Chroma Residual Scanning Aligned With Intra Prediction Modes
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Solution Overview
Problem
Existing video encoding and decoding technologies face inefficiencies in handling chroma signals, particularly in high-resolution and high-quality images, as they do not effectively separate and optimize encoding/decoding processes for luma and chroma signals.
Innovation Solution
Adopting different frequency transform methods and scanning methods based on the intra-prediction mode for chroma signals, and using the same scanning type for both luma and chroma signals, or deriving the chroma signal's scanning direction from the luma signal's intra-prediction mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If different frequency transform methods and scanning methods are selected based on intra-prediction mode for chroma signals, then encoding efficiency of residual signals is improved, but device complexity increases
Solution Approach 1:
The patent applies different frequency transform methods (DST or DCT) and scanning methods (horizontal or vertical) to chroma residual signals based on the intra-prediction mode. Specifically, when the intra-prediction mode indicates horizontal prediction, horizontal scanning is used; when it indicates vertical prediction, vertical scanning is used. This local adaptation of transform and scanning methods to the specific prediction direction improves encoding efficiency by matching the transform characteristics to the residual signal characteristics, while the rules-based selection keeps the complexity manageable.
2Manufacturing precision
If chroma signal is handled separately from luma signal with optimized methods, then picture quality and resolution are improved, but processing time and complexity increase
Solution Approach 1:
The patent segments the video signal processing into separate handling for luma and chroma components. The chroma residual signal undergoes specific frequency transform and scanning operations based on intra-prediction mode, while luma is processed independently. This segmentation allows optimized processing for each component according to its characteristics, improving overall picture quality without requiring complete reprocessing of the entire signal.
Solution Approach 2:
The patent changes processing parameters (frequency transform type and scanning direction) based on the intra-prediction mode parameter. When intra-prediction mode indicates horizontal direction, horizontal scanning and appropriate frequency transform are applied; when vertical, vertical scanning is applied. This parameter adaptation improves chroma signal quality while keeping processing efficient through conditional selection rather than exhaustive processing.
Data Source
AI summary
An encoding method and decoding method, and a device implementing the same are provided. The encoding method obtains an intra prediction mode related to a current block from a video signal, obtains prediction samples of the current block by performing intra prediction on the current block based on the intra prediction mode, scans transform coefficients of the current block based on a scanning type of the current block, obtains dequantized transform coefficients of the current block by dequantizing the transform coefficients, obtains residual samples of the current block by performing an inverse-transform on the dequantized transform coefficients, the inverse-transform being performed in a horizontal direction and a vertical direction, reconstructs the current block using the residual samples and the prediction samples, and applies a deblocking filter on the reconstructed current block.