Combined Key Picture Drift Reduction in Scalable Video Coding

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Solution Overview

Problem

Scalable Video Coding (SVC) experiences drift propagation and bit rate increase when enhancement layer key pictures are dropped, leading to video quality artifacts and reduced efficiency in packet dropping mechanisms.

Innovation Solution

The method involves encoding a combined base layer and enhancement layer with key pictures that cannot be dropped during decoding, reducing drift by using combined key pictures across layers for prediction, which maintains video quality and allows for flexible bit rate adaptation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If enhancement layer key pictures are dropped to adapt to varying network conditions and terminal capabilities, then bit rate is reduced and scalability is improved, but drift propagation occurs and video quality deteriorates

Engineering Contradiction:

ImprovescalabilityVSAvoidvideo quality

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent combines base layer and enhancement layer key pictures into a single combined key picture structure. This merging allows the decoder to use the combined key picture as a reference for both layers simultaneously, preventing drift propagation when enhancement layer key pictures are dropped while maintaining video quality through consistent reference picture usage across layers

Inventive Principle:

Principle #5Merging (Combining)

2Quantity of substance

If enhancement layer key pictures are dropped to reduce bit rate, then bit rate savings are achieved and network adaptability is improved, but drift propagation occurs increasing complexity

Engineering Contradiction:

Improvebit rateVSAvoiddrift management

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

By merging base layer and enhancement layer key pictures into a single combined structure, the patent eliminates the need for separate drift management mechanisms for each layer. The combined key picture serves as a unified reference point, simplifying drift management while achieving bit rate reduction through selective dropping of enhancement layer pictures

Inventive Principle:

Principle #5Merging (Combining)

3Productivity

If separate base layer and enhancement layer key pictures are used, then layer independence is maintained, but drift propagation occurs and bit rate efficiency decreases

Engineering Contradiction:

Improvebit rate efficiencyVSAvoiddrift propagation

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The patent merges base layer and enhancement layer key pictures into a combined key picture that serves both layers. This improves bit rate efficiency by preventing redundant key picture transmissions while eliminating drift propagation through unified reference picture usage, as the combined key picture contains reference information for both layers in a single structure

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS9578325B2Drift reduction for quality scalable video coding

Publication Date: 2017.02.21 TEXAS INSTRUMENTS INC

AI summary

This invention is a method of scalable video encoding and decoding. The scalable video encoding codes both a base layer and an enhanced layer having greater resolution and/or refresh rate. Upon decoding some enhanced layer pictures may be dropped to reach a best resolution and refresh rate within a target data rate. Upon encoding a key picture in at least one group of pictures forming the video is a combined base layer/enhanced layer key picture. Such a combined base layer/enhanced layer key picture cannot be dropped on decoding. This technique reduces drift in the decoder.