Video Codec Secondary Transform Signalling by Block Characteristics
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Solution Overview
Problem
Existing video coding technologies, such as VVC, face inefficiencies in the use of secondary transforms, leading to increased computational complexity and data requirements, which are not optimized based on primary transform types, resulting in unnecessary dependencies between transform and quantization pipelines.
Innovation Solution
A method is introduced to derive secondary transform sets based on block dimensions, color components, and other block characteristics, eliminating unnecessary secondary transforms where primary transforms can suffice, thereby simplifying encoding and decoding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If secondary transforms are applied to all blocks regardless of primary transform type, then coding precision is improved, but device complexity and computational requirements increase
Solution Approach 1:
The patent applies different treatment to different blocks based on their characteristics. Specifically, secondary transforms are selectively applied only to blocks that have undergone primary transforms, while skipping secondary transforms for blocks that did not undergo primary transforms. This local differentiation optimizes the balance between coding precision and decoder complexity by applying the more complex processing only where beneficial.
Solution Approach 2:
The patent introduces dynamic adaptability in the transform processing by allowing the decoder to determine whether to apply secondary transforms based on the specific block characteristics and primary transform type. This dynamic approach enables the system to adjust its complexity level according to the actual coding needs of each block rather than using a fixed complex approach for all blocks.
2Measurement precision
If secondary transforms are applied to all blocks, then coding precision is improved, but encoding time increases
Solution Approach 1:
The patent applies secondary transforms selectively based on block characteristics rather than uniformly to all blocks. By identifying which blocks benefit from secondary transforms and applying them only to those blocks, the system maintains coding precision where needed while reducing unnecessary processing time for blocks where primary transforms suffice.
Solution Approach 2:
The patent applies secondary transforms partially - only to the subset of blocks that require them based on their characteristics and primary transform type. This partial application avoids the excessive action of applying secondary transforms to all blocks, thereby reducing overall encoding time while maintaining sufficient precision for the majority of blocks.
3Measurement precision
If secondary transforms are applied universally, then coding precision is improved, but bit rate increases
Solution Approach 1:
The patent applies secondary transforms selectively based on block characteristics, which optimizes the bit rate by applying the more resource-intensive transforms only where they provide the most benefit. This local differentiation prevents unnecessary bit allocation for blocks where primary transforms already provide sufficient precision.
Solution Approach 2:
The patent applies secondary transforms partially rather than universally, which reduces the overall bit rate by avoiding the excessive data transmission required for blocks that do not benefit from secondary transforms. This partial application maintains sufficient coding precision for the critical blocks while reducing bit rate for blocks where it is not needed.
4Measurement precision
If secondary transforms are applied to all blocks, then coding precision is improved, but productivity decreases
Solution Approach 1:
The patent applies secondary transforms selectively based on block characteristics, which improves encoding efficiency by avoiding unnecessary processing for blocks where primary transforms suffice. This local differentiation allows the system to maintain high precision for critical blocks while improving overall productivity by skipping redundant processing for other blocks.
Solution Approach 2:
The patent applies secondary transforms partially rather than universally, which improves productivity by reducing the total processing load. This partial application maintains sufficient precision for the most important blocks while increasing encoding efficiency by avoiding excessive processing for blocks where it is not needed.
Data Source
AI summary
Encoding of video data in a video codec involves a transform of residuals. This can be composed of a primary transform and a secondary transform. The selection of the secondary transform is effected by considering the characteristics of a block to be encoded. The selection of secondary transform can be signalled to the decoder, or inferred therein.