Secondary Transform Kernel Signaling in Video Decoding
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Solution Overview
Problem
Existing video coding technologies face challenges in efficiently signaling and applying secondary transforms, which can lead to increased coding overhead and suboptimal compression efficiency.
Innovation Solution
A method for video encoding and decoding that involves determining and signaling a secondary transform kernel type for each block, allowing for precise application of secondary transforms only when necessary, thereby reducing coding overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If secondary transform parameters are explicitly signaled in the video bitstream, then coding efficiency is improved, but coding overhead increases
Solution Approach 1:
The patent applies different signaling strategies to different blocks based on their characteristics. For blocks where secondary transform provides significant improvement, the parameters are explicitly signaled. For other blocks, implicit derivation or default values are used, creating a locally optimized solution rather than a uniform approach across all blocks.
Solution Approach 2:
The patent changes the state of parameter signaling from always explicit to conditionally explicit. By introducing a kernel type indicator that can take different values (explicit signaling mode vs. implicit derivation mode), the system dynamically adjusts the signaling approach based on the specific block requirements, thereby optimizing the trade-off between coding efficiency and overhead.
2Productivity
If secondary transform is applied to all blocks, then compression efficiency is improved, but coding complexity increases
Solution Approach 1:
Instead of applying secondary transform to all blocks (excessive action), the patent applies it only to blocks where the kernel type indicator suggests it is beneficial (partial action). This selective application reduces the overall complexity while maintaining compression efficiency where it matters most.
Solution Approach 2:
The patent segments the video data processing into different pathways based on the kernel type indicator. Blocks are divided into those requiring explicit secondary transform and those using implicit derivation, allowing the system to manage complexity by handling different block types through different processing streams.
3Quantity of substance
If transform parameters are implicitly derived, then coding overhead is reduced, but transform accuracy decreases
Solution Approach 1:
The patent introduces a dynamic parameter selection mechanism where the transform parameters can switch between implicit derivation and explicit signaling based on the kernel type indicator. This dynamic approach allows the system to adapt to different block characteristics, using implicit derivation when sufficient and explicit signaling when higher accuracy is needed.
Data Source
AI summary
Methods and systems for encoding and decoding video are described. In one aspect, a method of video decoding includes receiving video data that includes a first block and a first syntax element from a video bitstream. The method also includes determining a secondary transform kernel type value for the first block based on the first syntax element. In accordance with a determination that the secondary transform kernel type has a first value, a secondary transform set identifier is determined based on a second syntax element from the video bitstream, and an inverse secondary transform is performed on the first block using the determined secondary transform kernel type and determined secondary transform set identifier. In accordance with a determination that the secondary transform kernel type has a second value, the inverse secondary transform is not performed on the first block.