Chroma Intra Prediction Reordering for Dual-Tree Video Coding

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Solution Overview

Problem

Existing video coding systems face inefficiencies in compressing chroma video blocks within intra-coded regions, particularly in determining optimal intra prediction modes for chroma and luma blocks, leading to suboptimal compression efficiency.

Innovation Solution

A video decoding device is configured to determine chroma video block location within intra-coded regions, enable dual tree partition modes, calculate combined costs for intra prediction modes, and reorder these modes based on calculated costs, using padded reference samples when necessary to enhance prediction accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional intra prediction modes are used for chroma blocks in inter-coded slices, then decoding complexity is reduced, but compression efficiency deteriorates

Engineering Contradiction:
Improvecompression efficiencyVSAvoiddecoding complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by reordering intra prediction modes before decoding based on pre-calculated combined costs. The decoder determines the location of chroma blocks within intra-coded regions in advance, calculates combined costs for multiple intra prediction modes beforehand, and reorders them according to these costs. This preparation work is done before actual decoding, enabling more efficient compression without significantly increasing real-time decoding complexity.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If dual tree partition mode is enabled for chroma blocks, then prediction accuracy improves, but computational cost increases

Engineering Contradiction:
Improveprediction accuracyVSAvoidcomputational cost
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The patent applies local quality by enabling dual tree partition mode selectively only for chroma blocks located within intra-coded regions of inter-coded slices, rather than applying it universally. The decoder determines the location of each chroma block and checks whether it falls within an intra-coded region before applying the dual tree partition mode. This localized application improves prediction accuracy for relevant blocks while avoiding unnecessary computational overhead for other blocks.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4661392A1Adaptive dual tree and chroma intra prediction modes reordering
Publication Date: 2025.12.10 INTERDIGITAL CE PATENT HOLDINGS SAS
  • EP4661392A1 patent drawingFigure 1A
  • EP4661392A1 patent drawingFigure 1B
  • EP4661392A1 patent drawingFigure 1C

AI summary

Disclosed herein are systems, methods, and instrumentalities associated with dual tree coding modes and chroma intra prediction modes reordering. A video coding device as described herein may determine whether a chroma video block is located in an intra-coded region of an inter-coded video slice. Based at least on a determination that the chroma video block is located in the intra-coded region of the video slice and a further determination that a dual tree partition mode is enabled for the intra-coded region, the video coding device may be further configured to determine a plurality of intra prediction modes for the chroma video block, calculate, for each of plurality of intra prediction modes, a respective combined cost associated with predicting the chroma video block and a luma video block co-located with the chroma video block using the intra prediction mode, and reorder the plurality of intra prediction modes based on the respective combined cost calculated for each of the plurality of intra prediction modes. The video coding device may then code the chroma video block based on the reordering of the plurality of intra prediction modes.