprises a value obtained by subtracting a predesignated first offset value from the value of the luma sample of the current block, a value obtained by subtracting a predesignated second offset value from the value of a Cb chroma sample of the current block, and a value obtained by subtracting a predesignated third offset value from the value of a Cr chroma sample of the current block.
6 . The decoding apparatus of claim 5 , wherein the predesignated first offset value is a value of a luma sample at a predesignated position among the neighboring samples of the current block, the predesignated second offset value is a value of a Cb chroma sample at the predesignated position, and the predesignated third offset value is a value of a Cr chroma sample at the predesignated position.
7 . The decoding apparatus of claim 6 , wherein in case that the value of the luma sample at the predesignated position does not fall within a predesignated range, the processor is configured to use a predesignated basic first offset value as the first offset value, a predesignated basic second offset value as the second offset value, and a predesignated basic third offset value as the third offset value.
8 . The decoding apparatus of claim 6 , wherein in case that the value of the luma sample at the predesignated position does not fall within a predesignated range, the processor is configured to determine that the chroma block of the current block is unable to use an coding mode based on the model, and omit to parse at least one syntax element related to the model.
9 . The decoding apparatus of claim 6 , wherein in case that the value of the luma sample at the predesignated position does not fall within a predesignated range, the processor is configured to determine in a predesignated order whether values of luma samples at a plurality of predesignated positions are valid as the first offset value, and in case that a luma sample value valid as the first offset value is discovered, the processor is configured to use the discovered luma sample value as the first offset value, the value of the Cb chroma sample corresponding to the discovered luma sample value as the second offset value, and the value of the Cr chroma sample corresponding to the discovered luma sample as the third offset value.
10 . The decoding apparatus of claim 6 , wherein the processor is configured to parse offset sample information indicating an offset sample from a bitstream including the video signal, and use the value of the luma sample indicated by the offset sample information as the first offset value, use the value of the Cb chroma sample indicated by the offset sample information as the second offset value, and use the value of the Cr chroma sample indicated by the offset sample information as the third offset value.
11 - 18 . (canceled)
19 . An encoding apparatus for encoding a video signal, the encoding apparatus comprising a processor, wherein the processor is configured to: acquire a model that models the relationship between the value of the luma sample of the current block and the value of the chroma sample of the current block, based on a value of at least one sample from among a neighboring luma sample of a current block, a chroma sample corresponding to the neighboring luma sample of the current block, a neighboring luma sample of a reference block, and a chroma sample corresponding to the neighboring luma sample of the reference block; and predict the chroma block of the current block by using the acquired model and the luma block of the current block.
20 . (canceled)
21 . A decoding method for decoding a video signal, the decoding method comprising: acquiring a model that models the relationship between a value of a luma sample of a current block and a value of a chroma sample of the current block, based on a value of at least one sample from among a neighboring luma sample of the current block, a chroma sample corresponding to the neighboring luma sample of the current block, a neighboring luma sample of a reference block, and a chroma sample corresponding to the neighboring luma sample of the reference block; and predicting a chroma block of the current block by using the acquired model and a luma block of the current block.
22 . (canceled)
23 . A non-transitory computer-readable storage medium storing a bitstream, wherein the bitstream is decoded using a decoding method, and wherein the decoding method comprises: acquiring a model that models the relationship between the value of the luma sample of the current block and the value of the chroma sample of the current block, based on a value of at least one sample from among a neighboring luma sample of a current block, a chroma sample corresponding to the neighboring luma sample of the current block, a neighboring luma sample of a reference block, and a chroma sample corresponding to the neighboring luma sample of the reference block; and predicting the chroma block of the current block by using the acquired model and the luma block of the current block.
24 . (canceled)

Description

TECHNICAL FIELD The disclosure relates to a method and an apparatus device for processing a video signal and, more particularly, to a video signal processing method and apparatus for encoding or decoding a video signal. BACKGROUND ART Compression encoding refers to a series of signal processing technologies for transmitting digitized information through a communication line or storing this information in a storage medium in an appropriate form. Examples of targets of compression encoding are voice, images, text, etc., and particularly, a technology for performing compression encoding of an image is called video image compression. Compression encoding of a video signal is performed by removing surplus information in consideration of spatial correlation, temporal correlation, probabilistic correlation, etc. However, recently, as various media and data transmission media have been developed, there is an increasing need for a highly efficient method and apparatus for processing a video signal. DISCLOSURE OF INVENTION Technical Problem This specification is to increase the coding efficiency of a video signal by providing a video signal processing method and an apparatus for the same. Solution to Problem A video signal decoding apparatus according to an embodiment of the disclosure includes a processor. The processor acquires a model that models a relationship between a value of a luma sample of a current block and a value of a chroma sample of the current block, based on a value of at least one sample from among a neighboring luma sample of the current block, a chroma sample corresponding to the neighboring luma sample of the current block, a neighboring luma sample of a reference block, and a chroma sample corresponding to the neighboring luma sample of the reference block, and predicts a chroma block of the current block by using the acquired model and a luma block of the current block. The processor may generate a chroma prediction block by using the acquired model and the luma block of the current block, and reconstruct the chroma block of the current block by adding an error block to the chroma prediction block. When the decoding apparatus acquires the model, the processor may acquire a first model and a second model, generate a first chroma prediction sample by using the luma sample of the current block and the first model, generate a second chroma prediction sample by using the luma sample of the current block and the second model, generate a third chroma prediction sample by performing weighted averaging of the first chroma prediction sample and the second chroma prediction sample, generate a chroma prediction block by using the third chroma prediction sample, and reconstruct the chroma block of the current block by adding the error block to the chroma prediction block. When the current block is coded in an inter-coding mode and is applied with bi-directional prediction, the processor may derive the first model by using a first prediction block predicted using L0 motion information and derive the second model by using a second prediction block predicted using L1 motion information. An input value input to the model may include a value obtained by subtracting a predesignated first offset value from the value of the luma sample of the current block, a value obtained by subtracting a predesignated second offset value from the value of a Cb chroma sample of the current block, and a value obtained by subtracting a predesignated third offset value from the value of a Cr chroma sample of the current block. The predesignated first offset value may be a value of a luma sample at a predesignated position among the neighboring samples of the current block, the predesignated second offset value is a value of a Cb chroma sample at the predesignated position, and the predesignated third offset value is a value of a Cr chroma sample at the predesignated position. When the value of the luma sample at the predesignated position does not fall within a predesignated range, the processor may use a predesignated basic first offset value as the first offset value, a predesignated basic second offset value as the second offset value, and a predesignated basic third offset value as the third offset value. When the value of the luma sample at the predesignated position does not fall within a predesignated range, the processor may determine that the chroma block of the current block is unable to use an coding mode based on the model, and may omit to parse at least one syntax element related to the model. When the value of the luma sample at the predesignated position does not fall within a predesignated range, the processor may determine in a predesignated order whether values of luma samples at a plurality of predesignated positions are valid as the first offset value, and when a luma sample value valid as the first offset value is discovered, the processor may use the discovered luma sample value as the first offset value, the