Video Bitstream Syntax Structure for General Constraint Information Signaling
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Solution Overview
Problem
Existing designs for signaling general constraint information (GCI) fields in video coding require more bits than necessary, leading to inefficiencies in bitstream representation and decoding processes.
Innovation Solution
The proposed solution involves modifying the syntax structure of the profile-tier-level (PTL) syntax structure to conditionally signal GCI fields. This includes adding a new syntax element, such as a 1-bit flag (gci_present_flag), to indicate the presence of GCI fields, and rearranging the byte alignment syntax to reduce unnecessary bit usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If GCI fields are always signaled in the PTL syntax structure, then compatibility with existing video coding standards is maintained, but the number of bits required for signaling increases unnecessarily
Solution Approach 1:
The patent applies dynamics by making the GCI syntax structure optional rather than fixed. A new syntax element `gci_present_flag` dynamically indicates whether the GCI fields are present in the PTL syntax structure, allowing the system to adapt between different signaling configurations based on actual needs while maintaining compatibility with standards that require these fields.
Solution Approach 2:
The patent changes the parameter of syntax structure flexibility by introducing conditional signaling. Instead of always including GCI fields, the system can now vary the presence of these fields based on the `gci present flag`, thereby changing the bitstream characteristics to reduce unnecessary bits while preserving compatibility where needed.
2Stability of the object's composition
If byte alignment syntax is always included after GCI fields, then structural consistency is maintained, but redundant bit usage increases when GCI fields are not present
Solution Approach 1:
The patent makes the byte alignment syntax dynamic by conditioning its inclusion on the presence of GCI fields. The alignment syntax is only included when `gci present flag` indicates GCI fields are present, thereby avoiding redundant alignment bits when GCI is not signaled while maintaining structural consistency where GCI fields exist.
Solution Approach 2:
The patent extracts the byte alignment syntax from a fixed position and makes it conditional. By taking out the alignment syntax and only including it when necessary (when GCI fields are present), the system eliminates unnecessary bits while preserving the structural integrity and alignment requirements where GCI fields are actually used.
3Loss of substance
If GCI fields are conditionally signaled using a flag, then bit efficiency is improved, but the syntax structure becomes more complex
Solution Approach 1:
The patent segments the PTL syntax structure into distinct parts: the mandatory profile-tier-level information, the optional GCI fields, and the byte alignment syntax. By segmenting the syntax and using a flag to indicate the presence of optional parts, the system achieves bit efficiency while keeping the overall structure manageable and parseable through clear segmentation.
Solution Approach 2:
The patent makes the `gci present flag` a universal indicator that serves multiple purposes: it signals the presence of GCI fields, determines whether byte alignment syntax should be included, and guides the parsing process. This multi-functionality reduces the need for separate control mechanisms, thereby limiting the increase in syntax complexity while achieving bit efficiency.
Data Source
AI summary
Methods, systems, and devices for signaling of general constraint information are described. An example method of video processing includes performing a conversion between a video including one or more pictures and a bitstream of the video according to a rule. The rule specifies that a syntax structure in a profile-tier-level syntax structure is after a syntax element. The syntax structure includes information related to general constraint information (GCI) for the bitstream. The syntax element indicates a level to which an output layer set associated with the profile-tier-level syntax structure conforms.