Deriving Active Reference Layer Pictures in Scalable Video Decoding

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Solution Overview

Problem

Current video compression technologies face challenges in efficiently identifying and utilizing active interlayer reference pictures for interlayer prediction, especially in variable network environments, which affects the scalability and performance of video encoding and decoding processes.

Innovation Solution

The proposed solution involves deriving the number of active reference layer pictures using specific equations and flags within the video parameter set (VPS) extension, allowing for efficient interlayer prediction by determining the availability and relevance of reference pictures across different layers, even in scenarios where entropy decoding is not possible.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If scalable video encoding is used to adapt to variable network environments, then adaptability is improved, but device complexity increases

Engineering Contradiction:
Improveadaptability to network environmentsVSAvoidencoding complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The video stream is divided into multiple layers (base layer and enhancement layers) with different quality levels. The encoder segments the video data into hierarchical layers that can be independently decoded, allowing receivers to select appropriate layers based on network conditions without requiring complex full-scale decoding of all layers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The encoder pre-processes and classifies reference pictures into different layer categories (interlayer reference pictures, intra-layer reference pictures) and prepares them in advance. This preliminary organization of reference pictures simplifies the decoding process by having ready-to-use reference structures already prepared according to the scalable hierarchy.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If multiple reference layers are used for interlayer prediction, then compression performance is improved, but processing time increases

Engineering Contradiction:
Improvecompression performanceVSAvoidprocessing time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

Different reference pictures are assigned to different layers based on their quality and temporal characteristics. Base layer reference pictures provide coarse temporal prediction while enhancement layer reference pictures provide finer quality prediction. This local differentiation allows the system to use multiple reference layers for improved compression while managing processing time by applying appropriate prediction strength at each layer level.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system selectively applies interlayer prediction using only the necessary number of reference layers based on current picture type and coding conditions. Not all reference layers are used for every picture - the system applies partial action by choosing which reference layers to utilize, thereby improving compression performance when beneficial while avoiding unnecessary processing overhead when simpler prediction suffices.

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If active reference layer picture derivation is implemented, then measurement precision is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvereference picture identification accuracyVSAvoiddecoding complexity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The decoding system automatically derives and identifies active reference layer pictures through predefined rules and syntax element parsing without requiring manual configuration or complex external control. The decoder self-manages the identification process by examining layer syntax elements and reference picture list structures, thereby achieving precise reference picture identification while maintaining ease of operation through automated self-service mechanisms.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

Syntax elements and data structures act as intermediaries between the encoded bitstream and the reference picture identification process. These structured intermediaries carry layer identification information and reference picture list data that bridge the gap between compressed data and the decoding system, enabling accurate identification of active reference layers through systematic data interpretation rather than complex analysis.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3086555B1Parameter derivation in multi-layer video coding
Publication Date: 2021.09.15 ELECTRONICS & TELECOMM RES INST
  • EP3086555B1 patent drawingFigure 1
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  • EP3086555B1 patent drawingFigure 3

AI summary

A method of decoding a image according to an embodiment of the present invention, which supports a plurality of layers, may comprise the steps of: receiving information on a reference layer used to decode a current picture for inter-layer prediction; inducing the number of valid reference layer pictures used to decode the current picture on the basis of the information on the reference layer; and performing inter-layer prediction on the basis of the number of valid reference layer pictures.