Scalable Nesting SEI Constraints for Subpicture Video Coding
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Solution Overview
Problem
The existing VVC design for specifying and signaling nested SEI messages for subpicture sequences has issues with subpicture ID persistence, filler payload handling, SLI message association, and missing constraints in scalable nesting SEI messages, leading to inefficiencies in video encoding and decoding processes.
Innovation Solution
Adopting subpicture indices instead of IDs for association, prohibiting filler payloads in scalable nesting SEI messages, ensuring specific flag values for SLI messages, and enforcing nal_unit_type constraints to improve bitstream conformance and extraction processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If subpicture IDs are used for association in scalable nesting SEI messages, then the association mechanism is established, but subpicture ID persistence issues arise leading to inefficiencies in video encoding and decoding
Solution Approach 1:
The patent changes the parameter used for subpicture association from subpicture ID to subpicture index. This parameter substitution resolves the persistence issues associated with IDs while maintaining the association functionality, thereby improving encoding and decoding efficiency without sacrificing the association mechanism's effectiveness.
2Adaptability or versatility
If filler payloads are allowed in scalable nesting SEI messages, then message flexibility is maintained, but bitstream conformance and extraction processes become problematic
Solution Approach 1:
The patent extracts and removes filler payloads from scalable nesting SEI messages. By taking out these problematic filler elements, the patent maintains the flexibility of SEI messages while eliminating the conformance and extraction issues that filler payloads cause in bitstream processing.
3Device complexity
If SLI messages are associated with scalable nesting SEI messages without specific flag constraints, then message association is simplified, but message precision and correctness are compromised
Solution Approach 1:
The patent introduces specific flag constraints as a feedback mechanism to control SLI message association with scalable nesting SEI messages. These flags provide precise control over association conditions, ensuring message correctness while maintaining manageable complexity through standardized constraint checking.
4Adaptability or versatility
If nal_unit_type constraints are not enforced in scalable nesting SEI messages, then encoding flexibility is maintained, but bitstream extraction and conformance become inefficient
Solution Approach 1:
The patent applies preliminary constraints on nal_unit_type values in scalable nesting SEI messages. By pre-defining acceptable nal_unit_type values, the patent maintains encoding flexibility for valid cases while significantly improving bitstream extraction efficiency and conformance checking, as the decoder can immediately validate without extensive processing.
Data Source
AI summary
Several embodiments for video encoding and video decoding are described. An example method of processing video data includes performing a conversion between a video including one or more subpictures and a bitstream of the video, wherein one or more supplemental enhancement information messages that have filler payloads are processed during the conversion according to a format rule, and wherein the format rule disallows the one or more supplemental enhancement information messages having filler payloads to be in a scalable nesting supplemental enhancement information message.