Subblock-Based Affine Motion Model for Video Coding
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Solution Overview
Problem
Current video coding technologies face challenges in efficiently compressing video data, particularly in reducing redundancy and managing motion vectors, which affects bandwidth and storage requirements, especially in high-resolution video streams.
Innovation Solution
The implementation of a subblock-based affine motion model for video encoding and decoding, which uses multiple control point motion vectors to determine affine parameters for selecting subblock characteristics such as size and interpolation filters, allowing for more precise motion compensation and prediction refinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If motion compensation with multiple control point motion vectors is used, then motion prediction accuracy is improved, but computational complexity and processing overhead increase
Solution Approach 1:
The current block is divided into multiple subblocks, each with its own motion characteristics. By segmenting the block and applying different subblock characteristics (such as different interpolation filter types or subblock sizes) based on affine parameters, the patent achieves more precise motion prediction for each region while managing computational complexity through selective processing.
Solution Approach 2:
Different subblocks within the current block are assigned different characteristics based on their local motion patterns. The patent determines subblock characteristics using affine parameters derived from control point motion vectors, allowing each subblock to be processed with appropriate quality and complexity levels matching its local motion complexity.
2Productivity
If subblock characteristics are determined based on affine parameters, then compression efficiency is improved, but processing time and computational load increase
Solution Approach 1:
The patent performs preliminary determination of subblock characteristics using affine parameters derived from control point motion vectors before actual motion compensation. This preliminary classification allows the system to pre-identify which subblocks require more intensive processing, enabling optimized processing paths that improve overall compression efficiency while managing processing time through early decision-making.
3Measurement precision
If multiple control point motion vectors are used for affine motion model, then motion compensation precision is improved, but bitrate overhead increases
Solution Approach 1:
The patent extracts and utilizes only the necessary affine parameters from the multiple control point motion vectors to determine subblock characteristics. By selecting and using only the essential parameters needed for accurate motion compensation rather than transmitting all raw motion vector data, the system achieves high motion compensation precision while minimizing bitrate overhead through selective parameter extraction.
Data Source
AI summary
Aspects of the disclosure provide methods and an apparatus for video coding. The apparatus includes processing circuitry that decodes coding information of a current block (CB) from a coded video bitstream. The coding information indicates that the CB is coded with a subblock-based affine motion model including affine parameters that are based on multiple control point motion vectors (MVs) for the CB. The processing circuitry determines, based on the coding information, whether to select a subblock characteristic for generating a prediction for a sample in an affine subblock of the CB based on a corresponding subblock MV. In response to selecting the subblock characteristic, the processing circuitry determines the subblock characteristic based on at least one of the affine parameters. The subblock characteristic indicates one of: (i) a subblock size used for generating the prediction for the sample and (ii) an interpolation filter type for the affine subblock.