Chroma Block Vector Derivation from Luma Coding Information
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Solution Overview
Problem
Existing video coding technologies face challenges in efficiently deriving chroma block vectors and coding modes, leading to suboptimal compression and reconstruction of chroma blocks in video encoding and decoding processes.
Innovation Solution
The proposed solution involves deriving chroma prediction modes based on luma coding information, using combinations of intra block copy (IBC) and intra prediction modes, local illumination compensation (LIC), or SKIP modes, and reconstructing chroma blocks using chroma block vectors derived from luma block vectors, with specific techniques for different coding modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If chroma blocks are coded independently without leveraging luma information, then chroma coding complexity is reduced, but chroma coding efficiency and reconstruction quality deteriorate
Solution Approach 1:
The patent merges luma and chroma coding processes by deriving chroma block vectors from luma block vectors and copying chroma prediction modes from luma coding information. This combining approach improves chroma coding efficiency by leveraging the already processed luma information without requiring separate independent chroma processing, thus achieving better compression while maintaining manageable complexity through shared processing pathways.
Solution Approach 2:
The patent applies universality by using the luma block vector derivation and prediction mode selection mechanisms for both luma and chroma coding. The same coding infrastructure serves multiple functions: luma processing and chroma processing, eliminating the need for separate dedicated chroma processing paths and improving overall coding efficiency through multi-functional use of the coding engine.
2Adaptability or versatility
If separate coding tree structures are used for luma and chroma regions, then coding flexibility is improved, but derivation of chroma prediction modes from luma information becomes more complex
Solution Approach 1:
The patent applies local quality by allowing different coding tree structures for luma and chroma regions (providing local adaptability) while simultaneously enabling chroma prediction mode derivation from luma information (providing local efficiency improvement). The solution permits region-specific coding flexibility where needed while leveraging available luma information locally to simplify chroma prediction mode derivation, thus resolving the contradiction between flexibility and complexity.
3Manufacturing precision
If chroma block vectors are derived from luma block vectors using combined coding modes, then chroma reconstruction quality is improved, but processing complexity increases
Solution Approach 1:
The patent applies preliminary action by completing luma block vector derivation and prediction mode selection before using that information to derive chroma block vectors and prediction modes. This sequential approach allows the chroma processing to leverage already-computed luma information, improving chroma reconstruction quality while avoiding the need to reprocess luma data, thus managing complexity through efficient ordering of operations.
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.