Chroma Block Vector Derivation for Separate Tree Video Coding
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Solution Overview
Problem
Existing video coding technologies face challenges in efficiently compressing chroma components using separate coding tree structures, leading to suboptimal compression efficiency and increased data volume.
Innovation Solution
The proposed solution involves deriving a chroma block vector based on luma coding information, utilizing combinations of intra block copy, intra prediction, local illumination compensation, and SKIP modes to reconstruct chroma blocks, thereby enhancing compression efficiency by leveraging luma block vectors and chroma prediction modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If separate coding tree structures are used for luma and chroma components, then chroma compression efficiency is improved, but chroma block reconstruction accuracy deteriorates
Solution Approach 1:
The patent uses luma block vectors as an intermediary to derive chroma block vectors. Since luma and chroma are coded separately with independent coding tree structures, the luma BV serves as a mediator that provides spatial information to reconstruct chroma blocks, enabling accurate chroma reconstruction while maintaining separate coding for efficiency
Solution Approach 2:
The patent changes the parameter approach by deriving chroma block vectors from luma block vectors rather than using independent chroma motion vectors. This parameter transformation allows the system to leverage luma's accurate spatial information to infer chroma block positions, resolving the contradiction between separate coding efficiency and chroma reconstruction accuracy
2Adaptability or versatility
If chroma blocks are coded independently with separate coding tree structures, then coding flexibility is improved, but data volume increases
Solution Approach 1:
The patent merges the coding of luma and chroma components by using luma block vectors to predict chroma block vectors. This merging approach allows both components to benefit from separate coding tree structures for flexibility while reducing overall data volume through shared spatial information from the luma component
3Speed
If luma and chroma use separate coding tree structures, then compression speed is improved, but prediction accuracy deteriorates
Solution Approach 1:
The patent applies preliminary action by using luma block vectors to pre-determine chroma block vectors before actual chroma coding. This allows the system to prepare spatial information in advance from the luma component, enabling faster processing while maintaining prediction accuracy through the pre-derived chroma block vector information
Data Source
AI summary
The disclosure includes methods and apparatuses that includes processing circuitry that derives a chroma prediction mode of a chroma block in a chroma coding region based on luma coding information of a luma block associated with a position in a reconstructed luma area that is collocated with the chroma block. The chroma coding region is partitioned separately from a collocated luma coding region including the reconstructed luma area. The luma coding information indicates that the luma block is coded with a first coding mode using a first luma BV (an IBC mode or an IntraTMP mode) and a second coding mode. The processing circuitry derives a chroma BV of the chroma block based on a luma BV of the luma block and reconstructs the chroma block based on the chroma prediction mode including the first coding mode and the second coding mode.