# US 11,909,976 B2 · Method and apparatus for improved context design for prediction mode and coded block flag (CBF)

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- Number: US 11,909,976 B2
- Document ID: US11909976B2
- Status: Granted
- Kind: B2
- Application number: 17/837,433
- Filed: 2022-06-10
- Published: 2022-09-22
- Granted: 2024-02-20
- Earliest claimed: 2018-11-14
- Assignees: Tencent America LLC
- Applicants: Tencent America LLC
- Inventors: Xin Zhao; Xiang Li; Shan Liu
- Web page: https://patentgrep.com/patent/US11909976B2

## CPC

- H04N 19/11: among a plurality of spatial predictive coding modes
- H04N 19/13: Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
- H04N 19/105: 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
- H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
- H04N 19/176: the region being a block, e.g. a macroblock
- H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

A method of controlling intra-inter prediction for decoding or encoding of a video sequence, is performed by at least one processor. The method may include setting a prediction mode flag associated with a current block to indicate whether the current block is coded in inter prediction mode, intra prediction mode, or inter-intra prediction mode; deriving a context value associated with a coded block flag associated with the current block based on the prediction mode flag associated with the current block. Deriving the context value may include based on the current block being determined to be coded in the intra prediction mode, setting the context value of the coded block flag to a first value, and based on the current block being determined to be coded in the inter prediction mode, setting the context value of the coded block flag to a second value.

## Claims

### Claim 1

A method of controlling intra-inter prediction for decoding or encoding of a video sequence, the method being performed by at least one processor, and the method comprising:
setting a prediction mode flag associated with a current block to indicate whether the current block is coded in inter prediction mode, intra prediction mode, or inter-intra prediction mode;
deriving a context value associated with a coded block flag associated with the current block based on the prediction mode flag associated with the current block, wherein the context value is based on at least two values, and wherein deriving the context value further comprises:
based on the current block being determined to be coded in the intra prediction mode-intra-inter prediction mode, setting the context value of the coded block flag to a first value,
wherein a same context value of the coded block flag is used when the current block being coded in the intra prediction mode or intra-inter prediction mode, and
based on the current block being determined to be coded in the inter prediction mode, setting the context value of the coded block flag to a second value; and
performing entropy coding of a luma coded block flag associated with the current block using the context value, wherein a sampling structure for entropy coding of the video sequence is 4:2:0.

### Claim 2 (depends on 1)

The method of claim 1, wherein the coded block flag is also associated with a chroma component of the current block and entropy coding of a chroma coded block flag associated with the current block is based on the context value.

### Claim 3 (depends on 1)

The method of claim 1, wherein the luma coded block flag is associated to both a luma component of the current block and a chroma component of the current block and entropy coding of a chroma coded block flag associated with the current block is based on the context value.

### Claim 4

An apparatus for controlling intra-inter prediction for decoding or encoding of a video sequence, the apparatus comprising:
at least one memory configured to store computer program code; and
at least one processor configured to access the at least one memory and operate according to the computer program code, the computer program code comprising:
setting code configured to cause the at least one processor to:
set a prediction mode flag associated with a current block to indicate whether the current block is coded in inter prediction mode, intra prediction mode, or inter-intra prediction mode;
derive a context value associated with a coded block flag associated with the current block based on the prediction mode flag associated with the current block, wherein the context value is based on at least two values, and wherein deriving the context value further comprises:
based on the current block being determined to be coded in the intra prediction mode or intra-inter prediction mode, set the context value of the coded block flag to a first value,
wherein a same context value of the coded block flag is used when the current block being coded in the intra prediction mode or intra-inter prediction mode, and
based on the current block being determined to be coded in the inter prediction mode, set the context value of the coded block flag to a second value; and
performing code configured to cause the at least one processor to perform entropy coding of a luma coded block flag associated with the current block using the context value, wherein a sampling structure for entropy coding of the video sequence is 4:2:0.

### Claim 5 (depends on 4)

The apparatus of claim 4, wherein the coded block flag is also associated with a chroma component of the current block and entropy coding of a chroma coded block flag associated with the current block is based on the context value.

### Claim 6 (depends on 4)

The apparatus of claim 4, wherein the coded block flag is associated with both the luma component of the current block and a chroma component of the current block and entropy coding of a chroma coded block flag associated with the current block is based on the context value.

### Claim 7

A non-transitory computer-readable storage medium storing instructions that cause at least one processor to:
set a prediction mode flag associated with a current block to indicate whether the current block is coded in inter prediction mode, intra prediction mode, or inter-intra prediction mode;
derive a context value associated with a coded block flag associated with the current block based on the prediction mode flag associated with the current block, wherein the context value is based on at least two values, and wherein deriving the context value further comprises:
based on the current block being determined to be coded in the intra prediction mode or intra-inter prediction mode, set the context value of the coded block flag to a first value,
wherein a same context value of the coded block flag is used when the current block being coded in the intra prediction mode or intra-inter prediction mode, and
based on the current block being determined to be coded in the inter prediction mode, set the context value of the coded block flag to a second value; and
perform entropy coding of a luma coded block flag associated with the current block using the context value, wherein a sampling structure for entropy coding of a video sequence is 4:2:0.

### Claim 8 (depends on 7)

The non-transitory computer-readable storage medium of claim 7, wherein the coded block flag is associated to a chroma component of the current block and entropy coding of a chroma coded block flag associated with the current block is based on the context value.