Adaptive Merging Candidates for Packet-Loss-Resistant Image Coding

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Solution Overview

Problem

Existing image coding and decoding methods using inter prediction lack sufficient error resistance, particularly in scenarios where information on co-located blocks is lost due to packet loss, leading to incorrect decoding of merging block candidate lists.

Innovation Solution

An image coding and decoding method that determines a maximum number of merging candidates on a block-by-block basis, derives first and second merging candidates, and codes/decodes an index for identifying the selected candidate, ensuring error resistance by allowing parallel processing and increased candidate variety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If inter prediction coding is used to compress moving pictures, then compression efficiency is improved, but error resistance deteriorates when packet loss occurs

Engineering Contradiction:
Improvecompression efficiencyVSAvoiderror resistance
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent pre-determines the maximum number of merging candidates before actual coding, and transmits this maximum number in the bitstream. This preliminary action allows the decoder to prepare the correct number of candidate positions in advance, enabling error-free decoding even when some candidates are lost due to packet loss, thus improving error resistance while maintaining compression efficiency

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent reserves additional merging candidate positions by determining a maximum number that is larger than the actual number of candidates needed. This creates a buffer or cushion that can absorb packet loss without affecting decoding accuracy. The extra reserved positions act as a safety margin that protects against errors, allowing the system to maintain reliability while achieving high compression

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Manufacturing precision

If the number of merging candidates is increased to improve coding accuracy, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvecoding accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent changes the parameter of merging candidate count from a fixed small number to a variable maximum number that is determined in advance and transmitted in the bitstream. This parameter change allows the system to adapt the number of candidates to actual needs while maintaining a manageable maximum limit, thereby improving coding accuracy without causing uncontrolled increase in processing complexity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent makes the merging candidate structure dynamic by allowing the maximum number of candidates to be determined based on actual coding conditions and transmitted in the bitstream. This dynamic approach enables the system to optimize the number of candidates for each coding unit, improving accuracy where needed while keeping complexity manageable in other areas, thus resolving the contradiction between precision and complexity

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4633163A1Image encoding method, image encoding apparatus, image decoding method, and image decoding apparatus
Publication Date: 2025.10.15 SUN PATENT TRUST
  • EP4633163A1 patent drawingFigure 1A
  • EP4633163A1 patent drawingFigure 1B~2
  • EP4633163A1 patent drawingFigure 3

AI summary

An image coding method bitstream includes: determining a maximum number of a merging candidate which is a combination of a prediction direction, a motion vector, and a reference picture index for use in coding of a current block (S201); deriving a first merging candidate (S202); determining whether or not a total number of the first merging candidate is smaller than the maximum number (S204); deriving a second merging candidate when it is determined that the total number of the first merging candidate is smaller than the maximum number (S205); selecting a merging candidate for use in the coding of the current block from the first merging candidate and the second merging candidate (S206); and coding, using the maximum number, an index for identifying the selected merging candidate, and attaching the coded index to the bitstream (S207).