Video Encoding Affine Motion Vector Handling for 4:4:4 and 4:2:2 Chroma Formats
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Solution Overview
Problem
Current video coding technologies, such as HEVC, face limitations in accommodating chroma formats like 4:4:4 and 4:2:2, particularly in affine motion vector derivation and interpolation filtering, which affect the efficiency of video encoding and decoding processes.
Innovation Solution
The proposed method involves encoding or decoding video sequences using 4:4:4 or 4:2:2 chroma formats, where affine motion vectors are handled by copying or averaging motion vectors of co-located blocks, and interpolation filters are aligned for motion compensation between luma and chroma components, allowing for flexible block partitioning and improved prediction modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If affine motion vector derivation uses averaging operation for 4:2:2 chroma format, then compatibility with existing HEVC standards is maintained, but encoding efficiency and compression performance deteriorate
Solution Approach 1:
The patent applies dynamics by making the motion vector derivation method adaptive to different chroma formats. For 4:4:4 format, it uses copying operation, while for 4:2:2 format, it uses averaging operation. This dynamic adaptation allows the system to optimize encoding efficiency for each specific chroma format while maintaining compatibility with HEVC standards.
Solution Approach 2:
The patent changes the motion vector derivation parameter based on chroma format. By switching between copying and averaging operations according to the chroma format (4:4:4 vs 4:2:2), the system optimizes compression performance for each format while maintaining standard compatibility.
2Device complexity
If interpolation filters are not aligned between luma and chroma components, then processing complexity is reduced, but prediction accuracy and compression performance deteriorate
Solution Approach 1:
The patent applies universality by using the same interpolation filter alignment approach for both luma and chroma components. This unified method improves prediction accuracy for both component types without significantly increasing processing complexity, as the same filtering mechanism is applied across different color components.
3Adaptability or versatility
If block partitioning is made more flexible to accommodate different chroma formats, then adaptability to various video content characteristics is improved, but device complexity and processing overhead increase
Solution Approach 1:
The patent applies segmentation by dividing the video block into luma and chroma components with different partitioning strategies. For 4:4:4 format, it uses separate luma and chroma block partitions, while for 4:2:2 format, it uses merged partitions. This segmented approach provides flexibility for different chroma formats without requiring complete redesign of the partitioning structure.
Data Source
AI summary
A method and apparatus for encoding or decoding a video sequence includes encoding or decoding the video sequence using a 4:4:4 chroma format, or encoding or decoding the video sequence using a 4:2:2 chroma format, wherein when encoding or decoding the video sequence using the 4:4:4 chroma format, copying an affine motion vector of one 4×4 luma block using an operation other than an averaging operation and associating the affine motion vector to a co-located 4×4 chroma block, and when encoding or decoding the video sequence using the 4:2:2 chroma format, associating each 4×4 chroma block with two 4×4 co-located luma blocks such that an affine motion vector of one 4×4 chroma block is an average of the motion vectors of the two co-located luma blocks.