Temporal Scalability Picture Timing for DU-Based HRD Conformance
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Solution Overview
Problem
Current video coding standards lack the inclusion of picture-level coded picture buffer (CPB) parameters for decoding unit (DU)-based hypothetical reference decoder (HRD) operations on sublayers, leading to inconsistencies in bitstream conformance and decoding accuracy.
Innovation Solution
Incorporating picture-level CPB parameters corresponding to DU-based HRD operations into supplemental enhancement information (SEI) messages to ensure proper coding and decoding of sublayers, using techniques such as picture timing (PT) and decoding unit information (DUI) SEI messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If video data is compressed to reduce data size for transmission and storage, then bandwidth consumption and storage requirements are reduced, but decoding accuracy and bitstream conformance may be compromised due to missing CPB parameters
Solution Approach 1:
The patent extracts and separates CPB parameters into dedicated SEI messages (BP SEI message, PT SEI message, DUI SEI message) that can be independently transmitted with the compressed video data. This allows the essential conformance information to be extracted from the compression process and transmitted separately, ensuring bitstream conformance is maintained even though the video data itself is compressed to reduce size.
Solution Approach 2:
The SEI messages act as intermediaries between the compressed video data and the HRD conformance checking process. These messages carry the CPB parameters that mediate between the compressed representation and the requirement for accurate bitstream conformance, allowing the system to maintain precision without increasing the core video data size.
2Manufacturing precision
If DU-based HRD operations are implemented to ensure bitstream conformance, then decoding accuracy is improved, but device complexity increases due to additional parameter processing requirements
Solution Approach 1:
The patent segments the CPB parameter processing into distinct functional components: BP SEI message for buffer conformance, PT SEI message for timing conformance, and DUI SEI message for decoding unit conformance. This segmentation allows the HRD to process conformance checks in modular stages, improving decoding accuracy while managing complexity through structured processing rather than monolithic analysis.
Solution Approach 2:
The SEI messages containing CPB parameters are transmitted and made available before the actual decoding process begins. This preliminary provision of conformance information allows the HRD to perform conformance checks in advance or during decoding without adding real-time processing complexity, as the parameters are pre-prepared and readily available when needed.
3Reliability
If picture-level CPB parameters are added to SEI messages to support DU-based HRD operations, then bitstream conformance is improved, but message structure complexity increases
Solution Approach 1:
The patent creates a universal SEI message framework that can carry different types of CPB parameters (BP, PT, DUI) using the same basic message structure and parsing mechanisms. This multi-functionality allows the system to improve bitstream conformance by adding picture-level parameters without proportionally increasing message structure complexity, as existing infrastructure is reused and extended rather than completely redesigned.
Data Source
AI summary
A method of decoding is provided. The method includes receiving a bitstream comprising a coded picture and a supplemental enhancement information (SEI) message, wherein the SEI message includes coded picture buffer (CPB) parameters corresponding to decoding unit (DU)-based hypothetical reference decoder (HRD) operations on sublayers; and decoding the coded picture from the bitstream to obtain a decoded picture. A corresponding method of encoding is also provided.