Mixed NAL Unit Subpicture Decoding for Efficient Video Compression
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Solution Overview
Problem
The increasing demand for high-resolution and high-quality images leads to a significant increase in transmission and storage costs due to the rise in the amount of transmitted information or bits, necessitating high-efficient image compression technology.
Innovation Solution
An image encoding/decoding method and apparatus based on a mixed NAL unit type, which partitions a current picture into subpictures with different NAL unit types and uses flag information to treat them as one picture, improving encoding/decoding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If image resolution and quality are improved to meet increasing demand for HD and UHD images, then image quality is improved, but transmission cost and storage cost increase due to increased amount of transmitted information
Solution Approach 1:
The current picture is divided into multiple subpictures, each with different NAL unit types (e.g., RASL, RADL, TRAIL). This segmentation allows different portions of the image to be encoded with different compression strategies, enabling high-quality regions to be preserved while other regions use more aggressive compression, thus reducing overall transmission and storage costs while maintaining image quality.
Solution Approach 2:
Different NAL unit types are assigned to different subpictures based on their importance or characteristics. Critical regions use NAL unit types that preserve quality better, while less critical regions use types with higher compression ratios. This local differentiation optimizes the balance between image quality and data volume for the entire picture.
2Productivity
If multiple subpictures with different NAL unit types are used to improve compression efficiency, then encoding efficiency is improved, but system complexity increases due to mixed NAL unit type handling
Solution Approach 1:
The system dynamically determines NAL unit types for different subpictures based on picture characteristics, importance, and transmission requirements. This dynamic assignment allows the encoding system to adapt to different content types and transmission scenarios, improving encoding efficiency while managing complexity through context-dependent decision-making rather than fixed complex structures.
Solution Approach 2:
The patent changes the NAL unit type parameter for different subpictures within the same picture. By varying this parameter based on subpicture characteristics, the system achieves different compression efficiencies for different regions while maintaining a relatively simple overall structure that only needs to manage parameter variations rather than complex architectural changes.
Data Source
AI summary
An image encoding/decoding method and apparatus are provided. The image decoding method comprises obtaining, from a bitstream, video coding layer (VCL) network abstraction layer (NAL) unit type information of a current picture and first flag information specifying whether a subpicture included in the current picture is treated as one picture, determining a NAL unit type of each of a plurality of slices included in the current picture, based on the obtained VCL NAL unit type information, and decoding the plurality of slices based on the determined NAL unit type and the first flag information. The current picture may comprise two or more subpictures based on at least some of the plurality of slices having different NAL unit types, and the first flag information may have a predetermined value specifying that each of the two or more subpictures is treated as one picture based on at least some of the plurality of slices having different NAL unit types.