Bilateral Filtering Before Chroma Subsampling in Video Coding

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Solution Overview

Problem

Existing video coding technologies face challenges in efficiently handling chroma subsampling and intra prediction modes, leading to inefficiencies in bandwidth usage and video quality, particularly in advanced codecs like VVC.

Innovation Solution

The implementation of bilateral filtering (BF) processes, including average, weighted, and Wiener functions, to enhance video data processing, combined with adaptive BF techniques, to improve video coding efficiency and quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If chroma subsampling is applied to reduce bandwidth, then bandwidth usage is reduced, but video quality deteriorates

Engineering Contradiction:
Improvebandwidth usageVSAvoidvideo quality
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The bilateral filter is applied before chroma subsampling to pre-process the chroma samples, enhancing their quality in advance. This preliminary filtering reduces noise and artifacts that would otherwise be amplified by subsampling, thereby maintaining video quality while still achieving bandwidth reduction through subsampling.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The bilateral filter acts as an intermediary between the original chroma samples and the subsampled chroma data. It processes the chroma samples to preserve important visual information while reducing noise, serving as a mediator that allows both bandwidth reduction and quality preservation to coexist.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If bilateral filtering is applied to enhance video quality, then video quality is improved, but computational complexity increases

Engineering Contradiction:
Improvevideo qualityVSAvoidcomputational complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The bilateral filter is applied selectively to chroma samples rather than all video data. By focusing the computational effort only on chroma subsampling enhancement and using localized filtering windows, the computational complexity is significantly reduced compared to applying full bilateral filtering to the entire video stream.

Inventive Principle:
Principle #3Local quality

3Productivity

If adaptive bilateral filtering with online-trained parameters is used, then video coding efficiency is improved, but processing time increases

Engineering Contradiction:
Improvevideo coding efficiencyVSAvoidprocessing time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

Filter parameters are pre-trained offline using training video sequences, creating lookup tables of optimal parameters. During actual video coding, these pre-computed parameters are directly applied without real-time training, significantly reducing processing time while maintaining the coding efficiency benefits of adaptive filtering.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS20250294144A1Using different sources for bilateral filter in video coding
Publication Date: 2025.09.18 BYTEDANCE INC
  • US20250294144A1 patent drawing
  • US20250294144A1 patent drawing
  • US20250294144A1 patent drawing

AI summary

A mechanism for processing video data is disclosed. The mechanism includes determining to apply a bilateral filter (BF) process to samples of a picture, wherein the BF process applies an average sum, a weighted sum, a linear sum, a non-linear sum, a Wiener function, or combinations thereof. A conversion is performed between a visual media data and a bitstream based on the BF process.