Chroma-From-Luma Filter Selection for Better Video Compression

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Solution Overview

Problem

Existing video coding technologies face challenges in efficiently selecting downsampling filters for chroma from luma prediction, leading to suboptimal compression efficiency and increased bit usage for less likely intra prediction directions.

Innovation Solution

A method for video processing that involves receiving an input chroma block, applying multiple downsampling filters, iteratively predicting the input chroma block, calculating error scores, and selecting a target downsampling filter based on these scores to enhance compression efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple downsampling filters are applied and error scores are calculated to select the optimal filter, then compression efficiency is improved, but device complexity and computational overhead increase

Engineering Contradiction:
Improvecompression efficiencyVSAvoidfilter selection complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent pre-calculates and stores error scores for different downsampling filters and intra prediction directions during an encoding phase. These pre-computed error scores are then reused during decoding, eliminating the need for real-time complex calculations and reducing computational overhead while maintaining compression efficiency.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses the calculated error scores to automatically select the optimal downsampling filter without requiring external intervention or complex decision-making processes. The error scores inherently guide the filter selection, making the system self-optimizing.

Inventive Principle:
Principle #25Self-service

2Loss of information

If optimal downsampling filter selection is implemented, then bit usage for less likely directions is reduced, but encoding complexity increases

Engineering Contradiction:
Improvebit usage efficiencyVSAvoidencoding complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent performs preliminary encoding passes to calculate error scores for different filter-direction combinations before final encoding. This pre-computation allows the system to identify the most efficient filter-direction pairs in advance, reducing bit usage while managing encoding complexity through staged processing.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the selection of downsampling filters and intra prediction directions based on calculated error scores. By changing parameters (filter type, direction) according to computed metrics, the system optimizes bit usage efficiency while maintaining manageable encoding complexity through systematic parameter selection.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20250392713A1Selecting Downsampling Filters for Chroma from Luma Prediction
Publication Date: 2025.12.25 TENCENT AMERICA LLC
  • US20250392713A1 patent drawing
  • US20250392713A1 patent drawing
  • US20250392713A1 patent drawing

AI summary

This disclosure relates to video processing that includes iteratively predicting a chroma block in a Chroma from Luma (CfL) prediction mode based on downsampled luma samples downsampled from a plurality of downsampling filters, and selecting a target downsampling filter from the plurality of downsampling filters that corresponds to an error score determined for the iteratively predicting.