Sublayer Signaling in Video Bitstream for VVC
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Solution Overview
Problem
The existing Versatile Video Coding (VVC) standard faces issues in specifying and signaling level information for subpicture sequences, including inconsistent level signaling across sublayers, limited availability of SLI SEI messages, restricted persistency scope, incomplete subpicture sequence definitions, and missing constraints in subpicture layer configurations.
Innovation Solution
Enhancements to the VVC standard include adding sli_max_sublayers_minus1, sli_sublayer_info_present_flag, and a loop for sublayers to signal level information consistently, allowing SLI SEI messages to be externally provided, expanding persistency scope to multiple coded video sequence sets (CVSs), and specifying subpicture sequence-specific variables to ensure accurate level conformance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If SLI SEI messages are provided only through bitstream, then parsing complexity is reduced, but flexibility and external configuration capability are limited
Solution Approach 1:
The patent introduces an intermediary mechanism that allows SLI SEI messages to be provided through external means (such as configuration files or side information) in addition to the bitstream. This intermediary approach enables flexible external configuration while maintaining backward compatibility with existing bitstream-based parsing methods, thus resolving the contradiction between flexibility and parsing complexity.
2Adaptability or versatility
If SLI SEI message persistency scope is limited to one CVS, then message processing simplicity is maintained, but applicability across multiple CVSs is restricted
Solution Approach 1:
The patent extends the persistency scope of SLI SEI messages from a single CVS to multiple CVSs, making the message structure universal and applicable across different coded video sequence sets. This multi-functionality approach allows a single message configuration to govern multiple CVSs, thereby increasing applicability without proportionally increasing processing complexity.
3Manufacturing precision
If level information is not signaled consistently across sublayers, then signaling overhead is reduced, but level conformance accuracy deteriorates
Solution Approach 1:
The patent segments the level information signaling into distinct components: a general level indicator that applies to all sublayers and subpicture sequences, and optional sublayer-specific refinements. This segmentation allows consistent level conformance to be enforced across all sublayers while maintaining signaling efficiency by avoiding redundant information repetition, thus resolving the contradiction between precision and complexity.
4Measurement precision
If subpicture sequence definition is incomplete, then implementation simplicity is maintained, but conformance checking accuracy is reduced
Solution Approach 1:
The patent incorporates preliminary definitions and constraints for subpicture sequences directly into the SLI SEI message structure before they are used during conformance checking. By establishing complete and precise definitions in advance, the patent enables accurate conformance verification without requiring complex post-processing or interpretation, thus improving measurement precision while keeping implementation manageable.
Data Source
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AI summary
Several techniques for video encoding and video decoding are described. One example method includes performing a conversion between a video and a bitstream of the video comprising one or more output layer sets (OLSs) according to a rule. The rule specifies that a subpicture level information (SLI) supplemental enhancement information (SEI) message includes information about a level of subpicture sequences in a set of coded video sequences of the one or more OLSs to which the SLI SEI message applies. A syntax structure of the SLI SEI message includes at least (1) a first syntax element specifying a maximum number of sublayers for the subpicture sequences and (2) a second syntax element specifying whether level information for the subpicture sequences is present for one or more sublayer representations.