Chroma Multiple Transform Selection With Implicit Index Derivation
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Solution Overview
Problem
Existing video coding systems face inefficiencies in compressing chroma components, particularly in determining optimal transform indices, leading to suboptimal compression and decoding performance.
Innovation Solution
Implementing chroma multiple transform selection (MTS) systems that determine transform indices for chroma components based on luma transform indices or intra prediction modes, allowing for implicit transform selection and inter-component transform considerations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If chroma transform indices are explicitly signaled in video data, then transform selection accuracy is improved, but bitrate consumption increases
Solution Approach 1:
The patent extracts the chroma transform index signaling from the explicit data stream by deriving it implicitly from luma transform indices and intra prediction modes. This removes the need to transmit chroma transform indices separately, thereby reducing bitrate consumption while maintaining transform selection accuracy through derivation relationships.
Solution Approach 2:
The chroma transform index determines itself through implicit derivation from already-available luma transform indices and intra prediction modes rather than requiring external signaling. This self-determination mechanism eliminates redundant information transmission while preserving the ability to select appropriate transforms for chroma components.
2Productivity
If chroma transform index is determined independently from luma transform index, then chroma component optimization is improved, but system complexity increases
Solution Approach 1:
The patent makes the luma transform index serve a dual function: it directly controls luma transform selection and simultaneously determines chroma transform selection through derivation relationships. This multi-functionality allows chroma component optimization without requiring a completely independent chroma transform index signaling system, thereby avoiding increased system complexity.
Solution Approach 2:
The luma transform index is determined first and then used as the basis for deriving the chroma transform index. This preliminary determination of luma transform index provides a foundation that simplifies subsequent chroma transform selection, achieving chroma optimization through a structured, hierarchical approach rather than requiring parallel independent decision-making processes.
3Quantity of substance
If implicit MTS is used for chroma components, then signaling overhead is reduced, but transform selection flexibility is limited
Solution Approach 1:
The patent implements a dynamic transform selection mechanism where the chroma transform index is derived based on the intra prediction mode and luma transform index. This dynamic derivation allows the system to adapt transform selection to different coding conditions and prediction modes, maintaining flexibility while using implicit signaling. The transform selection is not fixed but adjusts according to the derived relationships.
Solution Approach 2:
The patent changes the parameter derivation method by deriving chroma transform index from luma transform index and intra prediction mode rather than using fixed or independent values. This parameter change enables implicit signaling while preserving adaptability, as the derived chroma transform index can vary based on different luma transform selections and prediction modes, effectively encoding flexibility in the derivation logic itself.
Data Source
AI summary
Systems, methods, and instrumentalities are disclosed for performing chroma multiple transform selection (MTS). MTS may be enabled for one or more chroma components associated with a video block or video block data. A device may determine a transform index associated with performing MTS on chroma components. A decoder may obtain video block data. The decoder may determine MTS is used for one or more chroma components associated with video block data. The decoder may perform inverse transform using MTS on the chroma components associated with the video block data, for example, to generate chroma prediction residual data. The decoder may decode the video block data based on the chroma prediction residual data. An encoder may be configured to determine that MTS is used for chroma components associated with the video block. The encoder may perform transform using MTS on the one or more chroma components associated with the video block.