Video Signal Transform Coding With Sub-Block Coefficient Scanning
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Solution Overview
Problem
Existing video coding technologies face challenges in efficiently processing next-generation video content with high spatial resolution, high frame rate, and high dimensionality, leading to increased memory storage and processing demands.
Innovation Solution
Implementing a reduced transform using sub-block transforms (SBT) to split coding units into sub-blocks, applying horizontal and vertical direction transforms, and encoding/decoding information related to the transform, including SBT flags and position information of last significant coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a transform is applied to a coding unit in video coding, then the compression efficiency is improved, but the processing time and computational complexity increase
Solution Approach 1:
The patent applies sub-block transform (SBT) by dividing the coding unit into multiple sub-blocks and applying transform only to specific sub-blocks where significant coefficients are present. This segmentation approach reduces the overall transform processing time while maintaining compression efficiency by avoiding unnecessary transform operations on regions with negligible data.
Solution Approach 2:
Instead of applying transform to the entire coding unit, the patent performs partial transform only on sub-blocks containing significant coefficients. The transform is selectively applied to regions where it provides benefit, rather than uniformly across the entire block, thereby reducing computational load while preserving compression effectiveness.
2Quantity of substance
If sub-block transform is applied to reduce transform size, then the data amount is reduced, but the complexity of determining transform parameters increases
Solution Approach 1:
The patent performs preliminary actions by pre-determining the position of significant coefficients and pre-calculating transform parameters for different sub-block configurations. This allows the decoder to efficiently determine which sub-blocks require transform without complex real-time calculations, reducing the complexity of parameter determination while maintaining data reduction benefits.
Solution Approach 2:
The transform parameter determination process utilizes the scan order and significant coefficient position information already present in the bitstream, allowing the system to self-determine the appropriate transform parameters without requiring external complex calculations or additional signaling overhead.
Data Source
AI summary
Embodiments in the present specification provide a method and device for processing video signal including steps of: obtaining a sub-block transform (SBT) flag indicating whether a SBT is applied, wherein the SBT represents a transform applied to a transform unit corresponding to one of subblocks split from a coding unit; determining a variable value related to a transform target region based on the SBT flag and a size value of the transform unit, wherein if the SBT flag equals to 1 and the size value is greater than a threshold value, the variable value is determined as the threshold value; obtaining position information of a last significant coefficient according to a scan order within the transform unit, wherein the position information of the last significant coefficient is coded based on the variable value; and performing an inverse-transform based on the position information of the last significant coefficient.