Image Processing Apparatus Transform Skip Logic
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Solution Overview
Problem
Existing image encoding methods degrade encoding efficiency when transform skip is applied, as secondary transform is still applied even to sparse residual signals, leading to decreased energy compaction.
Innovation Solution
An image processing apparatus and method that skip both primary and secondary transforms when the primary transform is skipped, thereby avoiding unnecessary arithmetic operations and maintaining energy compaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If secondary transform is applied after transform skip is applied to primary transform, then transform processing can be performed on sparse residual signals, but energy compaction decreases and encoding efficiency is degraded
Solution Approach 1:
The transform processing is segmented into conditional paths: when transform skip is applied to primary transform, secondary transform is also skipped. This segmentation allows the system to avoid applying secondary transform to sparse residual signals, thereby maintaining energy compaction and preventing degradation of encoding efficiency.
Solution Approach 2:
Instead of the conventional approach where secondary transform is applied regardless of primary transform skip status, the invention inverts the logic: secondary transform is applied only when primary transform is NOT skipped. This inversion prevents the harmful combination of transform skip on primary transform followed by secondary transform, which would degrade energy compaction.
2Adaptability or versatility
If secondary transform is applied in a unit of CU when transform skip is applied, then transform processing flexibility is maintained, but unnecessary arithmetic operations are performed
Solution Approach 1:
The system performs preliminary determination of whether to apply secondary transform based on the transform skip status of primary transform. By deciding in advance to skip secondary transform when primary transform is skipped, the system avoids unnecessary arithmetic operations while maintaining the flexibility to apply secondary transform when appropriate.
Solution Approach 2:
The invention extracts the secondary transform operation from the mandatory processing chain and makes it conditional. By taking out the secondary transform application decision and linking it to the primary transform skip status, the system eliminates unnecessary arithmetic operations on sparse residual signals while preserving transform processing flexibility for other cases.
Data Source
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AI summary
The present disclosure relates to an image processing apparatus and method that make it possible to suppress degradation of the encoding efficiency. In the case where primary transform that is a transform process for a prediction residual that is a difference between an image and a prediction image of the image is to be skipped, also secondary transform, which is a transform process for a primary transform coefficient obtained by the primary transform of the prediction residual, is skipped. The present disclosure can be applied, for example, to an image processing apparatus, an image encoding apparatus, an image decoding apparatus and so forth.