Reference Picture Scaling Ratios in Video Coding

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Solution Overview

Problem

Existing video encoding and decoding technologies face inefficiencies when reference picture resampling and subpicture processing are applied simultaneously, leading to increased distortion and decreased coding efficiency.

Innovation Solution

Constraining the reference picture scaling ratios within an optimal range (between ⅛ and 2) by determining the scaling ratio based on the width and height of the scaling window of the current picture, and disabling subpicture processing when reference picture resampling is enabled to prevent distortion and enhance coding efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If reference picture resampling and subpicture processing are applied simultaneously, then more flexible video coding is achieved, but distortion increases and coding efficiency decreases

Engineering Contradiction:

Improvevideo coding flexibilityVSAvoidvideo quality distortion

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary anti-action by disabling subpicture processing when reference picture resampling is enabled. This preventive measure avoids the harmful interaction between the two processing techniques before distortion can occur, while still allowing both techniques to be used independently when appropriate

Inventive Principle:

Principle #9Preliminary anti-action

2Adaptability or versatility

If reference picture scaling ratios are not constrained, then scaling flexibility is maintained, but coding efficiency decreases and distortion increases

Engineering Contradiction:

Improvescaling flexibilityVSAvoidcoding efficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent applies parameter changes by constraining the scaling ratio to a specific range (between 1/8 and 2). This parameter constraint ensures that scaling operations remain within optimal boundaries, preventing excessive distortion while maintaining sufficient flexibility for various video coding scenarios

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If reference picture scaling ratios are not constrained, then scaling freedom is preserved, but manufacturing precision deteriorates

Engineering Contradiction:

Improvescaling freedomVSAvoidscaling accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by establishing bounds on the scaling ratio (between 1/8 and 2). This constraint ensures that scaling operations produce accurate results within acceptable parameters, preventing both excessive magnification and excessive reduction that would degrade video quality

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11632540B2Reference picture scaling ratios for reference picture resampling in video coding

Publication Date: 2023.04.18 QUALCOMM INC

AI summary

A video encoder and video decoder may be configured to disable subpicture processing in situations where reference picture scaling is enabled. In another example, when reference picture scaling is enabled, a video encoder may determine a reference picture scaling ratio for the reference picture resampling process based on a width of a scaling window (PicOutputWidthL) of the current picture and a height of the scaling window (PicOutputHeightL) of the current picture. The values of PicOutputWidthL and PicOutputHeightL are constrained, respectively, relative to a width of a scaling window (refPicOutputWidthL) of the reference picture and a height of the scaling window (refPicOutputHeightL) of the reference picture.