POC LSB Reset for Independent Non-Base Layer Extraction

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Solution Overview

Problem

Existing video coding technologies face challenges in extracting and decoding an independent non-base layer from a multi-layer bitstream without altering slice headers or other syntax, particularly in maintaining cross-layer alignment and identifying long-term reference pictures.

Innovation Solution

The techniques involve coding a picture of an independently decodable non-base layer by resetting the picture order count (POC) value only when the POC least significant bits (LSB) value is zero, ensuring that POC value resetting occurs appropriately to maintain bitstream compliance and allow the layer to be extracted and decoded without altering slice headers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If POC value resetting is applied to enable layer extraction, then the non-base layer can be decoded independently, but the slice headers and bitstream compliance may be compromised

Engineering Contradiction:
Improvelayer extraction capabilityVSAvoidbitstream compliance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies parameter changes by conditionally resetting the POC LSB value based on its current state. Specifically, the POC LSB is reset only when it equals zero, which maintains bitstream compliance while enabling independent layer extraction. This selective parameter modification resolves the contradiction between extraction capability and compliance.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If POC value resetting is performed frequently, then cross-layer alignment is maintained, but long-term reference picture identification becomes inaccurate

Engineering Contradiction:
Improvecross-layer alignmentVSAvoidreference picture identification
Core Design Contradiction:
Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The patent implements periodic action by resetting the POC LSB value at specific intervals (when it equals zero) rather than continuously. This periodic resetting maintains cross-layer alignment while preserving the accuracy of long-term reference picture identification, as the POC value is only reset when necessary to maintain alignment.

Inventive Principle:
Principle #19Periodic action

3Adaptability or versatility

If slice headers are modified to enable independent decoding, then decoding flexibility improves, but compatibility with existing decoders is reduced

Engineering Contradiction:
Improveindependent decoding capabilityVSAvoiddecoder compatibility
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent applies local quality by making selective modifications only to the POC LSB parameter in the slice headers, rather than modifying the entire header structure. This localized modification enables independent decoding capability while maintaining compatibility with existing decoders that expect standard slice header formats.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3120559B1POC value design for multi-layer video coding
Publication Date: 2021.05.26 QUALCOMM INC
  • EP3120559B1 patent drawingFigure 1
  • EP3120559B1 patent drawingFigure 2
  • EP3120559B1 patent drawingFigure 3

AI summary

In an example, a method of coding video data includes coding, by a video coder, at least a portion of a picture of an independently decodable non-base layer of a multi-layer bitstream. The method also includes coding, by the video coder, data indicating a picture order count (POC) value reset for a POC least significant bits (LSB) value of the picture only when the picture has a POC LSB value for the picture is equal to zero.