Adaptive Chrominance Downsampling for Video Encoding Efficiency

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Solution Overview

Problem

Conventional video encoding methods apply a uniform downsampling ratio to chrominance elements across frames, which can lead to inefficient code reduction and suboptimal image quality due to varying visual sensitivity within frames and localized changes.

Innovation Solution

Adaptive downsampling processing that adjusts the downsampling ratio for each frame and area within a frame based on characteristics, such as transition amounts, to efficiently reduce code while maintaining subjective image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If uniform downsampling ratio is applied to chrominance elements across frames, then processing complexity is reduced, but encoding efficiency deteriorates due to inability to adapt to varying visual sensitivity

Engineering Contradiction:

Improveencoding efficiencyVSAvoiddownsampling processing complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the downsampling ratio variable rather than fixed. The downsampling ratio is dynamically adjusted based on frame characteristics (transition amounts) and local area characteristics, allowing the system to adapt to changing visual sensitivity requirements while encoding video sequences

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements local quality by applying different downsampling ratios to different areas within the same frame. Areas with larger transition amounts receive lower downsampling ratios (less downsampling) while areas with smaller transition amounts receive higher downsampling ratios (more downsampling), optimizing encoding efficiency for each local region

Inventive Principle:

Principle #3Local quality

2Quantity of substance

If higher downsampling ratio is applied to chrominance elements, then code amount is reduced, but image quality deteriorates due to loss of chrominance detail

Engineering Contradiction:

Improvecode amountVSAvoidimage quality

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent changes the downsampling ratio parameter adaptively based on visual sensitivity characteristics. By detecting transition amounts in frames and areas, the system adjusts the downsampling ratio parameter to balance code reduction with image quality preservation, applying higher ratios where visual sensitivity is low and lower ratios where visual sensitivity is high

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9055303B2Video encoding method and decoding method, apparatuses therefor, programs therefor, and storage media for recording the programs

Publication Date: 2015.06.09 NIPPON TELEGRAPH & TELEPHONE CORP

AI summary

A video encoding method, in which a video signal consisting of two or more signal elements is targeted to be encoded, includes a step of setting a downsampling ratio is set for a specific signal element in a frame, in accordance with the characteristics in the frame; and a step of generating a target video signal to be encoded, by subjecting the specific signal element in the frame to downsampling in accordance with the set downsampling ratio. The frame may be divided into partial areas in accordance with localized characteristics in the frame; and a downsampling ratio for a specific signal element in these partial areas may be set in accordance with the characteristics in each partial area.