Video Bitstream Constraint Signaling for Efficient VVC Decoding
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Solution Overview
Problem
Existing video coding standards face challenges in efficiently managing and signaling constraints related to syntax structures, leading to inefficiencies in decoding processes, particularly in the development of the Versatile Video Coding (VVC) standard, which aims for significant bitrate reductions.
Innovation Solution
The implementation of a format rule-based conversion process for video processing, including constraint flags and syntax elements at various levels, to manage and signal constraints effectively, ensuring bitstream conformance and efficient decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If constraint flags and syntax elements are extensively signaled in the coded representation, then decoding accuracy and standard compliance are improved, but bitstream size and processing complexity increase
Solution Approach 1:
The patent extracts only the necessary constraint information from the general constraint structure and places it in the adaptation parameter set. By selectively taking out only the most critical constraint flags and syntax elements needed for accurate decoding, the patent reduces the overall bitstream size while maintaining decoding accuracy. This extraction principle allows the system to signal constraints efficiently without transmitting redundant information.
Solution Approach 2:
The patent segments the constraint information by creating a dedicated adaptation parameter set that is separate from the general constraint structure. This segmentation allows constraint flags and syntax elements to be organized hierarchically across different levels (sequence, picture, slice, and adaptation parameter set levels), enabling selective signaling of constraints only where needed in the bitstream, thereby reducing overall complexity and bitstream size.
2Manufacturing precision
If multiple levels of constraint flags are implemented in the coded representation, then control precision over syntax elements is improved, but device complexity increases
Solution Approach 1:
The patent divides constraint control into multiple hierarchical levels: sequence parameter set level, picture parameter set level, slice header level, and adaptation parameter set level. Each level handles specific types of constraints appropriate to its scope, allowing precise control of syntax elements without requiring the entire system to process all constraint flags at all levels simultaneously. This segmentation reduces processing complexity while maintaining control precision.
Solution Approach 2:
The patent applies different constraint flags and syntax elements at different hierarchical levels based on local requirements. For example, sequence-level constraints apply globally, while adaptation parameter set constraints apply only to specific video units. This local quality approach ensures that each part of the decoding system processes only the constraints relevant to its function, reducing overall device complexity while maintaining precise control where needed.
3Reliability
If general constraint information is extensively included in the coded representation, then decoding reliability is improved, but bandwidth usage increases
Solution Approach 1:
The patent extracts essential constraint information from the general constraint structure and places it in the adaptation parameter set. By taking out only the most critical constraint flags needed for reliable decoding of specific video units, the patent ensures decoding reliability is maintained while significantly reducing the bandwidth required to transmit constraint information compared to signaling all general constraint data.
Solution Approach 2:
The patent establishes constraint rules and format specifications in advance through the adaptation parameter set, which defines the structure and content of constraint information before actual video decoding occurs. This preliminary action allows decoders to be pre-configured with the necessary constraint information, ensuring reliable decoding without requiring extensive real-time transmission of constraint data, thereby reducing bandwidth usage.
Data Source
AI summary
Methods, systems, apparatus for video processing are described. The processing may include encoding, decoding or transcoding. One example video processing method includes performing a conversion between a video including one or more pictures and a bitstream of the video according to a format rule. The format rule specifies to include, in a general constrain syntax structure, a syntax element indicating whether each picture includes only one slice, and whether a picture header syntax structure is present in a slice header.