# US 12,003,705 B2 · Image decoding method and device using DPB parameter for OLS

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- Number: US 12,003,705 B2
- Document ID: US12003705B2
- Status: Granted
- Kind: B2
- Application number: 18/198,159
- Filed: 2023-05-16
- Published: 2023-09-14
- Granted: 2024-06-04
- Earliest claimed: 2019-12-30
- Assignees: LG Electronics Inc.
- Applicants: LG Electronics Inc.
- Inventors: Hendry Hendry
- Web page: https://patentgrep.com/patent/US12003705B2

## CPC

- 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 19/132: Sampling, masking or truncation of coding units, e.g. adaptive resampling, frame skipping, frame interpolation or high-frequency transform coefficient masking
- H04N 19/136: Incoming video signal characteristics or properties
- H04N 19/159: Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
- H04N 19/172: the region being a picture, frame or field
- H04N 19/176: the region being a block, e.g. a macroblock
- H04N 19/44: Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
- H04N 19/46: Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence)
- H04N 19/70: characterised by syntax aspects related to video coding, e.g. related to compression standards
- H04N 19/423: characterised by memory arrangements (H04N19/433 takes precedence)
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

An image decoding method performed by a decoding device according to the present document comprises the steps of: obtaining image information including an output layer set (OLS) decoded picture buffer (DPB) parameter index for a target OLS and DPB parameter information; deriving DPB parameter information for the target OLS on the basis of the OLS DPB parameter index; performing a picture management process on pictures of a DPB on the basis of the DPB parameter information for the target OLS; configuring a reference picture list for a current picture on the basis of the pictures of the DPB; and performing an inter prediction on a block in the current picture on the basis of the reference picture list.

## Claims

### Claim 1

An image decoding apparatus comprising:
a memory; and
at least one processor connected to the memory, the at least one processor configured to:
obtain image information including Decoded Picture Buffer (DPB) parameter syntax structures and an Output Layer Set (OLS) DPB parameter index for a target OLS;
derive DPB parameter syntax structure for the target OLS based on the OLS DPB parameter index;
perform a picture management process for pictures of a DPB based on the DPB parameter syntax structure for the target OLS;
construct a reference picture list for a current picture based on the pictures of the DPB; and
perform inter prediction for a block in the current picture based on the reference picture list,
wherein the OLS DPB parameter index specifies the DPB parameter syntax structure for the target OLS among the DPB parameter syntax structures,
wherein an OLS DPB parameter flag for whether the DPB parameter syntax structure for the target OLS is present in a Video Parameter Set (VPS) syntax is obtained,
wherein the OLS DPB parameter syntax structure is obtained in the VPS syntax based on a value of the OLS DPB parameter flag.

### Claim 2 (depends on 1)

The image decoding apparatus of claim 1, wherein the OLS DPB parameter flag is included in the VPS syntax.

### Claim 3 (depends on 1)

The image decoding apparatus of claim 1, wherein, for performing the inter prediction for the block, the at least one processor is configured to:
derive a reference picture in the reference picture list based on an obtained reference picture index for the block; and
derive a prediction sample by performing the inter prediction for the block based on the reference picture.

### Claim 4 (depends on 1)

The image decoding apparatus of claim 1, wherein the DPB parameter syntax structure for the target OLS includes information on DPB size, information on maximum picture reorder number of the DPB for the target OLS and information on maximum latency of the DPB.

### Claim 5

An image encoding apparatus comprising:
a memory; and
at least one processor connected to the memory, the at least one processor configured to:
generate Decoded Picture Buffer (DPB) parameter syntax structures including DPB parameter syntax structure of a target Output Layer Set (OLS);
perform a picture management process for pictures of a DPB based on the DPB parameter syntax structure of the target OLS;
construct a reference picture list for a current picture based on the pictures of the DPB;
perform inter prediction for a block in the current picture based on the reference picture list;
generate an OLS DPB parameter index for the DPB parameter syntax structure of the target OLS; and
encode image information including the OLS DPB parameter index, the DPB parameter syntax structures and prediction information for the block,
wherein the OLS DPB parameter index specifies the DPB parameter syntax structure for the target OLS among the DPB parameter syntax structures,
wherein an OLS DPB parameter flag for whether the DPB parameter syntax structure for the target OLS is present in a Video Parameter Set (VPS) syntax is encoded,
wherein the OLS DPB parameter syntax structure is signaled in the VPS syntax based on a value of the OLS DPB parameter flag.

### Claim 6 (depends on 5)

The image encoding apparatus of claim 5, wherein the DPB parameter syntax structure for the target OLS includes information on DPB size, information on maximum picture reorder number of the DPB for the target OLS, and information on maximum latency of the DPB.

### Claim 7

An apparatus for transmitting data for an image, the apparatus comprising:
at least one processor configured to obtain a bitstream of image information including Decoded Picture Buffer (DPB) parameter syntax structures and an Output Layer Set (OLS) DPB parameter index for a target OLS; and
a transmitter configured to transmit the data including the bitstream of the image information including the DPB parameter syntax structures and the OLS DPB parameter index,
wherein DPB parameter syntax structure for the target OLS is derived based on the OLS DPB parameter index, and a picture management process for pictures of a DPB is performed based on the DPB parameter syntax structure for the target OLS,
wherein the OLS DPB parameter index specifies the DPB parameter syntax structure for the target OLS among the DPB parameter syntax structures,
wherein an OLS DPB parameter flag for whether the DPB parameter syntax structure for the target OLS is present in a Video Parameter Set (VPS) syntax is obtained,
wherein the OLS DPB parameter syntax structure is obtained in the VPS syntax based on a value of the OLS DPB parameter flag.