Image Decoding Using Non-Zero Coefficient Guided Secondary Transform
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Solution Overview
Problem
Conventional image decoding techniques require additional processing to determine whether to apply secondary transform, increasing the processing load due to high throughput requirements.
Innovation Solution
An image decoding device and method that controls the decoding of a secondary transform index based on the position of non-zero coefficients within a target block, omitting unnecessary processing by not decoding the secondary transform index when the non-zero coefficient is at the direct current component of the target block.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If motion estimation is skipped for blocks with similar reference pictures, then decoding speed is improved, but prediction accuracy may deteriorate
Solution Approach 1:
The system uses the decoded picture buffer to store previously decoded pictures that serve as reference for future decoding operations. The motion estimation process serves itself by reusing previously decoded data without requiring additional external resources, enabling fast skipping when reference pictures are available while maintaining accuracy through self-generated reference data
Solution Approach 2:
The decoded picture buffer pre-stores reference pictures before they are needed for motion estimation. By having reference pictures readily available in the buffer from prior decoding operations, the system can perform motion compensation without re-decoding reference frames, thus improving decoding speed while maintaining prediction accuracy through pre-prepared reference data
2Manufacturing precision
If motion estimation is performed for all blocks, then prediction accuracy is improved, but decoding complexity increases
Solution Approach 1:
The decoding process is segmented into different operational modes: full motion estimation for blocks requiring high accuracy, and skipped motion estimation for blocks with similar reference pictures. This segmentation allows the system to apply complex processing only where necessary, reducing overall decoding complexity while maintaining prediction accuracy for critical blocks
Solution Approach 2:
Instead of performing motion estimation for all blocks (excessive action), the system performs motion estimation only for blocks where it is truly necessary (partial action). By identifying blocks with similar reference pictures and skipping motion estimation for those cases, the system reduces decoding complexity without significantly compromising prediction accuracy for the majority of blocks
3Loss of time
If motion estimation is skipped, then processing time is reduced, but motion compensation accuracy deteriorates
Solution Approach 1:
The system uses feedback from the decoded picture buffer to determine whether motion estimation should be performed. By continuously monitoring the availability and quality of reference pictures in the buffer, the system can make informed decisions about skipping motion estimation, thus reducing processing time while maintaining motion compensation accuracy through feedback-driven adaptive processing
Data Source
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AI summary
An image decoding device (200) includes: an inverse transform unit (220B/220C) configured to generate a prediction residual signal by inverse transform, the inverse transform unit (220B/220C) is configured to control a method of decoding a secondary transform index of a target block according to information indicating a position where a non-zero coefficient is generated in the target block.