Image Decoding DPB Update Timing for CVSS Access Units

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Solution Overview

Problem

The increasing demand for high-resolution and high-quality images leads to higher transmission and storage costs due to increased data volume, necessitating a more efficient image compression technique.

Innovation Solution

An image decoding method that determines whether to remove pictures from the Decoded Picture Buffer (DPB) before decoding the first picture of a Coded Video Sequence Start Access Unit (CVSS AU) other than AU 0, rather than before decoding all pictures, to maintain consistent DPB state across layers and improve coding efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If pictures are removed from DPB before decoding all pictures of CVSS AU other than AU 0, then transmission and storage costs are reduced through compression, but DPB state consistency across layers deteriorates and coding efficiency decreases

Engineering Contradiction:

Improvetransmission and storage costsVSAvoidcoding efficiency

Core Design Contradiction:

Loss of energyVSProductivity

Solution Approach 1:

The patent applies preliminary action by determining whether to remove pictures from the DPB before decoding the first picture of the CVSS AU, rather than waiting until all pictures are decoded. This early determination maintains consistent DPB state across layers while still achieving compression cost reduction.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent segments the DPB management process by applying different removal strategies to different access units. Specifically, it identifies CVSS AUs other than AU 0 as a special category that requires consistent DPB state maintenance, while other AUs can follow standard removal procedures.

Inventive Principle:

Principle #1Segmentation

2Manufacturing precision

If DPB is updated frequently to maintain picture quality, then image quality is improved, but device complexity and processing overhead increase

Engineering Contradiction:

Improveimage qualityVSAvoidbuffer update complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements periodic action by updating the DPB at specific intervals and conditions rather than continuously. It determines picture removal timing based on access unit boundaries and layer consistency requirements, reducing unnecessary buffer operations while maintaining image quality.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent applies local quality by treating different access units differently in the DPB management process. CVSS AUs other than AU 0 receive special handling to maintain consistent DPB state, while other AUs follow standard procedures, optimizing both quality and complexity for different regions of the video stream.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12610071B2Image decoding method and device therefor

Publication Date: 2026.04.21 LG ELECTRONICS INC

AI summary

An image decoding method performed by a decoding device according to the present document comprises the steps of: deriving a value of a variable on the basis of whether a current picture is a first picture of a current access unit (AU) that is a coded video sequence start access unit (CVSS) AU instead of AU 0, wherein the variable indicates whether all picture storage buffers within a decoded picture buffer (DPB) are emptied without being output; updating the DPB on the basis of the variable; and decoding the current picture on the basis of the updated DPB.