Video Block Decoding With Adaptive Quantization by Subdivision Level
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Solution Overview
Problem
Existing video coding standards face challenges in efficiently handling varying block partitioning constraints and chroma-luma differences, particularly in high-resolution and high-frame-rate video formats, requiring flexible quantization parameters and transform selection across different frame sections.
Innovation Solution
A method for decoding coding units from a bitstream that adjusts quantization parameters and transform selection based on subdivision levels and chroma-luma differences, allowing independent control for luma and chroma channels, and applying separate kernels for each color channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single quantization parameter is used for all coding units, then device complexity is reduced, but video quality and compression efficiency deteriorate due to inability to accommodate varying block constraints
Solution Approach 1:
The patent applies local quality by determining different quantization parameters for different coding units based on their specific block constraints and characteristics. Each coding unit can have a tailored quantization parameter that optimizes its compression, rather than using a uniform parameter across the entire frame. This resolves the contradiction by allowing high video quality through localized optimization while managing complexity through systematic rules for parameter determination.
Solution Approach 2:
The patent segments the video frame into multiple coding units with potentially different quantization parameters. By dividing the frame into smaller manageable units and applying different quantization strategies to each, the system achieves better overall compression efficiency and video quality while keeping the complexity of individual unit processing manageable.
2Manufacturing precision
If separate quantization parameters are used for luma and chroma channels, then video fidelity is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by using separate quantization parameters for luma and chroma channels, recognizing that these color components have different characteristics and require different quantization strategies. The luma channel, which carries brightness information, can use one quantization parameter while the chroma channel, carrying color information, uses another. This differentiated approach improves video fidelity by preserving important visual information while managing complexity through systematic parameter selection based on block constraints.
3Productivity
If transform selection is adjusted based on block constraints, then compression efficiency is improved, but encoding complexity increases
Solution Approach 1:
The patent applies dynamics by making transform selection adaptive based on block constraints and characteristics. Rather than using a fixed transform for all blocks, the system dynamically selects appropriate transforms based on the specific requirements of each coding unit. This resolves the contradiction by improving compression efficiency through optimized transform selection while managing encoding complexity through systematic rules that guide the selection process based on block properties.
Data Source
AI summary
A method of decoding a plurality of coding units from a bitstream to produce an image frame, the coding units being the result of decompositions of coding tree units, the plurality of coding units forming one or more contiguous portions of the bitstream. The method comprises determining a subdivision level for each portion of the bitstream, each subdivision level being applicable to the coding units of the respective contiguous portion of the bitstream; decoding a quantisation parameter delta for each of a number of areas, each area based on decomposition of coding tree units into coding units of each contiguous portion of the bitstream and the corresponding determined subdivision level; determining a quantisation parameter for each area according to the decoded delta quantisation parameter for the area and the quantisation parameter of an earlier coding unit of the image frame; decoding using the determined quantisation parameter of each area.