Image Decoding Scaling for Transform Coefficients
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Solution Overview
Problem
In image coding and decoding systems, scaling is often refrained from even when non-separable transforms are not applied, and implicit multiple transform selection is also not performed in such cases, leading to inefficiencies in image processing.
Innovation Solution
An image decoding apparatus is designed with a scaling list decoder, a scaling unit, and an inverse transform processing unit that performs non-separable transforms based on specific flags and transform indices, allowing for uniform quantization and implicit transform selection based on transform block sizes, enabling efficient scaling and transformation operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If scaling is refrained from when non-separable transforms are not applied, then processing complexity is reduced, but image processing efficiency deteriorates
Solution Approach 1:
The patent implements dynamic processing by making the scaling operation conditional based on the non-separable transform application status. When non-separable transforms are not applied, the system dynamically adjusts to perform uniform quantization instead of position-dependent scaling, optimizing processing efficiency while maintaining image quality when needed
Solution Approach 2:
The patent changes the quantization parameter from position-dependent scaling factors to uniform quantization parameters based on the transform type. This parameter adaptation allows the system to switch between different processing modes (position-dependent scaling vs. uniform quantization) depending on whether non-separable transforms are applied, resolving the contradiction between complexity and efficiency
2Loss of energy
If implicit multiple transform selection is not performed when non-separable transforms are not applied, then processing overhead is reduced, but transform efficiency deteriorates
Solution Approach 1:
The system dynamically selects between different transform processing paths based on the non-separable transform flag. When non-separable transforms are not applied, it dynamically switches to implicit multiple transform selection, optimizing the processing path to balance overhead and efficiency based on the actual transform requirements
Data Source
AI summary
An image decoding apparatus decodes a transform coefficient on a transform unit basis, decodes a flag scaling_matrix_for_lfnst_disabled_flag indicating whether to apply a quantization matrix during a non-separable transform, scales the transform coefficient by utilizing a scaling list, and performs a non-separable transform in accordance with a non-separable transform index lfnst_idx. In a case that scaling_matrix_for_lfnst_disabled_flag==1 and lfnst_idx!=0 and a size of a transform block is equal to or greater than a prescribed size, instead of scaling using the quantization matrix according to a position of the transform coefficient, uniform quantization not depending on the position of the transform coefficient is performed.