Video Coding Scalability via Cross-Layer Block Division
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Solution Overview
Problem
Existing video coding systems face inefficiencies in scalability extension due to fixed or varying unit sizes, lacking comprehensive methods for CU, PU, and TU division, which hinders effective compression across different resolutions and layers.
Innovation Solution
An image decoding method that calculates CU, PU, and TU division methods by referencing corresponding methods from other layers, using specific rules and flags to optimize coding efficiency across multiple resolutions, allowing for flexible block sizes and modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed block size is used for coding units (as in H.264/AVC and MPEG-2), then the coding structure is simple and easy to implement, but coding efficiency is reduced when adapting to different resolutions and scalability requirements
Solution Approach 1:
The patent implements dynamic block sizing where the coding unit (CU) size varies according to the layer and resolution requirements. The base layer uses one block size while enhancement layers use different block sizes, allowing the system to adapt dynamically to different decoding resolutions and scalability needs, thereby improving coding efficiency without sacrificing structural clarity
Solution Approach 2:
The patent changes the parameter of block size from fixed to variable across different layers. By defining different CU sizes for base layer and enhancement layers, and using syntax elements to indicate these size variations, the system achieves better compression performance for multi-resolution video while maintaining manageable complexity through standardized parameter definitions
2Productivity
If variable block sizes are used for coding units (as in HEVC), then coding efficiency is improved for different resolutions, but the description methods for PU and TU division are not defined, leading to incomplete scalability implementation
Solution Approach 1:
The patent creates a universal framework that defines division methods for CU, PU, and TU across all layers. The same syntax elements and division rules are applied consistently to all three unit types, providing a multi-functional solution that handles different unit divisions uniformly. This approach ensures complete scalability implementation while maintaining coding efficiency through consistent variable block size usage across all unit types
Solution Approach 2:
The patent segments the coding process into three distinct but coordinated stages: CU division, PU division, and TU division. Each stage has its own syntax elements and rules, but they work together in a hierarchical manner. This segmentation allows independent optimization of each division stage while ensuring their coordinated operation, thereby achieving both coding efficiency and implementation completeness
3Adaptability or versatility
If different block sizes are used between base layer (fixed size macroblock) and enhancement layer (variable size CU), then scalability to multiple resolutions is enabled, but no description method exists for this cross-layer size difference
Solution Approach 1:
The patent introduces syntax elements as intermediaries to bridge the base layer and enhancement layer. These syntax elements carry information about CU size, PU size, and TU size for enhancement layers, allowing the decoder to correctly interpret the variable block sizes without requiring complex cross-layer mappings. This intermediary mechanism simplifies the description of cross-layer size differences while maintaining full scalability capability
Solution Approach 2:
The patent adds a layer dimension to the block size parameter space. Instead of a single block size parameter, the system now has block size parameters indexed by layer (base layer vs. enhancement layer). This dimensional extension allows independent optimization of block sizes for each layer while maintaining clear separation of concerns, thereby enabling scalability without excessive cross-layer complexity
Data Source
AI summary
To provide a video coding technique to reduce the amount of code, a coding apparatus configured to code layers at a plurality of resolutions as a stream determines the coding unit, prediction unit, and frequency transform unit for each layer in compliance with given rules with reference to the coding unit, prediction unit, and frequency transform unit of the lower layer, respectively, and switches the given rules with a flag. This adaptively and efficiently compresses a video.