Mixed NAL Unit Signaling for Adaptive Subpicture Resolution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing video coding technologies struggle with efficiently handling changes in picture size and resolution within a coded video sequence, particularly in modern standards like VVC, where adaptive resolution changes (ARC) are not adequately addressed, leading to inefficiencies in encoding and decoding processes.
Innovation Solution
The method involves identifying Network Abstraction Layer (NAL) unit types based on flags in mixed NAL units for subpictures, allowing for adaptive resolution changes (ARC) by signaling ARC parameters in various data structures such as slice headers, tile group headers, or higher-level parameter sets, enabling efficient decoding of subpictures with independent resolution changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If adaptive resolution changes are implemented within a coded video sequence, then video encoding and decoding flexibility is improved, but data complexity and processing overhead increase
Solution Approach 1:
The video sequence is divided into multiple Network Abstraction Layer (NAL) units, each representing a subpicture with its own resolution parameters. This segmentation allows independent resolution control for different portions of the video sequence, enabling adaptive resolution changes without requiring complex global reconfiguration. Each NAL unit can be processed and decoded independently with its specified resolution.
Solution Approach 2:
Different subpictures within the same video sequence are assigned different resolution qualities based on their importance or content characteristics. Critical regions or high-priority subpictures are encoded at higher resolutions, while less critical regions use lower resolutions. This local quality differentiation achieves overall video quality optimization with reduced total data complexity compared to uniform high-resolution encoding.
2Productivity
If mixed NAL unit types are used in subpictures, then decoding efficiency is improved, but signaling complexity increases
Solution Approach 1:
The NAL unit type for each subpicture is dynamically determined based on a flag indicating whether mixed NAL units are present. This dynamic signaling mechanism allows the decoder to adapt its processing mode for each subpicture, improving decoding efficiency by applying appropriate algorithms for each NAL unit type while keeping signaling complexity manageable through the use of compact flag-based indicators rather than extensive parameter sets.
Solution Approach 2:
The system changes the NAL unit type parameter for different subpictures based on their specific requirements. By allowing the NAL unit type to vary across subpictures (parameter change), the system optimizes decoding efficiency for each region while using efficient syntax elements and flags to signal these changes, preventing excessive signaling complexity.
Data Source
AI summary
A method, computer program, and computer system is provided for coding video data. Video data including one or more subpictures is received. A network abstraction layer (NAL) unit type associated with each of the one or more subpictures is identified based on checking a flag corresponding to mixed NAL units in the one or more subpictures. The video data is decoded based on the identified NAL unit types.