Multilayer Video HRD Signaling With Shared CPB Schedules
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Solution Overview
Problem
Existing video coding systems face inefficiencies in conformance checking for multi-layer bitstreams due to excessive signaling and redundant parameterization, leading to increased bitstream size and resource utilization.
Innovation Solution
Implementing a mechanism where all layers and sub-layers in a bitstream share the same number of coded picture buffer (CPB) delivery schedules, with HRD parameters signaled only once in the video parameter set (VPS), and optimizing SEI messages to reduce redundant information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If each layer defines its own CPB delivery schedules independently, then conformance checking can be performed for each layer with specific bandwidth requirements, but the amount of signaling data increases significantly
Solution Approach 1:
The patent merges the CPB delivery schedule parameters from multiple layers into a single shared set of parameters. Instead of each layer having independent CPB delivery schedule arrays, all layers reference a common set of delivery schedules defined at the sequence level, thereby reducing redundant signaling while maintaining conformance checking capability across layers
Solution Approach 2:
The patent creates a universal CPB delivery schedule structure that serves all layers simultaneously. The HRD parameters are defined once at the sequence level and can be applied to multiple layers, making the parameters multi-functional and eliminating the need for separate parameter definitions for each layer
2Adaptability or versatility
If multiple CPB delivery schedules are defined for different bandwidth scenarios, then adaptability to various network conditions is improved, but the complexity of parameter signaling increases
Solution Approach 1:
The patent introduces dynamic selection of CPB delivery schedules through the use of delivery schedule index arrays that can be configured per layer or per output layer set. This allows the system to adaptively select appropriate delivery schedules based on network conditions while maintaining a structured parameter organization that manages complexity
Solution Approach 2:
The patent segments the CPB delivery schedule parameters into hierarchical levels: sequence-level global parameters and layer-specific or OLS-specific index selections. This segmentation allows the system to maintain adaptability for different bandwidth scenarios while organizing parameters in a manageable hierarchical structure
3Reliability
If redundant HRD parameters are signaled for each layer, then each layer can be independently validated, but bitstream size and processing resources increase
Solution Approach 1:
The patent uses indexing to reference the shared CPB delivery schedule parameters rather than copying the full parameter sets for each layer. Each layer contains only lightweight index references to the global parameter arrays, dramatically reducing bitstream size while enabling independent validation through the shared parameters
Data Source
AI summary
A video coding mechanism is disclosed. The mechanism includes encoding a bitstream comprising one or more layers of coded pictures. A hypothetical reference decoder (HRD) parameters syntax structure is encoded into the bitstream. The HRD parameters syntax structure specifies that all of the layers are associated with a same number of coded picture buffer (CPB) delivery schedules. A set of bitstream conformance tests are performed on the layers based on the CPB delivery schedules. The bitstream is stored for communication toward a decoder