US-12627791-B2 - Video encoding and decoding method for predicting chroma component, and video encoding and decoding device for predicting chroma component

US12627791B2US 12627791 B2US12627791 B2US 12627791B2US-12627791-B2

Abstract

Proposed is a video decoding method including: determining a weight of a residual sample of a Cr component and a weight of a residual sample of a Cb component, based on a prediction type of a coding unit, cbf information for the Cr component, and cbf information of the Cb component, obtaining a chroma joint residual sample of a current block from a bitstream, reconstructing the residual sample of the Cr component by using the chroma joint residual sample of the current block and the weight of the residual sample of the Cr component, and reconstructing the residual sample of the Cb component by using the chroma joint residual sample of the current block and the weight of the residual sample of the Cb component.

Inventors

Yinji Piao
Anish TAMSE
MinSoo Park
Minwoo Park
Seungsoo JEONG
Kiho Choi
Narae Choi
Woongil CHOI

Assignees

SAMSUNG ELECTRONICS CO., LTD.

Dates

Publication Date: 20260512
Application Date: 20240524

Claims (3)

1 . A video decoding method comprising: when a prediction type of a current block is intra prediction mode, extracting chroma joint information based on one of a value of coded block flag (CBF) information for a Cr component and a value of CBF information for a Cb component being 1, wherein the chroma joint information indicates whether a chroma residual sample of a single block is encoded to represent a residual sample of the Cb component and a residual sample of the Cr component in the current block; when the prediction type of the current block is an inter prediction mode, obtaining the chroma joint information from a bitstream, based on the value of the CBF information for the Cr component being 1 and the value of the CBF information for the Cb component being 1; when the chroma joint information indicates that the chroma residual sample of the single block is encoded to represent the residual sample of the Cb component and the residual sample of the Cr component in the current block, determining a weight of the residual sample of the Cr component, obtaining, from the bitstream, a chroma residual sample of the current block; and reconstructing the residual sample of the Cr component by using the chroma residual sample of the current block and the weight of the residual sample of the Cr component.
2 . A video encoding method comprising: when a prediction type of a current block is intra prediction mode, determining, based on one of a value of coded block flag (CBF) information for a Cr component and a value of CBF information for a Cb component being 1, whether a chroma residual sample of a single block is encoded to represent a residual sample of the Cb component and a residual sample of the Cr component in the current block; when the chroma residual sample of the single block is encoded to represent the residual sample of the Cb component and the residual sample of the Cr component in the current block, determining a weight of the residual sample of the Cr component; obtaining a chroma residual sample of the current block by using the residual sample of the Cr component and the weight of the residual sample of the Cr component; encoding the chroma residual sample of the current block into a bitstream; and encoding chroma joint information into the bitstream, the chroma joint information indicating whether the chroma residual sample of the single block is encoded to represent the residual sample of the Cb component and the residual sample of the Cr component in the current block, wherein, when the prediction type of the current block is an inter prediction mode, the chroma joint information is encoded based on the value of the CBF information for the Cr component being 1 and the value of the CBF information for the Cb component being 1.
3 . A method of transmitting a bitstream, the bitstream being generated by the video encoding method of claim 2 .

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This is a Continuation of U.S. application Ser. No. 17/434,684 filed Aug. 27, 2021, which is a Continuation Application of International Application PCT/KR2020/002929 filed on Feb. 28, 2020, which claims benefit of U.S. Provisional Patent Application No. 62/811,672 filed on Feb. 28, 2019, U.S. Provisional Patent Application No. 62/840,003 filed on Apr. 29, 2019, the disclosures of which are incorporated herein in their entireties by reference. BACKGROUND 1. Field The disclosure relates to an image encoding and decoding field. More specifically, the disclosure relates to a video encoding and decoding method and device for predicting a chroma component. 2. Description of Related Art Video with high image quality may use a large amount of data upon being decoded. However, because a bandwidth allowed to transfer video data is limited, a data rate applied for transferring video data may be limited. Therefore, to efficiently transmit video data, there is a need for a video data encoding and decoding method for increasing a compression rate while minimizing degradation of image quality. Video data is compressed by removing spatial redundancy and temporal redundancy between pixels. Because adjacent pixels generally have common features, coding information is transmitted in a data unit configured with pixels to remove redundancy between the adjacent pixels. Instead of directly transmitting pixel values of pixels included in a data unit, a method for obtaining the pixel values is transmitted. A prediction method for predicting a pixel value as a value similar to its original value is determined for each data unit, and coding information about the prediction method is transmitted from an encoder to a decoder. Also, because the predicted value is not completely identical to the original value, residual data about a difference between the original value and the prediction value is transmitted from the encoder to the decoder. Accurate prediction increases coding information required to specify a prediction method, but decreases a size of residual data. Accordingly, a prediction method is determined in consideration of sizes of coding information and residual data. Particularly, data units split from a picture have various sizes, and a larger size of a data unit results in higher probability that the accuracy of prediction will be reduced, while more reducing coding information. Accordingly, a size of a block is determined according to a feature of a picture. Also, prediction methods include intra prediction and inter prediction. The intra prediction is a method of predicting pixels of a block from pixels neighboring the block. The inter prediction is a method of predicting pixels by referring to pixels of another picture referred to by a picture including a block. Accordingly, spatial redundancy is removed by intra prediction, and temporal redundancy is removed by inter prediction. As the number of prediction methods increases, an amount of coding information for representing the prediction methods increases. Accordingly, by predicting coding information that is applied to a block from another block, a size of coding information can be reduced. Because loss of video data is allowed within a range that cannot be recognized by the human eye, lossy compression is performed according to a process of converting and quantizing residual data, thereby reducing an amount of residual data. SUMMARY Provided are video encoding method, the video decoding method, the video encoding device, and the video decoding device for predicting the chroma component which may efficiently encode and decode chroma components, for example, a Cr component and a Cb component of a picture, according to an embodiment. Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments. According to an aspect of the disclosure, a video decoding method includes obtaining, from a bitstream, information indicating a prediction type of a coding unit including a current block; obtaining, from the bitstream, coded block flag (CBF) information for a Cr component of the current block and CBF information for a Cb component of the current block; determining a weight of a residual sample of the Cr component and a weight of a residual sample of the Cb component, based on the prediction type of the coding unit, the CBF information for the Cr component, and the CBF information for the Cb component; obtaining, from the bitstream, a chroma joint residual sample of the current block; and reconstructing the residual sample of the Cr component by using the chroma joint residual sample of the current block and the weight of the residual sample of the Cr component, and reconstructing the residual sample of the Cb component by using the chroma joint residual sample of the current block and the weight of the residual