POC Value Decrement for Multi-Layer Video Coding Alignment

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Solution Overview

Problem

Existing video coding technologies face challenges in maintaining cross-layer alignment of picture order count (POC) values during multi-layer video coding, leading to improper output order of pictures, especially when POC values are not properly reset or decremented, causing misalignment and errors in decoding processes.

Innovation Solution

The proposed solution involves decrementing POC values of all pictures stored in the decoded picture buffer (DPB) prior to decoding an initial picture of an access unit where POC resetting is performed, ensuring that POC values remain aligned across layers, and signaling additional POC least significant bit (LSB) information to maintain correct output order.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If POC values are not decremented before POC resetting, then the decoding process is simpler, but cross-layer alignment of POC values is lost causing improper output order

Engineering Contradiction:
Improvecross-layer alignment of POC valuesVSAvoiddecoding process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by decrementing POC values of all pictures stored in the DPB before performing POC resetting. This preparatory step ensures that when the POC reset occurs, the alignment between base layer and enhancement layer POC values is maintained, preventing output order errors while keeping the reset mechanism straightforward

Inventive Principle:
Principle #10Preliminary action

2Reliability

If POC values are decremented for all pictures in DPB, then cross-layer alignment is maintained, but additional processing steps are required

Engineering Contradiction:
Improveproper output order of picturesVSAvoidvideo decoding speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies local quality by selectively decrementing POC values only for pictures that are stored in the DPB and require alignment, rather than uniformly processing all pictures. This targeted approach maintains proper output order for pictures that need it while minimizing unnecessary processing operations

Inventive Principle:
Principle #3Local quality

3Reliability

If POC resetting is performed without decrementing previous POC values, then the encoding is simpler, but error resilience is reduced

Engineering Contradiction:
Improveerror resilience in video decodingVSAvoidPOC management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by decrementing POC values before resetting, which creates a more robust error resilience mechanism. This preparatory decrement ensures that even if errors occur during transmission or decoding, the POC values remain aligned across layers, preventing cascading errors and maintaining picture output order

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3075157B1POC value design for multi-layer video coding
Publication Date: 2020.01.22 QUALCOMM INC
  • EP3075157B1 patent drawingFigure 1
  • EP3075157B1 patent drawingFigure 2
  • EP3075157B1 patent drawingFigure 3

AI summary

In an example, a method of decoding video data includes decoding data that indicates a picture order count (POC) reset for a POC value of a first picture of a first layer of multi-layer video data, wherein the first picture is included in an access unit. The example method also includes, based on the data that indicates the POC reset for the POC value of the first picture and prior to decoding the first picture, decrementing POC values of all pictures stored to a decoded picture buffer (DPB) that precede the first picture in coding order including at least one picture of a second layer of the multi-layer video data.