CRA Reference Picture Lists With Preceding IRAP Exclusion

Solution Overview

Problem

Existing video coding techniques require significant bandwidth and network resources due to inefficient management of reference picture lists, leading to coding errors and suboptimal user experiences.

Innovation Solution

Constrain reference picture lists to exclude certain types of pictures, such as CRA, trailing, and RADL pictures, by ensuring no entries refer to preceding IRAP pictures, thereby optimizing the coding process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If reference picture lists include all preceding pictures for maximum compression efficiency, then compression ratio improves, but coding errors increase and reliability deteriorates

Engineering Contradiction:

Improvebandwidth consumptionVSAvoidcoding error rate

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent extracts and removes specific problematic picture types (CRA, trailing, and RADL pictures) from the reference picture lists. This selective extraction eliminates the source of coding errors while preserving beneficial reference pictures, thereby reducing coding errors without significantly impacting compression efficiency.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the reference picture list into different categories based on picture type and decoding order. By identifying and separating problematic pictures (CRA, trailing, RADL) from safe reference pictures, the system can selectively include or exclude them, achieving both error reduction and maintained compression performance.

Inventive Principle:

Principle #1Segmentation

2Reliability

If reference picture lists are constrained to exclude certain picture types, then coding reliability improves, but compression efficiency deteriorates

Engineering Contradiction:

Improvecoding error rateVSAvoidcompression efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies local quality by treating different picture types differently within the reference picture list. Instead of a uniform exclusion policy, it specifically identifies and excludes only those picture types (CRA, trailing, RADL) that cause coding errors, while preserving other reference pictures that are safe to use, thereby minimizing the impact on compression efficiency.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the parameters of reference picture selection by introducing picture type-specific constraints based on decoding order relationships. It modifies which pictures are eligible for inclusion in reference lists dynamically, excluding only those that precede CRA pictures in decoding order, thus optimizing the balance between reliability and compression efficiency.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If all preceding pictures are used as reference pictures, then compression ratio is maximized, but bandwidth and network resources increase

Engineering Contradiction:

Improvecompression ratioVSAvoidbandwidth requirement

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The patent extracts and removes specific problematic picture types (CRA, trailing, and RADL pictures) from the reference picture lists. This selective extraction eliminates the source of coding errors while preserving beneficial reference pictures, thereby reducing coding errors without significantly impacting compression efficiency.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the reference picture list into different categories based on picture type and decoding order. By identifying and separating problematic pictures (CRA, trailing, RADL) from safe reference pictures, the system can selectively include or exclude them, achieving both error reduction and maintained compression performance.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250330573A1Types of Reference Pictures in Reference Picture Lists

Publication Date: 2025.10.23 HUAWEI TECH CO LTD

AI summary

A method of decoding includes receiving a coded video bitstream including a current picture; deriving a first reference picture list and a second reference picture list for each slice of the current picture; determining that the current picture is a clean random access (CRA) picture, the CRA picture signifying that there shall be no picture referred to by an entry in the first reference picture list or the second reference picture list that precedes, in an output order or a decoding order, any preceding intra random access point (IRAP) picture in the decoding order; and decoding each slice of the CRA picture based on one or both of the first reference picture list and the second reference picture list.