Multiple Slice Mappings for Local Video Fidelity Control
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Solution Overview
Problem
The Luma Mapping with Chroma Scaling (LMCS) tool in VVC is restricted to one mapped domain per picture, limiting local fidelity adaptation and coding flexibility.
Innovation Solution
Implementing multiple mapping mechanisms within the same slice by using different mapping functions for different blocks within the same slice, allowing for enhanced coding flexibility and fidelity control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If one mapped domain is used per picture in VVC LMCS tool, then device complexity is reduced and ease of operation is improved, but coding flexibility and local fidelity adaptation are limited
Solution Approach 1:
The patent divides the picture into multiple slices, and each slice can have its own mapped domain parameters (offsets and scales). This segmentation allows different regions of the picture to use different mapping functions, enabling local fidelity adaptation while keeping the complexity manageable through hierarchical organization.
Solution Approach 2:
The patent enables different blocks within the same slice to use different mapping functions by allowing block-level selection of mapped domain parameters. This local quality approach allows precise control over coding fidelity in specific regions without requiring complex picture-wide remapping mechanisms.
2Manufacturing precision
If multiple mapping functions are implemented for different blocks within the same slice, then coding flexibility and fidelity control are enhanced, but device complexity increases
Solution Approach 1:
The patent introduces dynamic selection of mapping functions at the block level within each slice. Blocks can adaptively choose different mapped domain parameters based on local characteristics, enabling precise fidelity control where needed while maintaining simplicity in other regions through conditional parameter selection.
Solution Approach 2:
The patent modifies the LMCS tool by allowing multiple sets of mapping parameters (offsets and scales) to be defined and selected at different hierarchical levels (slice and block). This parameter changes approach enables flexible fidelity control by adjusting mapping parameters locally without fundamentally changing the overall mapping mechanism structure.
Data Source
AI summary
A method performed by a decoder for decoding, from a coded video bitstream, a first block of a first coded slice of a first picture and a current block of the first coded slice of the first picture. The method includes using first information from the coded video bitstream to obtain a first mapped residual block for the first block. The method also includes generating a first mapped reconstructed block using the first mapped residual block and a first prediction block for the first block. The method also includes using a first inverse mapping and the first mapped reconstructed block to generate a first output reconstructed block that is not identical to the first mapped reconstructed block. The method also includes using second information from the coded video bitstream to obtain a current mapped residual block for the current block. The method also includes generating a current mapped reconstructed block using the current mapped residual block and a current prediction block for the current block. The method also includes using a current inverse mapping and the current mapped reconstructed block to generate a current output reconstructed block that is not identical to the current mapped reconstructed block. The current inverse mapping is different than the first inverse mapping.